The three fundamental techniques for drying food include surface diffusion on pore surfaces, liquid or vapor diffusion resulting from changes in moisture content, and capillary action induced by surface forces in granular and porous food products. The thin-layer drying process of food products is significantly influenced by various variables, including drying time, temperature, relative air humidity, air flow rate, surface area, material thickness, volume, and local or partial pressure. Among these are the material thickness (size) and drying temperature, which have the most effects on fruit and vegetable drying. Numerous models are referenced in the literature for examining the drying of food materials. Methods of thin layer drying includes theoretical, semi-theoretical and empirical. However, most commonly employed categories are semi-theoretical and empirical thin-layer models. Using optimization techniques, optimal models for drying agricultural products in thin layers can be predicted.