Bio-preservation of processed watermelon (Citrullus lanatus) juice using Lactobacillus species isolated from processed fermented maize (akamu)

Abstract

Bio-preservation of processed watermelon (Citrullus lanatus) juice using Lactobacillus species isolated from processed fermented maize (akamu) was conducted using standard methods for shelf life study. Two Lactobacillus isolates designated L1 and L2 isolated from processed fermented maize (akamu) and identified as Lactobacillus fermentum and Lactobacillus brevis were used in the treatment. Three (3) different designates for inoculum volumes and species: L1T1/L2T1, L1T2/L2T2, L1T3/L2T3 were used for inoculated watermelon samples and the un-inoculated (T0) was used as control. All were stored at ambient temperature and monitored for shelf life study for seven days. The bacterial count (CFU/mL) ranged from 1.8 x 105 ±0.08 to 5.9 x 105 ±0.45, while fungal count ranged from 0.9 x 103 ±0.90 to 4.7 x 103 ±0.32. Reduced pH and increased acidity values were observed in the inoculated juice samples than in the un-inoculated samples. Sample L1T3 had the best shelf life study parameters followed by L2T3 and T0 as the least. Therefore, this study has shown that treated watermelon juice samples with Lactobacillus species isolated from fermented maize (akamu) could produce antimicrobial or organic compounds that are capable of stemming the problem of spoilage, retaining the organoleptic properties of the processed juice and eventually extending the shelf life of the preserved juice, ensuring non seasonal availability of watermelon juice possible.