Effects of soy protein hydrolysis and polysaccharides addition on foaming properties studied by cluster analysis

The objective of the work was to study foaming properties (foam overrun, drainage rate and collapse stability) of soy protein and their hydrolysates as affected by polysaccharides. As starting material a sample of commercial soy protein isolate was used (SP) and hydrolysates of 0.4, 5.0 and 5.2% degree of hydrolysis (DH) were produced by an enzymatic reaction. The polysaccharides added were xanthan, λ and κ-carrageenan, guar, locust bean gum and hydroxypropylmethylcelluloses as surface-active polysaccharides. The effect of polysaccharides addition on foaming properties depended in a complicated way on the degree of hydrolysis of protein, surface-activity of polysaccharide, concentration of both macromolecules, contribution of polysaccharide consistency to bulk viscosity and interfacial interactions between biopolymers. However, through cluster analysis the best combination of protein/polysaccharide to obtain defined foaming properties could be determined for an eventual industrial application.