Solar-Drying of Vegetables for Micronutrients Retention and Product Diversification

Abstract

Micronutrients retention of solar-dried vegetables were studied with an aim of increasing iron, zinc and β-carotene bioaccessibility as well as product diversification. Iron, zinc and β-carotene contents in fresh and dried Moringa oleifera leaves (ML), Ipomoea batatas leaves (IBL) and Daucus carota (DC) were evaluated. Iron and zinc were analyzed using Atomic Absorption Spectrophotometer (AAS) and β-carotene by High Performance Liquid Chromatography (HPLC). Moisture content for dried ML, IBL and DC was also determined. From results, final moisture values attained for dried ML, IBL and DC were 7.24, 7.46 and 10.51% respectively. Retention of specific micronutrients in dried vegetables was observed. A significant (p < 0.05) increase in iron (64.55 ± 0.39 mg/100 g) and zinc (2.73 ± 0.09 mg/100 g) contents were observed in dried ML. Zinc content in dried DC was 0.88 ± 0.05 mg/100 g. Iron content in dried IBL was 29.99 ± 0.42 mg/100 g which is 2.45 folds significant increase. On the other hand, dried IBL showed increased β-carotene content of 1.63 ± 0.25 mg/100 g, which is 9.59 folds significant increase, whereas insignificant (p > 0.05) increase was observed in ML. Furthermore, β-carotene loss from 6.72 ± 0.28 mg/100 g to 3.53 ± 0.41 mg/100 g (0.53 folds decrease) in dried DC. Solar drying of vegetables facilitates micronutrients retention and product diversification to enhance accessibility of nutrients for improved health through micronutrients supplementation.