Recovery of valuable compounds from pomegranate juice by PVDF hollow fibre membranes

The health benefits of consuming pomegranate juice (Punica granatum L.) are increasingly recognized. Over the past few years numerous studies have shown that pomegranate juice is characterised by significant anticarcinogenic, antimicrobial, anti-atherosclerotic and anti-inflammatory activities. All these activities can be attributed to its remarkably high antioxidant capacity which is correlated to the presence of different phenolic compounds including gallagyl-type tannins, ellagic acid derivatives and anthocyanins. Conventional fining and filtration methods for juice clarification are mainly devoted to the removal of phenolic compounds that, together with colloids and proteins, are responsible for haze and sediment formation during concentration and storage. In this work, polyvinylidenfluoride (PVDF) hollow fibre were prepared by the dry/wet spinning technique, as described elsewhere. The effect of the composition and injection rate of the bore fluid on the morphology and properties of the prepared membranes was investigated. The produced fibres were used to clarify the raw pomegranate juice in order to preserve some high-added value compounds, such as anthocyanins and other phenolic compounds, and to produce a clarified fraction suitable for further purification/concentration processes. The idea was to tailor the morphological characteristics (i.e. structure, pore size, porosity, etc.) of the prepared membranes for evaluating the possibility of producing fractions of interest for cosmeceutical and/or nutraceutical applications (fortification of food and beverages). Fibres were characterized for their pure water permeability (PWP), fouling index and rejection (R) towards compounds of interest.