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Master's Dissertation
DOI
10.11606/D.11.2010.tde-20102010-101541
Document
Author
Full name
Ana Paula Tiveron
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 2010
Supervisor
Committee
Alencar, Severino Matias de (President)
Brazaca, Solange Guidolin Canniatti
Santos, Luciana Ferracini dos
Title in Portuguese
Atividade antioxidante e composição fenólica de legumes e verduras consumidos no Brasil
Keywords in Portuguese
Antioxidantes
Consumo de alimentos - Brasil
Cromatografia a gás
Espectrometria d massas
Hortaliças
Legumes
Química de alimentos.
Abstract in Portuguese
As hortaliças são alimentos amplamente consumidos na dieta dos brasileiros. Há alguns anos, estudos sobre compostos presentes em vegetais, como os carotenóides, vitaminas, fibras e compostos fenólicos vem sendo bastante explorados devido aos seus possíveis efeitos biológicos e benefícios à saúde humana. Os compostos fenólicos são produtos do metabolismo secundário das plantas e se destacam principalmente por seu poder antioxidante. O objetivo deste trabalho foi avaliar os compostos fenólicos e a atividade antioxidante em algumas hortaliças consumidas no Brasil. Os métodos utilizados foram o do radical livre DPPH e ABTS, auto-oxidação do sistema -caroteno/ácido linoléico, redução do ferro, estabilidade oxidativa em Rancimat e identificação química por meio da técnica de cromatografia gasosa acoplada a espectrômetro de massas. Extratos etanólicos foram utilizados em todas as análises. O teor de compostos fenólicos variou entre 1,2 a 16,9 mg/g, sendo que a cenoura apresentou a menor quantidade e a alface a maior. As hortaliças que apresentaram a maior atividade antioxidante foram a alface (54,9% e 0,45 µmol Fe2+/mg), nos métodos do DPPH e FRAP , respectivamente, o açafrão (111,8µM trolox/g e 92,8%), nos métodos ABTS+ e -caroteno, o agrião e o brócolis no método do Rancimat (fator de proteção 1,29). Além dessas, a alcachofra, espinafre, e aspargo também apresentaram atividade antioxidante considerável. Os compostos fenólicos mais frequentemente encontrados nas amostras pela técnica de CG-EM foram os ácidos ferúlico, caféico e p-cumárico. O ácido ascórbico presente também contribuiu para a atividade antioxidante de alguns vegetais. Desta forma, pode-se verificar boa atividade antioxidante de várias hortaliças, ressaltando assim a importância em uma dieta equilibrada destes vegetais.
Title in English
Antioxidant activity and phenolic composition of vegetables consumed in Brazil
Keywords in English
Antioxidants
chemical food.
food consumption Brazil
gas chromatography
greenstuff
mass spectrometry
vegetables
Abstract in English
Vegetables are widely consumed foods in the diet of Brazilians. A few years ago, studies on compounds present in vegetables such as carotenoids, vitamins, fibers and phenolic compounds have been conducted due to their biological effects and benefits to human health. Phenolic compounds are distinguished mainly by their antioxidant power. The aim of this study was to evaluate the phenolic compounds and antioxidant activity in some vegetables consumed in Brazil. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, -carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, while the chemical composition used the gas chromatography - mass spectrometry technique (GC-MS). Ethanol extracts were used in all analysis. The content of phenolic compounds ranged from 1.2 to 16.9 mg / g, with carrots presenting the lowest amount and lettuce the highest. The vegetables with the highest antioxidant activity were lettuce (54.9% and 0.45 mmol Fe2+/ mg), through DPPH and FRAP methods, respectively, saffron (111.8 mM trolox / g and 92.8%) through the ABTS+ and -carotene methods, watercress and broccoli through the Rancimat method (protective factor 1.29). Besides these, the artichoke, spinach, and asparagus also showed considerable antioxidant activity. Phenolic compounds most frequently found through the GCMS technique were ferulic acid, caffeic acid and p-coumaric acid. Ascorbic acid also contributed to the antioxidant activity of some vegetables. Generally, it is confirmed the good antioxidant activity of some vegetables, emphasizing its importance in a balanced diet.
 
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Ana_Paula_Tiveron.pdf (2.29 Mbytes)
Publishing Date
2010-11-03
 
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