Abstract:

The changes in physicochemical properties of melon seed varieties during fermentation for ogiri condiment production was studied. Fermentation of melon seeds gives the product, ‘Ogiri egusi’, which is an oily paste condiment  used as flavouring agent in sauces, soups and stews in eastern Nigeria. Five melon seed varieties (Citrullus vulgaris (CV), Citrullus lanatus (CL), Colocynthis citrullus (CC), Cucurbita pepo (CP), and Cucumeropsis edulis (CE) procured were boiled respectively in deep water for 3h and dehulled. The cotyledons were wrapped with blanched banana leaves, boiled again for 2h and allowed to undergo primary fermentation at room temperature for 96h. The fermented seeds were pounded to paste, wrapped with leaves and hung over fire place to ferment again for another 144h. Determination of the physicochemical properties (Free Fatty Acid (FFA), Acid Value (AV), Total Titrable Acidity (TTA), pH and temperature) were simultaneously carried out as fermentation progressed. Data obtained from this study were statistically analyzed using ANOVA on Windows 2007; while the means were separated by Fisher’s Least Significant difference (LSD) at P<0.05 confidence level. Free fatty acid of the melon seeds increased significantly as fermentation progressed in all the samples, ranging from the lowest values; 3.83mg/g (CL & CV) to the highest; 26.36mg/g (CP). The increase in FFA is an indication of the production of lipases by the fermenting bacteria. CL and CP were significantly different (P<0.05) from others in acid value. TTA of the melon seed substrates increased with fermentation period; CL was significantly different (p?0.05) with the value (5.69%). This result could be attributed to the production of various organic acids from utilization of the carbohydrate in the seeds. pH values also increased from 5.64 (CC) to 7.94 (CP), indicating alkaline fermentation. The temperature also increased slightly from 28.5-31.5oC during primary fermentation, and peaked at 31.5oC (72h).