牛、羊乳酸乳发酵过程中质构学特性的变化规律

Changes of the Textural Characteristics of Yoghurt Made from Cow Milk and Goat Milk during Fermentation

探讨牛、羊乳酸乳发酵过程中质构学特性的变化规律,比较其差异性,为控制酸乳加工过程,提高酸乳质量提供参考依据。对凝固型和搅拌型牛、羊乳原味酸乳质构学特性采用TA.XTplus32物性测试仪进行分析比较,选用合适探头与检测程序,量化比较牛、羊酸乳随发酵时间变化的硬度、稠度、黏聚性、黏性指数等物性指标。结果表明:凝固型牛、羊乳酸乳比较,前发酵阶段牛酸乳4项物性指标均大于羊酸乳;随着发酵时间的延长,后发酵阶段亦表现出同样的规律,且各指标间差异显著(P<0.05);搅拌型牛、羊乳酸乳比较,牛酸乳4项物性指标均小于羊酸乳,各指标间无显著差异(P>0.05)。说明在发酵过程中,凝固型牛酸乳的质构指标大于羊酸乳,而搅拌型羊酸乳的质构指标大于牛酸乳。

The changes of the textural properties of yoghurt produced from cow or goat milk during fermentation were investigated comparatively. A texture analyzer （TA. XT plus, with Texture Exponent 32 software） was utilized for comparative analysis of texture properties of set yoghurt and stirred yoghurt samples produced from cow and goat milk. The right back extrusion probe and testing procedure were selected to quantify firmness, consistency, cohesiveness and viscosity during milk fermentation. The results showed that during the per-fermentation period, all these four texture properties exhibited a higher level in set cow yoghurt than set goat yoghurt, and the same results were observed during the post-fermentation period; moreover, significant differences in each texture parameter were observed between both samples （P 〈 0.05）. The texture parameters of stirred cow yoghurt were lower than those of stirred goat yoghurt, but these differences were not significant （P 〉 0.05）. In summary, the texture properties of set cow yogurt are higher than those of set goat yoghurt, while there is an improvement in texture properties of stirred goat yoghurt compared to stirred cow yoghurt.