Comparative study of the aroma profiles and chemical and microbiological properties of bovine kefir enriched with lyophilized colostrum of different milk kinds.

In this study, the effects of lyophilized colostrum powders (1%; cow, buffalo, sheep, and goat) on the aroma profiles and physicochemical and microbiological properties of kefir were investigated. The colostrum supplement maintained pH stability and improved water holding capacity and synergy. This also limited the decline in color parameters. According to the microbiological results, Lactococci counts (7.96-8.63 log CFU/mL) remained stable throughout storage. Lactobacilli counts markedly decreased in the control group, whereas all colostrum-supplemented samples maintained values above 7 log CFU/mL. A total of 34 aroma compounds were identified in the produced kefir samples, and their distribution significantly differed depending on the animal from which the colostrum was obtained (p < 0.05). The basic aroma classes included alcohols, ketones, acids, and aldehydes. The richest aroma profiles were found in kefir enriched with sheep, cow, goat, and buffalo colostrum, respectively. Acids (acetic, butanoic, and hexanoic acids) were the most prevalent compound group in all the samples. More alcohol varieties were detected in kefir made with sheep and cow colostrum. In conclusion, adding 1% colostrum powder from various animal species has a positive effect on the physical stability and microbial balance of kefir.