大豆蛋白亲水胶体混合凝胶的强度和相行为

Gel Rigidity and the Phase Behavior of Soy Protein-Hydrocolloid Mixtures

用小形变振荡流变仪测定了大豆蛋白 亲水胶体胶混合物的胶凝性能.通过聚合物"混合定律"对实验数据进行分析,结果表明,随着组分质量分数增加,大豆蛋白 卡拉胶混合物的胶凝强度沿着混合定律所计算出上限或下限而变化,显示有相变发生.大豆蛋白 黄原胶混合物的凝胶强度总是沿着上限变化,表明大豆蛋白始终是连续相.大豆蛋白和海藻酸丙二醇酯(PGA)的结合能产生强度高于上限的混合凝胶,可能是PGA和大豆蛋白间形成了共价键.大豆蛋白 槐豆胶(LBG)混合胶体的贮藏模量低于下限,可能是因为大豆蛋白 LBG混合物的去混合速率较低而降低了各组分的有效质量分数.大豆蛋白 槐豆胶(LBG) 黄原胶的三元混合物的凝胶强度沿着下限变化,但是当蛋白质质量分数较低时接近上限,表明大豆蛋白质的存在可能抑制了LBG 黄原胶混合物形成连续网状结构.

Gelling properties of soy protein-gum mixtures were determined by small deformation oscillation and the experimental data were analyzed with blending laws of polymers. Gel strength of soy protein-carrageenan mixture was found to follow either upper or lower bounds depending on the concentration of the constituents, suggesting the occurring of phase shift. Gel strength of soy protein-xanthan mixed gel always followed the upper bound, indicating that soy protein was the continuous phase regardless the variation in gum concentration. Combination of soy protein with propylene glycol alginate (PGA) could produce mixed gel with high strength that lay above the upper bound. Covalent bonds between PGA and soy protein is suggested to contribute the rigidity. Storage modulus of soy protein-locust bean gum (LBG) lay beyond the lower bound and low effective concentration due to the limited demixing process of LBG was suggested to result in low gel strength. Gel strength data of soy protein-LBG-xanthan followed the lower bound but approached upper bound on reducing protein concentration, suggesting that the presence of soy protein might inhibit LBG-xanthan mixture from forming continuous networks.