Volatiles formation by single strain starters of indigenously isolated lactic acid bacteria in Sourdough

Abstract

Volatile compounds in fermented sourdoughs were formed by using starter cultures [Lactobacillus brevis (St-I), Lactobacillus fermentum (St-II) and Lactobacillus plantarum (St-III)] along with control starter culture (Saccharomyces cerevisiae). Sourdough samples were obtained by fermenting the dough with starter cultures at different fermentation times (12, 18 and 24 hrs). Furthermore, the fermented samples were analyzed for pH, total titratable acidity (TTA), organic acids, sugars and volatile compounds. From the results, it is noticed that the pH decreased as a function of fermentation time in all starter cultures and maximum pH drop was observed in St-II after 24 h of fermentation followed by St-I at the same time interval. However, least drop in pH was recorded in the control starter culture. Moreover, highest TTA (10.30%) was produced by St-I after 24 h of fermentation followed by the same culture at 18 h of fermentation (9.90%). Conversely, the control samples yielded lowest TTA. In case of organic acids and sugars after evaluating by HPLC depicted that St-I gave more concentrations of sugar fractions (maltose and fructose) and St-II produce higher concentrations of organic acids, all sugar contents and organic acids increased with passage of time. Sourdough samples were analyzed for volatile compounds by GC-MS through headspace analysis. Sourdough produced by the addition of starter cultures yielded 1-hexanol, hexanal, octanal and ethyl acetate in general whereas, diacetyl was produced in St-III ferments only.