the effect of saccharomyces strains and fermentation condition on the ph, foam property and co2 concentration of non-alcoholic beer (ma-al-shaeer)

this study aims to determine the effect of fermentation condition and saccharomyces strains on the ph, foam property and co2 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, co2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. the results shows that the treatments with 4×107 cfu.ml-1 and periodic aeration at 24˚c showed the greatest decrease in ph, and the treatments with 107 cfu.ml-1 and aerobic-periodic aeration at 4˚c showed the lowest decrease in ph. the highest and lowest amounts of co2 and foam property were obtained in the treatments with 4×107 cfu.ml-1 inoculation, aerobic condition, and the treatments with 107 cfu.ml-1, periodic aeration, respectively. these results further demonstrated that the highest drop in ph, and the highest ability of producing co2 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 4×107 cfu.ml-1 inoculation and aerobic condition at 4˚c has promising potential for producing ma-al-shaeer with good physicochemical properties.