Kefir is a type of fermented milk obtained thanks to the introduction of “kefir grains” in mammalian milk. Kefir grains consist of lactic and acetic acid bacteria and yeasts in alternative proportions that are held together by a matrix of complex sugars known as “kefiran.” Thanks to the fermentative process, the kefir milk is rich in nutraceutical substances such as amino acids, vitamins, and mineral salts. The most valuable compounds of kefir fermentation are mainly lactic acid, exopolysaccharides, and bioactive peptides, the resulting products of proteolytic release from milk proteins (caseins and whey proteins). Among the nutraceutical properties of kefir are antimicrobial and antitumor activity, immunomodulating effect, and cholesterol‐lowering effect. Therefore, in light of these intriguing properties of kefir milk, in this work, a proteomic analysis, by two‐dimensional electrophoresis followed by mass spectrometry, has been performed. As a result, milk‐derived polypeptides were identified in commercial kefir milk from organic farming. In particular, polypeptides deriving from κ‐, α_s1‐, and α_s2‐caseins that may have potentially beneficial effects on human health have been detected.

中文翻译：

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通过二维电泳和质谱法对开菲尔牛奶进行蛋白质组学表征。

开菲尔是一种发酵乳，由于在哺乳动物乳中引入了“开菲尔谷物”。开菲尔谷物由不同比例的乳酸菌和醋酸菌以及酵母组成，它们由称为“开菲尔”的复合糖基质结合在一起。由于发酵过程，开菲尔牛奶富含营养物质，如氨基酸、维生素和矿物盐。开菲尔发酵最有价值的化合物主要是乳酸、胞外多糖和生物活性肽，它们是牛奶蛋白（酪蛋白和乳清蛋白）蛋白水解释放的产物。开菲尔的营养特性包括抗菌和抗肿瘤活性、免疫调节作用和降低胆固醇作用。因此，鉴于开菲尔牛奶的这些有趣特性，在这项工作中，通过二维电泳和质谱分析进行了蛋白质组学分析。结果，在来自有机农业的商业开菲尔牛奶中发现了牛奶衍生的多肽。特别地，衍生自κ-、α的多肽_S1 -和α _S2 -caseins可能对人类健康造成潜在有益效果进行了检测。