Mechanical and Structural Changes in Apple (Var. Granny Smith) Due to Vacuum Impregnation with Cryoprotectants

Freezing ensures the longterm preservation of fruits, but usually destroys cell compartmentation of fruit tissues, thereby increasing the probability of undesirable reactions. The use of cryoprotectants/cryostabilizers may reduce ice crystal damage by modifying the glass transition of frozen fruit or reducing freezable water content. The use of vacuum impregnation to introduce cryopreservatives into the fruits was tested. Apple samples were vacuum impregnated with concentrated grape musts and pectin solutions, by applying vacuum (50 mbars) for 5 min and afterwards restoring atmospheric pressure while fruit remained immersed. Most compositional, mechanical and structural properties improved as a result of vacuum impregnation.