冷藏原料乳中微生物及品质的动态变化规律

Dynamic Changes of Microorganisms and Quality in Refrigerated Raw Milk

摘要:

该研究采用了三代16S rDNA高通量测序技术监测了低温贮藏期间（4 ℃，8 d）的原料乳微生物动态群落结构和丰度，结合数据库分析原料乳中微生物功能基因代谢途径。结果表明，原料乳在低温贮藏过程中，嗜冷菌逐渐成为优势菌，它们的主要代谢途径碳水化合物代谢、脂质代谢和氨基酸代谢等与原料乳的品质变化密切相关，氨基酸的合成和代谢以及脂肪转运代谢丰度提高最终导致乳品风味、质地、组织趋于劣变状态。冷藏过程中以嗜冷菌为主的优势微生物大量繁殖并产生的耐热酶，水解原料乳中的蛋白质和脂肪，引起牛奶品质劣变。

Abstract:

In this study, the dynamic community structure and abundance of microorganisms in raw milk during low temperature storage (4 ℃, 8 days) were monitored by third-generation 16s rDNA high-throughput sequencing technology, and the metabolic pathways of microbial functional genes in raw milk were analyzed in combination with the database. The results showed that during the low-temperature storage of raw milk, psychrophilic bacteria gradually became dominant bacteria, and their main metabolic pathways, such as carbohydrate metabolism, lipid metabolism and amino acid metabolism, were closely related to the quality changes of raw milk. The increases in the synthesis and metabolism of amino acids and fat transport metabolism eventually led to the deterioration of the flavor, texture and organization of dairy products. During the refrigeration process, the dominant microorganisms dominated by psychrophilic bacteria multiplied in large numbers and produce heat-resistant enzymes, which hydrolyze the protein and fat in the raw milk, causing the deterioration of milk quality.