Food Drying

Fruits and vegetables are the most commonly consumed superior or functional foods, yet their high moisture content (over 80%) makes them especially susceptible to bacteria that cause spoilage. Keeping produce fresh is the best way to preserve the nutritional value of fruits and vegetables, but most storage methods necessitate low temperatures, which are difficult to maintain throughout the distribution chain. In contrast, drying is an effective post-harvest management strategy. To improve their shelf life and increase food security, approximately one-fifth of the world's fresh produce is dried. Dried fruits and vegetables make healthy eating more practical and can help close the gap between recommended and actual fruit consumption. By lowering water activity, dehydration keeps fruits and vegetables healthy and safe, prolonging their shelf life much beyond that of fresh produce. Drying used to be as simple as laying the product out on mats, rooftops, or drying floors in the sun, using solar radiation and convective air. Heat is transferred to the fruit or vegetable raw material through convection from the ambient air and radiation from the sun on its surface during sun drying. Since the food to be dried is exposed and climatic changes can occur, the method is highly unsanitary and volatile. Mechanized solar dryers such as tray, cabinet and tunnel dryers have been designed to overcome the challenges of damage, dust, pest infestation and unexpected rainfall encountered in open-air drying. In addition, the use of electromagnetic waves in the drying of fruits and vegetables is rapidly increasing. The process involves the use of indirect electro-plate heating and vegetable products are dried in less time and at lower temperatures.