Heat-Induced Milk Gels. V. Some Chemical Factors Influencing the Firmness

Abstract

Consistency and firmness of heatinduced milk gels is affected by various additives. Various chemicals up to .25 mole/i,000 g of gel and adjusted initially to pH 6.6 to 6.8, were screened for effects. Divalent cations promoted gelation, calcium being most efficient. Sulfhydryls, thiomalate, thiodiglycolate, and thiolactate, reduced glutathione, and cysteine, produced softer gels at from 1 to 50 mM but at ~ 70 mM increased filanness severalfold above that of standard gels; fi-mercaptoethanol was without effect. Milk gels prepared with (NH4)zS208 and KsFe(CN)6 as oxidizers or with NaBH 4 as a reducer, were up to 5 times firmer than gels with no additives. N-Ethylmaleimide, quinhydrone, NazSO3, KBrOs, NaIOa, NalO4, NaBO,, o-iodosobenzoate, H202, and calcium-binding anions all produced soft and sticky gels. Sodium chloride, KC1, and quinhydrone had no effect on gel fhmness.