Development of Kefir beverages: Standardization of process parameters

Resumo

This study aimed to characterize physico-chemically Kefir grains and standardize the process parameters of the beverages, in order to obtain an optimum product. Kefir grains consisted basically of water (85.61 ± 0.41%) and had an acidic pH (4.45) and low acidity (0.44 ± 0.09% lactic acid). To determine the process parameters, it was used a 2³ factorial design with three replications at the central point, being evaluated the amount of grain (2-6%), amount of sugar (10-14%) and fermentation time (18-24 hours) at 25^oC. The amount of sugar or grains had no influence on the pH and titratable acidity. A longer fermentation time (24 hours) resulted in products with pH and acidity within the recommended values, while fewer grains (2%) did not result in too firm beverages. The formulation with the best physicochemical and sensory characteristics had 2% grain, 10% sugar and 24 hours of fermentation, being described as creamy, slightly acidic and with intermediate sweetness.