Cereal Chem 67:35-38   |  VIEW ARTICLE

Thermal Denaturation of Soy Glycinin in the Presence of 2-Mercaptoethanol Studied by Differential Scanning Calorimetry.

Z. M. Zarins and W. E. Marshall. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

The effect of 2-mercaptoethanol on the thermal properties of soy glycinin was determined at protein concentrations of 1 and 10% in buffered salt solution. Heating glycinin at 1% concentration in a buffered salt solution resulted in an endothermic denaturation; heating it in the presence of 2-mercaptoethanol, ethanol, or 2-propanol resulted in an exothermic transition. Increasing 2-mercaptoethanol concentration from 0.01 to 10% lowered the exothermic denaturation temperature (Td) from 94.8 to 46.2 C. The denaturation enthalpy (delta H) remained relatively unchanged (30 J/g). High concentrations of glycinin (10% suspensions) always exhibited an endotherm during denaturation. Increasing concentrations of 2- mercaptoethanol lowered the Td and the delta H of denaturation. Our data indicate that both disulfide bonds and hydrophobic interactions affect the thermal behavior of soy glycinin.