Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang 310058, China; Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing, Zhejiang 314100, China.
Food Res Int. 2023 Dec;174(Pt 1):113489. doi: 10.1016/j.foodres.2023.113489. Epub 2023 Sep 28.
Soy protein isolate (SPI) has become a promising plant-based material as an animal protein products alternative. However, its application was limited due to the weak gelling properties. To investigate the effect of kefir fermentation on SPI gels properties, SPI-polysaccharide gels was produced by unfermented and kefir-fermented SPI using different concentration of KGM, chitosan, and calcium chloride in this study. Characterization of fermented SPI gels showed that fermentation by kefir grains can be applied to improve the textural strength, mechanical structure, and thermal characteristics of SPI gels. Compared to unfermented SPI gels, the water-holding capacity was remarkably enhanced to 63.11% and 65.71% in fermented SPI-chitosan gels. Moreover, the hardness of fermented SPI-KGM gels were significantly increased to 13.43 g and 27.11 g. And the cohesiveness and resilience of fermented-KGM gels were also improved than unfermented samples. Results of rheological characterization and thermogravimetric analysis revealed the strengthened mechanical features and higher thermal stability of fermented SPI gels. Additionally, the main role of hydrophobic interactions and secondary structure variations of SPI gels were demonstrated by intermolecular force measurements, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the network structure was observed more compact and homogeneous performed by microstructural images in fermented SPI gels. Therefore, this research provided a novel approach combining multi-species fermentation with protein gelation to prepare SPI gel materials with improved nutrition and structural properties.
大豆分离蛋白（SPI）作为动物蛋白产品的替代品，已成为一种很有前途的植物基材料。然而，由于其凝胶性能较弱，其应用受到限制。为了研究克菲尔发酵对 SPI 凝胶特性的影响，本研究采用未发酵和克菲尔发酵的 SPI，用不同浓度的 KGM、壳聚糖和氯化钙制备 SPI-多糖凝胶。发酵 SPI 凝胶的特性表明，克菲尔发酵可以应用于改善 SPI 凝胶的质构强度、机械结构和热特性。与未发酵的 SPI 凝胶相比，发酵 SPI-壳聚糖凝胶的持水能力显著提高到 63.11%和 65.71%。此外，发酵 SPI-KGM 凝胶的硬度分别显著增加到 13.43 g 和 27.11 g。发酵-KGM 凝胶的粘性和弹性也比未发酵样品有所提高。流变特性和热重分析的结果表明，发酵 SPI 凝胶的机械性能得到了增强，热稳定性更高。此外，通过分子间力测量、傅里叶变换红外光谱和 X 射线衍射证实了 SPI 凝胶的疏水性相互作用和二级结构变化的主要作用。此外，发酵 SPI 凝胶的网络结构观察到更紧凑和均匀，这是由微观结构图像表现出来的。因此，本研究提供了一种将多物种发酵与蛋白质凝胶相结合的新方法，用于制备具有改善的营养和结构特性的 SPI 凝胶材料。
