热处理与离子强度对肌原纤维蛋白溶液与乳液稳定性的比较

Effect of Ionic Strength and Heat Treatment on the Stability of Myofibrillar Protein Solutions and Emulsions

摘要:

为制备稳定的肌原纤维蛋白乳液，该研究探讨了在加热条件下不同的离子强度对肌原纤维蛋白溶液及乳液的影响。研究离子强度（NaCl浓度分别为0.1、0.3、0.6 mol/L）与热处理（85 ℃，10 min）对大豆油-肌原纤维蛋白溶液及乳液的蛋白组成、粒径分布、Zeta电位、粘度、SEM、显微结构等影响。结果表明，加热导致肌原纤维蛋白发生聚集，粒径增大，当离子强度为0.1 mol/L时，热处理后溶液粒径从32 nm最大增加到4 043 nm；而乳液粒径从最大768 nm减小至79 nm，肌原纤维蛋白乳液的稳定性增强。随着离子强度的增加，肌原纤维蛋白溶液表观粘度下降，Zeta绝对值由7.47 mV下降至6.72 mV，经热处理后，Zeta绝对值增大；乳液的Zeta电位经加热后，绝对值减小；加热使得肌原纤维蛋白乳液液滴数增加，且液滴更小，分散性增强，乳化活性提高，肌原纤维蛋白乳液稳定性增加。综上所述，在离子强度为0.6 mol/L时，经热处理的肌原纤维蛋白乳液稳定性最佳。该研究为稳定肌原纤维蛋白乳液的制备提供一定参考。

Abstract:

The stability of myofibrillar protein solutions and emulsions is affected by ionic strength and heat treatment. To prepare stable myofibrillar protein emulsions, soybean oil-myofibrillar protein solutions and emulsions were prepared to investigate the effect of ionic strength (sodium chloride concentrations: 0.1, 0.3, 0.6 mol/L) and heat treatment (85 ℃, 10 min) on protein composition, particle size distribution, zeta potential, viscosity, and microstructure (as revealed by scanning electron microscopy and optical microscopy). The results showed that the particle size of myofibrillar protein increased with heating owing to aggregation. In heat-treated solutions and emulsions prepared from 0.1 mol/L sodium chloride, the particle size increased from 32 nm to 4 043 nm (in solution), whereas the particle size decreased from 768 nm to 79 nm (in emulsion), indicating an improved stability of myofibrillar protein emulsions. Myofibrillar protein solutions experienced a decrease in apparent viscosity and the absolute value of the zeta potential (from 7.47 mV to 6.72 mV) with increasing ionic strength; however, after heating, the absolute value of the zeta potential increased. In contrast, the absolute value of the zeta potential of emulsions decreased after heating. Heating increased the number of droplets in myofibrillar protein emulsions while reducing droplet size, thus enhancing the dispersity and emulsification activity of droplets and improving the stability of myofibrillar protein emulsions. In conclusion, an ionic strength of 0.6 mol/L, together with heat treatment, resulted in the most stable myofibrillar protein emulsion. This study serves as a reference for the preparation of stable myofibrillar protein emulsions.