超声糖基化大豆分离蛋白冻融稳定性的研究

Freeze-thaw Stability of Soy Protein Isolate Modified by Ultrasonic Assisted Glycosylation

摘要:

本文采用超声波技术促进美拉德反应改性大豆蛋白提高其冻融稳定性。比较研究了由大豆分离蛋白（SPI）、大豆分离蛋白+葡聚糖（SPI+D）混合物以及超声SPI-D接枝物作为乳化剂的乳液的冻融稳定性，分析了乳析指数、出油率、絮凝程度、聚结程度、粒径、zeta电位、显微结构等性质，与SPI相比，经过3次冻融循环后超声SPI-D制备的乳液仍保持较好的稳定性，其乳析指数和出油率分别降低了96.20%、80.53%，粒径维持在50~60 μm范围内，呈窄单峰分布，絮凝程度和聚结程度分别降低了187.8%、235.3%。zeta电位和显微结构可以看出其乳液仍处于相对稳定的状态。扫描电镜研究得知改性后蛋白颗粒状态更加疏松，大小均匀，分子间聚集程度显著降低。超声SPI-D乳化体系具有较好的冻融稳定性，为生产出冷冻产品专用大豆分离蛋白提供理论依据。

Abstract:

The ultrasound technique was adopted to improve the freeze-thaw stability of soy protein isolate (SPI) modified using Maillard reaction in this paper. The freeze-thaw stabilities of emulsions of SPI, SPI+dextran (D) mixture, and the SPI-D grafts prepared from ultrasonic assisted glycosylation were comparatively studied, and the creaming index, oiling off, flocculation degree, coalescence degree, particle size, zeta potential, and microstructure measurements were analyzed. Compared with the control SPI, the emulsions stabilized by of SPI-D still had a relatively good stability after three freeze-thaw cycles. The creaming index and oiling off were reduced by 96.20% and 80.53%, respectively. The particle size had a narrow unimodal distribution in the range of 50 to 60 μm, and the flocculation degree and coalescence degree were reduced by 187.8% and 235.3%, respectively. Zeta potential and microstructure showed that the emulsions were still in a relatively stable state. The scanning electron microscopy (SEM) images indicated that the modified protein particles became loose and had a uniform size, and the degree of intermolecular aggregation decreased significantly. The SPI-D emulsification system resulted in good freeze-thaw stability. This method provides a theoretical basis for the production of SPI specifically for frozen foods.