Effects of Initial Acidification on the Microbial and Physiochemical Changes During Fermentation of Cabbage Juice

Abstract

Cabbage (Brassica oleracea L. var. sabauda) juice fermentation for sauerkraut production takes about 30 days due to initial pH lowering before actual production. Direct acidification to achieve the required initial pH reduction can invariably shorten the processing time and give comparable fermentation end products. Salted (2% w/v NaCl) cabbage juice dispensed into six fermentation vessels were inoculated with varying initial lactic acid (v/v) concentrations of 0.0%, 0.1%, 0.3%, 0.5%, 0.7% and 1.0% respectively and allowed to ferment at ambient temperature (28 ± 2oC) for 10 days. The microbial and physiochemical changes were evaluated. The bacterial counts of the fresh juice was 2.5 × 104 cfu/ml while fungal counts was 1.3 × 103 cfu/ml. Six different bacterial isolates were observed from the raw sample; Serratia spp, Bacillus spp, Lactobacillus spp, Micrococcus spp, Pseudomonas spp and Leuconostoc spp. while fungal isolates were Rhizopus spp, Aspergillus spp and Penicillum spp. After day 10 of fermentation, only two bacterial isolates; Lactobacillus spp, and Bacillus subtilis were observed in all the treated samples. The initial pH of the juice was 5.97 ± 0.06 and dropped with fermentation time. The rate of production of final lactic acid was significantly (p = 0.05) influenced by the level of initial acidification. The addition of initial 0.3% (v/v) of lactic acid with 2% (w/v) NaCl mixture to cabbage juice fermentation at ambient temperature lowered the pH consistently and rapidly, resulting in accelerated process which was comparable to that fermented naturally for 30 days.