Determination of chemical and microbiological properties of coffee infused kefir

Nutrition has a significant effect on the regulation of the microbiota in the gastrointestinal tract in favor of probiotics. Kefir is a functional food that has antioxidant, antihypertensive, anti-inflammatory, antitumoral, antidiabetic, antiallergic, anti-obesity effects. A long with this, it strengthens the immune system, regulates the gastrointestinal system, helps reduce serum cholesterol levels, lactose intolerance symptoms, and diarrhea. Coffee on the other hand, is effective in reducing the risks of some chronic diseases by promoting the development of probiotics in the colon thanks to the bioactive components, such as polyphenols. In this study, control kefir (K) was produced by adding the traditional kefir grain 3% (m/v) to UHT cow's milk, pre-fermentation kefir (FÖK) was produced by adding 0.5% (m/v) instant coffee and after-fermentation kefir (FSK) was produced by adding 0.5% instant coffee to matured kefir at 4±1 oC for 24 hours. K, FÖK and FSK kefir samples were stored at 4±1 oC for 21 days. Some chemical (total dry matter, fat and ash content, titratable acidity and pH value), microbiological (TMAB, Lactobacillus spp., mesophilic lactic cocci and yeast count) and sensory properties of kefir samples (appearance and texture, odour, taste and overall acceptability) were examined on the 1st, 7th, and 14th days of storage. After storage, Lactobacillus spp. (8.5 log cfu/g), the mesophilic lactic cocci (8.5 log cfu/g) and yeast count (5.9 log cfu/g) indicated that coffee adapts well to kefir samples. In addition, it has been determined that the use of coffee in kefir production does not have a negative effect on the chemical properties of kefir. The effect of add coffee to kefir at different stages of fermentation on the chemical, microbiological and sensory properties of kefir was evaluated for the first time. According to the sensory evaluation result; FÖK kefir was preferred more in terms of appearance, texture, and odor characteristics, whereas FSK kefir was more appreciated in terms of taste and overall acceptability (p<0,05). More studies are needed on symbiotic foods containing coffee and probiotic strains.