Recovery and solubility of flavonoid and phenolic contents from arachis hypogea in supercritical carbon dioxide assisted by ethanol as cosolvent

Abstract

Supercritical carbon dioxide (ScCO2) extraction assisted by Ethanol is one of the development methods to extract polar and nonpolar compounds. Thus, the objective of the study was to optimize extraction parameters to recover total phenolic content (TPC) and total flavonoid content (TFC) from peanut skin. Chrastil, Del Valle Aguilera, and Adachi-Lu models were applied to determine the solubility behaviors. The optimum condition was found at 29.43 MPa, 319.16 K, and 0.09 ml/min with 290.12 mg/L TPC and 488.26 mg/L TFC. Chrastil model gives good agreement to fit the solubility of flavonoid and phenolic contents due to the lowest Average absolute relative deviation were 3.27% and 7.75%, respectively. Practical applications: Peanut skin as waste of peanut industries contains high phenolic and flavonoid contents. Currently, conventional extraction process with toxic solvent has been used to extract peanut skin. ScCO2extraction is one of the solutions to break the limitation of solvent's toxicity. However, ScCO2 has the drawbacks that ScCO2 is powerful to extract the nonpolar compounds, but failure to extract the medium polar compounds especially for the flavonoid compounds. Thus, the addition of ethanol is one of development method to break this limitation. Furthermore, Semi-empirical model has been used in this study to determine the solubility behavior to enhance the solubility of phenolic and flavonoid contents. The results show that high temperature condition is suitable to enhance the solubility of TPC, otherwise low temperature condition is preferable in the enhancement of TFC solubility.