Kyoko Saio

Food processing characteristics of soybean 11s and 7s proteins. Part I. Effect of difference of protein components among soybean varieties on formation of tofu-gel

This paper deals with the contribution of protein components in soybean seeds to the physical properties of tofu-gel. Results obtained in tofu-making, using crude 11S and 7S components from defatte...

Food Processing Characteristics of Soybean Proteins: Part II. Effect of Sulfhydryl Groups on Physical Properties of Tofu-gel

Relation between sulfhydryl groups in soybean proteins and the physical properties of tofu was studied. Changes in the amount of sulfhydryl groups by heating or treatment with urea were more rapid in 11S protein as compared with 7S protein. Moreover, by changing the amount of sulfhydryl groups in proteins by N-ethylmaleimide, 2-mercapto-ethanol and dithiothreitol, the physical properties of tofu from 11S protein were more significantly effected than that from 7S protein. Namely, tofu-gel from 11S. protein got harder and stronger as the amount of sulfhydryl groups increased.The results may suggest that tofu prepared from IIS protein has more disulfide bonds in its gel than that from 7S protein.

Inactivation Mechanism of Soybean Lipoxygenase

大豆種子リポキシゲナーゼの攪はんによる失活の機構を解明するため,失活によって生成した沈澱物の溶解性,攪はん中のSH基の挙動,SH試薬に対する安定性,起泡と失活との関係について検討した.攪はんによる沈澱物は分子間SS結合その他による重合物であった.攪はん中にリポキシゲナーゼ分子内SH基の露出がみられた.リポキシゲナーゼは酸化剤やSH封鎖剤に対して安定でSS還元剤には不安定だった.起泡によっても失活し,攪はんおよび起泡による失活は界面活性剤を添加すると抑えられた.以上の結果から,リポキシゲナーゼは攪はんによりアンホールディングし分子間SS結合やその他の結合により重合して沈澱することが明らかとなった.起泡による表面変性がリポキシゲナーゼ失活の原因であると推定された.

Protein-Calcium-Phytic Acid Relationships in Soybean:Part II. Effects of Phytic Acid on Combination of Calcium with Soybean Meal Protein

This paper constitutes the second in a research series undertaken to clarify the interactive relationships among soybean meal protein, calcium and phytic acid. The extent of bound calcium by cold insoluble fraction protein which is low in phosphorus content was examined by differential equilibrium dialysis, differing concentrations of calcium and phosphorus. The results indicate clearly that many molecules of calcium and phosphorus may be bound by a single protein molecule and that extent of calcium increases as phosphorous compounds in dialysis system such as phytic acid increase. The maximum number of bound calcium was calculated after statical equation by Klotz.

Vegetable Protein as a Human Food — Research and Development in the National Food Research Institute

Beside the traditional use of soybean, a vide variety of soybean proteins have emerged as new food materials in Japan. The change of eating habits of the Japanese people towards increased meat consumption has particularly encouraged industrialists to produce meat-like materials from vegetable proteins.