Whey and water-ethanol solution as extractants of biologically active substances: Comparative analysis

Industrial whey wastes contain organic substances that cause serious harm to the environment, which makes whey recycling a relevant research objective. Whey can serve as an extractant of biologically active substances from plant raw materials. This research compared a 70% aqueous-ethanol solution and whey as extractants of bioactive components from a plant blend of Heracleum sibiricum L., Syringa vulgaris L., Arctium tomentosum Mill., Achillea millefolium L., Thymus vulgaris L., and Pulmonaria officinalis L. The method of high-performance liquid chromatography revealed catechin, chlorogenic acid, astragalin, ferulic acid, coumaric acid, and some trace amounts of other compounds. The samples subjected to water-ethanol extraction demonstrated a better quantitative and qualitative profile than those processed with whey: 637.92 vs. 380.45 mg/kg for chlorogenic acid, 93.05 vs. 2.34 mg/kg for coumaric acid, and 53.12 vs. 3.09 mg/kg for astragalin. Whey proved unable to extract catechin and ferulic acid. However, whey made it possible to obtain compounds that water-ethanol solution failed to extract, namely rutin and caffeic acid. By fractionating the extracts and isolating individual biologically active substances, we obtained chlorogenic acid (90.0%), ferulic acid (92.0%), and coumaric acid (88.0%) with water and ethanol, as well as caffeic acid (84.5%) and rutin (78.0%) with whey. Both ethanol and whey proved industrially relevant and demonstrated good prospects for commercial extraction of biologically active substances from various plant raw materials.