Lan Hong, Luo Xier, Xu Dingyun, Cui Kuiqing, Li Ling, Li Chuan, Qi Hao, Liu Qingyou
Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Animal Science and Technology, Foshan University, Foshan, China.
Guangxi Buffalo Research Institute, Chinese Academy of Agricultural Sciences, Nanning, China.
PLoS One. 2025 Sep 8;20(9):e0331277. doi: 10.1371/journal.pone.0331277. eCollection 2025.
Double-Layer Steamed Milk Custard (DLSMC) is a famous traditional Chinese dessert. This study aimed to analyze the flavor and the changes in metabolites during different stages of DLSMC preparation, including raw buffalo milk, thermo-processing, first and second-layer milk skin formation. Electronic nose and electronic tongue were employed to preliminarily assess the overall flavor characteristics between these stages. The results indicated that DLSMC demonstrated increased sweetness, saltiness, and umami compared to raw buffalo milk, along with heightened levels of nitrogen oxides, methane, alcohols, aldehydes, ketones, and sulfur-containing compounds. Thus, the thermo-processing and second-layer milk skin formation were pinpointed as critical for flavor alterations. Additionally, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) detected a total of 46 volatile organic compounds (VOCs), with 8 compounds identified as key flavor components. Untargeted metabolomics revealed 98 differential metabolites, including amino acids, lipids, and nucleotides, that were significantly linked to changes in key flavor compounds. Indeed, the fluctuations in the levels of amino acids, lipids, and nucleotides play a crucial role in influencing flavor changes during the production of DLSMC made from buffalo milk.
双层蒸奶冻（DLSMC）是一种著名的中国传统甜点。本研究旨在分析双层蒸奶冻制作不同阶段（包括生水牛奶、热处理、第一层和第二层奶皮形成）的风味及代谢物变化。采用电子鼻和电子舌初步评估这些阶段之间的整体风味特征。结果表明，与生水牛奶相比，双层蒸奶冻的甜度、咸度和鲜味增加，同时氮氧化物、甲烷、醇类、醛类、酮类和含硫化合物的含量升高。因此，热处理和第二层奶皮形成被确定为风味变化的关键因素。此外，顶空-气相色谱-离子迁移谱（HS-GC-IMS）共检测到46种挥发性有机化合物（VOC），其中8种化合物被确定为关键风味成分。非靶向代谢组学揭示了98种差异代谢物，包括氨基酸、脂质和核苷酸，它们与关键风味化合物的变化显著相关。事实上，氨基酸、脂质和核苷酸水平的波动在影响水牛奶制成的双层蒸奶冻生产过程中的风味变化方面起着关键作用。
