Publisher: Bachudo Science Co. Ltd

Effect of Drying Conditions On The Micronutrient Content of Five Leafy Vegetables of Eastern Nigeria

J. U. Nworie, N. Nwachuku
KEYWORDS: Sun drying; oven drying 'lesser known leaf vegetables' Micro-nutrient composition.


The effect of sun and oven drying at 100°C on the micronutrient composition of five selected 'lesser known' leafy vegetables of Eastern Nigeria was investigated. The vegetables are Ipomea batatas (potato leaf), Pterocarpus santolinoides (uturukpa leaf), Zanthoxylium zanthoxyloides (nka leaf), Pterocarpus mildbreadii (oha leaf), and Ceiba pentandra (akpuota leaf). They were divided into three groups, representing fresh (wet), sun dried, and oven dried at 100°C until constant weight was obtained before grinding into flour like sample and used for analysis. The minerals analyzed include sodium, potassium, magnesium, manganese, iron, zinc, calcium and phosphorus, while the vitamins include A, C, E, B1, B2, and folic acid. The result of fresh analysis shows that P. mildbreadii has the highest value; 9.00 ± 0.2mg/100g of potassium; Z .zanthoxzyloides, 1.72 ± 0.18mg/100g of magnesium,  P. mildbreadii, 6.87 ± 0.18mg/100g of iron; Z. zanthoxyloides, 6.47 ± 0.10mg/100g of phosphorus; I.batatas,14.27 ± 0.41mg/100g   of calcium,   and 83.79t1.41mg/100g of sodium respectively. Zinc and manganese occurred in trace amounts. The levels of these elements were generally increased both by sun, and oven drying at 100°C with a greater increase when oven dried. Also the result of fresh analysis shows that the highest values of vitamins A, 15.20.01 ± 2.0i.u occurred in I. batatas, vit. B1, 4.57 ± 0.86mg/100g; folic acid, 3.24±0.00mg/100g occurred in P. santolinoides respectively, vitamin C, 9.04 ± 0.72mg/100g occurred in Z. zanthoxyloides. Vitamins B2 and E levels were relatively low. Both sun and oven drying at 100°C decreased the levels of all the vitamins, with sun drying exerting a greater reduction effects. Oven drying therefore appears to be a better drying condition.

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