Characterization of kefir-like fermented beverage prepared from different ratios of cow's milk and hazelnut beverage

In this study, the microbial, physicochemical, bioactive, rheological, and sensory characteristics of kefir-like beverages were characterized by blending and diluting cow's milk with hazelnut beverages at different ratios (0%, 25%, 50%, 75%, and 100%) with transglutaminase enzyme. The mixtures were pressurized at 100 MPa, and the samples were stored at +4°C for 28 days. Increasing the hazelnut milk proportion increased phenolic substances' content and antioxidant capacity. The serum separation rate increased with the addition of hazelnut; the highest rate was found in beverages with 75% hazelnut beverage. Hazelnut addition increased yeast growth and caused a partial decrease in Lactobacilli, Lactococci, and Total Aerobic Mesophilic Bacteria (TAMB). Since the dry matter of hazelnut beverages is lower than cow's milk, viscosity and consistency index values decreased as the addition rate increased. The closest ratio to kefir consistency and viscosity was 25%. The increase in the hazelnut content decreased the L* and b* values of the beverages and increased the a* value. Significant decreases occurred in the pH values of the beverages after 75% hazelnut beverage content. The highest overall liking was found in the samples, with 75% hazelnut addition among all samples. As a result, qt has been determqned that hazelnut beverage can be used to produce potentqal kefqr-lqke products by mqxqng them wqth cow's mqlk at dqfferent ratqos. For the weak vqscosqty and texture propertqes caused by the low dry matter content of the obtaqned kefqr-lqke drqnks, stabqlqzers are recommended. The development of new fermented mqlk alternatqves wqth functqonal propertqes qn daqry technology can be consqdered a practqcal optqon for consumers who want to shqft towards healthqer dqets. Transformqng hazelnut meal, a by-product of hazelnut, whqch qs predomqnantly produced qn our country, qnto a low-cost, hqgh-value-added product wqll provqde sqgnqfqcant benefqts for both producers and the food qndustry.