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Atividade antioxidante do alho (Allium sativum L.) quando submetido a diferentes processos tecnológicos
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Abstract(s)
O alho tem sido utilizado ao longo da história para fins medicinais e culinários. Para além do sabor caraterístico que confere aos pratos em que é utilizado, o alho é conhecido pelas suas atividades biológicas, nomeadamente, pela sua capacidade antioxidante. Os compostos bioativos do alho são bem conhecidos por possuírem efeitos benéficos para a saúde, nomeadamente na prevenção de diversas patologias, como por exemplo, doenças cardiovasculares, doenças ateroscleróticas e cancro.
No âmbito da avaliação da atividade antioxidante do alho, foi efetuada a determinação dos teores de fenóis e de flavonoides totais de extratos das diferentes formas de apresentação / partes do alho (bulbo, casca, em pó, comprimidos/cápsulas). Determinou-se também a capacidade antioxidante dos mesmos, através do método do radical DPPH• e por redução do ião férrico (FRAP). Foi ainda avaliada a capacidade de captação de espécies reativas (O2-•, H2O2, NO•) dos referidos extratos. Por fim, estudou-se a influência da fervura e do congelamento nas propriedades do bulbo.
Concluiu-se, com base nos resultados obtidos, que quanto maior o teor de fenóis totais obtido, maior a capacidade de inibição das espécies reativas (NO•, O2-• e H2O2) dos diferentes extratos. Embora todos os extratos tenham evidenciado valores significativos de compostos fenólicos e flavonoides, o extrato de alho congelado foi aquele que apresentou uma maior quantidade destes compostos, o que consequentemente o torna o extrato com maior capacidade de captação das espécies reativas NO•, O2-• e H2O2.
Quanto ao método do radical DPPH• e ao método FRAP, obteve-se para o extrato de alho cozido uma maior atividade antioxidante. O extrato de cascas de alho evidenciou uma atividade antioxidante significativa, enquanto que os extratos de comprimidos à base de alho e do condimento de alho picado apresentaram uma menor atividade antioxidante em comparação com a do alho fresco.
Garlic has been used throughout history for medicinal and culinary purposes. Besides the characteristic flavor that it gives to the dishes in which it is used, the garlic is known for its biological activities, namely, for its antioxidant capacity. Garlic bioactive compounds are well known to have beneficial health effects in prevention of various conditions, for example, heart diseases, atherosclerotic diseases and cancer. In the evaluation of the antioxidant activity of garlic, total phenolic and flavonoid contents of extracts of the different forms of presentation / parts of the garlic (bulb, peel, powder, tablets / capsules) were determined. The antioxidant capacity was also determined by the DPPH• radical and the ferric ion reduction (FRAP) method. It was also evaluated the capacity of capture of reactive species (O2-•, H2O2, NO•) of said extracts. Finally, the influence of boiling and freezing on the properties of the bulb was studied. Based on the results obtained, the higher the total phenol content obtained, the greater the inhibition capacity of the reactive species (O2-•, H2O2 and NO•) of the different extracts. Although all the extracts showed significant values of phenolic compounds and flavonoids, the frozen garlic extract was the one that presented a greater amount of these compounds, which consequently makes it the extract with greater capacity of capture of the reactive species O2-•, H2O2 and NO•. In relation to DPPH• radical method and FRAP method, a higher antioxidant activity was obtained for the extract of cooked garlic. The extract of garlic peels showed a significant antioxidant activity, whereas extracts of garlic tablets and garlic seasoning had a lower antioxidant activity compared to fresh garlic.
Garlic has been used throughout history for medicinal and culinary purposes. Besides the characteristic flavor that it gives to the dishes in which it is used, the garlic is known for its biological activities, namely, for its antioxidant capacity. Garlic bioactive compounds are well known to have beneficial health effects in prevention of various conditions, for example, heart diseases, atherosclerotic diseases and cancer. In the evaluation of the antioxidant activity of garlic, total phenolic and flavonoid contents of extracts of the different forms of presentation / parts of the garlic (bulb, peel, powder, tablets / capsules) were determined. The antioxidant capacity was also determined by the DPPH• radical and the ferric ion reduction (FRAP) method. It was also evaluated the capacity of capture of reactive species (O2-•, H2O2, NO•) of said extracts. Finally, the influence of boiling and freezing on the properties of the bulb was studied. Based on the results obtained, the higher the total phenol content obtained, the greater the inhibition capacity of the reactive species (O2-•, H2O2 and NO•) of the different extracts. Although all the extracts showed significant values of phenolic compounds and flavonoids, the frozen garlic extract was the one that presented a greater amount of these compounds, which consequently makes it the extract with greater capacity of capture of the reactive species O2-•, H2O2 and NO•. In relation to DPPH• radical method and FRAP method, a higher antioxidant activity was obtained for the extract of cooked garlic. The extract of garlic peels showed a significant antioxidant activity, whereas extracts of garlic tablets and garlic seasoning had a lower antioxidant activity compared to fresh garlic.
Description
Keywords
Alho Allium sativum Congelamento Cozimento Cascas de alho Condimento de alho Suplemento de alho Polifenóis Fenólicos Flavonoides Atividade antioxidante Captação de espécies reativas Garlic Allium sativum Freezing Cooking Garlic peels Garlic seasoning Garlic supplement Polyphenols Phenolics Flavonoids Antioxidant activity Antioxidant activity