Seyed Jafar Hashemi - Biosystem Engineering Department, Sari Agricultural Sciences & Natural Resources University, POB: ۵۷۸, Iran
Azadeh Ranjbar Nedamani - Biosystem Engineering Department, Sari Agricultural Sciences & Natural Resources University, POB: ۵۷۸, Iran

Purpose: Selecting the most effective factors and their combination during food processing, is critical to reduce the energy consumption, the time of process and also maintaining the final product properties. Research method: A definitive screen design of response surface methodology was designed by Design Expert software. Factors such as drying time (A: ۲۰-۶۰ ℃), air velocity (B: ۰.۵-۲.۵ m/s), sample thickness (C: ۳-۷ mm), sample diameter (D: ۴-۶ cm), and drying time (E: ۶۰۰۰-۱۰۰۰۰s) were investigated. The treatments from response surface methodology were simulated in COMSOL software ۵.۳a. The simulated data such as moisture content, moisture ratio, central temperature of sample, and total shrinkage were used as surface responses in Design-Expert in order to find the effective process factors on orange drying. Findings: Orange drying simulations show the air temperature and its interaction with other process factors is effective on central temperature of samples. The moisture rate and moisture content depends on sample thickness and drying time, the shrinkage was a linear model as a function of thickness and process time. In orange samples, at thickness of ۰.۵mm, diameter of ۴.۸ cm, and drying time of ۷۳۷۹s the least shrinkage will occur according to prediction models. Research limitations: Calculating the experimental shrinkage, moisture ratio, and moisture rate were the research limitation for further simulation. Originality/Value: Combination the response surface methodology and COMSOL simulation in order to reducing the number of studied treatments. Finding the effective factors and their interactions and also the prediction model for final dried orange characteristics. Finding the shrinkage model of orange fruit with respect to the studied drying process factors.

CFD simulation, Fruit shrinkage, modeling, Orange drying, Response surface methodology