Organic acids formation during the production of a novel peanut-milk kefir beverage.

Abstract

The aim to this study was to evaluate the organic acids formation, ethanol and Exopolysaccharides (EPS) production during the fermentation of a novel beverage made from peanut-milk using a commercial kefir starter culture. Samples were collected at 0, 18, 22, 26 and 30 h of fermentation (final pH 4.2). Samples were analyzed for lactic, citric, acetic and pyruvic acids by HPLC. Ethanol production was analyzed using GC equipped with headspace autosampler. The results showed that the concentration of lactic and acetic acids increased from 0 to 1011 :g/g and from 2 to 22 :g/g, respectively while the citric acid decreased from 2098 to 249 :g/g over the same period. Similarly, peanut-milk kefir pH decreased to 4.21 after 30 h of incubation. The production of ethanol increased sharply reaching a mean value of 14 mg/mL. The level of EPS production reached its high content (525.83 :g/g) after 22 h of fermentation.