RESUMO
The Amazon region has many sources of fruits, especially native ones not yet explored, but which have some potential for use, as is the case with certain palms. The objective of this study was to evaluate the content of bioactive compounds and total antioxidant capacities of fruits from native palms from the Brazilian Amazon. The fruits of five palm species (bacaba, buriti, inajá, pupunha, and tucumã) were evaluated for levels of ascorbic acid, anthocyanins, yellow flavonoids, total carotenoids, and total extractable polyphenols, as well as the total antioxidant capacities. The fruits had high contents of extractable total polyphenols, especially bacaba and tucumã (941.56 and 158.98 mg of galic acid·100g(-1)), total carotenoids in the case of tucumã and buriti (7.24 and 4.67 mg·100g(-1)), and anthocyanins in bacaba (80.76 mg·100g(-1)). As for the antioxidant capacity, bacaba had the highest total antioxidant activity by the Oxygen Radical Antioxidant Capacity (ORAC) (194.67 µM·Trolox·g(-1)), 2,2-diphenyl-1-picrylhydrazyl (DPPH) (47.46 g·pulp·g(-1) DPPH), and ß-carotene/linoleic acid (92.17% Oxidation Inhibition (O.I) methods. Bacaba phenolic profile revealed the presence of cyanidin-3-O-rutinoside and other flavonoids. The palm fruits studied can be considered good sources of bioactive compounds, some containing higher amounts than that of commonly consumed fruits. Total extractable polyphenols and anthocyanins were directly correlated to antioxidant activity in these fruits.
RESUMO
The present research work describes the major changes in the antioxidant properties during development of acerola from five different clones. Ripening improved fruit physicochemical quality parameters; however, total vitamin C and total soluble phenols (TSP) contents declined during development, which resulted in a lower total antioxidant activity (TAA). Despite the decline in TSP, at ripening, the anthocyanin and yellow flavonoid content increased and was mainly constituted of cyanidin 3-rhamnoside and quercetin 3-rhamnoside, respectively. The activities of oxygen-scavenging enzymes also decreased with ripening; furthermore, the reduction in vitamin C was inversely correlated to membrane lipid peroxidation, indicating that acerola ripening is characterized by a progressive oxidative stress. Among the studied clones, II47/1, BRS 237, and BRS 236 presented outstanding results for vitamin C, phenols, and antioxidant enzyme activity. If antioxidants were to be used in the food supplement industry, immature green would be the most suitable harvest stage; for the consumer's market, fruit should be eaten ripe.