Reutilization of food wastes (14): New integrated process extraction-adsorption for selective recovery of phenolic antioxidants

The main objective of our team is to develop and optimize efficient eco-processes for selective recovery of functional biomolecules from agro-food wastes, allowing also to preserve their activities in the obtained extracts. Selective recovery of such biomolecules (antioxidants, colorants etc.) from food industry by-products has an ecological dimension. Firstly, the extraction of target biomolecules allow to valorize these by-products by obtaining extracts rich in these molecules. The obtained natural extracts present an interest for food, cosmetic and pharmaceutical industries as substitutes of analogous synthetic ingredients. Secondly, for extraction and purification of the target molecules, eco-friendly processes are developed and used, with low consumption of time and energy. For example, ultrasound-assisted extraction is very efficient for the recovery of antioxidant phenolics from black chokeberries (Aronia melanocarpa berries) and their wastes [1,2]. Aronia berries are one of the richest sources in phenolic antioxidants, particularly in anthocyanins, and are mainly used to produce fruit juice. The wastes of pressed berries (juice production by-products) still contain important amount of phenolics, and could be valorised by extracting these antioxidant molecules. An enrichment of the extracts can be necessary for some applications, and adsorption process appears as the most relevant technique for such purification.Recently, our team has developed a new process for selective recovery of antioxidant phenolics from Aronia wastes, by integration of the extraction and the purification steps [3]. It allows to recover selectively polyphenols from Aronia wastes in a single operation and to enrich the native Aronia extracts up to 15 times on polyphenols and on anthocyanins. Comparing this integrated process to extraction and adsorption steps conducted successively, a clear positive impact of integration was observed. Process integration enhanced more than 25% the extraction yields of Aronia polyphenols and anthocyanins, preserving also the antioxidant capacities of the extracted Aronia phenolics. The considerable time reduction by integration of the two steps in a single operation allowed to increase process productivity more than twice. In the view of applying it for the production of larger quantities of antioxidant-rich extracts, pilot scale feasibility of this process was studied. Firstly, an optimization of the integrated extraction-adsorption process was performed at laboratory scale. The optimal operating conditions were then transposed to pilot scale, with a scale-up factor of 50 for quantities of raw source, adsorbent (both from 4 to 200 g) and solvent (from 0.8 to 40 L). Results obtained at pilot scale were similar to those at laboratory scale, for all responses (total polyphenols, anthocyanins and antioxidant capacity of the extracts). This new integrated process could be applied also for a selective recovery of antioxidant phenolics from other sources such as berries or antioxidant-rich wastes. In this way, products of high quality could be obtained in a simple process with low consumption of time and energy.The full presentation and the recording of the session can only be accessed by IFA-members. Non IFA-members can ask for access against a small handling fee of 30 € at office [AT] iseki-food [dot] net