Dehydrofreezing technique involves one step of partial dehydration before freezing, in order to diminish
the tissue damage by removing part of water from vegetable tissue prior to freezing. The objective of the
present study was to evaluate the effect of osmotic dehydration and hot air-drying, applied previous to
the freezing process, on the end quality of pineapple slices. Quality loss was quantified through drip loss,
ascorbic acid content and mechanical properties changes of tissue. Freezing was carried out in a conventional
air-blast tunnel at 31.5 ± 2 C. Mechanical properties of fresh and dehydrated fruit, with and
without the later process of freezing, were evaluated through compression tests. Ascorbic acid content
was quantified by liquid chromatography. Osmotic dehydration and hot air-drying have the beneficial
effect of reducing the time necessary for pineapple samples freezing. The freezing–thawing process
affects the values of pineapple samples mechanical properties. Ascorbic acid losses were somewhat
greater during the osmotic dehydration than with air dehydration