Kefir Grains Change Fatty Acid Profile of Milk during Fermentation and Storage

Abstract

Several studies have reported that lactic acid bacteria may increase the production of free fatty acids by lipolysis of milk fat, though no studies have been found in the literature showing the effect of kefir grains on the composition of fatty acids in milk. In this study the influence of kefir grains from different origins [Rio de Janeiro (AR), Viçosa (AV) e Lavras (AD)], different time of storage, and different fat content on the fatty acid content of cow milk after fermentation was investigated. Fatty acid composition was determined by gas chromatography. Values were considered significantly different when p<0.05. The highest palmitic acid content, which is antimutagenic compost, was seen in AV grain (36.6g/100g fatty acids), which may have contributed to increasing the antimutagenic potential in fermented milk. Higher monounsaturated fatty acid (25.8g/100g fatty acids) and lower saturated fatty acid (72.7g/100g fatty acids) contents were observed in AV, when compared to other grains, due to higher Δ9-desaturase activity (0.31) that improves the nutritional quality of lipids. Higher oleic acid (25.0g/100g fatty acids) and monounsaturated fatty acid (28.2g/100g fatty acids) and lower saturated fatty acid (67.2g/100g fatty acids) contents were found in stored kefir relatively to fermented kefir leading to possible increase of antimutagenic and anticarcinogenic potential and improvement of nutritional quality of lipids in storage milk. Only high-lipidic matrix displayed increase polyunsaturated fatty acids after fermentation. These findings open up new areas of study related to optimizing desaturase activity during fermentation in order to obtaining a fermented product with higher nutritional lipid quality.

Chemical, Microbiological, and Functional Characterization of Kefir Produced from Cow’s Milk and Soy Milk

“…e different behaviour of citric acid levels in cow's milk and soy milk kefir (Table 4) indicated that the microbiota can influence the organic acid balance resulting in organoleptic and antimicrobial characteristics of kefirs [2,13]. Similar results for organic acid content have been reported for cow's milk kefir [13,25,26] and soy milk kefir [27,28]. e total free amino acid concentration for cow's milk kefir differs between the reports.…”

Effect of dietary kefir on the growth performance, feed utilization and fatty acid profile of juvenile rainbow trout,Oncorhynchus mykiss

“…According to Vieira et al. (), higher oleic acid and MUFA were determined to fermented kefir, whereas lower SFA contents were found. They also displayed increase in PUFA after fermentation.…”

Dairy Fats and Cardiovascular Disease: Do We Really Need to Be Concerned?

“…The aforementioned kefir grains are microbially derived protein and polysaccharide matrices that contain a community of bacterial and fungal species that are essential to kefir fermentation [ 260 ]. When fermenting, lactic acid, bioactive peptides, exopolysaccharides, antibiotics and bacteriocins are produced [ 225 , 261 ] and the fatty acid composition is altered [ 262 ]. The microorganisms in kefir have probiotic potential and may have a positive impact on gut health.…”