Drying and Instant Controlled Pressure Drop Swell Drying
Abstract
All drying processes, except freeze drying, suffer from shrinkage/collapse. This inevitably leads to poor process performance, low technological abilities of the material during the operation, and weak sensory, hygienic, and nutritional qualities of the finished product. By combining conventional drying methods with the instant controlled pressure drop (Détente Instantanée Contrôlée, DIC) texturing process, it is possible to overcome the shrinkage phenomenon and its various impacts. Once the DIC treatment is correctly defined, the swell-dried foods acquire high availability of nutritional molecules (vitamins and antioxidant ingredients) and similar capacity and kinetics of rehydration as freeze-dried materials, while the color, aroma, and taste of swell-dried products are significantly superior. Swell drying leads to highly controlled crunchy/crispy texture, thus providing high-quality starch-free snacks. In addition, the controlled texture allows manufacturing expanded granule powders. The energy consumption is much lower than freeze drying or even convective air drying, and the kinetics and capacity of rehydration are particularly advantageous. The DIC is distinguished by its exceptional ability to ensure efficient decontamination of bacteria (vegetative and sporulated forms), insects, and eggs, thus inducing a shelf life of more than two years. DIC can also advantageously be inserted within dehydrofreezing operations.