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African Health Sciences
Makerere University Medical School
ISSN: 1680-6905
EISSN: 1680-6905
Vol. 4, No. 2, 2004, pp. 125-130
Bioline Code: hs04022
Full paper language: English
Document type: Research Article
Document available free of charge

African Health Sciences, Vol. 4, No. 2, 2004, pp. 125-130

 en Alterations in Fruit and Vegetable β-carotene and Vitamin C Content Caused by Open-sun Drying, Visqueen-covered and Polyethylene-covered Solar-dryers
Ndawula, J.; Kabasa, J.D & Byaruhanga, Y B

Abstract

This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylenecovered solar dryer) on β-carotene and vitamin C content of edible portions of mango fruit ( Mangifera indica check for this species in other resources ) and cowpea leaves ( Vigna unguiculata check for this species in other resources ). Commercial samples were analysed for vitamin C by titrimetry and β-carotene by spectrophotometery at 450nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (p<0.05. The fresh cowpea leaf β-carotene and vitamin C content was 140.9 and 164.3 mg / 100g DM respectively and decreased (p<0.05) with drying. Open sun drying method caused the greatest β-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved β-carotene and vitamin C retention by 15% and 7.5% respectively. The β-carotene and vitamin C content of fresh ripe mango fruit was 5.9 and 164.3 mg/100g DM respectively. Similar to effects on cowpea leaves, the mango micronutrient content decreased (p<0.05) with drying. The open sun drying method caused the greatest β-carotene (94.2%) and vitamin C (84.5%) loss, while the visqueen-covered solar dryer caused the least (73 and 53% respectively). These results show that the three solar drying methods cause significant loss of pro-vitamin A and vitamin C in dried fruits and vegetables. However, open sun drying causes the most loss and the visqueen-covered solar dryer the least, making the later a probable better drying technology for fruit and vegetable preservation. The drying technologies should be improved to enhance vitamin retention.

 
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