Protein substances of rice flour and its use in wheat bread technology

Abstract

Rice flour contains less amount of total protein than wheat flour, but it is more complete. It was established that the limiting amino acid of wheat flour is lysine, the amino acid score of which is 0.44, in rice flour it is 6.92. The limiting amino acid of rice flour is tryptophan, the amino acid score of which is 1.61. This indicates that rice flour is complete in terms of amino acid composition, since the amino acid score of the limiting amino acid is more than 1. The difference in the protein composition of wheat and rice flour affects the structure of the dough. The content of raw gluten decreased when replacing part of the wheat flour with rice flour by 21.6—55.6% with an increase in the percentage of replacement. The elasticity, hydration capacity of gluten and its extensibility also decreased. The limiting amino acid in all bread samples is lysine, but in the control sample its amino acid score is 0.46, while with an increase in the percentage of replacement of wheat flour with rice flour, it increased to 0.82—2.10. In the sample with the replacement of 20% flour and more, the amino acid score for lysine exceeds 1, which means that the protein of these samples is complete.