Zhang Weibo, Chen Chong, Wang Pengjie, Xu Jingni, Zhang Feng, Wang Jing, Zhu Yinhua, Luo Jie, Zhao Liang, Ren Fazheng
Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China.
Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, Department of Nutrition and Health, China Agricultural University, Beijing 100190, China; Food Laboratory of Zhongyuan, Luohe 462000, China.
Carbohydr Polym. 2025 Feb 1;349(Pt B):123012. doi: 10.1016/j.carbpol.2024.123012. Epub 2024 Nov 15.
Low-acyl gellan gum (LA) is a typical cold- and Ca-set gelation polysaccharide and is widely used to improve the stability of yoghurt. Acid and endogenous calcium can induce the formation of skimmed milk (SM)/LA double gels. However, the effect of acidification temperature on the formation and physical properties of SM/LA double gels has not been elucidated. In this study, temperature above and below the LA transition temperature (38 °C) were used as acidification temperatures, which adjusted the gelation sequence of SM and LA. The LA gel prior to the SM gel formed at acidification temperature of 37 °C, exhibiting the highest WHC and G' among all samples. Moreover, SM/LA-37 double gels showed two networks: one was a porous network and the other was a dense network. By contrast, SM/LA mixtures acidified at 42 °C formed double networks during the cooling stage, and the previously formed SM gel hindered the formation of the LA gel. Consequently, SM/LA-42 double gels showed lower WHC and G' compared with SM/LA-37 double gels. Overall, gelation sequence substantially affected the physical properties of SM/LA double gels. Our findings provide basis for adopting optimal methods to improve yoghurt quality and revealing the gelation mechanism involved in SM/LA double gels.
低酰基结冷胶（LA）是一种典型的冷致和钙致凝胶多糖，被广泛用于提高酸奶的稳定性。酸和内源性钙可诱导脱脂乳（SM）/LA双凝胶的形成。然而，酸化温度对SM/LA双凝胶形成及物理性质的影响尚未阐明。在本研究中，将高于和低于LA转变温度（38℃）的温度用作酸化温度，以此调节SM和LA的凝胶化顺序。在37℃酸化温度下形成的LA凝胶先于SM凝胶，在所有样品中表现出最高的持水力（WHC）和储能模量（G'）。此外，SM/LA - 37双凝胶呈现出两种网络结构：一种是多孔网络，另一种是致密网络。相比之下，在42℃酸化的SM/LA混合物在冷却阶段形成双网络结构，且先前形成的SM凝胶阻碍了LA凝胶的形成。因此，与SM/LA - 37双凝胶相比，SM/LA - 42双凝胶的WHC和G'较低。总体而言，凝胶化顺序对SM/LA双凝胶的物理性质有显著影响。我们的研究结果为采用优化方法改善酸奶品质以及揭示SM/LA双凝胶的凝胶化机制提供了依据。
