Effects of Processing Methods on Nutrient Retention of Processed Okro (Abelmoschus Esculentus) Fruit

Non-leafy vegetables are highly perishable products and require good processing treatment to prevent post harvest losses. The common traditional method of their preservation is sun-drying or blanching followed by sun-drying. Okro fruit is generally preserved through sun-drying in Nigeria with little documentation on its nutrient retention. This study was therefore carried out to determine effects of processing methods on micronutrient retention of processed okro. Okro fruit was purchased from Bodija market, Ibadan and divided into three portions treated as raw, sun-dried, and blanched/sun-dried samples. Market sun-dried sample was purchased from the market for comparison. The four samples were analysed for proximate, mineral and vitamin composition using standard methods of AOAC, atomic absorption spectrophotometric and spectrophotometric methods. Edible portion of 100g of fresh sample contained 84.5g moisture, 2.9g crude protein, 0.2g lipid, 2.1g ash, 8.3g carbohydrate, 46.47mg sodium, 102.27mg potassium, 86.37mg calcium, 64.80mg phosphorus, 11.40mg magnesium, 1.63mg iron, 3.70mg zinc, and yielded 41.13kcal of energy. Market sun-dried sample had the highest value of ash and carbohydrate while blanched sun-dried sample had highest gross energy (p<0.05). Fresh okro sample had the highest ascorbic acid (33.02mg) and lowest β-carotene (196.57µg) values (p<0.05). The calcium, phosphorus, magnesium, copper and manganese content of sun-dried sample was significantly higher than other samples (p<0.05) while market sample was significantly higher in sodium, potassium, iron and zinc value compared with fresh, blanched sun-dried and sun-dried samples (p<0.05). Sun-drying seemed to be the better method of okro preservation to retain most micronutrients.