Osmodehydrofreezing of sensitive fruit and vegetables: Effect on quality characteristics and shelf life
Some fruit and vegetables such as cucumber, tomato, strawberry and watermelon are not suitable for traditional freezing process, due to texture degradation, color alteration, nutritional loss, high energy costs, etc. Poor quality of these frozen tissues can significantly be improved by means of the cryoprotection accomplished by the pre-osmotic dehydration. The application of osmotic pre-treatment of fresh tissue with alternative osmotic solutes, oligofructose and a high-DE maltodextrin, at mild temperature (35°C) caused substantial water loss and solid enrichment. Based on the comparative kinetic study of the quality degradation, the protective effect of both osmotic solutes on vitamin C, lycopene and color was demonstrated. The obtained sugar enrichment and partial water removal improved the sensory characteristics of treated samples (attractive appearance: bright color, good texture and pleasant taste) when compared to untreated ones. The untreated samples suffered from a detrimental texture and taste deterioration during storage.