Al Mahfuz Abdullah, Tsukamoto Chigen, Kudou Shigenitsu, Ono Tomotada
Department of Agro-bioscience, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan.
J Agric Food Chem. 2004 Nov 17;52(23):7070-4. doi: 10.1021/jf0491557.
The effect of isoflavone on soy milk and tofu astringency was investigated, and no consistency was found between an undesirable astringent taste and isoflavone contents. Isoflavone-enriched extract (approximately 39% isoflavones) showed no astringency. Soybean foods having high amounts of isoflavones showed less astringency. About 80% of isoflavones exist freely in both soy milk and tofu, but 55% of phytates (which play an important role in the formation of the tofu curd network) exist freely in the soy milk, and 6-13%, on the basis of coagulation, existed freely in the tofu curds. A 1% potassium phytate solution at pH 7 showed the very same astringency as soy milk; however, calcium phytate at the same concentration and pH showed no undesirable sensation. Thus, it is assumed that the astringent characteristics caused by phytic ions in soy milk are lost upon conversion of phytic ions to their insoluble salt forms during soy milk coagulation.
研究了异黄酮对豆浆和豆腐涩味的影响，结果发现不良涩味与异黄酮含量之间不存在一致性。富含异黄酮的提取物（约含39%的异黄酮）没有涩味。异黄酮含量高的大豆食品涩味较小。约80%的异黄酮在豆浆和豆腐中均以游离形式存在，但植酸盐（在豆腐凝块网络形成中起重要作用）的55%在豆浆中以游离形式存在，基于凝固情况，6%-13%在豆腐凝块中以游离形式存在。pH值为7的1%植酸钾溶液与豆浆具有相同的涩味；然而，相同浓度和pH值的植酸钙没有不良口感。因此，可以推测豆浆中植酸离子引起的涩味特征在豆浆凝固过程中由于植酸离子转化为不溶性盐形式而消失。
