ペプチドの解析と開発に関する食品・栄養学的研究

抄録

In our series of studies aimed at improving food proteins by enzymatic hydrolysis and resynthesis (plastein reaction), we first isolated and identified a series of bitter peptides occurring in a peptic hydrolysate of soybean protein. We then applied the plastein reaction to the bitter hydrolysate and succeeded in debittering it. We also found that the papain-catalyzed resynthesis reaction permitted covalent incorporation of added amino acid esters. This led to improving the functional and nutritional properties of food proteins, giving rise to peptide surfactants with considerable oil-emulsifying capacity and modified peptides with balanced amino acid compositions. The products we then developed are exemplified by a low-phenylalanine, high-tyrosine peptide for patients with phenylketonuria. The products aiso include peptides with maximized branched-chain amino acids and minimized aromatic amino acids as well as those with an enriched glutamine content. Recently, we extended our studies to analysis of cereal allergens and the design of hypoallergenic foods. Our first success was the design of rice grains with removed allergenic prateins. The process for producing this kind of functional food was subsequently industrialized, and the product “Fine Rice” was approved as the first “food far specified health use” by the Japan Ministry of Health and Welfare. This was followed by the current study, aimed at producing a hypoallergenic wheat flour preparation by controlled enzymatic hydrolysis. In this study, we have determined a major epitope unit (Gln-Gln-Gln-Pro-Pro) of glutenin origin and also developed a haptenic peptide that may be usable as an antiallergenic factor for patients with wheat-associated atopic dermatitis. An important aspect of these studies is that we took special care not to jeopardize acceptability or palatability, which is one of the most important considerations when dealing with food.