The ABTS assay is commonly applied to determine antioxidant activity in plants. It is based on the ability of antioxidants to scavenge the long-life radical cation ABTS+. The antioxidant activity of the fibre concentrates extracted with methanol:acetone ranged from 5.5 lM TE/g for passion fruit to 38.0 lM TE/g for mango. The antioxidant activity of ethanol extracts were lower than those of the methanol:acetone extracts, with values ranging from 1.7 lMTE/g for pineapple to 15.3 lM TE/g for mango, with no statistically significant differences (p > 0.05) between passion fruit, pineapple and guava.