Evaluation of antioxidant capacity of some fruit and vegetable foods: efficiency of extraction of a sequence of solvents

Abstract

All methods for assessing the total antioxidant capacity (TAC) of food samples are strongly affected by the solvents used during extraction. In recent years a sequential solvent extraction procedure utilising water and acetone has been widely used for TAC measurements of foods. To better understand the efficiency of this procedure in terms of the amount of extracted antioxidants and the subsequent measurement of TAC, two vegetables (onion and spinach) and two fruits (orange and tomato) were sequentially extracted with water, acetone and chloroform. Each extract fraction was analysed separately for its content of known antioxidant compounds by specific procedures and for its TAC by the Trolox equivalent antioxidant capacity assay. The results showed that the compounds in the water and acetone extracts were the main contributors to TAC. The chloroform extracts did not contribute to TAC, with the exception of the spinach extract, owing to the presence of low levels of carotenoids. In conclusion, the analysed extraction procedure was more effective for foods rich in water-soluble antioxidants than for those rich in lipid-soluble antioxidants.

The effect of solvent extraction on antioxidant properties of apricot fruit

“…Scalzo et al [9] performed sequential extractions with methanol/water (80% v/v) and acetone on fruit samples of the 'San Castrese' apricot cultivar and found that the lipophilic extracts contributed 7% of the total antioxidant capacity. Pellegrini et al [27] reported that tomato lipidsoluble antioxidants in the acetone extracts for TAC determination were lower than those obtained from THF extraction, which is more efficient than acetone at extracting carotenoids. In view of these results, the higher percentage of the lipophilic TAC contribution, nearly 15%, to the total TAC obtained in our study, compared to published results, is likely related to the specific solvent efficiency for less polar compounds such as carotenes in apricot fruit.…”

Physicochemical characterization and antioxidant capacity of pitanga fruits (Eugenia uniflora L.)

“…The extraction of phenolic compounds was performed using the method of Escarpa and González (2001) with some modifications, as described by Pellegrini et al (2007). This method allows a quantitative extraction of the main polyphenolic classes: hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids.…”

Bioactive compounds, antioxidant activity and minerals of Caju (Anacardium humile St. Hill) during the ripening

“…Due to the complexity of the composition of foods, their antioxidant power depends on the synergistic effects and redox interaction between the different nutrient and "nonnutrient" molecules, which together contribute to the possible health benefits. Therefore, attention has been given to the antioxidant activity of fruits, a parameter that allows a real evalution of the nutritional value of foods (Lenucci et al, 2006;Pellegrini et al, 2007).…”