effect of saccharomyces strains and fermentation condition on the ph, foam property and CO2 concentration of non-alcoholic beer [Ma-al-shaeer]

ABSTRACT

This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO[2] concentration of non-alcoholic beer [Ma-al-shaeer]. For this, the beer samples were inoculated with four different species of Saccharomyces [Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424] and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO[2] concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×10[7] CFU.ml[-1] and periodic aeration at 24?C showed the greatest decrease in pH, and the treatments with 10[7] CFU.ml[-1] and aerobic-periodic aeration at 4?C showed the lowest decrease in pH. The highest and lowest amounts of CO[2] and foam property were obtained in the treatments with 4×10[7] CFU.ml[-1] inoculation, aerobic condition, and the treatments with 10[7] CFU.ml[-1], periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO[2] and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×10[7] CFU.ml[-1] inoculation and aerobic condition at 4°C has promising potential for producing Ma-al-shaeer with good physicochemical properties