Simultaneous optimisation of surface quality during the sterilisation of packed foods using constant and variable retort temperature profiles

Abstract

The differences in temperature dependence between spore inactivation and degradation of quality factors allow the optimisation of thermal processes in terms of maximisation of quality retention by choosing an optimum heating profile. While the maximisation of the retention for a single quality factor has received considerable attention in research, the possibilities of simultaneously maximising the retention of different quality factors have up to now not been addressed. In this article the possibilities of the simultaneous optimisation for more than one quality factor were theoretically assessed. The use of both constant and variable retort temperature profiles was considered. A special emphasis was given to the formulation of appropriate objective functions for the simultaneous optimisation of the surface retention of quality factors. For the simultaneous optimisation of quality factors the objective functions should be formulated in terms of maximising final retention and not, as in the case of single component optimisation, in terms of minimisation of cook values. The use of variable retort temperature profiles was shown to be particularly interesting for the simultaneous optimisation of more than one quality factor, as the final retention calculated compared well with the maximum retention achieved using individual calculated optimum constant retort temperature control for each of the components.