Differential Scanning Calorimetry of Edible Plant-based Protein Using Glycerol as a Medium

Abstract

Plant-based protein isolates are common food ingredients. Differential scanning calorimetry is used to forecast functional properties of these isolates as well as to evaluate the propensity of these isolates for bioplastic formation through heat-induced formation of intermolecular disulfide, hydrophobic, and other types of bonds. In this work, differential scanning calorimetry was employed in the study of a suspension containing soy protein isolate and glycerol. It was shown that heat release occurred upon heating the isolate in the presence of glycerol. Preheating-induced denaturation of soy proteins in aqueous solution (95°С, 30 min) made the observed heat more exothermic, whereas exothermic reaction was not observed during enzymatic hydrolysis of the protein. Since adding β-mercaptoethanol to soy protein isolate had no effect on the observed exothermic process, this chemical compound could not contribute to formation of new disulfide bonds. Thus, bioplastic formation using soy protein isolate occurs independently of the formation of new disulfide bonds, and differential scanning calorimetry can be used to assess protein solubility.