Response Surface Methodology Approach for the Optimization of LAB Fermentation Using Vegetable Based Substrate

In the present studies, an attempt was made to optimize the conditions for the lactic acid bacteria (LAB) fermentation using Irish York cabbage (Brassica oleracea var. capitata alba subvar. conica) as a substrate. Prior to fermentation with Lactobacillus plantarum, York cabbage was blanched at 95°C for 12 min to inactivate surface microflora. To achieve an optimal fermentation condition which would result in higher release of phytochemicals and antioxidant capacity in the broth, Box-Behnken design integrating a desirability approach was used. The optimized factors (fermentation time 36h, solid/liquid ratio 0.25 g/ml and agitation rate 100 rpm) were used for fermenting York cabbage. Results showed that there was ≈5 log cfu/ml increment in bacterial growth after fermentation; whereas lactic acid production reached up to 4.97 mg/ml. Fermentation retains 95-98% and 90-95% of total phenolic content (TPC) and antioxidant (AO) capacity, respectively. On contrary, none of the glucosinolates were observed in the York cabbage broth while Isothiocyanates content almost doubled after fermentation.