title: Initiation of protein association in tofu formation by metal ions.
abstract: Magnesium and calcium ions are important factors in making tofu. However, the molecular role of these ions remains unclear in tofu formation. We have previously shown that magnesium chloride concentration-dependent produced silken tofu-like (SP) and regular tofu-like (RP) precipitates, but was an inconsequential factor for the retention of tofu. We investigated in this present study, the effect of various metal chlorides on the metal chloride concentration-dependent changes in tofu formation. These changes occurred in a similar manner to that of the magnesium ion, in which SP formation was followed by RP formation. It is interesting that the midpoint concentration for the formation of SP and RP represented a good correlation with the stability constant of EDTA. This correlation demonstrated the possibility that metal ions would interact with the carboxyl groups of soy proteins. We consider from these results that metal ions were the initiators of protein association in tofu formation.
authors.affiliation: a Department of Food Science and Nutrition , School of Human Environmental Sciences, Mukogawa Women's University , Nishinomiya , Hyogo 663-8558 , Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Arii
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Takenaka
mesh_terms: D011232:Chemical Precipitation; D002712:Chlorides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005511:Food Handling; D008670:Metals / Q000737:chemistry / Q000494:pharmacology*; D045730:Soy Foods; D030262:Soybean Proteins / Q000737:chemistry*; D014867:Water / Q000032:analysis
chemical_list: D002712:Chlorides; D008670:Metals; D030262:Soybean Proteins; D014867:Water
keywords: coagulant; metal ion; protein association; regular tofu; silken tofu