Capsicum annuum enhances L-lactate production by Lactobacillus acidophilus: implication in curd formation.

Lactobacillus acidophilus is commonly used lactic acid bacteria for producing fermented milk products. In general household practice, curdling is known to occur faster in the presence of red chili. Herein we analyzed the enhanced effect of red chili (Capsicum annuum) and its major component, capsaicin, on Lactobacillus acidophilus (ATCC 4356) in the production of L-lactate in de Man, Rogosa, and Sharpe medium at various temperatures (15, 20, 25, 30, and 37°C). The addition of red chili showed significant increase in the amount of L-lactate produced by L. acidophilus compared with the control at all temperatures. Similar results were observed with addition of capsaicin alone. This was accompanied by an increase in the consumption of d-glucose. Capsazepine, a known antagonist of capsaicin, inhibited the production of L-lactate by L. acidophilus in the presence of both capsaicin and red chili. Because no increase occurred in the growth of L. acidophilus in the presence of red chili, the enhanced production of L-lactate in the presence of red chili or capsaicin is due to increased metabolic activity.