ABSTRACT

Rancidification is a process that affects palm oil quality and reduces its nutritional value. The present study is aimed at establishing  antimicrobial and antirancidity effects of crude extracts of Citrus sineensis, Citrus limon, Citrus aurantifolia leaves on the shelf life of palm oil. Fifteen (15) samples were purchased from local dealers from good shed Umuahia. Five (5) each for treatment 1,2 and 3 respectively. Treatment one (1)represented the fresh oil sample, treatment two (2)represented five(5) months stored palm oil while treatment three (3) represented a one (1)year stored palm oil sample. The different treatments were subjected to isolation of fungal and bacterial organisms. The  microbial isolates were further subjected to antimicrobial test based on specific inhibition zones. The crude extracts of the citrus species: Citrus aurantifolia, Citrus limon, and citrus senensis were obtained with methanol. The extract were used in the antirancidity test. From the results treatment (3) which is a one year stored palm oil showed the highest microbial load, followed by the  five (5) months storage and then fresh oil sample has the least. The microbes isolated from the oil samples includes Bacillus spp, Enterococcus spp, Microccocus spp, and Staphylococcus spp. Among the three (3) species of citrus used citrus aurantifolia (lime) had a better zone of inhibition against the isolated microbes. The antirancidity results showed no significant difference (P>0.05) at 1600/ml of all the extract when compared to ascorbic acid (vitamin C) control treatment. In conclusion the extracts of the leaves of citrus species showed antimicrobial and antirancidity effect on palm oil stored at different durations.