Wang Diandian, Zhou Yaxi, Zhao Jian, Guo Yu, Yan Wenjie
College of Biochemical Engineering, Beijing Union University, Beijing 100023, China.
Beijing Key Laboratory of Bioactive Substances and Functional Food, Beijing Union University, Beijing 100023, China.
Foods. 2025 Jan 1;14(1):91. doi: 10.3390/foods14010091.
The aroma of yak milk powder is a crucial sensory indicator for evaluating its quality and flavor. Yak milk powders collected from different lactation periods exhibit distinct flavors, but no studies have thoroughly investigated the aroma characteristics and variation patterns of yak milk powders across these periods. This study identified and analyzed the volatile compounds in freeze-dried colostrum powder (YCSP), freeze-dried mature milk powder (YMMP), and freeze-dried ending milk powder (YEMP) using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and multivariate statistical analysis. A total of 48 volatile compounds were identified, with significant differences in the types and contents of these compounds across the three samples. Compared to YCSP and YEMP, YMMP contained higher levels of acids and esters, while the levels of alkanes and alcohols were lower. Principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and hierarchical clustering heatmap analysis revealed a high degree of differentiation and notable variation in volatile compounds between the samples from different lactation periods. Key compounds such as aldehydes, alcohols, and esters were found to distinguish the lactation stages, with certain compounds more prevalent in colostrum and others in mature and ending milk. These findings suggest that the methodologies employed-HS-SPME-GC-MS combined with multivariate analysis-can effectively distinguish flavor differences among yak milk powders from different lactation periods. This approach allows for the rapid and comprehensive analysis of volatile components in milk powders, aiding in the identification of collection periods and providing valuable insights for improving the flavor quality of dairy products. Furthermore, the results can benefit the dairy industry by enhancing product development, quality control, and flavor profiling of milk-based products across different stages of lactation.
牦牛奶粉的香气是评估其品质和风味的关键感官指标。从不同泌乳期采集的牦牛奶粉呈现出不同的风味，但尚无研究全面探究这些时期牦牛奶粉的香气特征及变化规律。本研究采用顶空固相微萃取结合气相色谱 - 质谱联用技术（HS - SPME - GC - MS）以及多元统计分析方法，对冻干初乳粉（YCSP）、冻干成熟乳粉（YMMP）和冻干末乳粉（YEMP）中的挥发性化合物进行了鉴定和分析。共鉴定出48种挥发性化合物，这三种样品中这些化合物的种类和含量存在显著差异。与YCSP和YEMP相比，YMMP中酸和酯的含量较高，而烷烃和醇的含量较低。主成分分析（PCA）、正交偏最小二乘法判别分析（OPLS - DA）和层次聚类热图分析表明，不同泌乳期样品之间挥发性化合物存在高度分化和显著差异。发现醛、醇和酯等关键化合物可区分泌乳阶段，某些化合物在初乳中更普遍，而其他化合物在成熟乳和末乳中更普遍。这些研究结果表明，所采用的方法——HS - SPME - GC - MS结合多元分析——能够有效区分不同泌乳期牦牛奶粉的风味差异。这种方法能够快速、全面地分析奶粉中的挥发性成分，有助于确定采集时期，并为改善乳制品的风味品质提供有价值的见解。此外，研究结果可通过加强乳制品在不同泌乳阶段的产品开发、质量控制和风味剖析，使乳制品行业受益。
