Partition of antioxidants available in biowaste using a green aqueous biphasic system

Abstract

The most common feedstocks for natural antioxidants, i.e., chemicals which delay the oxidative damage by reactive oxidative species, are fruits and vegetables, but using food as raw material raises moral issues and contributes to several environmental and social problems, such as larger farming areas and global hunger. Therefore, the use of antioxidant-rich biowaste is a more feasible option for the production of dietary supple-ments, contributing simultaneously to a more circular economy and to more sustainable therapeutics. In this work, the partition of epicatechin and of vitamins B9, B12 and C was conducted, for the first time, in the green Aqueous Biphasic System (ABS) {ethyl lactate (1) + trisodium citrate (2) + water (3)} at 298.15 K and atmo-spheric pressure for future valorisation of common biowastes, such as fruit pomaces and vegetable peals. The largest partition coefficients (K) and extraction efficiencies (E) were obtained for vitamin B12 (K = 55.44, E = 98.5 %) and epicatechin (K = 5.44, E = 84.8 %) for the longest tie-line (TLL = 69.68 %), while, in the same conditions, vitamin B9 (K = 1.48, E = 61.6 %) and vitamin C (K = 0.44, E = 32.2 %) presented smaller affinity for the ethyl lactate-rich phase. These results were obtained with low biomolecule mass losses in quantification and after a careful study of the biomolecule stages present for each pH value.