Microwave Vacuum Drying on Fruit: A Review

Abstract

Fruit is very perishable in the storage process and has short of shelf-life. To extend the shelf life, fruits need preservation process. Drying is generally acknowledged as a cost-effective and commonly used technique for preserving food by reducing post-harvest losses. The major challenge of drying fresh foods and agricultural products is to reduce the moisture content to an absolute minimum while preserving quality characteristics such as colour, texture, chemical components, and shrinkage. The vacuum drying technique has been explored as a possible method for generating high-quality dried food items such as fruits, vegetables, and grains. Microwave vacuum drying is a method that adopts the benefits of microwave drying and vacuum drying, especially enhancing energy efficiency in conjunction with product quality. This article reviews several studies on fruit drying using microwave vacuum drying, including cranberry, apple, dragon fruit, strawberry, Saskatoon berry, and pomegranate. Studies show that drying using microwave vacuum drying saves drying time many times over than conventional drying. The microwave vacuum drying technique can reduce undesired sensory transitions and nutrient loss caused by longer drying times or high surface temperatures. The use of microwave vacuum drying resulted in dried fruit similar to freeze-drying which did not significantly affect the color of the fruit and the phenolic content of the fruit.