Statistical optimization of elephant foot yam (Amorphophallus paeoniifolius) lacto-pickle for maximal yield of lactic acid

The most common fermented foods are prepared using lacto-fermentation. In this study, we have investigated the production of “Lacto-pickle” using a plant Elephant Foot Yam (Amorphophallus paeoniifolius; Cultivar: IGAM-1) in presence of Lactobacillus plantarum (MTCC-1325). Response Surface Methodology was used to evaluate the effects of three optimum variables, i.e., salt concentration (8%, w/v), inoculum volume (10%, v/v), and incubation period (22 days) on lactic acid (LA; a natural preservative) production, using a full factorial Central Composite Design. Under optimized conditions, the predicted response for “LA production” (3.992 g/kg) were found very close to the experimental response (3.873 g/kg) providing the validity of the model. The treatment with 8-10% brine solution during LA fermentation was found to be the most acceptable organoleptically. EFY Lacto-pickle with 8 and 10% (w/v) brine solutions had a proximate composition of starch, 55-68 g/kg; total sugar, 1.3-1.6 g/kg; crude protein, 37.9-38.5 g/kg; and fat, 22.5-23.0 g/kg on fresh weight basis. The viability of the strains was determined during long-term storage (6 weeks) of EFY Lacto-pickle at room-temperature and viable cell counts were remain constant. The antagonistic activity of viable cells against food-borne pathogenic microorganism was also determined and shown to process inhibitory activities towards pathogens.