Phenolic composition and antioxidant activity of agroindustrial residues/Composicao fenolica e atividade antioxidante de residuos agroindustriais.

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From: Ciencia Rural(Vol. 41, Issue 6)
Publisher: Universidade Federal de Santa Maria
Document Type: Article
Length: 2,917 words

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Abstract :

Nowadays, the agro-industrial processing produces millions of tons of wastes. Many of them are rich in bioactive compounds, being a potential natural source of these substances. This study aimed to evaluate the content of total phenolics, antioxidant activity and phenolic composition of residues generated by three Brazilian agribusiness: Isabel grape pomace (PI) (Vitis labrusca), Verdejo grape pomace (PV) (Vitis vinifera) and guava pomace (PG) (Psidium guajava). The results of total phenolics content (mg GAE [g.sup.-1]) found in the ethanol and aqueous extracts of residues were: PV (20.94 ± 0.46; 8.03 ± 0.43) PI (16.57 ± 0.19; 4.41 ± 0.01) PG (3.41 ± 0.09; 1.88 ± 0.06). High antioxidant activity of these extracts, particularly PV and PI, was found by the methods DPPH*, ABTS * and beta-carotene bleaching method. A strong positive correlation between antioxidant activity and content of total phenolic compounds was found. The following phenolic compounds were found by gas chromatography with mass spectrometry (GC-MS): gallic acid, epicatechin, quercetin (PV, PI and PG); isovanilic acid (PI, PG), p-coumaric acid (PI), caffeic acid and resveratrol (PV, PI). The results show that these residues, particularly the wineries, are rich in bioactive substances and should be exploited by the food industry and pharmaceuticals. Key words: agroindustrial residues, phenolic compounds, antioxidant activity, DPPH*, ABTS*, betacarotene bleaching method, GC-MS. Atualmente, sao produzidas milhoes de toneladas de residuos provenientes do processamento agroindustrial. Muitos deles sao ricos em compostos bioativos sendo potenciais fontes naturais dessas substancias. Assim, este trabalho teve como objetivo avaliar o teor de compostos fenolicos totais, a atividade antioxidante e a composicao fenolica de tres residuos gerados por agroindustrias brasileiras: bagaco de uva Isabel (BI) (Vitis labrusca), bagaco de uva Verdejo (BV) (Vitis vinifera) e bagaco de goiaba (BG) (Psidium guajava). Os resultados do teor de compostos fenolicos totais (mg GAE [g.sup.-1]) encontrados nos extratos etanolicos e aquosos dos residuos foram, respectivamente: BV (20,94 ± 0,46; 8,03 ± 0,43) BI (16,57 ± 0,19; 4,41 ± 0,01) BG (3,41 ± 0,09; 1,88 ± 0,06). Alta atividade antioxidante, principalmente em BV e BI, foi verificada nos ensaios realizados (ABTS*, DPPH* e autooxidacao do sistema beta-caroteno/acido linoleico). Uma forte correlacao positiva entre atividade antioxidante e o teor de compostos fenolicos totais foi encontrada. Os compostos fenolicos encontrados, por cromatografia gasosa com espectrometria de massas (CG-EM), foram: acido galico, epicatequina, quercetina (BV, BI e BG); acido isovanilico (BI, BG); acido p-cumarico (BI); acido cafeico e resveratrol (BV, BI). Esses resultados mostram que os residuos agroindustriais analisados, particularmente os vinicolas, sao ricos em substancias bioativas e podem ser explorados pela industria de alimentos e farmaceutica. Palavras-chave: residuos agroindustriais, compostos fenolicos, atividade antioxidante, DPPH*, ABTS*, auto-oxidacao do sistema betacaroteno/acido linoleico, CG-EM.

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Gale Document Number: GALE|A442116003