Effect of temperature and time storage towards alcohol level in cow milk kefir

Abstract

Kefir is an acidic-alcoholic fermented milk product with little acidic taste and creamy consistency and has a distinctive yeasty aroma. Bacteria in the grain produce lactic acid and flavor components, carbon dioxide, and alcohol. Increased alcohol levels can occur with longer storage. The optimal temperature for the growth of alcohol-producing microorganisms can be at room temperature, whereas low temperatures can inhibit microbial growth and biochemical processes. This study aimed to determine the effect of temperature and storage time on the alcohol content of cow milk kefir. The research method used Randomized Block Design Factorial with two factors and three levels. The first factor was the storage time that consists of 7, 14 and 21 days. While, the second factor was storage temperature that consists of freezing storage (-10°C), refrigerator storage (15°C), and room storage (20°C). Data were analysed using ANOVA, then the further test DMRT with a 95% confidence interval. The best treatment result was tested using Zeleny. The best treatment result was attributed to freezing storage (day 7) at -10°C, with physical parameters include pH of 4.47 and total soluble solids of 10.00% Brix. Then, chemical parameters are total sugar (3.07%), total acid (0.26%), and alcohol content (0.04%). Lastly, microbiological parameters include the total of lactic acid bacteria (5.91 Log CFU/ml) and the total of yeast (6.56 Log CFU/ml). Kefir with the best treatment could decrease the alcohol level and safe for consumption.