ASSESSMENT OF THE PRESERVATIVE EFFICACY OF AZADIRACHTA INDICA A.JUSS. (NEEM) AND PSIDIUM GUAJAVA L. (GUAVA) LEAF EXTRACTS ON CAPSICUM ANNUUM L. (BELL PEPPER)

Abstract

This study assessed the preservative efficacy of Azadirachta indica (Neem) and Psidium guajava (Guava) leaf extracts on Capsicum annuum (Bell pepper). The proximate, anti-nutrients compositions and antioxidant properties of Capsicum annuum were determined using standard techniques while the phytochemical compositions of Azadirachta indica (Neem) and Psidium guajava (Guava) leaf extracts were also determined. Proximate analysis was carried out to determine the effect of the leaf extracts on the proximate composition of red and green bell pepper at room and refrigeration temperature of storage. The proximate composition revealed that there was no significant difference (p≤0.05) in the protein contents of the red and green bell peppers before and after storage at refrigeration temperature. However, there were significant differences (p≥0.05) in the fat and carbohydrate contents of the red bell pepper before and after storage at refrigeration temperature. The proximate composition also revealed that there was significant difference (p≥0.05) in the fat, protein and carbohydrate contents of the red and green bell peppers before and after storage at room temperature Phytochemical analysis revealed the presence of saponnin, anthraquinone tannin, steroid, terpenoid flavonoid and glycosides in ethanolic extracts of Guava and Neem leaves while tannin, terpenoid, flavonoid and glycosides are present in n-hexane extracts of Guava and Neem leaves. Terpenoid was the highest in value (25.79mg/g) while saponnin has the least value (3.27mg/g). Out of all the extracts, the ethanolic extracts of Guava inhibited the growth of Staphyloccoccus aureus (35.00±1.15mm) being the most inhibited while the n-hexane extracts of Neem leaves inhibited the growth of Staphyloccoccus sp (8.00±0.57mm) being the least inhibited. The ethanolic extract of Neem leaf inhibited Saccharomyces cerevisiae (58.66±0.88mm) being the most inhibited while the n-hexane extracts of Neem leaves inhibited the growth of Rhizopus oligosporus (12.00±0.57mm) being the least inhibited. Based on the findings of this study, it can be concluded that the ethanolic extracts of Guava and Neem leaves are more effective than the n-hexane extracts of Guava and Neem leaves because it inhibited the growth of the microorganisms significantly. The mean sensory scores of all coated bell pepper were compared with the uncoated samples and there were significant differences. Sensory quality scores for various attributes on the basis of colour, appearance, texture, aroma and overall acceptability were highest in bell pepper fruits coated with neem and guava leaf extracts whereas the control fruits recorded the lowest mean scores owing to the rapid deterioration in quality of the bell pepper fruits. The bell pepper fruits coated with the leaf extracts were preserved for 14-28 days during storage compared to the uncoated fruits. All these results therefore suggest that the leaf extracts of Guava and Neem can be used as biopreservatives for the extension of the shelf life of bell pepper.