Food drying: A review

Foods are complex biological substances that are obtained from animal or plant origin and because of that they contain high moisture contents which make them highly perishable and thereby requiring preservation in some forms. This review assessed different techniques of drying food and optimization of drying parameters to obtain good and acceptable quality food products. Among the useful processes used in preserving food products reviewed is minimal processing, dehydration or drying. The authors explored the available literature from journals, textbooks and search engines to develop this review paper. Food dehydration or drying is used to reduce losses and improving food commercial value. The use of artificial dryers has been found to reduce drying time when compared with natural drying method although at higher consumption level. Natural drying methods are sun drying and solar drying which could involve the use of solar dryers. Artificial drying methods are radiation, freeze drying, osmotic drying, dielectric drying etc. Novel technologies like microencapsulation and nanotechnology are increasingly used in food drying. Microencapsulation has been found to improve the stability of nutrients, preventing ingredient interactions and degradation as the coating matrix effectively separates particles and prevents them from contacting each other. Nanotechnology has found wide applications in food production, processing and packaging. Nanotechnology is an emerging technology that could impact every aspect of food system from cultivation and production of food to processing, packaging, transportation, shelf life and bioavailability of nutrients in foods.