State diagrams in low temperature and atmospheric freeze drying of organic fruid products

Abstract

The influence of environmental parameters on freeze-drying of blanched organic apples was investigated. The changes of material when dried were also studied since the reduction of moisture content during drying decreases the freezing point significantly which influences the process efficiency and final product quality. The process of freeze-drying was described with the help of state diagram in order to study the dependencies between moisture content and freezing point depression as well as the nature of shrinkage. The processes of ice formation in apples were described by modified Clausius-Clapeyron equation. The processes of glass transition was described by Gordon-Taylor equation. The drying methodology for organic apples was proposed.