─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 336 Consumer properties of biodegradable edible cups for hot drinks Oksana Shulga1, Iryna Koretska1, Anastasiia Chorna1, Sergij Shulga1, Yingmei Lin2 1 – National University of Food Technologies, Kyiv, Ukraine 2 – Harbin Institute of Technology, Weihai, China Keywords: Disposable cup Edible Ecological Biodegradable Quality criteria Abstract Introduction. Determining the biodegradable edible cup consumer properties will allow finding an ecological alternative to disposable cups for hot drinks. Materials and methods. Butter cookies were made in the shape of a cup, followed by the application of a waterproof layer, the basis of which was pectin or polyvinyl alcohol. A 10-point scale for evaluating cups by individual indicators was developed, and the Harrington`s function was used. Results and discussion. Biodegradable edible cups in terms of organoleptic, ergonomic and geometric parameters fully correspond to disposable cups that are currently used. Due to the thicker walls and the material (biscuits) properties, the edible cup allows you to hold a cup with a hot drink in your hands without an additional layer. The absence of an additional layer is important from an economic and environmental point of view. The edible cup could keep the drink inside from 20 minutes to 1 hour. The cup appearance did not change under the influence of drinks at different temperatures: 10–15 °C (Glaze, Frappe, Cold Americano, Ice Cream), warm, 60–65 °C (Latte, Cappuccino, Mochaccino, Macchiato, Flat White, Raff) and hot, 85–90 °С (Americano, Espresso and their varieties). The biodegradable edible cup is resistant to acetic acid and ethyl alcohol that is important because some types of coffee-based drinks require the addition of alcoholic beverages, in particular, Irish coffee, Farisei, Karsk, Coffee punch. The cups can be used for a wide drinks range with a temperature from 10 to 90 °C. It has excellent ergonomic performance and is environmentally friendly, as it can be decomposed like any other confectionery product. Conclusions. The biodegradable edible cup has excellent ergonomic indicators, is environmentally friendly because it can be easily decomposed like any other confectionery. Article history: Received 27.03.2023 Received in revised form 14.08.2023 Accepted 29.09.2023 Corresponding author: Iryna Koretska E-mail: tac16@ukr.net DOI: 10.24263/2304- 974X-2023-12-3-3 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 337 Introduction The problem of the accumulation of plastic materials in the environment requires society to reconsider its habits, including the refusal of using polymer disposable cups when consuming hot drinks. A possible solution for utilization of disposable non-biodegradable coffee cups could be replacement them with (a) reusable cups; (b) biodegradable non-edible cups and (c) biodegradable edible cups. Reusable cups are the most optimal way, but the least convenient in practice, since in this case you need to carry the cup with you, have enough space for it in your bag, protect the cup from breakage, and follow sanitary rules (Allison et al., 2021). To follow this way, Starbucks, the largest coffeehouse chain in the world, offers a discount to consumers, who bring a reusable coffee cup (Ziada, 2009). Some coffee shops propose discount for use the ceramic mugs available in store instead of using paper cups (Jung et al., 2011). Additional motivating factors include environmental commitments, financial support, corporate initiatives, customer demand, and public pressure (Ma, 2014). There is a worldwide increase in coffee consumption in disposable cups-to-go. For example, about 3 billion disposable coffee to-go-cups are used each year in Germany (Loschelder et al., 2019). However, encouraging café customers to become part of the 'choose a reusable mug' movement in a 14-week intervention trial in which 23,946 hot drinks were sold resulted in a reduction in the use of disposable cups and an increase in the use of reusable cups by 17.3% (Loschelder et al., 2019) Different approaches to the classification of disposable cups such as by purpose, by the number of uses, by the presence of a barrier coating, and by the type of main raw material for cup making were proposed (Bidiuk et al., 2020). Paper cups are coated with a thin layer of plastic, usually petro-plastic, to prevent liquid to intrude into the cup. Particularly petro- plastic cups are frequently associated with an unnecessary use of limited resources and superfluous production of waste (Van der Harst et al., 2013). However, polyethylene can be replaced with a biodegradable material, for example, natural polymers (Mahinpei, 2020). Waste paper cups can be pyrolyzed at temperatures ranging from 325 to 425oC to produce commercial fuel (Biswal et al., 2013) or used for production of the bio-eco-based cellulose nanomaterials by citric acid hydrolysis (Nagarajan et al., 2020). Another type of disposable cups are foam cups, which are cheaper compared to paper ones. However, Styrofoam cups are also not biodegradable and should be landfill or incinerated (Jung et al., 2011). Sazeli et al. (2021) proposed to make disposable tableware and cutlery from organic material such as corn and barley to develop fully biodegradable tableware. Kaya et al. (2016) proposed the production of chitin and chitosan cups from the abdominal exoskeleton of the insect Pimelia sp. as an alternative to synthetic materials in the food industry. Both chitin and chitosan cups exhibited antimicrobial activity against two common food pathogens Candida albicans and Listeria monocytogenes. Liu et al. (2020) developed an all-natural biodegradable, hygienic, water- and oil-resistant, mechanically strong, and low-cost tableware using environmentally friendly sugarcane fiber and bamboo fiber using a scalable molding method cellulose. Choeybundit et al. (2022) propose the production of cutlery from soy protein isolate with the addition of 5-20 % crude fiber from morning glory stems. The production of these biodegradable cutlery involves hydraulic hot pressing at a temperature of 160 °C for 5 min. Production of environmentally friendly, biodegradable plates made of areca leaves were proposed (Nayak et al., 2021). The technology of a new disposable cups type made from bioplastics based on spent coffee grounds and using natural binding food components has been developed (Bidiuk et al., 2020). Currently, there are already developments of alternatives to disposable cups that have been implemented into production. The Inferra Pack Company produces biodegradable tableware from various natural raw materials: sugar cane cake, corn starch, and coffee waste. Using the innovative secondary processing technology of cellulose, kraft tableware contains 30 % more recycled raw materials than ordinary paper tableware. The uniqueness of this ecological product is that the term of its complete disposal in the soil is about 180 days. The ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 338 advantage of using environmentally friendly single-use bioplastic packaging is its computability. Manufacturers who are already engaged in the production of such disposable tableware most often position them as a confectionery product and offer coffee in such cookies in the shape of a cup/glass. Although a straw is not a mandatory attribute for drinking coffee, many consumers prefer to drink it by this way. For example, only in Taiwan three billion non-degradable plastic straws are consumed annually (Cheng et al., 2022). Currently many countries are already planning to increase strict legislation of plastic straws. The literature analysis showed that scientists all over the world are actively engaged in the replacing non-biodegradable tableware with biodegradable ones. Because currently quite a limited number of developments have been put into production, the development and research of edible cups is still relevant. Therefore, the development of technology for ecological biodegradable disposable tableware for widespread use is currently an extremely important task to ensure sustainable development and environmental protection. Materials and methods Materials Wheat flour (40–60%); native potato starch or native corn starch (10–25 %); white sugar (5–20 %); margarine (5–20%); leavening agents (0.5–2 %); drinking water (10–30 %) were used as raw materials for the biodegradable edible cup production. Pectin (E440) or polyvinyl alcohol (E1203), and drinking water served as raw materials for making a waterproof layer. Production of experimental cups From the specified raw materials, dough for butter cookies having shape of cups was prepared. The shape of the cup could be changed according to the customer's requirements. The formed cup was baked, after which a waterproof layer was applied to the inner surface of the baked product by praying, glazing or brushing on the surface, and the cup was kept for 10±2 h until the waterproof coating is dry. The variants of the developed biodegradable cups is shown (Figure 1). Figure 1. The biodegradable edible cups ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 339 Research methods The properties of the developed biodegradable tableware were studied according to Bidiuk et al. (2020): organoleptic (color, appearance, physical condition, presence of smell) according to the technical specifications for the corresponding disposable cups; the sound when struck with a wooden stick was determined by hitting the edge of the cup, indirectly this method indicates the presence of voids inside the material); defects (heterogeneity of the surface, uneven and visible loose seam for a paper cup, color heterogeneity for an edible cup, indistinct pattern for paper and polymer tableware); ease of use was determined by the subjective perception of holding and consuming the drink; actual capacity, ml, distilled water was poured into the cup under study, after which it was poured into a measuring cylinder and the volume was determined; height, mm, was measured with a caliper; the diameter in the upper part, mm, was measured with a caliper; the diameter in the lower part, mm, was measured with a caliper; wall thickness, mm, was measured with a caliper; the thickness of the bottom, mm, was measured with a caliper; mass fraction of moisture, %, method of drying to constant mass; short-term exposure to hot water: for this, the tested product is immersed in distilled water with 85–90 °C, the water should not change color or a sediment should appear, the tableware were removed from the water, wiped dry and compared with a similar sample that was not immersed in water; short-term exposure to an alcohol solution: for this, the tested product is immersed in a 30 % solution of ethyl alcohol at 60–65 °C, the alcohol solution should not change color or a sediment should appear, the tableware were removed from the water, wiped dry and compared with a similar sample that did not was immersed in an alcohol solution; short-term exposure to an acetic acid solution: for this, the product under investigation is immersed in a 9% acetic acid solution at 85–90 °C, the acetic acid solution should not change color or a sediment should appear, the dishes were removed from the water, wiped dry and compared with a similar sample, which was not immersed in an acid solution; the method of temperature influence on disposable cups. The waterproofness of the developed biodegradable cups was checked according to the method, which involves dense placement of filter paper on the outer surface. After that, a liquid (distilled water or a drink of the appropriate temperature) is poured into the cup. The duration of aging is determined by the usual drink consumption duration. The minimum acceptable duration is 40±5 min, which is due to the coffee consumption traditions. The spots appearance on the filter paper indicates cup water penetration. The waterproofing performance was tested empirically by placing a beverage in a designed cup and placing the cup in filter paper and visually observing the appearance of spots on the filter paper surface. The biodegradable edible cup does not pass liquid, because not a single plume appeared on the filter paper during the entire research duration. The research duration was determined by the keeping expediency the liquid inside the drink – the time until the drink is consumed. A hot drink is consumed on average within 20-30 min according to personal observations. If the drink is consumed in the consumer company, the duration may increase to 1 hour. Processing of research results The degree of expert opinions consistency regarding product quality indicators was assessed using the average determining sum ranks method and the squared sum ranks deviations from the average sum (Koretska et al., 2018). ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 340 The grades variance was calculated using the formula: 2 1 1/ ( 1) ( ) n j j ij j i n C N      , (1) where 1 / n j ij j i N C n   – average value in points; Сі,j – evaluation of the і expert in the j direction; 5jn  The grades variation coefficient in the j direction was calculated using the formula: / 100%j j jN   (2) Melnik et al. (2020) and Chen et al. (2012), which allows universalizing the general approach regarding the expediency of using and/or replacing paper and polymer disposable cups with biodegradable edible ones. One of E. K. Harrington's logistic functions was taken as a basis – the «desirability curve», which is the geometric mean of individual desirability functions: 1 2 ...q qD d d d   (3) where d1, d2…dq – desired level (separate desirability function) of the 1-st, 2-nd, etc. optimization parameter (changes from 0 to 1); q – the parameters number. Harington’s scale To construct a significance scale, was used a well-known table of ratings correspondence in empirical or numerical systems. Standard correspondences of the significance scale (Harington’s scale) are given in Table 1. Table 1 Harrington's scale desirability for individual assessments Grade Value intervals Very good 0.80–1.00 Good 0.63–0.80 Satisfactory 0.37–0.63 Poor 0.20–0.37 Very bad 0.00–0.20 The values choice 0.63 and 0.37 is partially explained by the calculation convenience: е  2.7; 0.37  1/е; 0.63  1-1/е For further research, the scale was presented in the form of a graph. To determine the reliability of such a replacement, was proposed the restrictions introduction on the main quality indicators of experimental samples and the restrictions formation on the values of individual indicators (Kim et al., 2002; Marinković, 2021; Sharma et al., 2022). To do this, Harington's scale was transformed into a ten-point scale and superimposed it on the ordinate scale (Figure 2). ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 341 Figure 2. The quality indicators generalized analysis of the researched tableware for drinks samples On this scale, five intervals were used in the general scale interval from 10 to 0: very good (VG), 10.0- 8.0; good (G), 8.0–6.3; satisfactory (S), 6.3–3.7; bad (B), 3.7–2.0; very bad (VB), 2.0–0.0. The Figure 2 shows the desired indicators limits, according to which the samples quality will be within the range of «good – very good». The estimate arrival at the point d1 will indicate the submission to the minimum value point of the given critical limit. A 10-point scale to evaluate cups was developed. Groups of main indicators Pi were used for evaluation: 1, temperature of the cup surface with a drink; 2, environmental friendliness; 3, organoleptic indicators; 4, structural and mechanical properties and their descriptors (Pij) (Table 2). The obtained objective indicators were transformed into objective values by converting them into points. The profilograms area (S) (quality criterion) is equal to the areas sum of the triangles formed by the corresponding rays of individual (partial) quality indicators: 1 1 1 1 1 1 1 1 1 2 1 2( sin ) sin ( ), 2 2 n n j j n j j S f f f f f f n n             (4) Instead of the function S, the function F was used, which differs from S only by a constant factor that does not affect the choice of the largest value. To choose the most successful option with the largest value of the complex criterion, it is enough to use the criterion definition formula: 1 2 2 3 1 1... n n nF f f f f f f f f      (5) ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 342 Table 2 General scoring scale for evaluation the quality of polymer, paper and biodegradable cups taking into account the weighting factors of the main indicators Indicators (notation) Test method Weighting factor Evaluation, points Assessment, points min max min max The temperature of the cup surface with a drink (Р1) objective 1.5 6 10 9 15 Environmental friendliness (Р2) objective or organoleptic 2.5 6 10 15 25 Organoleptic properties (Р3) organoleptic or objective 3.5 6 10 21 35 Sensation when touching the cup surface organoleptic 4.0 6 10 24 40 Color (Р32) organoleptic or objective 2.0 6 10 12 20 Odor (Р33) organoleptic 1.0 6 10 6 10 Taste (Р34) organoleptic 1.0 6 10 18 30 Structural and mechanical properties (Р4) organoleptic or objective 2.5 6 10 15 25 The structure (Р41) organoleptic 2.0 6 10 12 20 Deformation under the temperature influence 85-90 оС (Р42) organoleptic 5.0 6 10 30 50 Waterproof (Р43) objective 3.0 6 10 18 30 Product quality based on the sum of all indicators calculated 10.0 24 40 60 100 Notes: The deformation index was determined for two temperatures, which are typical for cold and hot drinks. The temperature of 60-65 °C (Table 2) was not used, because if the cup does not deform at 85-90 °C, then at a lower temperature (60-65 °C) there will be no deformation. In the case of a one-sided restriction on the optimization parameters, a separate desirability function di takes the known form (Fig. 2):  [ ] 'i id exp exp y   (6) yi’ – some dimensionless quantity related to the optimization parameter yi by a linear law: 0 1 i iy b b y  (7) b0, b1 – coefficients that can be determined if two values of the optimization 1 2 2 3 1 1n n nF f f f f f f f f    parameter yi are given corresponding values of a separate desirability function. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 343 The indicator average value was calculated for the series of each experiment: 1 1 n n Y Y n   (8) Y – the indicator average value; YI – the indicator value in each experiment; N – the parallel number experiments. Next, was evaluated the variance of the arithmetic mean S2 for each series of experiments: 2 1 2 2 1 ( ) 1 n n y y S n      (9) The repeating experiments frequency was 3–5 times. Results and discussion Consumer properties of experimental samples The disposable cup is represented by edible and non-edible samples. Biodegradable edible tableware should also have similar mechanical, ergonomic and operational indicators as non-edible tableware. The most daring idea is the complete replacement of paper, polymer (polystyrene and polypropylene) cups by edible tableware. Authors of this research have opinion that replacing non-edible tableware by edible ones is not an equivalent replacement, therefore, non-edible tableware should be replaced with biodegradable ones, in particular, the polyethylene layer in paper cups should be replaced with ecological ones, and polypropylene and polystyrene should be replaced with natural polymers. An edible cup also serves as a snack and a sweet for a drink. Quality indicators are determined by the technical specifications of the market operator. Сharacteristic of disposable tableware was provided according to the following indicators: (1) organoleptic (color, appearance, physical condition, smell); (2) sound when struck with a wooden stick; (3) the presence of defects; (4) ease of use; (5) the actual capacity, ml; (6) the height, mm; (7) the diameter of the upper part, mm; (8) the diameter of the bottom part, mm; (9) the wall thickness, mm; (10) the bottom thickness, mm;(11) the moisture mass fraction, %; (12) short-term hot water influence (60–65 оС and 85–90 °С); (13) short-term cold water influence (10–15 оС); (14) short-term alcohol solution influence; (15) short-term influence of acetic acid solution. Organoleptic, ergonomic and geometric properties of biodegradable edible cups Organoleptic, ergonomic and geometric properties of biodegradable edible cups were compared with properties of disposable paper and polymer cups (Table 3). The developed cup fully corresponds in terms of organoleptic, ergonomic and geometric parameters to the disposable cups that are currently in use. In addition, the developed edible cup also has an advantage over paper and polymer analogues, because due to the greater thickness of the walls and the material properties (cookies), it is possible to hold a cup with a hot drink in your hands without an additional layer. From the outside, the designed cup can be coated with edible polymer, which can be consumed or thrown away without negative impact on the environment. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 344 Table 3 Properties of various disposable cups for hot drinks Indicators Paper cup Polymer cup Biodegradable edible cup Organoleptic (color, appearance, physical condition, smell, taste*) White, opaque, no smell, soft, visible side seam of gluing, there is a border on top Transparent, polypropylene glass is soft in the hands, deforms with a slight effort; polystyrene cup is hard in the hands, does not deform. There is a border on top The color inherent in baked butter cookies, the pleasant smell of cookies, there is a border on top, it is firm in the hands and does not deform, the pleasant taste, characteristic of butter cookies Sound when struck with a wooden stick Unvoiced Presence of defects Absent in the studied samples Ergonomic indicators It is comfortable to hold in the hand, but needs an additional intermediate layer to hold a hot drink It is convenient to hold in the hand, polystyrene cups do not need an additional thermal insulation layer, unlike polypropylene The shape is similar to a paper or polymer cup Actual capacity, ml In accordance with the standard size and consumer needs Height, mm 90±0.1 90±0.1 90±0.1 Diameter of the upper part, mm 70±0.1 70±0.1 70±0.1 Diameter of the bottom part, mm 40±0.1 42±0.1 40±0.1 Wall thickness, mm 1±0.1 0.5±0.1 5±0.1 Bottom thickness, mm 1±0.1 0.5±0.1 8±0.1 Moisture mass fraction, % 5.5±0.5 5.0±0.5 14±0.5 Short-term hot water influence The shape and appearance of the cups remained unchanged Short-term cold water influence Short-term alcohol and acetic acid solution influence * the taste was determined only for edible cups ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 345 Coffee contains organic acids, and some types of coffee-based drinks, such as Irish coffee, Dumas, Karsk, Espresso Martini, and Coffee punch, are prepared with the addition of alcohol. Therefore, the effect of alcohol and acetic acid on the developed biodegradable cup was studied. The key characteristic of the biodegradable edible cups is their waterproofness, which allows to completely replace disposable cups. As mentioned above, the cup waterproofness was created due to the inner natural polymer layer. The manufactured biodegradable cup with a drink was kept for 2 hours and no place of liquid leakage was found. Effect of temperature on the biodegradable edible cup properties Bidiuk et al. (2020) recommend to test tableware at temperatures for typical drinks offered by restaurants: 10-15 °C (Glaze, Frappe, Cold Americano, Ice Cream); 60-65°C (Latte, Cappuccino, Mochacino, Macchiato, Flat White, Raff), and 85-90°C (Americano, Espresso and their varieties). The effect of different temperatures on the change in appearance on disposable cups are present in Table 4. Table 4 Temperature influence on disposable cups Experimental conditions Paper cup Polymer cup Biodegradable edible cup Drink with a temperature of 10-15 °C No changes in appearance Drink with a temperature of 60-65°C No changes in the appearance for holding in hand No changes in appearance, the polypropylene cup needs an additional heat- insulating layer to hold in the hand No changes in appearance, it is possible to hold without an additional insulating layer to hold in the hand Drink with a temperature of 85-90°C No changes in the appearance of the cup, but it is impossible to hold it in your hands without an additional layer A beverage with a temperature above 70 °C cannot be placed in a polypropylene cup (manufacturer's recommendation on the label); polystyrene cup unchanged No changes in appearance, it is possible to hold without an additional insulating layer for holding in the hand The results are quite acceptable since the polymers used are insoluble in water and the water drink will not dissolve the inner waterproof layer of the biodegradable edible cup. Naik et al. (2019) substantiated the importance of possible burn depending on the drinkware type. That is why in the Table 4 presents the sensations characteristics when holding a cup with a drink in your hands. The results agree with Bidiuk et al. (2020): the developed cups do not show any changes at 85-90 °C, therefore a lower temperature does not change the cups appearance. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 346 Quality assessment of test samples The quality criterion determination of test samples was carried out in several stages: (1) determination of characterize indicators, conversion of measurement units into dimensionless units (if necessary); (2) mathematical model development and calculation of product quality criteria. А critical limit was set for a specific indicator for 0.6 points during the determinations. If the absolute value of the property indicator corresponds to the limit provided for in the regulatory documentation for the product, then a score of Кij = 0.37 is an unacceptable indicator quality for the sample. An important issue for the scientific substantiation of expert evaluation is the degree consistency assessment of expert opinions using the indicator system (Koretska et al., 2003). To assess the generalized agreement opinions measure from all directions, it was calculated the expert opinions agreement degree. The calculations results are given in the Table 5. Table 5 Assessment results of the consistency experts' opinions degree The samples The indicator The average value (rank) Biodegradable edible cup The variance 0.0236 Rate of variation, % 2.657 Paper cup The variance 0.0187 Rate of variation, % 2.784 Polymer cup The variance 0.0192 Rate of variation, % 2.852 It can be seen that the variance value the estimates is close to zero from the obtained data (Table 5), and the variation estimates coefficient is no more than 3%. Such a result indicates a high assessment by experts of the finished product quality and shows consistency in the samples assessment between experts. This is explained by the fact that the group of experts was selected correctly. For the first time was calculated the conformity assessment results of experts' opinions for disposable cups. Quality assessment of disposable cups using Harington’s scale Table 6 presents the results of s disposable polymer, paper and biodegradable edible cups evaluation. The edible cup is completely biodegradable compared to other ecological cups, because it is a food. Tableware made of polylactide can completely decompose into water and carbon in 3 months (Ziada, 2009). There is an indicator environmental friendliness (Р2) in Table 6 that is why decomposition requires temperatures of at least from 55 to 70 °C and humidity, which can only be provided by commercial composting plants (Changwichan et al., 2020). In addition, much less carbon dioxide and other greenhouse gases are released during biopolymer production. Switching from conventional plastic to bioplastic would reduce greenhouse gas emissions by up to 25% (Ziada, 2009). The use of polylactide will reduce dependence on petroleum-based polymer materials, which, in turn, will reduce demand for it. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 347 Table 6 Score evaluation quality of disposable cups taking into account the importance of the main indicators Indicators (notation) Biodegradable edible cup Disposable cups polymer paper The temperature of the cup surface with a drink (Р1) 13.5 9 10.5 Environmental friendliness (Р2) 25 15 15 The organoleptic properties (Р3) 31.9 24.5 25.0 Sensation when touching the cup surface (Р31) 36 28 30.4 Color (Р32) 18 18 18 Odor (Р33) 8.9 6* 6* Taste (Р34) 28.8 18 18 Structural and mechanical properties (Р4) 22.1 25.0 24.8 The structure (Р41) 17 20 20 Deformation under the temperature influence 85-90 оС (Р42) 45 50 50 Waterproof (Р43) 27 30 29.4 Criterion of product quality, point 92.52 73.50 75.36 * to avoid the exclusion of the indicator, its value was taken as the critical limit Polygon of the quality assessment of disposable cups The quality criterion were used to construct diagrams, according to the planar principle, that is, the value of the complex quality criterion corresponds to the area of a polygon in which the distances from its center to the vertices are equal to the normalized values of individual quality indicators (Koretska et al., 2003) (Figure 3). This is because the biodegradable edible cup has the advantage of being environmentally friendly. Other researchers have obtained the similar results (Liu et al., 2020). The generalized quality criterion determined by the desirability function is calculated and presented in Table 7. Table 7 Ranking of disposable cups according to the generalized desirability function Type of cup Biodegradable cup Polymer cup Paper cup Quality criterion 92.52 73.50 75.36 When rating the tested samples, the quality criterion of a paper cup, 75.36 points, was accepted as 100%. The quality criterion of the developed biodegradable edible cup was higher, 122.8% = 92.50 points, compared to the polymer cup, 97.53% = 73.5 points. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 348 а b c Figure 3. The quality profilograms of the researched cups biodegradable edible cup (a); polymer cup (b); paper cup (c). P1 is the temperature of the cup surface with a drink; P2 is environmental friendliness; Р3 is the organoleptic indicators: Р31 is sensation when touching the cup surface, Р32 is color, Р33 is odor, Р34 is taste; Р4 is structural and mechanical properties; Р41 is the structure, Р42 is deformation under the temperature 85-90 °С, P43 is waterproof. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 349 Environmental benefits The expediency of replacing the existing disposable cups with a biodegradable edible cup is evident because nowadays environmental friendliness is a priority compared to other characteristics of the cups. In addition, do not forget about the capital investment required for the collection and processing of used paper and polymer cups. The biodegradable edible cup does not need to be recycled, because it is edible and is consumed completely with a drink or could be completely decomposed like any other confectionery product. Environmental initiatives will have a positive effect only under the condition of a comprehensive approach and the population's awareness of the need for such initiatives. It is more difficult to convince the adult population to change their preferences and habits, and that is why ecological products are becoming the subject of sociological research in the field of marketing (Ivanov et al., 2021; Kim et al., 2019; Lee et al., 2023; Marinova et al., 2022). Today, consumers are becoming more aware of the importance of caring for the environment, which will be reflected in their attitude towards quality disposable edible new cups (Bertossi et al., 2023). Environmentalism must be brought up in children, so that in adulthood it is already perceived as a norm, a habit and a necessity of everyday life. A separate segment that also needs to be provided with eco-friendly tableware is hotels (Subbiah et al., 2011). Such dishes keep their shape well when hot dishes are packed into them and can be used to store liquid dishes and sauces for 24 h without getting wet or softening. Biodegradable tableware is an ideal solution for catering and is suitable for heating in microwave ovens of different power. Bioware can be easily disposed of together with other food scraps, which will greatly facilitate the work of the restaurant by reducing the amount of waste and will allow to completely abandon the sorting of plastic. Conclusions 1. The biodegradable edible cup is a full-fledged replacement of currently used polymer and paper cups. It has been confirmed using the Harrington`s function. 2. The biodegradable edible cup is a cookie formed in the form of a cup. It is possible to change the shape of the cup according to the consumer requirements. The cup’s waterproofness is provided due to the waterproof layer inside it. 3. The developed cup can be used for a wide range of drinks with a temperature from 10 to 90 °C. 4. The biodegradable edible cup is resistant to the action of acetic acid and ethyl alcohol. 5. The biodegradable edible cup has excellent ergonomic indicators, is environmentally friendly and can be easily decomposed like any other confectionery. References Allison A.L., Lorencatto F., Miodownik M., Michie S. (2021), Influences on single-use and reusable cup use: a multidisciplinary mixed-methods approach to designing interventions reducing plastic waste, UCL Open Environment, 3, pp. 1–11, https://doi.org/10.14324/111.444/ucloe.000025 Bertossi A., Troiano S., Marangon F. (2023), What makes hot beverage vending machine cups eco-friendly? A research into consumer views and preferences, British Food Journal, 125(13), pp. 146-163, https://doi.org/10.1108/BFJ-03-2022-0263 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 350 Bidiuk D.O., Sereda O.H. (2020), Novyi vyd biorozkladuvalnoi tary, Vcheni zapysky Tavriiskoho natsionalnoho universytetu im. V.I. Vernadskoho, Ser. «Tekhnichni nauky», Kyiv, 31(70), pp. 85–94. Biswal B., Kumar S., Singh, R.K. (2013), Production of hydrocarbon liquid by thermal pyrolysis of paper cup waste, Journal of Waste Management, 2013, 731858, https://doi.org/10.1155/2013/731858 Changwichan K., Gheewala S. H. (2020), Choice of materials for takeaway beverage cups towards a circular economy, Sustainable Production and Consumption, 22, pp. 34– 44, https://doi.org/10.1016/j.spc.2020.02.004 Cheng S.Y., Shieh M.D. (2022), Development of eco-friendly bubble tea take-away cups, In: Lockton D., Lenzi S., Hekkert P., Oak A., Sádaba J., Lloyd P. (eds.), DRS2022: Bilbao, 25 June – 3 July, Bilbao, Spain. https://doi.org/10.21606/drs.2022.409 Choeybundit W., Shiekh K.A., Rachtanapun P., Tongdeesoontorn W. (2022), Fabrication of edible and biodegradable cutlery from morning glory (Ipomoea aquatic) stem fiber- reinforced onto soy protein isolate, Heliyon, 8(5), https://doi.org/https://doi.org/10.1016/j.heliyon.2022.e09529 Ivanov V., Shevchenko O., Marynin A., Stabnikov V., Gubenia O., Stabnikova O., Shevchenko A., Gavva O., Saliuk A. (2021), Trends and expected benefits of the breaking edge food technologies in 2021–2030, Ukrainian Food Journal, 10(1), pp. 7-36, https://doi.org/10.24263/2304-974X-2021-10-1-3 Jung L.W., Al-Shehhi M.R., Saffarini R., Warshay B., Arafat H.A. (2011), Paper or plastic? Clearing misconceptions on environmental impacts of coffee cups using life cycle assessment (LCA), Water, Energy and Environment, 563. Kaya M., Sargin I., Erdonmez D. (2016), Microbial biofilm activity and physicochemical characterization of biodegradable and edible cups obtained from abdominal exoskeleton of an insect, Innovative Food Science & Emerging Technologies, 36, pp. 68–74, https://doi.org/10.1016/j.ifset.2016.05.018 Kim K., Lin D. (2002), Simultaneous optimization of mechanical properties of steel by maximizing exponential desirability functions, Journal of the Royal Statistical Society, 49(3), pp. 311–325, https://doi.org/10.1111/1467-9876.00194 Kim T., Yun S. (2019), How will changes toward pro-environmental behavior play in customers’ perceived value of environmental concerns at coffee shops? Sustainability, 11(14), 3816, https://doi.org/10.3390/su11143816 Koretska I.L., Zinchenko T.V. (2003), Otsiniuvannia novykh kharchovykh vyrobiv za dopomohoiu kryteriiu «Bahatokutnyk yakosti», Naukovi pratsi NUKhT, 14, pp. 64– 65. Koretska I.L., Zinchenko T.V. (2018), Evaluation of research samples вy nonlinear quality criteria, World Science in 2018: Result: proceedings of II International scientific conference, Morrisville, USA, pp. 22–26. Lee W., Seo Y., Quan L. (2023), Consumer behavior toward eco-friendly coffee shops: moderating effect of demographic characteristics, Journal of Foodservice Business Research, pp. 1–25, https://doi.org/10.1080/15378020.2023.2214059 Liu C., Luan P., Li Q., Cheng Z., Sun X., Cao D., Zhu H. (2020), Biodegradable, hygienic, and compostable tableware from hybrid sugarcane and bamboo fibers as plastic alternative, Matter, 3(6), pp. 2066–2079. https://doi.org/10.1016/j.matt.2020.10.004 Loschelder D.D., Siepelmeyer H., Fischer D., Rubel J.A. (2019), Dynamic norms drive sustainable consumption: Norm-based nudging helps café customers to avoid disposable to-go-cups, Journal of Economic Psychology, 75, 102146, https://doi.org/10.1016/j.joep.2019.02.002 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 351 Ma J. (2014), Exploring the feasibility and desirability of in-house diversion programs for disposable hot beverage cups at the store level in Halifax Regional Municipality, Available at: https://dalspace.library.dal.ca/handle/10222/76526 Marinova D., Bogueva D., Wu Y., Guo X. (2022), China and changing food trends: A sustainability transition perspective, Ukrainian Food Journal, 11(1), pp. 126–147, https://doi.org/10.24263/2304-974X-2022-11-1-13 Mahinpei R. (2020), Minimizing the use of polyethene inside paper coffee cups, STEM Fellowship Journal, 6 (1), pp. 60–68, https://doi.org/10.17975/sfj-2020-011 Marinković V. (2021), Some applications of a novel desirability function in simultaneous optimization of multiple responses, FME Transactions, 49(3), pp. 534–548, https://doi.org/10.5937/fme2103534M Nagarajan K.J., Balaji A.N., Rajan S.T.K., Ramanujam N.R. (2020), Preparation of bio-eco based cellulose nanomaterials from used disposal paper cups through citric acid hydrolysis, Carbohydrate Polymers, 235, 115997, https://doi.org/10.1016/j.carbpol.2020.115997 Naik A., Lewis C.J., Allison K.P. (2019), Temperature dissociation of liquids in reusable thermoplastic containers – An eco-friendly scald risk? Burns, 45(7), pp. 1621–1624, https://doi.org/10.1016/j.burns.2019.07.013 Nayak S., Barik S., Jena P.K. (2021), Eco-friendly, biodegradable and compostable plates from areca leaf, Biopolymers and Biocomposites from Agro-Waste for Packaging Applications, pp. 127-139, https://doi.org/10.1016/B978-0-12-819953-4.00002-1 Sazeli Z., Zailani A., Tajudin I., Hamka A. (2021), Biodegradable cups: A substitute for single use plastic, Multidisciplinary Applied Research and Innovation, 2(2), pp. 197– 205, https://doi.org/10.30880/mari.2021.02.02.025 Sharma A.K., Mukherjee I., Bera S., Sengupta R.N. (2022), A robust multiobjective solution approach for mean-variance optimisation of correlated multiple quality characteristics, International Journal of Quality & Reliability Management, 39(9), pp. 2205–2232, https://doi.org/10.1108/IJQRM-12-2020-0409 Subbiah K., Kannan S. (2011), The eco-friendly management of hotel industry, International Conference on Green technology and environmental Conservation (GTEC-2011), pp. 285–290, https://doi.org/10.1109/GTEC.2011.6167681 Van der Harst E., Potting J. (2013), A critical comparison of ten disposable cup LCAs, Environmental impact assessment review, 43, pp. 86–96, https://doi.org/10.1016/j.eiar.2013.06.006 Ziada H. (2009), Disposable coffee cup waste reduction study, McMaster University: Hamilton, Canada, Available at: https://www.eng.mcmaster.ca/sites/default/files/uploads/disposable_coffe_cup_wast e_reduction.pdf ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 352 Effect of prolonged proteolisis on biochemical composition of the malt wort Yevhenii Ivanov, Vitalii Shutyuk National University of Food Technologies, Kyiv, Ukraine Keywords: Malt Wort Amino acid Proteolysis Mashing Abstract Introduction. Changes in mashing modes can increase extraction of biological compounds from malt. Biochemical composition of the malt wort with prolonged action of proteolytic enzymes during the mashing process was determined. Materials and methods. The raw material composition made from three types of malt: base malt, melanoidin malt and roasted malt. Analysis of the amino acid, carbohydrate and lipid profile in modified proteolytic wort was done by chromatographic methods. Results and discussion. Wort analysis identified 19 amino acids; ten of them were essential amino acids. Total content of amino acids in control wort was 1349 mg/l. Total amino acid content in wort modified by mashing mode 1 increased by 55% to 2096 mg/l. Total content of amino acid in wort modified by mashing mode 2 increased by 90% to 2572 mg/l. Proline content in modified wort was the highest: 437 mg/l in wort modified by mashing mode 1; 568 mg/l in wort modified by mashing mode 2. The high content of leucine, arginine, and phenylalanine was observed in modified wort. The percentage increase in the content of individual amino acids in the modified wort varied significantly. Thus, the content of valine and phenylalanine increased by 101-102%, meanwhile the amount of glycine increased only by 18%. Chromatographic analysis showed that prolonged proteolysis has no effect on the carbohydrate and lipid composition of the wort. Total fatty acid content was in the range from 5.6 to 11.4 mg/l. Difference in total content of fatty acids between samples of modified proteolytic wort was more than 30%. Analysis of wort showed the presence of 11 fatty acids. Palmitic and linoleic acids were predominant in fatty acid profile in modified proteolytic wort: the content of palmitic acid was 38-48%, and the content of linoleic acid (omega-6) was 30-37% from total fatty acid amounts. Carbohydrate profile of the modified proteolytic wort presented by maltose, 53.1%; dextrins, 23.4%; maltotriose, 15.2%, and glucose, 8.3%. Carbohydrate profile of modified proteolytic wort had no difference with traditional malt wort. Conclusions. Modified proteolytic wort after prolonged proteolysis during mashing is a good source of amino acids. Long proteolytic rest significantly increases the content of amino acids in malt wort, which can be further used in the technology of dietary supplement or functional drinks. Article history: Received 17.02.2023 Received in revised form 24.06.2023 Accepted 29.09.2023 Corresponding author: Yevhenii Ivanov E-mail: yevhenii.ivanov@ gmail.com DOI: 10.24263/2304- 974X-2023-12-3- 4 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 353 Introduction Malt wort is an intermediate in the production of beer, obtained by mashing malt with water. Next technological stages for the malt wort is boiling with hops and fermentation. Mashing is the most important process in wort production, providing the compounds such as sugars and amino acids necessary for yeast activity during wort fermentation. Sugars and amino acids play a special role in the final taste, aroma and color of the beer or other malt beverages (Castro et al., 2021; Jukic et al. 2022; Stewart et al., 2013). Main goal of the mashing process is to transfer, partially or completely, hydrolyzed compounds from malt and/or unmalted raw materials to water. Hydrolyzed compounds in wort are necessary for the yeast reproduction and activity. Optimal concentration of fatty acids (FA) and free amino nitrogen (FAN) in prepared wort are being considered as crucial for the final taste and aroma of beer (Ferreira et al., 2018). However, it is proven that high concentration of fatty acids has a negative effect on the quality of beer. Content of long-chain fatty acids is usually very low in the final product. Increase of long-chain fatty acid concentration may lead to increase of compounds formed through their oxidation, which affects beer’s qualities (Vanderhaegen et al., 2006). Fatty acids are needed for the yeast cells activity and play a significant role in fermentation. Another important group of compounds determines yeast growth is the free amino nitrogen substances, presented by amino acids, ammonium ions, peptides, and tripeptides (Lei et al., 2012). However, overdosed amino acids could be converted by yeasts to higher alcohols, which are highly toxic (Ferreira et al., 2018). The substitution of malt with unmalted barley, wheat, rye, corn or other is a common practice in brewing, but addition of unmalted materials decreases enzyme activity (Bogdan et al, 2020; Kok et al., 2019). Mashing process to extract malt raw materials is primarily focused on beer production technology. Under conditions of traditional beer production, the action of proteolytic enzymes is strongly limited. Longer action of proteolytic enzymes negatively affects on the stability of the foam in the beer and can cause turbidity, which significantly reduces the quality of the final product (Bamforth, 2023; Cvengroschová et al., 2003). The malt extract for the beer brewing must acquire the minimum amount of free amino nitrogen required for yeast reproduction. Enough quantity of free amino nitrogen, depending on the yeast culture, is in the range of 150-250 mg/l (Bogdan et al, 2020; Hill et al., 2019). Protein rest phase is usually limited by a lower limit level of free amino nitrogen content. With a high quality of malt protease, the rest phase can be skipped, because content of soluble proteins is high enough after malting. With a mash heating rate of 1 °C/min, the duration of heating in the range of action of proteolytic enzymes is enough to obtain a minimal level of free amino nitrogen (Ledley et al., 2023; Montanari et al., 2005). Longer mashing allows a deeper extraction of biologically active substances to the final wort. Proteolysis can be prolonged, if the wort should not be used for beer production and can be not completely transparent because in the classical method the amount of amino acids in the wort used for beer production, should be minimal. High amino acid content in the wort increases the nutritional value of malt beverages prepared on its base or malt extract used for production of dietary supplements. Therefore, a study of modified malt wort with an extended rest at optimal temperature for proteolytic enzyme activity followed with quantitative and qualitative determination of the amino acids, carbohydrates and fats profiles of the final product was conducted. The aim of the present research was to determine the amino acid, carbohydrate and lipid composition of modified proteolytic wort. Extraction was done by long-term mashing with long protein rest phase for the deeper malt proteolysis. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 354 Materials and methods Materials To prepare raw material composition a mixture of three types of malt was used: (a) barley brew malt Weyermann Pilsner Malt (Germany); extract (dry basis) ≤ 80 %; the color of the laboratory wort was 3 EBC; malt was produced according to the classical method of malting and next drying; (b) barley specialty melanoidin malt Bel-Her melanoidin (Ukraine); extract ≤ 77 %; the color of the laboratory wort was 57 EBC; malt was produced according to the classic method of malting followed by fermentation at a temperature of 50 °C and drying; (c) barley roasted malt Castle malting chocolate (Belgium); extract ≤ 70%; the color of the laboratory wort was 590 EBC; the malt was produced using the classic method of malting followed by roasting at a temperature of 220 °C and rapid cooling when the malt reaches the needed intense of color. To prepare raw material composition next ratio of malts was used: Weyermann Pilsner Malt, 50 %; Bel-Her melanoidin malt, 42 %; Castle malting chocolate malt, 8 %. Methods Moistening of malt was provided before grinding to give elasticity to the shells: malt was kept in the water for 15 minutes at a temperature of 30 ºС. Grinding of moistened malt was carried out on a LZM-1 laboratory mill, followed by passing through a sieve with a hole size of 1.0 mm. Mashing ratio between malt and water was 1:3; for the all experiments malt portion was 250 g, water portion was 750 ml. First portion of the water was added at the stage of hydration before grinding. Rest of the water was added just before mash preparation. Mashing goal was to extract maximal amount of amino acids and other biological compounds to the malt wort and compare with a control wort. Mashing process was carried out using the following modes (for first mash temperature was 20 °C): 1. Control mode - the temperature of the first mash rest was 63 °C, the duration of first rest phase for β-amylase catalysis during mashing was 25 min. At the end, the mash was heated to 72 °C for the saccharification rest phase followed by enzyme inactivation. Finally, wort had mass fraction of dry substances of 15 °P; 2. Mode 1 - the temperature of the first mash rest was 50 °C (heating of the mash with a rate of 1 °C/min). Duration of the first rest phase for proteolytic catalysis during mashing was 30 min. Next heating was to 63 °C. It took 13 minutes, and the mash was holding at this temperature for the rest phase for 25 min. At the end, the mash was heated to 72 °C for the saccharification rest phase followed by enzyme inactivation. Finally, wort had mass fraction of dry substances of 15 °P; 3. Mode 2 - the temperature of the first mash rest was 50 °C (heating of the mash with a rate of 1 °C/min). Duration of the first rest phase for proteolytic catalysis during mashing was 60 min. Next heating was to 63 °C. It took 13 minutes, and the mash was holding at this temperature for the rest phase for 25 min. At the end, the mash was heated to 72 °C for the saccharification rest phase followed by enzyme inactivation. Finally, wort had mass fraction of dry substances of 15 °P. Mashing was carried out with constant stirring on a laboratory reactor LR-2.ST the Compact Power IKA (Germany). The reactor is equipped with a stirrer EUROSTAR 100 control for intensification of mashing. According to each mashing condition were prepared three samples of wort, the average value for each condition is indicated in the results. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 355 The schematic difference in the duration and temperature indicators at different mashing conditions is shown in Figure 1. Figure 1. Schematic difference of mashing conditions Determination of amino acid content The content of amino acids in malt extracts was determined as an indicator of the effectiveness of prolonged protein rest phase (proteolysis) during the extraction of malt raw materials. According to each mashing condition, three samples of wort were prepared and analysed. Amino acids in wort were analyzed using ion exchange liquid chromatographic method by system LC-40D Shimadzu (Japan). The column chromatography method was used to determine the qualitative and quantitative amino acid composition. The chromatography conditions included the use of mobile phase, ninhydrin with added sodium citrate buffer (pH 2.2), eluent flow rate of 15 mL h−1 and a chromatography cycle of 120 min. Standard amino acids were used in parallel, while qualitative amino acid composition was determined from retention times. A mixture of 21 amino acids was used as an internal standard. The colorimetric measurement of the complex resulting from the ninhydrin reaction was carried out at 570 nm (440 nm for proline). The qualitative composition of the mixture of amino acids was determined by comparing the aminograms of the standard mixture of amino acids LAA21-1KT (Sigma-Aldrich) and the studied samples of malt wort. Quantitative analysis was done by automated determination of peak areas for identified acids by chromatograph software (Yilmaz et al., 2018). To calculate the number of amino acids in wort from malt raw materials, the peak area of each amino acid (or peak height) is calculated on the aminogram. The number of micromoles of each amino acid (X1) in the test solution is determined by the next formula: X1 = S1/S0 where S1 is the peak area (or peak height) of the amino acid in the test sample; S0 is the peak area (or peak height) of the same amino acid in a solution of a standard mixture of amino acids, which corresponds to 1 micromole of each amino acid (Savchuk et al., 2017). ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 356 Determination of carbohydrate profile The carbohydrate profiles of the worts were determined using high-performance liquid chromatography (HPLC) methods. Samples were centrifuged using laboratory centrifuge type MPW-351R (10 min, 5000 rpm) and subjected to 2-times dilution. Separation of the mixture was made using Rezex ROA Organic Acid H+ (300 × 7.8 mm) column made by Phenomenex. Respectively, a method of high-duty chromatography HPLC, using Shimadzu Prominence apparatus, was used to analyze concentration of glucose, maltose, maltotriose, dextrins and amount of produced glycerol and ethanol. A volume of 0.02 cm3 injection, celerity of the flow of eluent 0.6 cm3/min, temperature of separation 60 °C, solution H2SO4 0.005 mol/l as eluent and refractometric method of detection were used (Gasior et al., 2020). Determination of fatty acid profile Fatty acid profile was determined by gas chromatography. The analysis was performed by extracting the total fatty acid content from the sample (0.25 g) using 5 ml of a 9:1 chloroform: methanol solution. Heptadecanoic acid, 400 μg, as an internal standard was added to the extracted lipids and methylated by heating at 70 °C for 3 hours in a solution of 1 % H2SO4 in methanol. The composition of methyl esters of fatty acids was determined by gas chromatography on a Shimadzu GC 2010 Plus chromatograph under the following conditions: capillary column 50 m, flame ionization detector, carrier gas - nitrogen. The results of the research were processed using the computer software of the chromatograph (Cozzolino et al., 2014). Statistics Means with standard deviations (±SD) were calculated from the data obtained from three independent experiments. The univariate analysis of variance (ANOVA) of means was performed using SPSS (version 16.0). Multiple-means comparisons were determined with the Duncan’s multiple range test at the p <0.05 confidence level. Results and discussion Amino acid profile The effect of prolonged protein pause (proteolysis) on the content of amino acids and other biological components in wort from malt composition was studied. Three samples of wort were prepared according to each mashing condition. Result is indicated as average value of each amino acid made under the same mashing modes. All wort samples had a final concentration of dry substances of 15±0.5 °P. Analysis of wort identified the presence of 19 amino acids. Amount of each amino acid was calculated by specialized software. The average content of amino acids in different samples of wort is given in Table 1. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 357 Table 1 Content of amino acids in wort with different mashing modes Amino acid The content of amino acids in wort, mg/l Control Mode 1 Mode 2 Proline 288 ±9.8 a 437 ±14.0 b 568 ±15.9 c Leucine 112 ±4.2 a 166 ±6.3 b 208 ±6.7 c Arginine 99 ±3.5 a 156 ±4.4 b 187 ±7.3 c Phenylalanine 91 ±2.5 a 146 ±3.9 b 184 ±6.6 c Valine 94 ±3.7 a 150 ±5.5 b 190 ±4.7 c Glutamine 68 ±2.3 a 124 ±2.6 b 133 ±4.9 b Alanine 82 ±2.5 a 126 ±4.4 b 157 ±6.0 c Tyrosine 80 ±2.2 a 123 ±4.4 b 151 ±4.5 c Lysine 58 ±2.2 a 92 ±3.0 b 114 ±3.3 c Isoleucine 62 ±1.9 a 98 ±3.8 b 121 ±3.8 c Asparagine 48 ±1.8 a 75 ±2.7 b 90 ±2.5 c Aspartic acid 37 ±1.2 a 47 ±1.6 b 49 ±2.3 b Serine 37 ±1.4 a 58 ±1.6 b 62 ±2.6 b Glutamic acid 41 ±1.3 a 71 ±1.7 b 77 ±2.5 b Threonine 40 ±1.6 a 63 ±2.4 b 80 ±2.1 c Tryptophan 32 ±1.2 a 50 ±1.2 b 64 ±1.8 c Histidine 38 ±1.3 a 59 ±1.8 b 70 ±2.3 c Glycine 22 ±0.9 a 25 ±0.9 a 26 ±1.5 a Methionine 20 ±0.7 a 31 ±1.1 b 40 ±1.5 c Total amino acid content, mg/l 1349 2096 2572 Results expressed as mean values ± SE (n = 3); values with superscript different letters in the same line are significantly different (p < 0.1) The highest content of amino acids was in the samples of wort prepared according to the second modification mashing mode 2. Chromatogram of the amino acid content in malt wort prepared with a mash mode 2 is shown in Figure 2. Carbohydrate profile The main aim of the research was to select and determine regime for wort mashing providing the highest content of biologically active components. Wort prepared according to the second modification mashing mode had the highest content of amino acids, so it was used for further determination of carbohydrate and fatty acid profiles. All samples before the chromatographic study had 15±0.5 °P extract. The results of the carbohydrate profile analysis in modified proteolytic wort samples are shown in Table 2. Fatty acid profile Analysis made by high-efficiency capillary column identified 11 fatty acids and their isomers from C10:0 to C22:0 in modified proteolytic wort samples. Fatty acid profiles in modified wort samples are shown in Table. 3. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 358 Figure 2. Chromatogram of amino acids of wort (15±0.5 °P): aspartic acid (ASP), glutamic acid (GLU), asparagine (ASN), serine (SER), glutamine (GLN), histidine (HIS), glycine (GLY), threonine (THR), arginine (ARG), proline (PRO), alanine (ALA), tyrosine (TYR), methionine (MET), valine (VAL), tryptophan (TRP), phenylalanine (PHE), isoleucine (ILE), leucine (LEU) and lysine (LYS). Unsigned peaks are not identified. Table 2 Carbohydrate profile in the malt wort samples Sample Carbohydrates content, g/l Maltose Dextrins Maltotriose Glucose 1 43.91 a 21.07 a 13.21 a 8.11 a 2 50.06 b 21.05 a 13.17 a 7.9 b 3 47.42 c 20.2 b 14.05 b 6.14 c Values with superscript different letters in the column are significantly different (p < 0.05) ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 359 Table 3 Fatty acid profile of malt wort samples Fatty acid Concentration, % Sample 1 Sample 2 Sample 3 С10:0 0.99±0.05 a n/d n/d С12:0 0.92±0.05 a n/d n/d С14:0 3.09±0.1 a 2.50±0.1 b 2.44±0.1 b С16:0 48.45±0.25 a 38.21±0.25 b 38.21±0.25 b С16:1 2.47±0.1 a 2.32±0.1 a 2.7±0.1 b С18:0 5.31±0.1 a 11.6±0.15 b 8.56±0.1 c С18:1 2.59±0.1 a 5.53±0.1 b 2.88±0.1 a С18:2 30.78±0.25 a 33.92±0.25 b 37.64±0.25 c С18:3 0.55±0.05 a 0.80±0.05 b 0.45±0.05 a С20:0 3.46±0.1 a 5.18±0.1 b 2.70±0.1 a С22:0 1.23±0.1 a n/d 1.31±0.1 a Total fatty acid content, mg/l 8.09±0.1 a 5.6±0.1 b 11.45±0.15 c Not determined (n/d) refers means amount was < 0.5%; values with superscript different letters in the same line are significantly different (p < 0.05) Discussion The raw material for the production of the studied wort was barley malt. According to the traditional technology of malt production and its subsequent processing, one of the most important quality indicators is the high content of carbohydrates needed for the fermentation during next processing (Duke et al., 2009; Yousif et al., 2020). However, the aim of the present research was to determine the effect of the long protein rest phase on the content of amino acids in the wort. It was shown that pause in the mash at 50 °C for 60 minutes significantly increased the content of all amino acids. The highest increase in the amounts of amino acids in modified wort, by 101-102%, was observed for valine and phenylalanine. The content of proline, leucine, and arginine increased by 97.5, 85.7, and 89.4%, respectively. The smallest changes, an increase of the content by 31% and 18%, were recorded for aspartic acid and glycine, respectively. The content of total amino acids of modified proteolytic wort increased by 90.5% due to long-term proteolysis during mashing. Holding the mash at 50 °C for 30 minutes also increased the content of amino acids in the wort samples. The highest content increases, 81% and 74 %, were observed for glutamine and glutamic acid, respectively, but the increase in the amounts of the most amino acids in the wort was within the range from 50 to 60%. However, the increase of the amount of aspartic acid was only 25%. The smallest quantitative change, 13%, was recorded for glycine. Under these mashing conditions, the total content of amino acids increased by 55.3%. The temperature of 50 °C, the main mode of mash rest phase in the present study, is below the limit of activation of cytolytic enzymes. Therefore, the carbohydrates profile of the malt wort did not have significant changes. The proportion of carbohydrate content in the wort remained close to the types of wort prepared by the classic mashing mode (Ferreira, 2009). The malt extract samples had a content of reducing carbohydrates in the range from 86 to 92 g/l. Chromatography analysis showed that the main sugar in mashed wort was maltose, 53.1%, followed by dextrins, 23.4%, and maltotriose, 15.2%, and glucose 8.3%. Graphically, the carbohydrate profile of the obtained malt extract is shown in Figure 3. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 360 Figure 3. Diagram of the carbohydrates profile in the malt wort Analysis of modified wort showed the presence of 11 fatty acids. Total content of fatty acids was in the range of from 5.6 to 11.4 mg/l. The largest amount of fatty acids was presented by palmitic, 38-48%, and linoleic acids, 30-37%. Low content of fatty acids in the wort can be related to the laboratory filtration technique due to the filter layer formed by crushed malt. The content of fatty acids in wort filtrated on industrial vacuum filter presses was significantly higher (Kühbeck et al., 2006). Total protein content in the grain crops ranges from approximately 10 to 15 % of the dry weight of the grain. Barley grains contain four different classes of proteins: albumin, globulin, prolamin (hordein), and glutelin. The storage proteins, prolamin and glutelin, account for approximately 50% of the total protein in mature cereal grains. With the exception of oats and rice, the main reserve proteins of the endosperm of all cereal grains are prolamins. Prolamins have a relatively high content of proline and amide nitrogen, and other specific amino acids, such as histidine, glycine, methionine, and phenylalanine. Prolamins are mostly deficient in lysine, threonine, and tryptophan (Allai et al., 2022; Sterna et al., 2022). Amino acid profile of the wort showed the biggest changes under different mashing modes. Amount of amino acids in the wort was influenced by many factors: biological characteristics of cereals, optimal conditions for enzymes during mashing, method and equipment for filtering of mash. Starchy endosperm contains approximately two-thirds of the grain's total protein, and its internal pH during malting is 5.0-5.2. Carboxypeptidases, which are present in the endosperm at a high content, are very active pH and likely play a central role in the mobilization of reserve proteins during malting and fermentation in the technology of special melanoidins malt. The high activity of peptidase in the modified cotyledon (shield) of the grain indicates absorption in the form of peptides of some hydrolysis products, which are further hydrolyzed to amino acids in this tissue (Geißinger et al., 2022). Generally known that up to 70% of wort free amino nitrogen is formed during malting. Accordingly, barley with a higher nitrogen content is used to produce FAN-rich extracts; meanwhile barley with a low nitrogen content is used for the production of extracts rich with carbohydrates. Although nitrogen levels vary by grain variety, the general types of amino acids present are similar (Thompson-Witrick et al., 2020; Wefing et al., 2021). There are some researchers reporting about possible relationship between the amount of free amino nitrogen and the content of amino acids (Nie et al., 2010). 0 20 40 60 80 100 Carbohydrates profile in modified wort, % Maltose Dextrins Maltotriose Glucose Other ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 361 During malting, germination of barley grain is started with water absorption (soaking). Hydration initiated production of enzymes needed to convert starch reserves into fermentable sugar. Proteolytic enzymes are also activated and protein degradation occurs after hydration of grain (Arif et al., 2011). Proteolysis is important during malting because soluble nitrogen is needed for enzyme synthesis, and it results in the release of the associated α-amylase enzymes required for starch breakdown. Amount of proteolytic enzymes including at least 40 different endoproteinases with high activity. Proteolytic enzymes were founded in the aleurone layer and endosperm during the germination process of barley grains (Benešová et al., 2017; Jones, 2005). Use of plant hormones, such as gibberellic acid, during germination caused a change of the ratio of amino acid synthesized to their utilization in the germinating grains that can have effect on the final amino acid composition of the wort (Liu et al., 2013). Bromate, a substance used to limit the growth of roots, also affects the relative amount of free amino acids (especially proline and methionine) in malt and wort (Dufková, 2020). Malt drying conditions also influence on the content of amino acids in the wort. An increase of the temperature in the dryer from 82 to 104 °C causes a noticeable decrease in amino acid content (Chursinov et al., 2015). All these should be taken into account providing a mashing process with prolonged action of proteolytic enzymes. Based on the obtained research results, it is possible to increase total content of amino acid over 3 g/l in modified proteolytic wort. Conclusions Technology of long-term proteolysis during wort preparation can be used in technology of dietary supplements or functional drinks. Modified wort has higher content of amino acids. High amino acid content has a strong impact on the functional properties of the wellness products. Research results: 1. Modified proteolytic wort prepared according to the two mashing modes: with 30 min of proteolysis and 60 min of proteolysis. Control wort was prepared without protease rest phase. Analysis of wort identified 19 amino acids, and ten of them were essential amino acids. Total amino nitrogen content in control wort was 1349 mg/l. Total amino acid content of wort modified by mashing mode 1 increased by 55% to 2096 mg/l. Total amino acid content of wort modified by mashing mode 2 increased by 90% to 2572 mg/l. 2. Individual amino acid content in the modified wort increased in a different range. Valine and phenylalanine content in modified wort increased by 101-102%, at the same time the amount of glycine increased only by 18%. 3. Total amino acid content in wort could exceed 3000 mg/l by using gibberellic acid and bromate in the malting process, by making prolonged proteolysis rest phase and using industrial separation machines. 4. Carbohydrate profile of modified proteolytic wort had no difference compared to traditional malt wort because prolonged proteolysis rest temperature mode is below the activation limit of cytolytic enzymes. Carbohydrate profile of the modified wort presented by maltose, 53.1%; dextrins, 23.4%; maltotriose, 15.2%, and glucose, 8.3%. 5. Wort analysis identified 11 fatty acids. Total content of fatty acids was not higher than 11.4 mg/l. Therefore, prolonged proteolysis rest phase allows a significant increase of total amino acid content. Malt wort with high amino acids content can be used in production of dietary supplements or functional drinks. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 362 References Allai F.M., Azad Z.R.A.A., Gul K., Dar N. (2022), Wholegrains: A review on the amino acid profile, mineral content, physicochemical, bioactive composition and health benefits, International Journal of Food Science & Technology, 57(4), pp. 1849–1865, https://doi.org/10.1111/ijfs.15071 Arif M., Bangash J.A., Khan F., Abid H. (2011), Effect of soaking and malting on the selected nutrient profile of barley, Pakistan Journal of Biochemistry and Molecular Biology, 44(1), pp. 18–21. Bamforth C.W. (2023), The physics and chemistry of beer foam: a review, European Food Research and Technology, 249(1), pp. 3–11, https://doi.org/10.1007/s00217-022- 04134-4 Benešová K., Běláková S., Mikulíková R., Svoboda Z. (2017), Activity of proteolytic enzymes during malting and brewing, Kvasny Prumysl, 63(1), pp. 2–7. https://doi.org/10.18832/kp201701 Bogdan P., Kordialik-Bogacka E., Czyżowska A., Oracz J., Żyżelewicz D. (2020), The profiles of low molecular nitrogen compounds and fatty acids in wort and beer obtained with the addition of quinoa (Chenopodium quinoa Wild.), amaranth (Amaranthus cruentus L.) or maltose syrup, Foods, 9(11), pp. 1626, https://doi.org/10.3390/foods9111626 Castro L.F., Affonso A.D., Lehman R.M. (2021), Impact of specialty malts on wort and beer characteristics, Fermentation, 7(3), 137, https://doi.org/10.3390/fermentation7030137 Chursinov Yu.O., Kovalova O.S., Filipenko D.V., Petrovenko V.V. (2015), Tekhnolohichni osoblyvosti sushinnia zhytnoho fermentatyvnoho solodu, Zbirnyk Naukovykh Prats Vinnytskoho Natsionalnoho Ahrarnoho Universytetu. Seriia: Tekhnichni nauky, 1(2), pp. 144-152. Cozzolino D., Roumeliotis S., Eglinton J.K. (2014), The role of total lipids and fatty acids profile on the water uptake of barley grain during steeping, Food Chemistry, 151, pp. 231–235, https://doi.org/10.1016/j.foodchem.2013.11.073 Cvengroschová M., Seplova G., Smogrovicová D. (2003), Effect of mashing-in temperature on free amino nitrogen concentration and foam stability of beer, Monatsschrift fur Brauwissenschaft, 56(7/8), pp. 128–131. Dufková H. (2020), Seed germination promoting chemical compounds and their potential use in the malting industry, Kvasny prumysl, 66(1), pp. 201–207, https://doi.org/10.18832/kp2020.66.201 Duke S.H., Henson C.A. (2009), A comparison of barley malt osmolyte concentrations and standard malt quality measurements as indicators of barley malt amylolytic enzyme activities, Journal of the American Society of Brewing Chemists, 67(4), pp. 206–216, https://doi.org/10.1094/ASBCJ-2009-0629-01 Semenenko K., Kapinus L., Boiko I., Kucherenko V., Skryhun N. (2022), Effective frequency of displaying the communication message to consumers of beer brand in digital media (2022), Ukrainian Food Journal, 11(4), pp. 629–647, https://doi.org/10.24263/2304-974X-2022-11-4-11 Ferreira I.M. (2009), Beer carbohydrates, In: V.R. Preedy ed., Beer in health and disease prevention, Academic press, pp. 291–298, https://doi.org/10.1016/B978-0-12- 373891-2.00027-4 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 363 Ferreira I.F.M., Guido L.F. (2018), Impact of wort amino acids on beer flavour: A review, Fermentation, 4, pp. 23, https://doi.org/10.3390/fermentation4020023 Gąsior J., Kawa-Rygielska J., Kucharska A.Z. (2020), Carbohydrates profile, polyphenols content and antioxidative properties of beer worts produced with different dark malts varieties or roasted barley grains, Molecules, 25(17), pp. 3882, https://doi.org/10.3390/molecules25173882 Geißinger C., Gastl M., Becker T. (2022), Enzymes from cereal and fusarium metabolism involved in the malting process: A review, Journal of the American Society of Brewing Chemists, 80(1), pp. 1-16, https://doi.org/10.1080/03610470.2021.1911272 Hill A.E., Stewart G.G. (2019), Free amino nitrogen in brewing, Fermentation, 5(1), pp. 22, https://doi.org/10.3390/fermentation5010022 Jones B.L. (2005), Endoproteases of barley and malt, Journal of Cereal Science, 42(2), pp. 139–156, https://doi.org/10.1016/j.jcs.2005.03.007 Jukic M., Nakov G., Komlenic D.K.., Sumanovac F., Koljderaj A., Lukinac J. (2022), Quality assessment of sponge cake with reduced sucrose addition made from composite wheat and barley malt flour, Ukrainian Food Journal, 11(1), pp. 64–77, https://doi.org/10.24263/2304-974X-2022-11-1-8 Kok Y.J., Ye L., Muller J., Ow D.S.W., Bi X. (2019), Brewing with malted barley or raw barley: what makes the difference in the processes?, Applied Microbiology and Biotechnology, 103, pp. 1059–1067, https://doi.org/10.1007/s00253-018-9537-9 Korzh N., Onyshchuk N. (2023), Balanced development of the food industry in the post- war period: assessment, trends, management, Ukrainian Journal of Food Science, 11(1), pp. 16–28, https://doi.org/10.24263/2310-1008-2023-11-1-5 Kühbeck F., Back W., Krottenthaler M. (2006), Influence of lauter turbidity on wort composition, fermentation performance and beer quality—A review, Journal of the Institute of Brewing, 112(3), pp. 215–221, https://doi.org/10.1002/j.2050- 0416.2006.tb00716.x Ledley A.J., Elias R.J., Cockburn D.W. (2023), Evaluating the role of mashing in the amino acid profiles of worts produced from gluten-free malts, Beverages, 9(1), pp. 10, https://doi.org/10.3390/beverages9010010 Lei H., Zhao H., Yu Z., Zhao M. (2012) Effects of wort gravity and nitrogen level on fermentation performance of brewer’s yeast and the formation of flavor volatiles, Applied Biochemistry and Biotechnology, 166, pp. 1562–1574, https://doi.org/10.1007/s12010-012-9560-8 Liu C., Zhu L., Yin X., Xu Z., & Li Q. (2013), Study on the gibberellic acid residues in brewing, Journal of the American Society of Brewing Chemists, 71(2), pp. 76–82, https://doi.org/10.1094/ASBCJ-2013-0408-01 Montanari L., Floridi S., Marconi O., Tironzelli M., Fantozzi P. (2005), Effect of mashing procedures on brewing, European Food Research and Technology, 221, pp. 175–179, https://doi.org/10.1007/s00217-005-1166-8 Nie C., Wang C., Zhou G., Dou F., Huang M. (2010), Effects of malting conditions on the amino acid compositions of final malt, African Journal of Biotechnology, 9(53), pp. 9018–9025, https://doi.org/10.5897/AJB10.370 Savchuk Y.Y., Usatiuk S.I. (2017), Doslidzhennia biolohichnoi tsinnosti napoiu z yader voloskoho horikha, Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies. Series: Food Technologies, 19(75), pp. 124–128, https://doi.org/10.15421/nvlvet7525 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 364 Sterna V., Ence E., Strausa E. (2022), Research of a dry extruded mixture of protein rich plant composition, Rural Sustainability Research, 47(342), pp. 16–22, https://doi.org/10.2478/plua-2022-0003 Stewart G.G., Hill A.E., Russell I. (2013), 125th anniversary review: developments in brewing and distilling yeast strains, Journal of the Institute of Brewing, 119(4), pp. 202–220, https://doi.org/10.1002/jib.104 Thompson-Witrick K.A., Pitts E. (2020), Nitrogen content in craft malts: Effects on total ester concentration in beer, Journal of the American Society of Brewing Chemists, 78(4), pp. 308–313, https://doi.org/10.1080/03610470.2020.1778432 Vanderhaegen B., Neven H., Verachtert H., Derdelinckx G. (2006), The chemistry of beer aging-A critical review, Food Chemistry, 95, pp. 357–381, https://doi.org/10.1016/j.foodchem.2005.01.006 Wefing P., Conradi F., Rämisch J., Neubauer P., Schneider J. (2021), Determination of free amino nitrogen in beer mash with an inline NIR transflectance probe and data evaluation by machine learning algorithms, Monatsschrift für Brauwissenschaft, 74, pp. 108, https://doi.org/10.23763/BrSc21-10wefing Yilmaz S., İlbaş A.İ., Akbulut M., Çetin A. (2018), Grain amino acid composition of barley (Hordeum vulgare L.) cultivars subjected to selenium doses, Turkish Journal of Biochemistry, 43(3), pp. 268–276, https://doi.org/10.1515/tjb-2017-0027 Yousif A.M., Evans D.E. (2020), Changes in malt quality during production in two commercial malt houses, Journal of the Institute of Brewing, 126(3), pp. 233–252, https://doi.org/10.1002/jib.609 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 365 Influence of foliar fertilizers application on the volatile composition of red wines Dimitar Dimitrov, Nikolay Iliev, Ivan Pachev Agricultural Academy, Institute of Viticulture and Enology, Pleven, Bulgaria Keywords: Foliar Ferilizers Red wine Volatile compounds Abstract Introduction.The aim of the present study was to determine the influence of different foliar fertilizers (in four harvests – 2019, 2020, 2021, and 2022) on the composition of volatile and aromatic compounds of red wines from the Bulgarian hybrid variety Storgozia. Materials and methods. Gas chromatography-flame ionization detection was used to determine the volatile compounds in red wines. Results and discussion. The results obtained regarding the total content of volatile compounds in the analyzed wines showed that the variant of vine treatment with fertiliser MaxGrow NS, consist of N, 20%, S, 7%, Mg, 14%, P, 5%, Mn, 1%, Zn, 0.01%, Cu, 0,05%, Fe, 0.05), Cu, 0.01%, Zn, 0.01%, B, 0.025%, Mo, 0.002%, demonstrated final high levels of volatile and aroma compounds in wines of three from the four investigated harvests (2019, 2020 and 2021). As individual representatives from the group of higher alcohols, 2-methyl-1-butanol and 3-methyl-1- butanol dominated in all four harvests. The two alcohols are the main metabolites of the yeast microflora. The application of different foliar fertilizers did not negatively affect the acetaldehyde content in the resulting wines. Its presence corresponded to the appearance of its positive influence. From the obtained results, it could be concluded that in the 2020 and 2022 harvests, the foliar application of nitrogen and mineral sources affected the content of esters. In the other two harvests, individual variants showed higher ester accumulation than the untreated control, but others demonstrated lower levels. As a result, no specific conclusion could be made about the influence of foliar fertilizers on the final wines ester concentrations. A major ester from this fraction was ethyl acetate. Foliar fertilization affects the synthesis of ß-citronellol, leading to increased levels of this terpene. Conversely, for geraniol, a decrease in its concentrations was observed in the wines obtained after the application of foliar fertilization. Conclusions. The application of foliar fertilizers led to changes in composition of volatile compounds of the researched red wines and influenced both on the different groups of volatiles and individual compounds. Article history: Received 20.04.2023 Received in revised form 16.07.2023 Accepted 29.09.2023 Corresponding author: DimitarDimitrov E-mail: dimitar_robertov@ abv.bg DOI: 10.24263/2304- 974X-2023-12-3-5 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 366 Introduction The need for organic and ecological agriculture at the current stage is fundamental due to the significant climate changes. They are a stress factor not only for vine plants but also for different crops. This stress is formed because of extreme, unpredictable and unexpected changes in weather, which can lead to a significant reduction in the yield of the vine and the composition of the grapes (Azabard, 2022; van Leeuwen and Dariet, 2016). The vine is a plant with high sensitivity to extreme high temperatures, and the heat stress caused by them significantly affects the content of organic acids, the titratable acidity and pH of the grapes (Hewitt et al., 2023; Venios et al., 2020). Increasing temperatures and decreasing rainfalls, intensifying grape ripening, lead to a deterioration of the aromatic wine profile (Gutiérrez- Gamboa, 2018). This necessitates the application of various viticultural practices to ensure controlled metabolic development of the vine, improving the yield and quality of its grapes. One of the essential treatments in this aspect is mineral fertilization. Nitrogen has a significant impact on the metabolomics and life cycle of the grapevine, and directly affects the yield, composition and quality of its fruit (Delas et al., 1991; Soubeyrand et al., 2014). Foliar fertilization is an effective strategy for improving crop nutrition when the soil is poor in nutrients and under dry climatic conditions (Lv et al., 2017). It essentially represents spraying of nutrients on the canopy of the crops, which leads to the direct absorption of these substances by the crop leaves and stems (Cooper, 2003). It is actively entering in viticulture, due to the improved and efficient assimilation of nitrogen and mineral components, improving the vitality of the vine and the qualitative composition of grapes and wine (Rubio- Bretόn et al., 2018). Wine, being a product of grape juice fermentation by the yeast belonging to the genus Saccharomyces, contains many volatile compounds produced mostly due to the yeast metabolic activity. These compounds includes higher alcohols, aldehydes and ketones, esters, terpenes, lactones, phenols, the amounts of which varied from a few ng/l to hundreds of mg/l (Delgado et al., 2020; Manolache et al., 2018; Tang et al., 2019). However, it was reported that some of volatile compounds present in wine come into wine directly from the grapes (Cordente et al., 2012; González-Barreiro et al., 2015). Higher alcohols are synthesized by yeasts that metabolize sugars and amino acids (direct precursors for higher alcohols formation) (Bell and Henschke, 2005).The biological synthesis of esters is also associated with yeasts metabolism during alcoholic fermentation. This is a clear indicator that the presence of nitrogen in the must (vitally necessary for the yeasts) is extremely important for the proper course of fermentation and generating aromatic compounds that determine the wine quality (Lacroux et al., 2008; Miller et al., 2007). In the scientific literature, there are not many studies determining the influence of foliar fertilization directly on the wine’s aromatic profile. Trdenić et al. (2020) determined the effect of foliar application of K, B and other microelements on the content of aromatic compounds in grapes of the white variety Škrlet bijeli from Croatia. The team identified the presence of 24 volatile compounds in the three years study. In two of the harvests (2013 and 2014) Trdenić et al. (2020) found high contents of 1-hexanol, linalool, ß-damascenone, trans- 2-hexenal and geranyl-acetone. Lacroux et al. (2008) found that N and S foliar fertilization of Sauvignon Blanc vines improved the aromatic profile of wines by increasing the volatile thiols and glutathione. On the other hand, Rubio-Bretόn et al. (2012) when studying the foliar application of two nitrogen sources – phenylalanine and urea, applied as fertilizers to vines of the red Tempranillo variety, concluded that the studied nitrogen sources did not change the wine aromatic profile. Gutiérrez-Gamboa et al. (2018) investigated the effect of applying different foliar nitrogen fertilizers on Cabernet Sauvignon wines. The team found that the ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 367 urea + sulfur treatments and the application of a commercial BA preparation had a positive effect by increasing the amounts of three very important wine esters – ethyl hexanoate, ethyl octanoate and ethyl decanoate. When treated with urea and arginine, the team found an accumulation of high total levels of terpenes, which are a product of the vine. The aim of the present study was to determine the influence of different foliar fertilizers on the production of volatile and aromatic compounds in red wines from the Bulgarian hybrid variety Storgozia. Materials and methods Variety and plantation The red hybrid grapevine variety Storgozia grafted on the rootstock Berlandieri x Riparia selection Oppenheim 4 was used in the study. The plantation was located on the territory of the Experimental Base of Institute of Viticulture and Enology (IVE)-Pleven in the area "Tomovskoto". The variety was planted according to a scheme of 1 m intra-row and 2.5 m inter-row distance, in which there were 4000 vines per hectare. They were trained monostemmed and with a single cordon at a height of 1 m. The rows were oriented in the southeast-northwest direction. The exposure had a slight slope to the north. The support structure consisted of one supporting wire 100 cm from the ground, and two pairs for shoots tucking in, respectively 30 and 60 cm above it. The load on the vines was leveled at 20 buds provided through spurs and fruit canes. Experimental variants of foliar fertilization The Ka-Bor liquid fertilizers (Agro-Bio Trading Ltd., Bulgaria) and the Max Grow series (Maxgrow Chemical Ltd. Bulgaria), recommended for vineyards, were tested. Applied fertilizers differed by their elemental composition. Content of macronutrients – nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg) and micronutrients – iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), boron (B), chlorine (Cl), molybdenum (Mo). The influence of every single nutrient on vine is related with: nitrogen stimulates growth, grape berries size, bunch weight, it is component of enzymes, vitamins and chlorophyll; phosphorus participates in nucleic acids, phosphoric esters, lipids and nucleotides, participates in energy transfer and has a direct effect on the grapes quality and yield; potassium increases the growth of the vine root system, increases the disease resistance and the content of sugars in grapes; sulfur is a component of enzymes and proteins, participates in photosynthesis, increases resistance to diseases; calcium is extremely important for grape berries strength, leaf growth and disease resistance; magnesium participates in photosynthesis, protein synthesis, grapes quality and yield; boron improves the growth of the root system and aerial parts, increases the content of sugars and increases the yield; zinc stimulates general root growth, increases sugar content, berries strength and yield; Mn, Cu, and Fe increase photosynthetic activity and the development of leaf mass. The scheme of the experiment contained six variants; each with four repetitions of five vines is shown (Table 1). The soil type was chernozem. The vineries were grown without irrigation. For the purpose of the research, soil fertilization was excluded from the plantation agrotechnics. Foliar feeding was carried out four times and with doses recommended by the manufacturer. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 368 Table 1 Experimental vines variants and doses of fertilizers application Vines Fertilizer Content of elements, % Amount of fertilizer, ml/ha V1 Control – untreated - - V2 Ka-Bor K, 12; Ca, 6; B, 1.5 600 V3 Max Grow 999 N, 9; P, 9; K, 9; Fe, 0.05; Mn, 0.025; Cu, 0.01; Zn, 0.01; B, 0.025; Mo, 0.02 5000 V4 Max Grow PK N, 3; P, 20; K, 22; Fe, 0.05; Mn, 0.025; Cu,0.01; Zn, 0.01; B, 0.025; Mo, 0.002 4000 V5 Max Grow NS N, 20; S, 7; Mg, 14; P, 5; Mn, 1; Zn, 0.01; Cu, 0.5 5000 V6 Max Grow Co. Max Grow 999*, Max Grow PK, Max Grow NS as 2V3 + V4 + V5 Dose for fertilizer was indicated above * Max Grow 999 was taken in double dose Vinification. The study was conducted at the IVE – Pleven. The object of the present study were red wines obtained from four harvests (2019, 2020, 2021 and 2022) of the Storgozia variety. The grapes for each studied variant (30 kg each) were picked and vinified in the IVE Experimental Wine Cellar in the conditions of microvinification, according to the classic scheme for the production of red wines (González-Neves et al., 2013): crushing – destemming – sulphitation (50 mg/kg SO2) – alcoholic fermentation with SIHA Rubio Cru yeast Saccharomyces cerevisiae from Eaton's Begerow: 20 g of dry yeast per 100 l at temperature 28°C – separation from solids – additional sulphitation – storage. Gas chromatography-flame ionization detection (GC-FID) of the wine’s volatile composition. The content of the main volatile and aromatic compounds was determined based on a stock standard solution prepared in accordance with IS 3752:2005 method. The method describes the preparation of a standard solution of one congener, but the preparation step was followed to prepare a solution of more compounds. The standard solution in the present study included the following compounds (purity > 99.0%): acetaldehyde, ethyl acetate, methanol, 2-propanol, isopropyl acetate, 1-propanol, 2-butanol, propyl acetate, 1- butanol, isobutyl acetate, ethyl butyrate, 2-butyl acetate, 2-methyl-1-butanol, 3-methyl-1- butanol, 4-methyl-2-pentanol, 1-pentanol, pentyl acetate, 1-hexanol, ethyl hexanoate, hexyl acetate, 1-heptanol, linalool oxide, dimethyl succinate, phenyl acetate, linalool , ethyl caprylate, 2-phenylethanol, α-terpineol, nerol, ß-citronellol, geraniol, ethyl decanoate. The prepared standard solution containing all compounds was injected in an amount of 2 μl into a gas chromatograph Varian 3900 (Varian Analytical Instruments, Walnut Creek, California, USA) with a capillary column VF max MS (30 m, 0.25 mm ID, DF= 0.25 μm), equipped with flame ionization detector (FID). The carrier gas was helium. Hydrogen to support combustion was supplied to the chromatograph via a hydrogen bottle. The injection was manual, using a microsyringe. The gas chromatographic determination parameters were: injector temperature – 220 °C, detector temperature – 250 °C, initial oven temperature – 35 °C/1 min retention, rise to 55 °C with a step of 2 °C/min for 11 min, rise to 230 °C with a step of 15 °C/min for 3 min. Total chromatography time – 25.67 min. After the retention times of the compounds in the ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 369 standard solution were determined, the identification and quantification of the volatile compounds in the wines were conducted. The volatile composition was determined based on the injection of wine distillates. Samples were injected in an amount of 2 μl into a gas chromatograph and identification and quantification of volatile compounds was performed. Statistical data processing. Statistical processing of the data was performed, including determination of average content and standard deviation (±SD), with four replications (four harvests) for the main compounds identified in all of the four analized harvests. The statistical data processing was carried out using the Excel 2007 program (Microsoft Corporation, USA). Results and discussion The obtained results of the performed gas-chromatographic analysis of the wines from the respective four harvests (2019, 2020, 2021 and 2022) are presented in Tables 2 – 5. Changes of the wines total volatile content by harvests The highest total content of volatile compounds in the wines of the 2019 harvest was found in the variant V6. The determined concentration of volatile compounds in this combined variant of foliar fertilization was more than 4 times higher, compared to the untreated control. High levels of total volatile compounds were also reported in variants V5 and V3. Variant V2 showed a lower content of volatile components than the control, and variant V4 demonstrated a slightly lower level than the control. For the total amount of volatile compounds in the wines from the next harvest (2020) a different trend was observed. In this harvest, all experimental wines accumulated a significantly higher amount of volatile compounds, compared to the control. Very high concentration of total volatile compounds was found here in variants V2 and V5. They were respectively more than 24 times and more than 14 times higher compared to the untreated control. In the third harvest (2021), the wine of variant V5 dominated in terms of total volatile compounds concentration. In this harvest, it was noticeable that the levels of volatile compounds in the experimental variants were not significantly higher than those of the control variant. A correlation could be drawn here with the first harvest (2019), where variants V2 and V4 also showed lower total volatile content than the control variant. In contrast, for all three harvests (2019, 2020 and 2021) a high final amount of volatile compounds was observed for variant V5. In the last harvest (2022), only variant V2 showed levels of volatile compounds lower than the control. The highest total content of volatile compounds in this harvest was found in variant V3. The V4 variant also showed high levels. The results obtained regarding the total content of volatile compounds in the analyzed wines indicated that in three of the harvests – 2019, 2021 and 2022, the V2 variant showed levels of total volatile compounds lower than the control. The most constant in terms of high final content of volatile compounds turned out to be variant V5, which demonstrated final high levels in wines of three from the four investigated harvests (2019, 2020 and 2021). In this variant of used foliar fertilizer, the amounts of nitrogen are the highest. This led to more nitrogen in the grapes and during fermentation has led to the stimulation of the yeasts metabolic action and the secretion of higher amounts of volatiles. ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3─── 370 Table 2 Gas-chromatographic analysis, harvest 2019 *nd – not detected **Statistical data (Average ± SD) for four main compounds (acetaldehyde, methanol, 3-methyl- 1-butanol and ethyl actate) identified in all harvests analysed is shown in Table 6. Table 3 Gas-chromatographic analysis of wines, harvest 2020 Identified compounds Content in wines, mg/l, from vines V1 V2 V3 V4 V5 V6 Ethyl alcohol, vol.% 13.63 14.25 13.02 13.06 12.56 12.66 Acetaldehyde 45.81 22.85 52.08 10.39 308.85 511.77 Methanol 7.33 7.01 35.27 65.74 198.72 115.14 2-methyl-1-butanol 45.69 3.85 28.16 46.28 110.94 302.46 3-methyl-1-butanol 102.25 8.39 17.07 96.20 230.08 71.57 2-phenyl ethanol nd 24.75 320.65 nd nd nd 1-propanol nd nd 22.59 9.00 ND 153.48 2-propanol nd nd 19.92 7.23 304.51 nd Total higher alcohols 147.94 36.99 408.39 158.71 645.53 527.51 Ethyl acetate 22.17 38.55 247.35 6.31 155.36 286.95 Pentyl acetate nd nd 54.13 nd nd nd Isopentyl acetate 23.48 ND 66.74 31.54 nd 116.86 Propyl acetate 27.69 12.46 119.69 77.03 nd nd Isopropyl acetate nd nd 5.63 1.51 nd nd Ethyl hexanoate 50.58 nd nd nd nd nd Phenyl acetate nd nd 85.20 nd nd 168.59 Ethyl caprylate 16.62 nd nd nd nd nd Hexyl acetate 28.13 nd nd 2.67 nd nd Total esters 168.67 51.01 578.74 119.06 155.36 572.40 Nerol nd nd 0.10 0.20 nd nd β – citronellol nd 0.56 nd 0.63 nd nd Geraniol 0.75 nd 0.14 0.12 nd nd Total terpenes 0.75 0.56 0.24 0.95 nd nd Total content 370.50 118.42 1074.72 354.85 1308.46 1726.82 Identified compounds Content in wines, mg/l, from vines V1 V2 V3 V4 V5 V6 Ethyl alcohol, vol.% 12.64 12.18 12.30 12.02 12.35 13.01 Acetaldehyde 8.58 102.44 200.88 119.41 162.63 81.25 Methanol 9.47 193.44 86.03 166.11 270.62 199.69 2-methyl-1-butanol 8.69 586.46 134.12 nd 169.13 nd 3-methyl-1-butanol 18.89 1500.35 137.58 126.60 439.75 66.36 1-propanol 0.05 0.05 nd 0.05 68.36 nd 2-propanol nd nd nd nd nd 56.26 1-pentanol nd 0.05 0.05 nd nd nd 1-heptanol 0.05 nd nd nd nd nd 2-phenylethanol 0.05 nd nd 305.88 nd 0.05 ─── Food Technology ─── ─── Ukrainian Food Journal. 2023. Volume 12. Issue 3 ─── 371 Table 3 (Contin