A multifunctional extract from corn steep liquor: antioxidant and surfactant activities

Abstract

In the last few years the awareness of consumers and institutions about the impact that our industrial processes has on health and the environment has increased, demanding more natural products. In this work, a multifunctional bioactive extract with surfactant and antioxidant properties, composed mainly of C16 and C18 fatty acids, and phenolic compounds (vanillic acid, p-coumaric acid, ferulic acid, sinapic acid and quercetin) was obtained from corn steep liquor (CSL). Different liquid–liquid extraction protocols were evaluated obtaining a natural extract, which was able to reduce the surface tension of water by more than 30 units, showing antioxidant activity with an EC₅₀ of 8.51 mg mL⁻¹ and a yield of 6.85 g of extract per kg of CSL. Additionally, it was observed that after liquid–liquid extraction with chloroform, the aqueous phase can be subjected to a hydrothermal treatment, followed by extraction with ethyl acetate, in order to obtain another extract (24.7 g of extract per kg of CSL) with a higher antioxidant capacity (EC₅₀ of 4.02 mg mL⁻¹). In this case the antioxidant extract is composed of protocatechuic acid, vanillic acid, caffeic acid, epicatechin, p-coumaric acid, ferulic acid, sinapic acid and quercetin.