Effect of Processing on the Nutritional Composition of Moringa olifera Leaves and Seeds

Abstract

Background/Objective: Processing improves the nutritional quality of food and may/not lead to nutrient losses. Processing is done to eliminate inactive microorganisms/ antinutrients and extend the shelf life of food. Moringa oleifera plant is an important tree in some part of Nigeria having been successfully used as food, medicinal and for industrial purpose. This study was designed to determine the effect of processing on the nutritional profile of Moringa olifrera leaves and seeds. Materials and Methods: The leaves and seeds were harvested from the forest. The leaves were washed, drained and divided into three portions. The first portion was processed raw, the sun and shade dried samples were the second and third portion. The seeds were cracked and divided into six portions. The first portion was processed raw and the other five portions were fermented for 24, 48, 72, 96 and 120 h respectively. The samples were analyzed for proximate, vitamin, mineral, and anti-nutrients contents using the standard method. Results: The proximate composition of the seeds showed that the samples had a range of moisture, 16.63-17.75%, protein 13.92-38.45%, fat 14.93-19.00%, fibre 3.94-7.10%, ash 1.96-6.22% and carbohydrate 9.08-36.61%/100 g respectively. The ranges for the mineral contents of the seeds were iron 2.10-33.35 mg, zinc 1.19-1.35 mg/100 g, and iodine 12.33-126.61 mg. Also, the ascorbic acid content of the seeds ranged from 3.57- 24.55 mg. The anti-nutrient contents of the seeds were 0.03 – 1.35/100 g saponin, 0.21 – 6.25 mg/100 g of oxalate, 0.11 – 0.28 mg tannins and 5.69 – 16.81 mg/100 g of phytate. The proximate composition of the vegetables ranged from 8.99 – 75.33% moisture, 6.01 – 17.78% protein, 0.64 – 3.89% fat, 3.14 – 11.96% fibre, 2.46 – 15.22% ash and 12.01 – 48.52% carbohydrate. The ranges for mineral contents of the vegetables were iron 0.04 – 0.23 mg, zinc 0.03 – 0.10 mg and iodine 13.66 – 46.61 mg. The vitamin levels of the vegetables were ascorbic acid 56.43 – 167.66 mg/100 g. The level of the anti-nutrients in the vegetables ranged from 0.04 – 1.26 mg/100 g saponin, 0.31 – 8.44 mg/100 g oxalate, 0.05 – 0.20 mg/100 g tannins while phytate varied from 3.31 – 13.20 mg/100 g. Conclusion: Processing of both leaves and seeds of Moringa olifera increased their nutrient density and reduced the concentration of anti-nutrients. The consumption of Moringa olifera should be popularized to diversify diet and extend their food use.