Department of Food Engineering, Süleyman Demirel University, Isparta, Turkey.
J Appl Microbiol. 2022 Jun;132(6):4349-4358. doi: 10.1111/jam.15532. Epub 2022 Mar 23.
Although kefir has been known for centuries, there is confusion between the two types of kefir grains, for example, milk kefir (MK) grain and water kefir (WK) grain. This study aimed to unravel the differences and similarities between WK grain and MK grain.
Microbiological analyses, identification of grains microbiota and enumeration of microbiological content of the grains as well as scanning electron microscope (SEM) imaging, dry matter, protein, ash, and mineral content, and colour analyses were carried out for the two types of grains. As a result, significant differences were found in microbiological content, chemical properties and colours (p < 0.05). Additionally, SEM images revealed the different intrinsic structures for the microbiota and the structure of the two types of grains.
MK grain has more nutritional content compared to WK grain. Despite not as widely known and used as MK grain, WK grain is a good source for minerals and health-friendly micro-organisms such as lactic acid bacteria and yeasts. WK grain is possibly suitable for vegans and allergic individuals to fulfil nutritional requirements. Moreover, in this study, the variety of WK grain microbial consortia was wider than that of MK grains, and this significantly affected the resultant WK products.
This is the first study that comprehensively compares two different kefir grains in microbial, chemical and physical properties.
尽管克菲尔（kefir）已经存在了几个世纪，但人们对两种克菲尔谷物（即牛奶克菲尔（MK）谷物和水克菲尔（WK）谷物）之间存在混淆。本研究旨在揭示 WK 谷物和 MK 谷物之间的异同。
对两种谷物进行了微生物分析、谷物微生物群落鉴定和微生物含量计数以及扫描电子显微镜（SEM）成像、干物质、蛋白质、灰分和矿物质含量以及颜色分析。结果发现，两种谷物的微生物含量、化学性质和颜色存在显著差异（p<0.05）。此外，SEM 图像揭示了两种谷物的微生物群落和结构的不同内在结构。
与 WK 谷物相比，MK 谷物具有更多的营养成分。尽管 WK 谷物不如 MK 谷物广为人知和使用，但它是矿物质和对健康有益的微生物（如乳酸菌和酵母）的良好来源。WK 谷物可能适合素食者和对某些物质过敏的人来满足营养需求。此外，在这项研究中，WK 谷物微生物群落的多样性比 MK 谷物更广泛，这显著影响了最终的 WK 产品。
这是首次全面比较两种不同克菲尔谷物在微生物、化学和物理性质方面的研究。
