Abstract：
Buttermilk, a potential material used to produce milk fat globule membrane (MFGM), is obtained as a byproduct of butter making from milk whole cream and cheese whey cream. This study investigated the effects of rennet and acid coagulation on the protein profiles of buttermilk rennet-coagulated whey (BRW) and buttermilk acid-coagulated whey (BAW). They were compared to those of whey cream buttermilk (WCB). Rennet coagulation was more efficient in removing casein, while retaining more IgG and lactoferrin than acid coagulation. BRW had more MFGM than BAW. Butyrophilin, xanthine dehydrogenase, and mucin1 were significantly higher (P < 0.05) in BRW, while fatty acid-binding protein 3 was enriched in BAW. KEGG analysis showed that complement and coagulation cascades had the greatest differences, and the abundance of proteins involved in this signaling pathway in BRW and BAW was higher, suggesting their potential anticoagulant and anti-inflammatory activity. BAW had higher apolipoprotein A4 and transcobalamin 2, which are essential carriers for transporting long-chain fatty acids and vitamin B12 from the intestine to the blood. Therefore, BAW intake might improve lipids and vitamin B12 absorption. This study can help deepen the understanding of protein composition of MFGM-enriched whey and facilitate the production of MFGM proteins for infants and old-aged populations.
摘要：
Buttermilk,一种用于生产乳脂球膜(MFGM)的潜在材料，是作为从牛奶全脂奶油和奶酪乳清奶油制作黄油的副产品获得的。这项研究调查了凝乳酶和酸凝固对酪乳凝乳酶凝固乳清（BRW）和酪乳酸凝固乳清（BAW）蛋白质谱的影响。将它们与乳清奶油酪乳（WCB）进行比较。凝乳酶凝固在去除酪蛋白方面更有效，同时保留比酸凝固更多的IgG和乳铁蛋白。BRW的MFGM比BAW多。丁基亲林,黄嘌呤脱氢酶,和粘蛋白1在BRW中显著升高(P<0.05),而脂肪酸结合蛋白3在BAW中富集。KEGG分析表明，补体和凝血级联具有最大的差异，BRW和BAW中参与该信号通路的蛋白质丰度更高，提示其潜在的抗凝血和抗炎活性。BAW具有较高的载脂蛋白A4和转钴胺素2，它们是将长链脂肪酸和维生素B12从肠道运输到血液的必需载体。因此,摄入BAW可能会改善脂质和维生素B12的吸收。这项研究可以帮助加深对富含MFGM的乳清蛋白组成的理解，并促进针对婴儿和老年人群的MFGM蛋白的生产。
