Chemical and Biochemical Changes in African Locust Bean (Parkia biglobosa) and Melon (Citrullus vulgaris) Seeds During Fermentation to Condiments

Abstract

The chemical (proximate composition, pH, total tocopherol, acid and iodine values, total and reducing sugars) and biochemical (alpha-amylase, sucrase and protease) changes occurring during the fermentation of locust bean and melon to the condiments - iru and ogiri respectively were monitored. Processing locust bean to the condiment involved boiling for 12 hours, soaking the seeds in water, dehulling, boiling for another 6 hours and fermentation for 3-4 days while melon is boiled for 6 hours, cooled and fermented. Boiling, soaking (in water) and dehulling of locust bean resulted in reduction of ash, crude fibre (CF) and total tocopherol but increased ether extract. Fermentation increased the pH value, crude protein (CP), reducing sugar, alpha-amylase, sucrase, protease and free amino acid, decreased the total sugar in both samples and also increased the CF of locust bean sample but had no effect on the CF in melon. Fermentation had no effect on total tocopherol content in both samples. Heat treatment and fermentation employed in processing both samples increased the acid value with a corresponding decrease in iodine value. High negative correlation was observed between acid and iodine values while a high positive correlation was observed between tocopherol and iodine value.