Concentration of citrus fruit juices in membrane pouches with solar energy Part 1: How solar drying setup and juice pretreatment determine the drying flux

摘要

The aim of this study was to investigate how solar drying setup and choice of juice pretreatment determine the drying flux in a fruit juice concentration process called solar assisted pervaporation. With this process, hygienic membrane pouches and solar energy are used to concentrate and preserve fruit juices. In this study, the feasibility of concentrating citrus (tangerine) juice into marmalade under realistic conditions in rural Mozambique was assessed with three solar drying setups and four juice pretreatments. The main findings were (a) tangerine marmalade with a soluble solids content >= 65 degrees Brix could be produced with all solar drying setups tested within 3-6 days, (b) sucrose addition as a juice pretreatment did not impact drying time and is recommended to increase yield, and (c) direct active and tilted passive solar drying reduced the drying time considerably; however, passive drying was more sensitive to poor weather conditions.