A review of drying technologies for the preservation of nutritional compounds in waxy skinned fruit

There are various aspects that must be considered when drying small fruits, whether for the food or nutraceutical and functional food industries. Fruits with a waxy skin, such as blueberries (Vaccinium myrtillus L.), cranberries (Vaccinium macrocarpon Ait.), and cherry tomatoes (Lycopersicon esculentum Mill.) are the focus of this discussion. These fruits have each been implicated to offer health benefits beyond basic nutritional requirements, and may require special pretreatment(s) to reduce the impermeability of their skin to moisture movement. A system which minimizes exposure to light, oxidation and heat, (i.e. high heat (70 ̊C) and shorter time duration) may help conserve critical bioactive compounds. This review focuses upon conventional and new drying technologies and pre-treatment methods based upon drying efficiency, quality preservation, and cost effectiveness.