Optimization by response surface method of ultrasound assisted vacuum osmotic dehydration pretreatment conditions applied to apricot

this study, the effect of ultrasound-assisted vacuum osmotic dehydration pretreatment applied simultaneously under different conditions was investigated on the drying behavior and quality parameters of kabaasi apricot samples after drying with hot air up to 20% moisture. For this purpose, modeling and optimization of ultrasound-assisted vacuum osmotic pretreatment were carried out according to the response surface method Box-Behnken trial plan under specified lower and upper conditions such as solution concentration (50-70%), treatment time (30-90 minutes), and treatment temperature (30-50 °C). The quality parameters such as color, texture, and rehydration rate of the samples were investigated in addition to kinetic parameters such as water loss, solid gain, drying time, and effective diffusion coefficient. It was determined that the water loss values of the samples were between 14.64% and 37.78% and these values increased especially under high solution concentration, temperature and processing time conditions. In addition, it was determined that the drying time with the hot air of the pretreated samples (70% solution concentration, 60 minutes treatment time, and 50 °C treatment temperature) was 49.17% shorter than the untreated samples. It was determined that the effective diffusion coefficient of the samples was between 6.633×10-10 and 8.925×10-10 and increased especially in parallel with the increase in the independent variables. At the same time, it was determined that while the color change value of the dried samples without pretreatment was 27.41, this value was 7.09 at high solution concentrations. It was found that the rehydration rate was between 1.71 and 2.04, and all three independent variables had a significant negative effect on this rate. Also, it was determined that the hardness value of the samples that were dried with hot air after pretreatment increased and was 55.21% higher than the untreated fresh samples. Additionally, Additionally, it was observed that the values of Hue color angle and chroma color saturation decreased with heat treatment and the highest decrease was obtained from dried samples without pretreatment compared to fresh samples. It was determined that the values of lack of fit, determination coefficients, and the sum of estimated error squares of the proposed models fit the quadratic polynomial model in all parameters. As a result, the optimum parameters of ultrasound-assisted vacuum osmotic dehydration pretreatment of apricot samples were determined as 70% sucrose solution concentration, 60.842 minutes application time, and 50 °C application temperature. It was revealed that the results obtained from the validation experiments are in the 95% confidence interval and that the ultrasound-assisted vacuum osmotic dehydration pretreatment could be used in terms of kinetic parameters and quality parameters for the specified conditions. Keywords: Apricot, optimization, osmotic dehydration, response surface method, ultrasound