Wang Xinlu, Kong Xiangzhen, Zhang Caimeng, Hua Yufei, Chen Yeming, Li Xingfei
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, PR China; School of Food Science and Technology, Jiangnan University, Wuxi, PR China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, PR China; School of Food Science and Technology, Jiangnan University, Wuxi, PR China.
Food Res Int. 2023 Feb;164:112375. doi: 10.1016/j.foodres.2022.112375. Epub 2022 Dec 28.
The aim of this study was to investigate and compare the physicochemical characteristics and volatile flavor compounds of three kinds of yoghurt made from reconstituted milk, soy drink and oat drink. The results showed that with the same fermentation ending pH of 4.5, reconstituted yoghurt had the highest titratable acidity mainly due to the highest buffering capacity and microbial counts (LAB). The textural and water holding capacity (WHC) parameters revealed that soy-based yoghurt had the highest firmness, consistency and WHC, indicating more rigid gel was formed. Meanwhile, rheological analysis showed soy-based yoghurt owned higher G' and G'' values and higher stability against external stress, demonstrating that more and stronger interactions between soy proteins were built during fermentation. The confocal laser scanning microscopy (CLSM) image witnessed that soy-based yoghurt had the densest and finest network, while oat-based yoghurt had much coarser and looser structure, which was consistent with the lowest firmness and G' value for oat-based yoghurt. In terms of color, reconstituted yoghurt was the lightest and oat-based yoghurt showed more reddish and yellowish. The main volatile flavor compounds in all yoghurts were ketones, while aldehydes contributed more in soy and oat yoghurt. PCA plot showed that volatile flavor compounds of reconstituted yoghurt and oat-based yoghurt were relatively similar, while soy-based yoghurt was much more different with high OAVs of hexanal, 1-octen-3-one, 1-octen-3-ol and 2-octenal. This study supplied a theoretical basis and an improvement direction for the better development of healthier plant-based yoghurt similar to dairy yoghurt.
本研究旨在调查和比较由复原乳、豆奶和燕麦奶制成的三种酸奶的理化特性和挥发性风味化合物。结果表明，在相同的发酵终点pH值为4.5时，复原酸奶的可滴定酸度最高，这主要归因于其最高的缓冲能力和微生物计数（乳酸菌）。质地和持水能力（WHC）参数显示，豆奶基酸奶具有最高的硬度、稠度和WHC，表明形成了更坚硬的凝胶。同时，流变学分析表明，豆奶基酸奶具有更高的G'和G''值以及更高的抗外部应力稳定性，这表明在发酵过程中大豆蛋白之间建立了更多更强的相互作用。共聚焦激光扫描显微镜（CLSM）图像显示，豆奶基酸奶具有最致密和最精细的网络，而燕麦基酸奶的结构则更粗糙和松散，这与燕麦基酸奶的最低硬度和G'值一致。在颜色方面，复原酸奶最浅，燕麦基酸奶则更偏红和偏黄。所有酸奶中的主要挥发性风味化合物为酮类，而醛类在豆奶和燕麦酸奶中贡献更多。主成分分析（PCA）图显示，复原酸奶和燕麦基酸奶的挥发性风味化合物相对相似，而豆奶基酸奶则有很大不同，己醛、1-辛烯-3-酮、1-辛烯-3-醇和2-辛烯醛的气味活度值（OAVs）较高。本研究为更好地开发类似于乳制品酸奶的更健康植物基酸奶提供了理论依据和改进方向。
