Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
J Dairy Sci. 2021 Feb;104(2):1424-1432. doi: 10.3168/jds.2020-19071. Epub 2020 Dec 11.
We studied the effects of seasonal variations on the quality of stirred yogurt, set yogurt, and Greek-style yogurt over 2 milking seasons in New Zealand. Correlations between the properties of the yogurts, the characteristics of the milk, and the acid gelation properties induced by glucono-δ-lactone, reported in our previous works, were also explored. Set yogurt and Greek-style yogurt from the early season had the highest firmness over the seasons. The yogurt firmness correlated with the gel strength of glucono-δ-lactone-induced acid gels, indicating that the latter could, to some extent, predict the seasonal variations in the firmness of set yogurt. The correlation studies highlighted the potentially important role of the glycosylation of κ-casein in the seasonal variations in the yogurt structures. Yogurt made from mid-season milk had the lowest water-holding capacity, which may have played a part in lowering its firmness and viscosity. Late-season stirred yogurt displayed the strongest resistance to shear-induced thinning, which might arise from the unique viscoelastic properties of late-season yogurt gels.
我们研究了季节变化对新西兰两个挤奶季节搅拌酸奶、凝固型酸奶和希腊式酸奶质量的影响。还探讨了之前研究中报告的酸奶特性、牛奶特性以及葡萄糖酸-δ-内酯诱导的酸凝胶形成之间的相关性。早季的凝固型酸奶和希腊式酸奶在整个季节中的硬度最高。酸奶的硬度与葡萄糖酸-δ-内酯诱导的酸凝胶的凝胶强度相关，表明后者在一定程度上可以预测凝固型酸奶的季节性变化。相关性研究突出了κ-酪蛋白糖基化在酸奶结构季节性变化中的潜在重要作用。从中季牛奶制成的酸奶的持水力最低，这可能在一定程度上降低了其硬度和黏度。晚季搅拌酸奶对剪切诱导变稀的抵抗力最强，这可能源于晚季酸奶凝胶的独特黏弹性。
