The ascorbic acid content of six tropical leafy vegetables (Vernonia amygdalina, Pterocarpus soyauxii, Manihot utilissima, Xanthosoma sagittifolium, Colocasia esculenta and Amaranthus hybridus) and changes in the vitamin content during traditional West African cooking were measured. Vitamin C losses in Vernonia amygdalina during the squeezing and crushing procedure, aimed at reducing bitterness, prior to utilization in the home for food preparation, were also determined. Initial ascorbic acid levels were found to be . Cooking led to significant losses (60–90% after 15 min). The squeezing and crushing of Vernonia amygdalina led to over 50% losses in the wash water. During market-sale, when the leaves remained exposed in the sun for several hours, losses as high as 97% of the remaining ascorbic acid were recorded. Some of the vitamin was leached into the water which was not sold to the consumer, but discarded. Vernonia amygdalina leaves, thus prepared, do not serve as a major source of ascorbic acid in local diets.
Food Chemistry 01/1987; 23(1):9-17. DOI:10.1016/0308-8146(87)90022-7