COMPARATIVE EFFICACY OF LACTIC ACID BACTERIA AND SODIUM BENZOATE IN THE PRESERVATION OF KUNU: A STUDY ON SHELF LIFE EXTENSION AND QUALITY MAINTENANCE
Abstract
Kunu, a traditional Nigerian beverage made from tigernuts, faces significant commercialization challenges due to its extremely short shelf life of 2-3 days under ambient conditions. The rapid spoilage limits market expansion and causes substantial economic losses for producers.This study investigated the comparative efficacy of lactic acid bacteria (LAB) biopreservation versus conventional sodium benzoate treatment in extending kunu shelf life. This experimental study was conducted at the Department of Microbiology, Prince Abubakar Audu University, Anyigba, Kogi State, Nigeria, using a completely randomized design with four treatment groups: control kunu (untreated), LAB-treated kunu with Lactobacillus plantarum KW1, LAB-treated kunu with Lactobacillus fermentum BH2, and LAB-treated kunu with mixed cultures (KW1+BH2). Additionally, sodium benzoate-treated samples were included for comparison. Each treatment was replicated three times and analyzed over a 6-day storage period at ambient temperature (28±2°C). Parameters evaluated included pH variation, total viable count, LAB count, spoilage organism identification, and sensory properties using a 9-point hedonic scale.LAB-treated samples demonstrated superior preservation efficacy compared to sodium benzoate treatment. LAB-treated kunu maintained controlled acidification with pH decreasing from 4.3-4.4 to 3.2-3.4, while sodium benzoate-treated samples showed moderate pH increase from 4.5 to 6.8, and control samples alkalinized from 4.5 to 7.8. Total viable counts in LAB-treated samples were significantly controlled (5.2-5.8 log CFU/mL) compared to sodium benzoate-treated samples (7.8 log CFU/mL) and control samples (9.8 log CFU/mL) after 6 days. LAB treatment achieved complete elimination of several spoilage organisms including Bacillus, Pseudomonas, Staphylococcus, Aspergillus, and Penicillium species, while sodium benzoate treatment only reduced spoilage organism populations to moderate levels.Sensory evaluation revealed that LAB-treated samples maintained good acceptability scores (>7.0) throughout the storage period, while sodium benzoate-treated samples showed moderate acceptability (6.0-7.2) and control samples became unacceptable (
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