Development of probiotic-enriched dried fruits by vacuum impregnation

Use of vacuum impregnation in food salting process

Drying kinetics of apple cylinders under combined hot air–microwave dehydration

Vacuum impregnation (VI) is considered as a useful technique to quickly introduce external liquids in the porous structures of animal and plant tissues, in a controlled way. As consequence some mass transfer processes (as dewatering) are improved and also some changes in food composition may be produced. VI has broad applications in fruit and vegetable processing and provides many unique advantages. This review analyzes the main factors and responses of porous fruits and vegetables to VI processing, summarizes important developments related to VI applications in the fruit and vegetable industry, and discusses quality aspects of VI processed fruits and vegetables, as well as technical challenges and future research needs in this field.

Practical applications of vacuum impregnation in fruit and vegetable processing

Vacuum impregnation for development of new dehydrated products

The behavior of several fruits (three varieties of apples, strawberry, kiwi-fruit, mango and peach) during vacuum impregnation (VI) treatments was studied by using specially designed equipment and methodology to determine deformation and impregnation levels in fruit samples. The coupling of the Hydrodynamic Mechanism (HDM) and the Deformation-Relaxation Phenomena (DRP) was analyzed throughout the two typical steps of VI process (first period at vacuum pressure and second period at atmospheric pressure). VI experiments were carried out over different lengths of time under vacuum (t1) and at atmospheric pressure (t2) duration in order to obtain kinetic information on the coupled HDM and DRP. Nevertheless, neither the duration of t1 or t2 was observed to have an influence on the deformation and impregnation levels in the examined time scales. The effective porosities (ɛe) of the fruits that were studied were determined and compared with the fruit porosity (ɛ) obtained from density data. In almost all cases the ratio ɛe/ɛ was lower than 1, which indicates that only a fraction of fruit pores was available to HDM action. DRP affects the volume fraction of impregnated liquid in all cases.

Daniela Salvatori

Papers

The response of some properties of fruits to vacuum impregnation