Forward osmosis (FO) and emulsification with dynamic membranes of tunable pore size (DMTS) were assessed to concentrate and encapsulate polyphenol extracts from carob pulp. In the FO step, a feed solution temperature of 40 °C resulted in the fastest concentration and the highest polyphenol yield. Moreover, FO at 35 °C enabled to concentrate up to about 20 times in 3 h using a pilot scale unit of 0.5 m2 of membrane area. Phenolic compounds were subsequently encapsulated in the inner water phase (W1) of water-in-oil-in-water (W1/O/W2) emulsions produced with DMTS, which enabled to obtain emulsions with a monomodal droplet size distribution (span<1, d3,2 ≤20 μm), and polyphenol encapsulation efficiencies ranging between 87.0 ± 0.2% and 77.4 ± 0.4%. To extend the shelf-life of the encapsulated polyphenols, solid microcapsules were produced by spray drying. After rehydrating the solid microcapsules, the structure of the W1/O/W2 emulsion was partially recovered.
The authors are grateful to the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement (No. 713679) and the Universitat Rovira i Virgili (URV), and the Ministerio de Economía i Competitividad (CTQ 2014-54520-P) for their financial support in this research.