Effects of fermentation temperature and two Saccharomyces yeasts on non-alcoholic Ma-al-shaeer properties

Non-alcoholic Ma-al-shaeer is among the most popular beverages in the world, and can be considered as an alternative to soft drinks. According to Its importance, the aim of this study was to consider the concurrent effects of fermentation temperature and Saccharomyces cerevisiae and Saccharomyces rouxii yeasts on non-alcoholic Ma-al-shaeer properties. Ma-al-shaeer was fermented using Saccharomyces cerevisiae at 12°C or 24°C for 48hr, under periodic aeration practice. After 48 hr of fermentation, Ma-al shaeer was subjected to heat treatment in order to inactive Saccharomyces cerevisiae cells and after cooling down, Saccharomyces rouxii DSM 2535 and Saccharomyces rouxii DSM 2531 were inoculated in to Ma-al-shaeer. The pH drop, gravity and ethanol content were analyzed. Also, the concentration of acetaldehyde, diacetyl, 2,3-pentanedione and sensory properties were assessed. The highest pH drop rate and gravity drop rate was observed for fermentation with S. cerevisiae at 24°C. Also, after 48 hr of fermentation, ethanol content start to decrease significantly for the treatment containing S. rouxii fermented at 24°C. In treatments containing only S. cerevisiae, the concentration of volatile compounds and also sensory evaluation were decreased and increased, respectively. The production of common Ma-al-shaeer by using S. cerevisiae at 24°C fermentation is suitable due to Its ability to decrease volatile compounds, which present worty off flavor However, for production of non-alcoholic Ma-al-shaeer successive application of Saccharomyces cerevisiae and Saccharomyces rouxii at 24°C is recommended.