Phenolic acid extraction from orange peel with natural deep eutectic solvents

Abstract

Abstract Orange peel were usually abandoned as waste. However, the valuable product in orange peel cannot be ignored. Essential oils, flavonoid and phenolic acid in orange peel are broadly exploited as important components in food, pharmaceutical and even cosmetic industries. Compared to conventional organic solvents, Natural Deep Eutectic Solvents (NADESs) is a category of environmental-friendly green solvents, providing a solution for toxic residues. Meanwhile, with the properties of non-flammability, low toxicity, non-volatility, high stability and low melting points, NADESs are promising in the application of plant extraction, such as oil and phenolic acid extraction. In recent researches, choline chloride based NADESs display excellent extraction properties from natural sources. Choline chloride as hydrogen bond acceptor and glucose as hydrogen bond donor, with ultrasonic-assisted extraction method, phenolic acid were extracted from orange peel. Different ratio of choline chloride and glucose were conducted in the experiment. In the result, when choline chloride/glucose/water (reaction medium) ratio is 5:2:5, the DPPH free radical scavenging activity reaches optimum; while when the ratio is 1:1:1, the tested tyrosinase inhibition rate reaches the largest, which means the extracted phenolic acid with NADESs is promising to be applied into pharmaceutical and cosmetic industries.