Effect of Spices on the Microbial Load and Physicochemical Properties of Fermented Pakia Biglobosa Seeds

Abstract

Fermented Parkia biglobosa seeds (iru) contain high protein content, serving as a major source of protein in rural areas, among people who cannot afford animal proteins. Spices are known to possess health benefits in humans. Hence, this study assessed the impacts of spices such as alligator pepper, ginger, garlic, nutmeg, turmeric, grains of Selim, cocoplum and skinplum on the microbial population and physicochemical properties of fermented Parkia biglobosa seeds. A 30g of each spice was added to 300g of previously pressure cooked and dehulled locust beans in separate containers. Each was sterilized and inoculated with Bacillus subtilis. All the samples including control (naturally fermented P. biglobosa alone) were fermented at 37⁰C for 36h. The microbial load, pH, total titratable acidity (TTA) and proximate analysis were determined. Commercially fermented iru had the highest microbial load of 5.40, with unfermented iru having the least load (4.78). Unfermented iru had the least pH (6.35), the pH of all fermented samples was significantly high (P=0.05) with values ranging from 7.27 to 8.29. TTA of all the samples varied with the highest value of 5.75 recorded in cocoplum fermented iru while Selim fermented iru had the least value (0.85). Protein and fat contents of all fermented samples significantly increased (P=0.05) while carbohydrate and crude fibre contents decreased. Selim fermented iru had the highest ash content of 6.07 while alligator fermented iru had the least ash content (2.86). This research confirmed that fermentation of P. biglobosa with edible spices improved its nutritional value in production of iru.