Extraction of total phenolic content and antioxidant activity of Capsicum chinense and Capsicum spp in different solvents and extraction time

Abstract

The purpose of this work was to evaluate the extraction and quantification of total phenolic compounds and the antioxidant activity of two peppers processed by four different methods (in natura, dried, preserved in vinegar and preserved in oil). The extraction efficiency of total phenolics using seven solvents (distilled water, ethanol, 50% ethanol, methanol, 50% methanol, ketone p.a and 50% ketone) were checked. Total phenolic analyzes were performed using the Folin-Ciocalteu and gallic acid method to obtain the standard curve with 650 nm absorbance reading. The antioxidant activity was determined using a spectrophotometric method using the reagent 2,2-diphenyl-1-picryl hydrazyl (DPPH). No significant differences were observed in the two extraction times 6 and 24 h. For samples preserved in vinegar, no significant differences were observed between the solvents used for the extraction. The Capsicum chinense pepper showed the highest amount of phenolic compounds in all treatments when compared to the chili pepper, except when conserved in oil. For the dry pepper, the lowest total phenolic extraction value was obtained with 99.5% ethanol (p.a.) and acetone p.a ACS 99.5% (p.a.), which differed from the peppers preserved in oil. The analysis of the antioxidant activity of Capsicum chinense and Capsicum spp did not present a significant difference (p>0.05) when compared to the dried or vinegar preserved samples. However, the sample of Capsicum chinense pepper in natura presented higher antioxidant activity than the samples conserved in oil.
It can be considered from the experimental results that the peppers in this study, especially in fresh and dried form are good sources of natural antioxidants.