Tea Fermentation Case Study

The increase in the tea concentrations enhanced the rate of fermentation, must having 5 g tea/100 ml apple juice had the highest rate of fermentation and 2 g tea/100 ml apple juice had the lowest (Table 1) which might be due to the presence of high quantity of amino acids which increased with increase in concentration of tea. Assimilable nitrogen from low molecular-weight nitrogenous compounds such as ammonium ions and amino acids is an essential nutrient for yeast growth. Nitrogen is used by the yeast for synthesizing structural proteins, enzymes, nucleic acids, and pyrimidine nucleotides (Buescher et al., 2001). Assimilable nitrogen has been shown to increase sugar fermentation and ethanol formation (Allen and Auld, 1988; Buescher et al.,

It is revealed from the data that the difference for TSS was non-significant among the different concentrations of tea and there was a significant decrease in reducing and total sugars content of apple tea wine but in case of 5 g tea, a slight increase in both was observed (Table 3). Highest titratable acidity was observed in apple tea wine having 5 g tea and the lowest was in apple tea wine having 2 g and 3 g tea. Highest pH was observed in apple tea wine having 5 g tea and the lowest was in apple tea wine having 2 g tea (Table 3). Highest volatile acidity was observed in apple tea wine having 5 g tea and the lowest was in apple tea wine having 3 g and 4 g tea. Among the different concentrations of tea, highest ethanol production was recorded in apple tea wine having 2 g tea (Table 3), which might be due to the occurrence of the natural microflora which helped in alcoholic fermentation. In accordance with this, the microflora isolated from the fermentation of apple tea must having 2 g tea was yeasts belonging to Saccharomyces cerevisiae. Therefore, this may have resulted in typical alcoholic fermentation producing more ethanol than other metabolites as is the usual case with natural fermentation (Ciani et al.,

ellipsoideus, which is clearly due to the difference between the fermentability of these both of the fermentations. Low pH, high acidity and volatile acidity in case of naturally fermented apple tea wine (Table 3) might be due to the presence of natural micro-flora including both yeast and bacteria. Higher volatile acidity of the apple tea wine fermented by natural fermentation is understandable due to the involvement of the mixed microflora other than the Saccharomyces as described by Caridi et al. (2004) that the wine fermented by Hanseniaspora quilliermondii had considerably high volatile acidity and this acetogenic property made the yeast unsuitable for wine production or acetic acid bacteria might have grown in the fermentation, though to smaller extent that might have increased the acetic acid concentrations consequently, the volatile