EFFECT OF DEBITTERING ON PHYTOCHEMICALS AND ANTIOXIDANT COMPOSITION OF VERNONIA AMYGDALINA AND GONGRONEMA LATIFOLIUM LEAVES

The astringent taste of Vernonia amygdalina (VA) and Gongronema latifolium (GL) leaves were de-bittered through boiling and squeeze-washing . The effect of boiling and squeeze-washing on the proximate, phytochemicals, vitamin (A,C,E) composition and in-vitro antioxidant activities of VA and GL leaves were evaluated. The in-vitro antioxidant activities of the vegetable extracts were estimated using reducing power, total phenol content and 1,1-Diphenyl-2-picryl hydrazyl radical (DPPH) inhibition. Boiling and squeeze washing significantly (p<0.05) reduced all the nutrients in VA and GL in a similar trend. Squeeze washing had lower values (p<0.05) in fibre (8.83 % and 10.80 % for VA and GL respectively) and carbohydrate (67.92 % and 64.58 % for VA and GL respectively). Both boiling and squeeze-washing drastically reduced vitamin C content (from 13.32 g/100g and 10.18 g/100g to 7.37 g/100g and 3.25 g/100g in VA and GL respectively). Phytochemicals content of both leaves showed that unprocessed VA had higher alkaloids (1.73 g/100g), tannin (0.2 3g/100g) saponin (8.02 g/100g) and phytate (0.246 g/100g) than GL. The antioxidant activity of the leaves reduced with squeezing as observed in the total phenol content, reducing power and DPPH inhibition activities. From the result it is seen that de-bittering these vegetable leaves for food preparation reduced both nutrients, phytochemicals and in vitro antioxidant activities of the leaves. the indication is that de-bittered leaves of VA and GL will not provide health benefits for which these vegetables are known for. The extract from squeezed-washing contain the necessary ingredients for health improvement.