The bioactive compounds and antioxidant capacities of polyphenolic extracts of 18 fresh and dry native non-traditional fruits from Brazil were determined using ABTS, DDPH, FRAP and b-carotene bleaching methods. The study provides an adaptation of these methods, along with an evaluation of the compounds related to antioxidant potential. The results show promising perspectives for the exploitation of non-traditional tropical fruit species with considerable levels of nutrients and antioxidant capacity. Although evaluation methods and results reported have not yet been sufficiently standardised, making comparisons difficult, our data add valuable information to current knowledge of the nutritional properties of tropical fruits, such as the considerable antioxidant capacity found for acerola-Malpighia emarginata and camu-camu-Myrciaria dubia (ABTS, DPPH and FRAP) and for puçá-preto-Mouriri pusa (all methods).

Many tropical fruits are rich in anthocyanins, though limited information is available about the characterization and quantification of these anthocyanins. The identification and quantification of anthocyanin pigments in four tropical fruits were determined by HPLC-MS/MS. Fruits studied included acerola (Malphigia emarginata), jussara (Euterpe edulis), jambolão (Syzygium cumini), and guajiru (Chrysobalanus icaco). All four fruits were found to contain anthocyanin pigments. Anthocyanidin backbones included cyanidin, delphinidin, peonidin, pelargonidin, petunidin, and malvidin. Guajiru contained several acylated forms, while acerola, jussara, and jambolão contained only nonacylated glycosides. These results demonstrate that these tropical fruits are rich in anthocyanins and that the anthocyanins are widely ranging in anthocyanidin backbone, glycosylation, and acylation.

The antiradical capacity (radical-scavenging capacity, RSC) of seven tropical fruit from the Brazilian northeast (açaí, acerola, cashew apple, mangaba, murici, umbu and uvaia) were studied using the 2,2diphenyl-1-picrylhydrazyl radical (DPPH Å) assay. To determine their RSC, the second-order rate constants (k 2) for the oxidation of these extracts by DPPH Å were calculated. The values of k 2 were compared to natural and synthetic antioxidants. The k 2 values (l/mol g s), in methanol at 25°C, were 38.