Recovery & reutilization of high added-value compounds from food wastes: (V) Ultrafiltration for the fractionation of winery sludge phenols

Recovery of high added-value components from food wastes is principally conducted in 5 sequential stages: macroscopic pretreatment, macro- and micro-molecules separation, extraction, purification and product formation. Ultrafiltration (UF) is among the conventional technologies that are  utilized mainly prior or even after extraction process because it is able to separate macromolecules from smaller compounds in a physicochemical and non-destructive way. Depending on the nature of the desired separation and target compounds, concentrate or permeate stream is recaptured or rejected. For example, UF has broadly been used to treat fruit juices by discharging pectin and obtaining fractions enriched in phenolics. Red grapes and wine are among the foodstuff that contain an appreciable amount of phenolics such as Winery sludge (WS), the solid waste generated during wine decanting, contains a notable concentration of phenolics ( low molecular weight acids, hydrolysable tannins, flavonols and anthocyanins) ranging from 1.2 to 19.0 g·Kg-1. Due to their increased antiradical and reducing power, these compounds can be used either as nutritional supplements or natural preservatives in foods.The scope of the current webinar is to present a recent study dealing with the fractionation of several phenolic compounds using UF. Particularly, a hydro-ethanolic mixture was extracted from WS and two phenolic rich samples (a concentrated and a diluted) were processed with different membranes and transmembrane pressures (TMP:s) in a cross-flow UF apparatus, under constant temperature and circulation flux. UF monitoring was conducted by determining permeate and relative flux values, permeability as well as retention percentages of pectin, reducing and non-reducing sugars, hydroxycinnamic acid derivatives, o-diphenols, flavonols, polymeric and monomeric anthocyanins.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