Abstract
Fining agents, such as bentonite, are usually added to fruit juices and fruit-wines by processors in order to avoid secondary haze due to heat caused by (for example) thermolabile proteins. A suitable heat treatment may be an alternative to fining agents, however, currently there are no metrics known to find the right heat treatment for stabilisation. Moreover, in literature there are conflicting recommendations regarding the optimal temperature and holding time for the stability tests (heating test). The goal of this work was to characterise the impact of a heat treatment to reduce the potential secondary haze formation in clear apple juice, as well as to find the optimal temperature and holding time for the stability test. These trials were carried out on a lab-scale and D-values and z-values of haze avoidance were determined. Based on this data for the stability test a temperature of 75 °C and a holding time of 5 minutes are recommended for apple juices. The calculations resulted in an average D-value of 25.6 minutes at 60°C and an average z-value of 19.1 °C. This data is the first step in determining the necessary temperature and holding time of heat treatments to avoid secondary haze in fruit juices and fruit-wines.