Antioxidants and sensory properties of the infusions of wild passiflora from Brazilian savannah: potential as functional beverages.

BACKGROUND: The study of biodiversity for species recovery and sustainable use has encouraged research with plants from Brazilian savannah. We aimed to characterize chemical and sensory properties of infusions of passifloras, due to their potential as functional beverages. Infusions and hydroalcoholic extracts of four species of wild passifloras, three varieties of Passiflora edulis and a commercial passiflora tea were evaluated for total phenolics (TPs), total flavonoids (TFs), condensed tannins (CTs), and antioxidant activity (DPPH and FRAP). Free-choice Profile and acceptance, compared with green tea, were performed for sensory characterization. RESULTS: In general, infusions had higher levels of TPs and CTs than hydroalcoholic extracts, which in turn had higher levels of TFs. Infusion of P. nitida showed higher amounts of TPs and antioxidant activity. Acceptance of passiflora infusions was similar or higher than that of green tea, except for P. alata. P. setacea presented a sensory profile similar to other commercial teas and higher acceptance by a group of consumers. CONCLUSION: Passiflora infusions showed different degrees of suitability as acceptable functional beverage. Identification of phenolics and other bitter compounds is needed to understand the intense bitterness of P. alata, as it did not present the highest contents of TPs, CTs and TFs.

Variations in antioxidant properties of strawberries grown in Brazilian savannah and harvested in different seasons.

BACKGROUND: Strawberries are nutritive fruits and a source of antioxidants. We evaluated antioxidant properties of 'Camino Real' strawberries grown in the Brazilian savannah, harvested in different seasons. Analytical and meteorological data were analyzed by partial least squares regression. RESULTS: Fruits from May showed the lowest contents of total phenolics (1789.78 mg kg⁻¹ fresh weight (FW)), catechin (21.37 mg kg⁻¹ FW), quercetins (4.89 mg kg⁻¹ FW) and total ellagic acid (208.68 mg kg⁻¹ FW) and the lowest antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) (11.39 mg Butylated hydroxytoluene (BHT) eq. g⁻¹ FW) and ferric reducing antioxidant power (FRAP) (22.01 mg ferrous sulfate eq. g⁻¹ FW) assays. Strawberries harvested in July presented the lowest concentrations of total (190.61 mg kg⁻¹ FW) and individual anthocyanins (73.88 mg kg⁻¹ FW and 5.96 mg kg⁻¹ FW for pelargonidin-3-glucoside and cyanidin-3-glucoside, respectively), but the highest contents of vitamin C (685.47 mg kg⁻¹ FW), DPPH (18.87 mg BHT eq. g⁻¹ FW) and FRAP (39.30 mg ferrous sulfate eq. g⁻¹ FW). The highest contents of free ellagic acid (26.11 mg kg⁻¹ FW), pelargonidin-3-glucoside (291.82 mg kg⁻¹ FW) and cyanidin-3-glucoside (11.84 mg kg⁻¹ FW) were found in strawberries from September. Rain in the previous 30 days to harvest influenced negatively many phenolics and antioxidant activity of strawberries harvested in May. In July, longer photoperiod and lower temperature at 30 days previous to harvest probably led to higher antioxidant activity and vitamin C. Increased photoperiod and temperature at the final stage of maturation seem to raise pigments and free ellagic acid in strawberries. CONCLUSION: It was possible to observe significant relationships among meteorological and antioxidant variables for strawberries grown in the Brazilian savannah.