10th U6+ Consortium of African Universities International Conference

Tropical fruits are important sources of carbohydrates, dietary fibre, essential minerals, vitamins, and natural antioxidants that contribute significantly to food security, nutrition, and human health. However, increasing demand for fresh fruits has encouraged adulteration practices including artificial ripening using ethylene gas, addition of artificial sweeteners, and application of synthetic dyes to improve fruit appearance, sweetness, and marketability. These practices alter the nutritional quality and antioxidant potential of fruits, yet limited scientific information exists on their effects on different fruit fractions. This study evaluated the effects of common fruit adulteration practices on the nutritional composition and antioxidant properties of selected tropical fruit fractions in Eldoret, Uasin Gishu County, Kenya. A completely randomized laboratory-based experimental design was employed using banana, mango, pineapple, and watermelon. Fresh fruits served as controls, while banana and mango were subjected to ethylene-induced ripening, pineapple was treated with saccharin, and watermelon was adulterated using a synthetic food dye. Flesh, peel, and/or seed fractions were analysed on Days 1, 3, and 7 after treatment. Nutritional analyses included moisture, ash, crude fat, carbohydrate content, ascorbic acid and mineral composition, while antioxidant activity was determined using the Ferric Reducing Antioxidant Power assay following standard AOAC analytical procedures. Adulteration significantly (p < 0.05) affected several nutritional and antioxidant parameters. Mineral composition remained relatively stable across treatments, although slight declines were observed with prolonged storage due to tissue deterioration. Fruit peels consistently exhibited significantly (p < 0.05) higher mineral content, and antioxidant activity compared to edible flesh, while watermelon seeds contained appreciable levels of minerals and antioxidant compounds. This study concludes that common fruit adulteration practices compromise the nutritional composition and antioxidant properties of tropical fruits. Therefore, there is need to strengthened regulation of fruit adulteration practices and further research on safer technologies for maintaining fruit quality while preserving nutritional and antioxidant integrity.