Effect of Heat Pump Drying on Quality of Fruits and Vegetables: A Review

Abstract

Drying is one of the most important unit operations used in food processing sector at large scale to extend shelf-life, enhance appearance, maintain nutritional value, reduce packaging and transporting cost. The high temperature convective hot air drying process reduces the nutritional and organoleptic quality of food products. Heat pump drying is one of the options for drying of fruits and vegetables at low temperature with high nutritional and organoleptic quality apart from saving in energy consumption and operation under controlled conditions. Heat pump drying works on the principle of refrigeration cycle which controls the temperature and relative humidity of drying air in the drying process. Researchers have found that high-value heat-sensitive food products can be dehydrated through heat pump drying while preserving nutrition and phytochemicals, improving rehydration (lesser cellular structure damage) and organoleptic (odor, flavor, taste, texture and appearance) properties. This paper discusses the principle of operations, nutrient and color degradation kinetics and quality of heat pump dried fruits and vegetables.