ENHANCING NUTRITIONAL VALUE AND SENSORY APPEAL OF Cleome gynandra AND Solanum nigrum THROUGH CONTROLLED FERMENTATION USING Lactoplantibacillus plantarum

Abstract

The study explored the impact of blanching temperature (80°C/10 minutes vs. 90°C/5 minutes), glucose concentration (0%, 1%, 2%, 3%), and fermentation time (up to 21 days using Lactoplantibacillus plantarum isolate) on various properties of the two ILVs. The results indicated that blanching at 80°C/10 minutes resulted to better nutrient retention compared to the higher temperature of 900C for 5 minutes. Black nightshade vegetables blanched at 800C/10min had significantly high protein (4.81%) vitamin C(0.50g/100g), vitamin A(10.69mg/100g) and iron(4.59mg/100g). The same trend was observed for spider plant vegetables where blanching at 80 0 C/10min resulted in significantly high protein (4.03%) vitamin C(0.58g/100g), vitamin A(10.18mg/100g) and iron(3.07mg/100g). While blanching reduced antinutrients (phytates and tannins) in both vegetables, the higher temperature (90°C/5 minutes) resulted in a more significant decrease. With Black night shade vegetables recording (0.12%) tannins and (3.68ppm) for phytates while spider plant recorded for (0.14%) tannins and (4.28ppm) phytates. Fermentation with added glucose (compared to controls without glucose) significantly improved the nutritional profile of the vegetables. Protein content, vitamins C and A, titratable acidity, and beneficial lactic acid bacteria (LAB) all increased with fermentation time and higher glucose supplementation. However, longer fermentation also led to reductions in moisture content, minerals (calcium and iron), and antinutrients (phytic acid and tannins). The extent of these changes depended on the amount of glucose and fermentation duration. Finally, sensory evaluation revealed that samples undergoing controlled fermentation received significantly higher ratings across all sensory attributes (appearance, aroma, texture, taste, and overall acceptability) in contrast with their spontaneously fermented equivalents. The findings imply that controlled fermentation with glucose can be a promising strategy for preserving ILVs in Kenya. This method not only enhances their shelf life but also improves their nutritional value by increasing protein and vitamins while reducing antinutrients. Additionally, fermentation leads to more appealing sensory characteristics, potentially encouraging wider consumption of these underutilized vegetables.