EFFECTS OF POSTHARVEST FUNGI OF GROUNDNUT (Arachis hypogaea L.) SEED ON ITS PROXIMATE COMPOSITION AND OIL QUALITY

Abstract

Groundnut, the second most valuable legume in the world based on total production, have seeds that are susceptible to attack by fungi. This work identified the fungi that attack Arachis hypogaea seed in store in Uyo, studied the physicochemical characteristics of the oil from this seed and evaluated the effect of the fungal infection on the proximate composition of the seeds. Fungi from diseased seeds were isolated using the direct plate method. Diseased and healthy seeds were subjected to proximate analysis using the Association of Official Analytical Chemists (AOAC) method. Oil was also extracted from infected and healthy seeds using the Soxhlet extraction method with petroleum ether. The oils were subjected to physicochemical profiling using the AOAC method. Data from the isolation showed the presence of Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer. Results also showed that the fungi had a significant effect (p?0.05) on the percentages of fat (16.76and 25.02), moisture (8.10and 6.37), protein (13.30 and 14.18) and carbohydrates (42.13 and 45.55) between the infected and healthy seeds respectively. Oil from infected seeds showed higher indices of deterioration and rancidity by having higher free fatty acid, peroxide, saponification and acid values than the oil from the healthy seeds. Oil from diseased seeds can be utilized mainly for industrial purposes, while those from healthy seeds can be utilized for human and animal consumption as well as for industrial purposes. The relationship between seed deterioration and moisture content was also highlighted in this work.