Rehman Hameedur, Saipriya Kanchanpally, Singh Ashish Kumar, Singh Richa, Meena Ganga Sahay, Khetra Yogesh, Sharma Heena
Dairy Technology Division, ICAR-National Dairy Research Institute, Karnal 132001, Haryana, India.
Dairy Chemistry Division, ICAR-National Dairy Research Institute, Karnal 132001, Haryana, India.
Foods. 2024 Mar 17;13(6):913. doi: 10.3390/foods13060913.
Goat milk has poorer fermentation characteristics due to the absence or only traces of αs1-casein, due to which goat yoghurt contains a less dense gel structure. Moreover, the fermentation characteristics of the milk vary between the breeds of the same species. Therefore, it becomes imperative to explore a few metabolites which could regulate the techno-functional properties of goat yoghurt.
This study was aimed at relating the metabolite profile of yoghurt prepared from milk of , an indigenous goat breed of India, and its techno-functional properties (firmness, whey syneresis, and flow behaviour) using multivariate data analysis and regression models.
Goat yoghurt was prepared with two different total solids (TS) levels (12 and 16%) and cultures, namely, commercial culture comprising a thermophilic yoghurt culture (A) and NCDC-263 comprising a mixed yoghurt culture (B). Results demonstrated a significant difference ( < 0.05) in whey syneresis with the increase in the TS level. Flow behaviour of all yoghurt samples showed a decrease in viscosity with an increase in shear rate, which confirmed its non-Newtonian behaviour and shear thinning nature, whereas frequency sweep confirmed its viscoelastic nature. Firmness was the most affected under the influence of different TS and culture levels. It was higher ( < 0.05) for 16-A, followed by 16-3B, and minimum for 12-2B. GC-MS-based metabolomics of the yoghurt revealed a total of 102 metabolites, out of which 15 metabolites were differentially expressed ( < 0.05), including 2-hydroxyethyl palmitate, alpha-mannobiose, and myo-inositol. Multivariate data analysis revealed clear separation among groups using principal component analysis and several correlations using a correlation heat map. Further, regression analysis exhibited methylamine (0.669) and myo-inositol (0.947) with higher regression coefficients (R values) exceeding 0.6, thus demonstrating their significant influence on the techno-functional properties, mainly firmness, of the yogurt.
In conclusion, A gas chromatography-based metabolomics approach could successfully establish a relationship between the metabolome and the techno-functional properties of the yoghurt.
由于缺乏或仅含有微量的αs1-酪蛋白，山羊奶具有较差的发酵特性，这导致山羊酸奶的凝胶结构较疏松。此外，同一物种不同品种的奶的发酵特性也有所不同。因此，探索一些能够调节山羊酸奶工艺功能特性的代谢产物变得势在必行。
本研究旨在利用多变量数据分析和回归模型，研究印度本土山羊品种的奶制成的酸奶的代谢产物谱及其工艺功能特性（硬度、乳清脱水收缩和流动行为）之间的关系。
制备了两种不同总固形物（TS）水平（12%和16%）的山羊酸奶，并使用了两种培养物，即包含嗜热酸奶培养物的商业培养物（A）和包含混合酸奶培养物的NCDC-263（B）。结果表明，随着TS水平的增加，乳清脱水收缩存在显著差异（P<0.05）。所有酸奶样品的流动行为均显示，随着剪切速率的增加，粘度降低，这证实了其非牛顿行为和剪切变稀特性，而频率扫描证实了其粘弹性特性。在不同TS和培养水平的影响下，硬度受到的影响最大。16-A的硬度较高（P<0.05），其次是16-3B，12-2B的硬度最低。基于气相色谱-质谱联用的酸奶代谢组学分析共鉴定出102种代谢产物，其中15种代谢产物差异表达（P<0.05），包括棕榈酸2-羟乙酯、α-甘露二糖和肌醇。多变量数据分析通过主成分分析显示了各组之间的明显分离，并通过相关热图显示了几种相关性。此外，回归分析显示甲胺（0.669）和肌醇（0.947）的回归系数（R值）较高，超过0.6，从而表明它们对酸奶的工艺功能特性（主要是硬度）有显著影响。
总之，基于气相色谱的代谢组学方法能够成功建立酸奶代谢组与工艺功能特性之间的关系。
