Effects of fat level, prebiotics, and production methods on the quality and shelf life of synbiotic kefir from Buffalo milk

Kefir is a traditional and functional dairy product that is widely consumed around the world. The aim of this research is to produce synbiotic kefir to enhance the functional properties and storage stability. In this study, the effect of fat level (0.5%, 3.5%), prebiotics (galacto-oligosaccharides (GOS), inulin), production method (traditional, commercial), and storage period (21 days at 3 ± 1 °C) on the quality characteristics of synbiotic kefir produced from buffalo milk was investigated. Significant effects (<i>P</i> < .01) of production method, fat level, prebiotics, and storage period on the protein, pH, and total solids of kefir samples were observed, with the total solids content being higher in kefirs produced with 3.5% fat, the traditional method, and the addition of GOS compared to other samples (<i>P</i> < .05). The pH value increased in parallel with the increase in fat level (<i>P</i> < .05), and higher values (<i>P</i> < .05) were recorded in kefirs produced using GOS and commercial cultures. During storage, pH, protein, and total solids decreased (<i>P</i> < .05), while total titratable acidity and water activity values increased (<i>P</i> < .05). Higher lactic cocci and lactic bacilli counts were obtained in kefirs produced with commercial cultures compared to traditional methods (<i>P</i> < .05). Yeast counts were affected by all treatments (<i>P</i> < .01), with the lowest values found in samples containing 3.5% fat, commercial cultures, and inulin (<i>P</i> < .05). The <i>Enterobacteriaceae</i> count was below the detectable limit (<1 log cfu/ml) in all samples. The sensory properties of the kefir samples were influenced by the treatments, with the kefir samples produced using 3.5% fat, GOS addition, and traditional methods being more acceptable in terms of overall acceptability (<i>P</i> < .05).