Volume 47, No. 02, Month APRIL, Year 2020, Pages 164 - 172
Effect of ethanol percentage upon various extraction methods of peanut based on antioxidant activity with trans-resveratrol and total phenolic contents
The aim of this study was to determine the effect of ethanol percentage in the extraction solvent on the constituents of peanut extracts prepared from three extraction methods including Solid-Liquid Extraction (SLE), Ultrasound-Assisted Extraction (UAE) and Microwave-Assisted Extraction (MAE). Evaluation was performed through antioxidant tests together with trans-resveratrol and total phenolic contents. The ethanol content was set at 20 and 80%v/v. Although extraction with 80%v/v ethanol gave higher percentage yield of the extract, it provided lower resveratrol amount and total phenolic content in all extraction techniques. Lower ethanol content mostly showed positive influence on radical scavenging antioxidant capacity of the extract (DPPH and ABTS assay). Moreover, with DPPH and ABTS assay, trans-resveratrol and total phenolic contents demonstrated strong and moderate correlation with antioxidant activity, respectively. On the contrary, solvent with higher percentage of ethanol in SLE and UAE caused higher reducing power extracts with Ferric Reducing Antioxidant Power (FRAP) assay. This implied that, different ethanol composition in SLE and UAE extracted different types of compounds that possessed different mechanisms of antioxidant activity. Concerning extraction methods, UAE was the most effective extraction method which provided the highest antioxidant activity of the extract. According to this study, the percentage of ethanol and extraction methods had significant influence on the composition of the extracts assessed through antioxidant activities as well as trans-resveratrol and total phenolic contents.
Keywords
Ethanol percentage; Extraction solvent; Antioxidant activity; trans-Resveratrol; Total phenolic content