Deacidification of cranberry juice by electrodialysis: Impact of membrane types and configurations on acid migration and juice physicochemical characteristics

Cranberry is a typical fruit from North America having a very high acidity that makes raw juice hardly acceptable for consumers. In this study, the reduction of juice acidity was investigated using electrodialysis (ED) with different types of membranes and cell configurations. Electrodialysis is an ecofriendly membrane technology used in a large range of food applications. Three different ED configurations were tested at the laboratory scale: bipolar and anion-exchange membranes (ED2MB), bipolar and ultrafiltration membranes (ED2MBUF), and cation-exchange and ultrafiltration membranes (EDUF). Each configuration was evaluated in terms of juice physicochemical parameters (titratable acidity, conductivity, total soluble solids, color, anthocyanins, organic acids and mineral contents) and electrodialytic parameters (membrane conductivity and thicknesses, global system resistance). In ED2MB configuration, a 40% deacidification rate was reached after 3 h of treatment (80% after 6 h) whereas 0% and only 8% were obtained after 3 h with ED2MBUF and EDUF configurations, respectively. Furthermore, a selective migration of organic acids was observed with the ED2MB configuration: citric acid (22 ppm/min), malic acid (11 ppm/min) and quinic acid (6.5 ppm/min). Consequently, ED2MB configuration allows the deacidification of cranberry juice and the production of pure acids (no waste generated) without any chemical consumption due to the bipolar membrane in-situ generation of proton and hydroxyl species from water.