Effects of Oligosaccharides and Soy Soluble Polysaccharide on the Rheological and Textural Properties of Calcium Sulfate-Induced Soy Protein Gels

This study investigated the rheological and textural properties of calcium sulfate (CaSO4)-induced gels formed by soy protein containing oligosaccharides (sucrose, raffinose, and stachyose) and soy soluble polysaccharide. The results showed that the hardness and water holding capacity of the gels were significantly strengthened (P < 0.05) by the incorporation of oligosaccharides at the 1, 3, and 5% (w/v) levels and soy polysaccharide at the 0.3 and 0.5% (w/v) levels. The storage modulus after the temperature cycle, frequency sweep, creep recovery tests, and large deformation properties demonstrated that the affixion of above cosolutes enhanced the rigidity (elastic properties) of gels. Confocal scanning laser microscopy (CLSM) analysis indicated that the cosolutes also improved the microstructures of the gels and herein the gels containing stachyose exhibited the greatest compactness. The gel solubility in different buffers verified the speculation that the protein-protein interactions were enhanced by the incorporation of cosolutes and hence accounted for the improvement of the gel properties. The results of this study would potentially promote the use of health-promoting raffinose, stachyose, or soy polysaccharide and facilitate the development of novel soy protein-based gel products with firmer texture and higher nutritional value.