Xu Min, Li Jiayi, Wang Ying, Liu Jiamin, Liu Ping, Wang Qin, Che Zhenming
School of Food and Bioengineering Xihua University Chengdu China.
Department of Nutrition & Food science University of Maryland College Park Maryland USA.
Food Sci Nutr. 2022 Aug 7;10(12):4178-4188. doi: 10.1002/fsn3.3009. eCollection 2022 Dec.
The complex coacervation of soybean protein isolate and polysaccharide has been widely applied for preparing biopolymer materials like microcapsule. In this study, hydrolytic soy protein isolate (HSPI) was prepared by mild hydrolysis of soy protein isolate (SPI) with fungal protease 400 (F400). The degree of hydrolysis (DH) for the enzymatic products was controlled at 1%-5%. Emulsification, oxidation resistance, and thermal stability were used to evaluate the performances of HSPI with different DH. The results showed that the HSPI with the hydrolysis degree of 2% had the optimal property. Subsequently, the complex polymer of HSPI/SA was prepared by the coalescence reaction of HSPI and sodium alginate (SA). The turbidity curves manifested the optimal complex coacervation occurred at the ratio of 7:1 (HSPI:SA). Fourier transform infrared spectroscopy (FTIR) presented that the reaction involved electrostatic interactions between -NH in HSPI and -COO in SA. Isothermal titration calorimetry experiments indicated that the complex coacervation reactions of HSPI and SA arose spontaneously. The microencapsulation by complex coacervation of HSPI and SA was further produced for embedding sweet orange oil. The thermogravimetric analysis (TGA) result revealed that the microencapsulation system of HSPI/SA had a better heat resistance than that using the SPI/SA complex polymer.
大豆分离蛋白与多糖的复合凝聚已被广泛应用于制备微胶囊等生物高分子材料。在本研究中，通过用真菌蛋白酶400（F400）对大豆分离蛋白（SPI）进行温和水解制备了水解大豆分离蛋白（HSPI）。酶解产物的水解度（DH）控制在1%-5%。采用乳化性、抗氧化性和热稳定性来评价不同DH的HSPI的性能。结果表明，水解度为2%的HSPI具有最佳性能。随后，通过HSPI与海藻酸钠（SA）的凝聚反应制备了HSPI/SA复合聚合物。浊度曲线表明，在7:1（HSPI:SA）的比例下发生了最佳的复合凝聚。傅里叶变换红外光谱（FTIR）表明，该反应涉及HSPI中的-NH与SA中的-COO之间的静电相互作用。等温滴定量热实验表明，HSPI和SA的复合凝聚反应是自发产生的。进一步通过HSPI和SA的复合凝聚进行微胶囊化以包埋甜橙油。热重分析（TGA）结果表明，HSPI/SA微胶囊体系比使用SPI/SA复合聚合物的体系具有更好的耐热性。
