A Novel Two-Step Process to Co-valorize Antioxidant Rich By-products of Olive and Grape Processing Industries

An integrated process for collective recovery of phenolic compounds from olive mill wastewater (OMW) and grape pomace (GP), which would also benefit easier biodegradation of OMW in a further process, was developed. Response surface methodology was employed to optimize the process parameters. Treatment of GP with OMW resulted in the transfer of 64.41 % of total polyphenols contained in OMW to GP under the optimal conditions predicted by the model. In the following step, extraction of phenolic compounds in treated-GP with ethyl alcohol:water under the optimum conditions predicted by the model was performed and 11.97 mg g−1 phenolics was recovered. The total antioxidant activity of the recovered phenolics was 81 % (inh.).