Impact of Processing on Nutrients and anti-Nutrients in Tubers and Leaves of Cassava (Manihot Esculenta Crantz)

Abstract

Purpose The study investigated the effect of boiling and deep-frying on the levels of selected nutrients and anti-nutrients in tubers and leaves of new Migyera and MM96/2480 varieties planted in Busia County. Although cassava contains high levels of nutrients (elements and vitamins) that meet nutrient requirements when consumed as the main diet, it requires thorough cooking to reduce high levels of phytochemicals, anti-nutrients affecting nutrient bio-accessibility, and carcinogenic compounds; procedures which also affect the nutrient levels. Methods Tubers and leaves from the tips of the plant were harvested after 8 months. A portion of the tubers was boiled in water (100 ºC, 20 minutes), while another deep-fried in vegetable cooking oil until it turned brown (5 minutes). Leaves were pounded until uniformly macerated and boiled in water (100 ºC, 45 minutes). Levels of nutrients and antinutrients were determined by standard methods. Results The levels of nutrients and anti-nutrients were significantly higher in leaves than in tubers, and also differed significantly in different cassava varieties. Boiling of tubers significantly reduced the nutrients and anti-nutrients levels more compared to frying (P<0.001), ranging from 13.7 to 97.7%. Deep frying of Migyera variety had higher nutrient reduction than in MM96/2480 variety. Essential elements and antinutrients molar ratios indicated that the elements were not bio-accessible. Conclusion Boiling and deep-frying of cassava tubers and leaves results in significant reduction of nutrient and anti-nutrient levels, implying that cassava cannot be used as the main diet; explaining the high level of child malnutrition in such communities.