Fatty acid profile, conjugated linoleic acid (CLA) content, microbiological and sensory properties of kefir produced from sheep milk using kefir grains and starter culture in comparison with the respective kefir from cow milk

The present study aimed to reveal the detailed fatty acid profile, conjugated linoleic acid (CLA) levels, and microbiological and sensory properties of kefirs produced by grain or starter culture using sheep milk compared to cow milk. The use of different milk types, grains, or starter cultures significantly affected the results. Production with starter culture increased both lactococci and lactobacilli counts of kefirs compared to the production by grain while the highest counts of yeast were enumerated in the samples produced with grain (p < 0.05). Sheep milk kefir had a higher count of lactobacilli than cow milk kefir (p < 0.05). The levels of polyunsaturated fatty acids (PUFA), CLA and Omega-3 of sheep milk kefirs were higher than the cow milk kefirs (p < 0.05). In addition, the production of grain increased the PUFA value of cow milk kefir and the CLA content of both sheep and cow milk kefirs. The thrombogenic indices and the Omega-6/Omega-3 ratios of sheep milk kefirs were lower than those of cow milk throughout the storage (p < 0.05). The atherogenic indices of sheep milk kefirs were also found lower than the samples from cow milk until the middle of storage. Sensorially, cow milk kefirs had higher scores in terms of taste and overall acceptability, whereas sheep milk kefirs had better texture. Sheep milk improved the nutritional quality and health benefits of kefir by increasing the levels of PUFA, CLA and Omega-3. The use of grains also increased the levels of CLA, which has many health benefits, in both cow and sheep milk kefirs.