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Coating the fruits using edible gums increases the appearance quality, improves the color and reduces their shrinkage at the end of the drying process. The purpose of this study was to investigate the effect of coating with wild sage seed, basil seed and xanthan gums on the appearance characteristics of dried quince slices in the infrared system. In this study, quince slices with a thickness of 0.5 cm were coated using wild sage seed, basil seed and xanthan gums (concentration of 1%) and then placed in an infrared dryer and the effects of radiation power (250 and 375 W) on the appearance characteristics were examined. Also, for modeling the color change index, the Power, Quadratic, Gompertz, Logistic, Richards, MMF, and Weibull models were used. Color indexes including lightness, redness, yellowness and color changes as well as changes in the samples area during drying time were examined. The calculated lightness index for the drying process of quince samples showed that the coated samples with wild sage seed gum were brighter. In terms of color change index, coated quince slices with wild sage seed gum showed the lowest color changes during drying time and the average values of this index for the uncoated sample, coated with wild sage seed, basil seed and xanthan gums were equal to 35.09, 20.20, 43.40 and 28.33, respectively (250 W). For modeling the color change index, the MMF model had less error than the others models. The results showed that the coating with wild sage seed gum maintained the appearance of the dried product and also the least shrinkage in the drying duration and at different radiation powers were observed in these coated samples.

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In this research, the effect of ultrasound treatment at different powers and temperatures on the drying process of cornelian cherry by infrared dryer was investigated and modeled. The effect of the applied power by the ultrasonic device at three levels of 0, 75 and 150 W and the effect of the ultrasonic treatment temperature at three levels of 20, 40 and 60 °C on the mass transfer rate and the effective moisture diffusivity coefficient during the drying process of cornelian cherry were investigated. The results of this research showed that ultrasonic pretreatment before drying cornelian cherry by the infrared dryer, by creating microscopic channels on the product surface due to the cavitation phenomenon, makes it easier for moisture to exit from the product and thus reduces the drying time. By increasing the ultrasonic power from 0 to 150 W, the average drying time of cornelian cherry decreased from 73.2 minutes to 51.4 minutes. By increasing the treatment temperature from 20 to 60 °C, the average drying time of cornelian cherry decreased from 69.7 minutes to 55.7 minutes. The effect of power and time of ultrasound treatment on the effective moisture diffusivity coefficient changes of cornelian cherry was investigated and the results showed that with the increase in the power and temperature of the ultrasonic device, the values of this coefficient increase. By increasing the sonication power from 0 to 150 W, it was observed that the effective moisture diffusivity coefficient increased from 6.63×10^-9 m²s^-1 to 10.11×10^-9 m²s^-1. The average effective moisture diffusivity coefficient of cornelian cherry treated at temperatures of 20, 40 and 60 °C were 7.26×10^-9 m²s^-1, 8.10×10^-9 m²s^-1, and 9.45×10^-9 m²s^-1, respectively. In order to investigate the drying kinetics of cornelian cherry, mathematical models were fitted to the experimental data.