Avaliação da atividade antioxidante e identificação dos ácidos fenólicos presentes no bagaço de maçã cv. Gala

Abstract

O crescente interesse pelos antioxidantes naturais de extratos de plantas é devido à sua baixa toxicidade em relação aos antioxidantes sintéticos. Extratos de frutas, vegetais, cereais e seus subprodutos industriais são ricos em antioxidantes, em áci-do ascórbico, tocoferóis, carotenóides e em compostos fenólicos e têm demonstrado eficaz atividade antioxidante em sistemas modelos (WOLFE;WU;LIU, 2003;MANACH et al., 2004).Os compostos fenólicos são formados no metabolismo secundário dos vegetais e possuem funções de defesa contra o ataque de pragas. Já em animais e humanos tem-se observado que são capazes de reagir com radicais livres, formando radicais estáveis. Esse poder de neutralização das estruturas radicalares dos compostos fenólicos é devido à sua estrutura química formada por pelo menos um anel aromático com grupamentos hidroxilas (GIADA; MANCINI-FILHO, 2006). Além da sua atividade antioxidante direta, pesquisas recentes têm destacado múltiplas funções e mecanismos importantes relacionados à habilidade dos compostos fenólicos de se ligarem AbstractApple processing to obtain juice produces a great amount of discarded material constituted by peel and seed. Several substances, including phenolic compounds, to which antioxidant activity is attributed, are found in these fractions. This work aimed at evaluating total phenolic compounds and in vitro antioxidant activity of extracts and phenolic fractions (free, soluble esterified and insoluble esterified) of apple, cv. Gala, residues. The methodologies used were DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid] to evaluate antioxidant activity and gas chromatography to determine phenolic acids. Extraction with 75% acetone (v/v) in water was the most efficient to obtain total phenolic compounds. The antioxidant activity in this extract was 4.83 and 25.46 µmol TEAC.g -1 by the ABTS method and 7.43 and 39.15 µmol TEAC.g -1 by the DPPH method for wet and dry samples, respectively. Flavanol contents in the same samples were 11.05 and 58.20 mg.100 g -1 for wet and dry samples, respectively. A positive correlation between total phenolics and antioxidant activity (r 2 = 0.9283) was observed. In the three fractions used, the following phenolic acids were identified: salicylic, gallic, propyl gallate and synaptic acid, being the first present in the highest amount in all the fractions studied. The results obtained showed the antioxidant potential of apple pomace. Keywords: Gala variety apple pomace; antioxidant activity; phenolic acids. ResumoNo processamento da maçã para obtenção do suco, ocorre a formação de uma elevada quantidade de resíduo, representado pelas cascas e sementes, no qual são encontradas diversas substâncias, como os compostos fenólicos, aos quais são atribuídas as propriedades antioxidantes. Este estudo teve como objetivo avaliar o conteúdo de compostos fenólicos totais e a atividade antioxidante in vitro de extratos e frações de ácidos fenólicos livres, esterificadas solúveis e esterificadas insolúv...

The influence of ripening stage and cultivation system on the total antioxidant activity and total phenolic compounds of yellow passion fruit pulp

“…The levels of the three independent variables—fruit pulp volume (FPV), methanol volume (MV) and extraction solution volume (ESV)—were coded as (i) − 1 and + 1, representing the levels of the 2 3 factorial design; (ii) 0 (zero), representing the central point of the design, which made it possible to estimate the lack of fit of the linear statistical model obtained as well as the pure error of the experiments; and (iii) − α and + α, representing the axial points, allowing for the study of a quadratic statistical model (Table 1). 21, 22 The maximum and minimum levels of each variable were selected based on previous experience and on the scientific literature 5, 11, 12…”

“…The extraction of phenolic compounds from a vegetable matrix deserves attention as it depends on the vegetable's intrinsic characteristics in addition to the extraction conditions. Studies reveal that ethanol, methanol and acetone are efficient agents for phenolic extraction 3, 11–14. Using the right solvent and extraction conditions is crucial and this is only assured by performing an appropriate experimental design.…”

Inhibition of Pancreatic Lipase and Characterization by Extracts From Fruit Pomaces Cultivars Grown in Brazilian Semiarid

“…Li et al (2006) compared content of phenolic compounds of pulp and peel from pomegranates and they observed that inside of fruit presented 24.4 mg GAE -1 of phenolic compounds, peel 249.4 mg GAE -1 . Soares et al (2008) analyzing total phenolics of Vitis labrusca peel and Vitis vinifera (Isabel) found values of 219.56 and 1.24 mg GAE -1 , respectively, using concentration acetone 75% (v/v) as solvent extractor. Values obtained in this study were lower than those found by cited researchers.…”

Optimization of Phenolic Compounds Extraction in an Apple Pomace Flour Enriched WithAgaricus brasiliensis

“…O bagaço permanece com seus componentes bioativos em sua biomassa fresca, mesmo após o processo de produção do suco. A maçã apresenta elevado teor de metabólitos, tais como flavonóides, polifenóis e ácidos fenólicos, encontrados na polpa e, principalmente, em sua casca, que fornece as propriedades antioxidantes dessa fruta [29]. …”