Microfi ltration of centrifuged açaí pulp was performed using two types of membrane (ceramic and polymeric), each one at two temperatures (25 and 35°C), aiming to evaluate the infl uence of these parameters on its chemical composition and antioxidant activity. Temperature and membrane material did not signifi cantly infl uence the bioactive components contents and the antioxidant activity of the two obtained fractions. However, permeate fl ux was strongly dependent on both factors, reaching the highest mean value (117 l/h m 2) with the ceramic membrane at 35°C. Clarifi ed juice, the permeate fraction, contained about 16 mg/100 g of anthocyanins, 138 mg/100 g of total phenolics and 9 μmol Trolox/g of antioxidant activity. The retained fraction, with characteristics similar to the original açaí fruit, presented 75 mg/100 g of anthocyanins, 433 mg/100 g of total phenolics and 31 μmol Trolox/g of antioxidant activity. Therefore, microfi ltration of açaí resulted in two fractions with distinct characteristics, both rich in bioactive components and with potential industrial application.
Wine industry produces large quantities of by‐products rich in bioactive compounds from grapes, which could be utilized for nutraceutical purposes. We aim to evaluate antioxidant activity (AC) and bioactivity of grape pomace extract from Brazilian wine industry in human hepatocarcinoma cells (HepG2). The content of bioactive compounds and AC of extracts were determined by ORAC, TEAC (ABTS•‐) and TRAP assays. Bioactivity was assessed on HepG2 and on normal human fibroblasts (BEAS). Cellular viability was accessed by MTT reduction and cellular antioxidant capacity (CAC) by dichlorofluorescein oxidation, under short‐, medium‐, and long‐term incubation periods. Total phenolics, flavonoids and anthocyanins of extracts where, respectively, (mean±SD) 473.8±52.4 mg GAE/100g, 147.5±2.77 mg CE/100g and 105.5±7.27 mg cyanidin3‐glycoside/100g. Extract AC was (mean±SD; µmol TE/g) 27.1±0.33, 9.33±6.74, 122.2±2.40. HepG2 viability reduced in a time‐ and dose‐dependent manner. Short‐term incubation had no effect whereas medium‐ and long‐term incubation induced, respectively, a 37% and a 75% reduction in viability. BEAS viability was not affected by the extract, regardless of time and concentration used. Interestingly, short‐term incubation promoted a dose‐response increase in HepG2 CAC, suggesting that decreased oxidative stress signals to decrease HepG2 proliferation. Taken together, wine industry by‐products present important antioxidant activity and potential selective anticancer and antiproliferative effects on HepG2 cells.
Grant Funding Source: Supported by FAPERJ, CNPq, CAPES, EMBRAPA (Brazil)
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