Kamiński Stanisław, Cieślińska Anna
Department of Animal Genetics, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland.
Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland.
Int J Mol Sci. 2025 Sep 4;26(17):8612. doi: 10.3390/ijms26178612.
The A1 and A2 variants of bovine β-casein (CSN2) have gained attention in the dairy industry due to potential health effects. The A1 variant, prevalent in Holstein-Friesian cattle, is a major source of β-casomorphin-7 (BCM-7)-an opioid-like peptide released during digestion and associated with lower digestive comfort. In this study, β-casein A1 and A2 variants and BCM-7 levels were quantified in raw milk and three commonly consumed dairy products (pasteurized milk, UHT milk, and milk powder) using ELISA. The samples came from dairy plants within a single operating zone. The A1 variant was significantly more frequent (13.69-22.41 ng/mL) than the A2 variant (8.10-12.60 ng/mL), although the local Holstein cattle population had a higher frequency of the A2 allele (63%) than A1 (37%). This discrepancy could be due to a more efficient expression of the A1 allele in cows with heterozygous or A1A1 genotypes. BCM-7 levels were low and did not vary significantly with genotype or processing method. These results provide new insights into the composition of dairy products and contribute to the ongoing debate on the health implications and consumer acceptance of milk with the A1 β-casein variant.
由于潜在的健康影响，牛β-酪蛋白（CSN2）的A1和A2变体在乳制品行业受到关注。A1变体在荷斯坦-弗里生牛中普遍存在，是β-酪蛋白衍生七肽（BCM-7）的主要来源，BCM-7是一种在消化过程中释放的类阿片肽，与较低的消化舒适度有关。在本研究中，使用酶联免疫吸附测定法（ELISA）对生乳和三种常见消费乳制品（巴氏杀菌乳、超高温瞬时灭菌乳和奶粉）中的β-酪蛋白A1和A2变体以及BCM-7水平进行了定量。样品来自单个作业区内的乳制品厂。A1变体（13.69 - 22.41纳克/毫升）的出现频率明显高于A2变体（8.10 - 12.60纳克/毫升），尽管当地荷斯坦牛群中A2等位基因（63%）的频率高于A1（37%）。这种差异可能是由于A1等位基因在杂合子或A1A1基因型奶牛中表达更有效。BCM-7水平较低，并且不会因基因型或加工方法而有显著差异。这些结果为乳制品的成分提供了新的见解，并有助于正在进行的关于含有A1β-酪蛋白变体的牛奶对健康影响和消费者接受度的辩论。
