Effects of solvent extraction system on concentration and antioxidant activity of strawberry phenolics
Strawberry fruits contain phenolic compounds that exhibit antioxidant, anticancer, antitherosclerotic, antiinflammatory and anti-neurodegenerative properties. This study was aimed to evaluate and characterize the phenolic composition and antioxidant activities of wild and cultivated strawberries native to Serbia. Three solvent systems were used for phenolic extraction (methanol, ethanol, and acetone) at the same concentrations (70 percent) and with 100 percent deionized water in presence 0.1 percent HCl. The efficiency of the solvents used to extract phenols from the 4 dried strawberry samples varied considerably. The polyphenol content of the dried strawberry samples was 9.54 to 20.38 mg gallic acid equivalent/g dried fruit. Photodiode-array detection (DAD) has been used for screening of the different classes of phenolic compounds. The total phenolics and antioxidant activities in extracts of a wild strawberry were higher than those cultivated samples.
Berries such as strawberres are widely appreciated for its characteristic aroma, bright red colour, juicy texture and sweetness. They are used as processed food materials for juice, jam, dried fruits, ice cream, etc., and therefore are quite prevalent in our lives. Berries contain many phenolic substances, and attention is being paid to health promoting foods that have phenolic bioactivities (1). Strawberries are a very rich source of polyphenols in the human diet containing polyphenols from all classes. The variety and high content makes strawberries a very interesting sample for studies of polyphenols (2-4).
The critical point in studying polyphenols in fruit materials is the extraction procedure used since it dictates the nature and quantity of polyphenols that will be transferred to the extract and futher characterized. Their polarity makes them soluble in several types of polar solvents, such as methanol, ethanol, acetone, and water. Solvent extraction of polyphenolics is the initial step prior to quantification, purification, separation, and characterisation and generally involved the use of an acidified extragent.