Effect of Traditional Methods of De-bittering on the Proximate and Vitamin Contents of Fresh and Squeezed-Washed Bitter Leaf

Abstract

Bitter leaf is a leafy vegetable that is widely consumed and cherished in South-Eastern Nigeria. The effect of traditional methods of de-bittering of bitter leaf (Vernonia amygdalina) on the proximate and vitamin contents was studied using potash, palm oil, and salt and boiling process in squeeze-washing at 3 pre-processing methods of squeeze-wash and periods of 3 to 8 minutes. The percentage retention and losses of nutrients increased simultaneously during squeeze-washing. The sample squeezed-washed with palm oil had nutrient retention ranging between 55 to 100% of moisture, ash, crude fibre, fat, vitamin A and vitamin C than other squeeze-washed samples. This could be due to the rigidity of the cells of the sample squeezed-washed with palm oil which did not allow much nutrient to leach into the squeezed leaf water; whereas, the loss of nutrient was practically of the same magnitude (27.3 to 80.5%) in all other samples. The loss of nutrients was observed to be influenced directly by the cause-and-effect of disintegration changes which usually leads to softening due to the severity of the squeeze-washing on the bitter leaf instead of cellular composition or level of nutrient initially present. Palm oil should be used in the squeeze-washing of bitter leaf for better nutrient retention.