Abstract

Although researchers have established the fact that vegetables play a vital role in the contribution of essential nutrients to the body and thus help to maintain a healthy life style, prevent diseases, and reduce mortality from infectious diseases such as measles and HIV; the traditional practice of boiling vegetables before consuming has been going on for ages in Uyo, without questioning their nutritional values such as vitamin components before and after heat treatments. Prompted by this, this research work was carried out to analyze vitamin A content of ten selected leafy vegetables. The concentration of vitamin A was determined for both raw and boiled vegetables samples at 60 and 80 ºC (i.e., before and after heat treatments) for 15 min using UV-Spectrophotometry. The results of the analysis showed that all the vegetables contain vitamin A in this order: (Gnetum africana) > Telfairia occidentalis > Piper guineense > Ocimum gratissimum > Vernonia amygdalina > Talinum fruticosum > Heinsia crinita > Justicea flava > Gongronema latifolium > Lasianthera africana) both in raw and boiled samples at 60 ºC and at 80 ºC for 15 min. It was further observed that as heating temperature increased, the vitamin A content of the vegetables also increased at constant heating time. It can be concluded that the heating temperature affected the vitamin A content of all the vegetables tested.

Keywords: Vegetables, Vitamin A, Heat treatment, Retinol, UV spectrophotometry, Fat Soluble