Department of Food Quality and Safety, College of Food Science and Technology, Ocean University of China, Qingdao, Shandong 266100, China.
Key Laboratory of Dairy Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
J Agric Food Chem. 2022 Jun 22;70(24):7515-7524. doi: 10.1021/acs.jafc.2c01391. Epub 2022 Jun 10.
Proteins not only serve as a nitrogen source for microorganisms but are the main skeleton of kefir grains. After subculturing in goat milk for 4 months, proteins and peptides in three kefir grains from China, Germany, and the United States were analyzed. Except for the S-layer protein from special , α-casein, α-casein, and β-casein from goat milk were found in kefir grains. These proteins could form aggregates through a covalent interaction with polysaccharides to maintain the morphological stability of the grains. Furthermore, they were highly related to the microbiota in kefir grains. Additionally, a number of hydrophilic/hydrophobic peptides that were hydrolyzed by extracellular proteases were found from kefir grains. A correlation may exist between peptides and . in kefir grains. Bioactive peptides, including DKIHPF, LGPVRGPFP, and QEPVLGPVRGPFP, were found from these kefir grains. The results indicated that goat milk as a substrate affects the protein and peptide composition of kefir grains.
蛋白质不仅是微生物的氮源，也是克菲尔粒的主要骨架。经过 4 个月在山羊奶中的传代培养，分析了来自中国、德国和美国的 3 个克菲尔粒中的蛋白质和肽。除了特殊的 S-层蛋白外，克菲尔粒中还发现了来自羊奶的α-酪蛋白、α-酪蛋白和β-酪蛋白。这些蛋白质可以通过与多糖的共价相互作用形成聚集体，以维持颗粒的形态稳定性。此外，它们与克菲尔粒中的微生物群高度相关。此外，还从克菲尔粒中发现了大量由细胞外蛋白酶水解的亲水性/疏水性肽。肽和在克菲尔粒中可能存在相关性。从这些克菲尔粒中发现了生物活性肽，包括 DKIHPF、LGPVRGPFP 和 QEPVLGPVRGPFP。结果表明，山羊奶作为底物影响克菲尔粒的蛋白质和肽组成。
