Optimisation of pH for minimising juice degradation during evaporation

During juice evaporation, sucrose loss can occur due to degradation reactions that are influenced by heat, pH, residence time, and dry substance content. The impacts of heat can be controlled through process and equipment design, and juice pH could be optimised to reduce its effects on degradation reactions. A factory sampling program was conducted with juices collected across an evaporator station comprised of six Robert (rising film) effects in series for a range of juice pH levels and analysed for sucrose loss and overall pH drop from clarified juice to syrup. Measured losses were compared to predictive correlations and showed strong agreement. Using the factory data, two pH control strategies to minimise sucrose degradation and the subsequent impacts on downstream processing were simulated with predictive correlations. The modelling results highlight the potential benefits that can be achieved.