Effect of Drumstick Tree (Moringa oleifera) and Neem (Azadirachta indica) Leaf Powders on Shelf Life and Physiological Quality of Okra Fruits During Storage

Abstract

Healthy okra fruits of some varieties; clemson spineless and stubby okra were obtained from the experimental farm at Apir, Makurdi at harvest stage. The experiment was a 2 x 3 factorial combination of treatments, fitted in a completely randomized design and replicated three times. The okra fruits were coated with Moringa oleifera and Azadirachta indica leaf powders and stored at room temperature. Data collected were subjected to Analysis of Variance (ANOVA) using GENSTAT statistical package, and Fisher’s Least Significant Difference (F-LSD) at a 5%. Results showed significant differences in the parameters studied. For example, stubby okra produced significantly higher weight loss than clemson spineless on days 12 and 15 of storage. Moringa oleifera produced significantly lowest weight loss while the highest weight loss was obtained with untreated okra. Significant differences in firmness was also observed within the varieties at days 3, 6, 9 and 12 as clemson spineless produced the highest firmness of okra fruit while stubby okra recorded the lowest. Moringa oleifera produced the highest firmness value across all days while the control gave the lowest firmness value. The highest titratable acidity content among the okra varieties was produced by clemson spineless on all days of storage. Untreated okra generally gave higher titratable acidity values on all days. Moringa oleifera produced significantly lower titratable acidity on all days. Stubby okra gave higher total soluble solids value on day 3. Moringa oleifera gave the highest total soluble solids value while Azadirachta indica and untreated (control) produced similar values which represented the lowest total soluble solids value. The vitamin C content of stored okra was significantly higher with stubby okra as compared to clemson spineless. Moringa oleifera produced higher vitamin C content at days 3, 9, 12 and 15 and the difference was significant, while untreated okra recorded the lowest vitamin C content on all days of storage. Moringa oleifera also gave the highest pH value on all days. Control gave the lowest pH value and this was significantly lower than that produced by Azadirachta indica. The shelf life of the treated okra fruits ranged from days 1-15 while the control ranged from 1-7 days. The temperature of the storage room ranged from 27.1 – 29.9⁰C and the relative humidity ranged from 29.5 – 44.5%. It is concluded that leaf powders of Moringa oleifera and Azadirachta indica enhanced the shelf life and physiological quality of okra during storage. The phytochemical analysis of these botanicals used in the study revealed the presence or absence of active compounds such as steroids, glycosides, saponins, alkaloids, carbohydrates, flavonoids, cardiac glycosides, tannins and phenols, and anthraquinones. These botanicals are environmentally friendly, cost-effective, easy to produce and easy to apply formulations and are also safe for consumers. Moringa oleifera and Azadirachta indica leaf powders are recommended in the storage of fresh okra most especially the clemson spineless okra variety.