Effects of Single and Mixed Cultures of Pediococcus pentosaceus Strain DSM20336 and Bacillus subtilis subsp. subtilis Strain-168 on the Total Viable Counts and Physicochemical Properties of Fermented Cabbage and Soybeans

Abstract

The study determined the effects of single and mixed starter cultures of Pediococcus pentosaceus strain DSM20336 and Bacillus subtilis subsp. subtilis strain-168 on the total viable counts (TVCs) of bacteria and physicochemical properties of fermented cabbage and soybeans. A controlled experiment of microbial fermentation was set up in a completely randomized design, using test and standard isolates as starter cultures in single and mixed treatment combinations. Fermentation was allowed to progress at room temperature (28 ± 2°C) from week 1 to week 4. Optimized conditions were established for temperature, pH, and titratable acidity. Results showed that P. pentosaceus-based ferments contained the lowest TVCs in both cabbage (19 x 10⁶ cfu/g) and soybean (51 x 10⁶ cfu/g). The TVC in the mixed culture of Bacillus + Pediococcus in cabbage ferment was 120.9 x 10⁶ cfu/g, while it was 147 x 10⁶ cfu/g in soybean ferment. TVC reduced sharply as microbial fermentation progressed over time. In the controlled fermentation of cabbage, it was established that temperature, titratable acidity, and TVCs of fermenters had very high positive relationships with each other. Meanwhile, in the fermentation of soybean product, the TVCs of bacteria were negatively affected by high temperature and low pH (acidity) of the medium. Therefore, lower temperature and pH are recommended for the fermentation of soybean products. The study established some fermentation parameters for cabbage and soybean. This information is important for the commercial production of these products to achieve food security in Nigeria.