Department of Food Science and Technology, South China University of Technology, Guangzhou, People's Republic of China.
J Agric Food Chem. 2011 Apr 27;59(8):4071-7. doi: 10.1021/jf104834m. Epub 2011 Mar 21.
The mechanical properties, water-holding capacities (WHC), and microstructures of emulsion gels, induced by glucono-δ-lactone (GDL), CaCl(2), and microbial transglutaminase (MTGase) from unheated and heated soy protein isolate (SPI)-stabilized emulsions (at protein concentration 5%, w/v; oil volume fraction, 20%, w/v), were investigated and compared. The influence of thermal pretreatments (at 90 °C for 5 min) before and/or after emulsification was evaluated. Considerable differences in mechanical, water-holding, and microstructural properties were observed among various emulsion gels. The thermal pretreatment after emulsification increased the strength of the emulsion gels induced by GDL and CaCl(2), whereas in the case of MTGase, thermal pretreatments before and/or after emulsification on the contrary greatly inhibited gel network formation. The application of the enzyme coagulant exhibited much higher potential to form SPI-stabilized emulsion gels with higher mechanical strength than that of the other two coagulants. The WHC of the emulsion gels seemed to be not directly related to their gel network strength. Confocal laser scanning microscope analyses indicated that the network microstructure of the formed emulsion gels, mainly composed of aggregated protein-stabilized oil droplets and protein aggregate clumps, varied with the type of applied coagulants and emulsions. The differences in microstructure were basically consistent with the differences in mechanical properties of the gels. These results could provide valuable information for the formation of cold-set soy protein-stabilized emulsion gels.
研究了由戊二酸内酯（GDL）、氯化钙（CaCl₂）和微生物转谷氨酰胺酶（MTGase）诱导的未加热和加热的大豆分离蛋白（SPI）稳定乳液（蛋白质浓度为 5%，w/v；油体积分数为 20%，w/v）形成的乳化凝胶的力学性能、持水能力（WHC）和微观结构，并进行了比较。评估了在乳化前后（90°C 加热 5 分钟）进行热预处理的影响。各种乳化凝胶的力学、持水和微观结构性能存在明显差异。乳化后进行热预处理会增加 GDL 和 CaCl₂诱导的乳化凝胶的强度，而 MTGase 则相反，乳化前后的热预处理会极大地抑制凝胶网络的形成。酶凝固剂的应用表现出比其他两种凝固剂更高的形成具有更高机械强度的 SPI 稳定乳液凝胶的潜力。乳化凝胶的 WHC 似乎与凝胶网络强度没有直接关系。共焦激光扫描显微镜分析表明，形成的乳化凝胶的网络微观结构主要由聚集的蛋白稳定的油滴和蛋白聚集团块组成，其类型随应用凝固剂和乳液的类型而变化。微观结构的差异基本上与凝胶的力学性能差异一致。这些结果可为冷凝大豆蛋白稳定乳液凝胶的形成提供有价值的信息。
