Recovery of Natural Hypoglycemic Compounds from Industrial Distillation Wastewater of Lamiaceae

The food industry generates the largest number of valuable by-products. The recovery of compounds such as fatty acids and polyphenols with notorious biological properties from biowaste is a new challenge in the circular economy scenario, as they represent value-added starting materials for the preparation of functional foods, food supplements, cosmetics and over-the-counter drugs. Less commonly explored are industrial wastewaters, which return to the nearby water streams without adequate treatment. Distillation wastewater (DWW) from the essential oils or agro-food industries may represent a valuable source of bioactive compounds to be valorized. In this work, DWW from rosemary was treated with different resins through dynamic and static adsorption/desorption approaches, for the recovery of phenolic compounds including rosmarinic acid. The most effective methodology, selected according to total phenolic and rosmarinic acid contents, as well as antioxidant activity evaluation, was applied to sage, thyme and oregano DWWs. The procedure provides several advantages compared with conventional separation processes, as it involves the lower consumption of reagents/solvents, low operational costs, ease of handling, and simplicity of scale-up. The results of this work highlight a fast and sustainable procedure for the recovery of rosmarinic acid and other phenolics (caffeic acid derivatives and flavonoid glycosides) from DWWS, thus affording a fraction with antioxidant and hypoglycemic activities.