Antioxidant activity of apple and strawberry (fresh fruits and purees) was evaluated using different extraction solvent: water, water/acetone, acetone, buffer solution (pH 2) and two different methods of analysis: DPPH· radical scavenging activity and crocin bleaching competition kinetic. The different solvents affected the antioxidant activity and, in particular, extracts having similar responses to the Folin- Ciocalteau assay showed very different antioxidant activities. The antioxidant activity of ascorbic acid and some selected phenolic compounds (p-coumaric acid, caffeic acid, chlorogenic acid, gallic acid, epicatechin, phloridzin, quercetin, pelargonidin) diluted in the previously considered solvents was tested by both the above mentioned methods of analysis. The solvent showed to influence dramatically the antioxidant activity of the bioactive compounds even if it is added to the reaction mixture in small amounts. In particular ascorbic acid showed the maximum antioxidant activity in acqueous solution at pH 2 while phenolic compounds showed the maximum antioxidant activity in water and water/acetone solution (respectively for crocin bleaching and DPPH· method) and a very low antioxidant activity at pH 2. Pelargonidin was the only polyphenol whose antioxidant activity was not influenced by the pH of the solution. These results suggests that in order to compare the antioxidant activity of vegetables extracts it is important to consider the solvent, not only because it could influence the extraction of bioactive compounds but also because it could directly influence their antioxidant activity.[...]

Effect of solvent and method of analysis on the antioxidant activity of fruit extracts and natural compounds

SACCHETTI, Giampiero;MASTROCOLA, Dino;
2004-01-01

Abstract

Antioxidant activity of apple and strawberry (fresh fruits and purees) was evaluated using different extraction solvent: water, water/acetone, acetone, buffer solution (pH 2) and two different methods of analysis: DPPH· radical scavenging activity and crocin bleaching competition kinetic. The different solvents affected the antioxidant activity and, in particular, extracts having similar responses to the Folin- Ciocalteau assay showed very different antioxidant activities. The antioxidant activity of ascorbic acid and some selected phenolic compounds (p-coumaric acid, caffeic acid, chlorogenic acid, gallic acid, epicatechin, phloridzin, quercetin, pelargonidin) diluted in the previously considered solvents was tested by both the above mentioned methods of analysis. The solvent showed to influence dramatically the antioxidant activity of the bioactive compounds even if it is added to the reaction mixture in small amounts. In particular ascorbic acid showed the maximum antioxidant activity in acqueous solution at pH 2 while phenolic compounds showed the maximum antioxidant activity in water and water/acetone solution (respectively for crocin bleaching and DPPH· method) and a very low antioxidant activity at pH 2. Pelargonidin was the only polyphenol whose antioxidant activity was not influenced by the pH of the solution. These results suggests that in order to compare the antioxidant activity of vegetables extracts it is important to consider the solvent, not only because it could influence the extraction of bioactive compounds but also because it could directly influence their antioxidant activity.[...]
2004
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11575/9021
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