一步法构建大豆蛋白双重乳液及其性质研究

One-Step Fabrication of Double Emulsions Stabilized by Soy Protein

摘要:

本研究发现在中性条件下可以利用酸热处理的大豆分离蛋白（SPI）并通过简单的一步均质法制备得到W/O/W双重乳液，进一步研究了不同酸热处理时间对SPI在中性条件下的溶解度及其乳液性质（如乳析率、粒度）的变化。结果表明，不同时间的酸热处理会导致SPI在中性条件下的溶解度出现不同程度的下降（未加热SPI高达78.60%，酸热处理SPI为36.02%~53.29%），可能是由于形成了不溶性的蛋白纤维聚集体，维系这些不溶聚集体的主要作用力是氢键和二硫键。酸热处理可以显著改善SPI稳定的乳液的乳析稳定性，且长时间的酸热处理效果更佳（如未加热SPI，38.70%；酸热处理2~6 h，34.90%~36.50%；酸热处理12~20 h，17.50%~19.70%），但是酸热处理会导致乳滴粒度增大（如未加热SPI，24.63 μm；酸热处理SPI，28.12~33.97 μm）。增大乳液体系中的油含量也可以明显降低乳液的乳析率和粒度，随着油含量从20%增加到60%，乳析率从76.20%下降到3.30%，粒度从28.23 μm减小到19.06 μm。本研究结果为制备性质可控的双重乳液提供了新方法。

Abstract:

The present work found that at neutral pH, double emulsions could be simply fabricated with SPI preheated at acidic pH by one-step method. The effects of heating time on the solubility of SPI at pH 7.0 and the properties (e.g. cream rate, particle size) of double emulsions were further studied. The results showed that the acidic heating treatment decreased the solubility of SPI at pH 7.0 (native SPI, 78.60%; preheated SPI, 36.02%~53.39%), and the behavior was dependent on the heating time. This phenomenon may be related to the formation of insoluble protein fibrillar aggregates, which are mainly sustained by hydrogen bond and disulfide bond. The acidic heating treatment obviously improved the creaming stability of emulsions, and the longer heating time resulted in better effects (native SPI, 38.70%; SPI preheated with 2~6 h, 34.90%~36.50%; SPI preheated with 12~20 h, 17.50%~19.70%). However, the droplet size of emulsions became larger (native SPI, 24.63 μm; preheated SPI, 28.12~33.97 μm). In addition, an increase in the oil content also decreased the cream rate and droplet size. With the oil content increased from 20% to 60%, the cream rate decreased from 76.20% to 3.30%, and the droplet size decreased from 28.23 μm to 19.06 μm. The present work provides a new way to fabricate double emulsions with controllable properties.