ITRODUCTIONNowadays there is a shortage of protein intake in different groups of population, which leads to a de-crease in efficiency, metabolic disorders, and the emer-gence of a number of diseases. The proteins of mu-shrooms may play an important role in meeting the needs of food protein.Mushrooms belong to vegetable products with a relatively high content of protein, which takes up to 40% solids, an average of 24.9±1.75% [1]. However, up to date there is no consensus about the usefulness and comprehensibility of fungal proteins. Recognizing the great protein content in mushrooms, we cannot ignore the high content of dietary fiber and chitin. Defi-nite proof of complexity of fungal protein digestibility by a human body can also be considered by the fact that the degree of extractability of the protein by vari-ous solvents, depending on the species of fungi is on the level 35-60% [2].Biological value of food is determined by indica-tion of protein quality, what reflects the extent to which its amino acid composition corresponds to the body needs in amino acids for protein synthesis. In fungal protein hydrolyzates up to 22 amino acids are revealed [3]. Essential amino acids are contained in mushrooms up to 33-44% of amino acids total sum. And their numbers are growing in direct proportion to an increase in protein content [4]. Alongside with the implementation of their biological function certain amino acids make great contribution into flavor properties of mushrooms [5].It is also known that fungi include antinutritional substances capable to selectively reduce the digestibili-ty of certain nutrients. They are primarily antienzymes or proteinase inhibitors, which block the activity of enzymes of the gastrointestinal tract, and reduce the absorption of protein substances [6, 7]. These are tryp-sin inhibitors capable to form inactive complexes with enzymes that break down proteins in a human body; wherein the enzymes lose their catalytic activity. Therefore, prolonged use of such food leads to hyper-trophy of a pancreas and hence a slower growth. Thus, high levels of proteinase inhibitors content significantly lowers the nutritional value of proteins and has nega-tive effects on an organism.According to studies [8] of the content of trypsin inhibitors, in 55 kinds of edible mushrooms a trypsin inhibitor activity is observed to be within 0.36-10.42 mg/g of dry weight.L.A. Gzogyan showed that the fertile bodies of 18 different species of basidiomycetes in Krasnodar re-gion contain these enzymes, with the exception of po-lypore (Coriolus versicolor (Fr.) Karst) and blackber-ries (Hericium erinaceus (Fr.) Quel). The highest level of activity of trypsin-like proteinases was found in fruit bodies of brown cap boletus (Leccinum melanum (Fr.) Karst) (5.3 mg/g), white mushrooms (Boletus edulis) (3.7 mg/g) and the chanterelles natural (Cantharellus cibarius Fr.) (3.6 mg/g), autumn honey agarics (Armil-lariella mellea (Fr.) Karst.) (2 mg/d) [6].