The effect of edible coating and different drying methods on quality properties of carrot

In this study, the effects of chitosan-based edible coating prepared in various concentrations and thicknesses on the rehydration properties, rehydration kinetics, color intensity, textural properties, antioxidant properties such as total phenolic substance, antioxidant activity and β-carotene content and microstructure of freeze-dried and vacuum-dried carrot slices were investigated. Edible chitosan coating solution prepared with different concentrations of chitosan (0.25, 0.5, 1% w/v, water) acetic acid (1% v/v, water) and glycerol (1% w/v chitosan) was applied to the carrot slices by dipping method, vacuum drying at 70°C and 0.4 bar pressure, freeze drying at 0.024 mbar pressure and - 60°C condenser temperature were applied. By applying rehydration to the dried samples at 25, 40 and 55 °C, the effect of temperature change on the rehydration properties was examined and the rehydration kinetic model was determined. The interaction of the factors in terms of important parameters in the rehydration process was investigated by applying the experimental design method to the Ç31K, Ç32K and Ç34K samples. While the highest antioxidant activity (AA) rate, β-carotene content and the best rehydration rate (RR) at 55 °C were obtained by the freeze-drying method with Ç34K coating, the best total phenolic content (TPC) result was obtained in vacuum drying with Ç34K coating. It has been determined that the chitosan-based edible coating can be used as a pre-treatment to improve the quality characteristics of dried carrots.