|LI, XUAN - University Of California|
Submitted to: Food and Bioprocess Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2013
Publication Date: 10/1/2013
Citation: Li, X., Pan, Z. 2013. Predictive modeling of infrared radiative heating in tomato dry-peeling process: Part II. Model validation and sensitivity analysis. Food and Bioprocess Technology. 7:2005-2013.
Interpretive Summary: A three dimensional heat transfer model was developed to predict the temperature changes on the surface and within a tomato under the typical IR dry-peeling condition. Since the uniformity of temperature on tomato surfaces is very important for achieving complete removal of tomato skin, the model was validated and used to study the effect of different processing parameters on the temperature uniformity. Sensitivity analysis suggested that strategies to enhance IR heating rate and uniformity could be implemented through varying emissive power, adjusting the distance between emitters, and presorting tomatoes according to size. The knowledge gained from this modeling study can be used to improve the IR peeling technology by optimizing the heating rate and uniformity through use of curved shaped emitters, provision of an adjustable distance between emitters, and pre-sorting of tomatoes. These new measures should reduce process time, improve peeling throughput, and increase overall energy efficiency.
Technical Abstract: A predictive mathematical model was developed to simulate heat transfer in a tomato undergoing double sided infrared (IR) heating in a dry-peeling process. The aims of this study were to validate the developed model using experimental data and to investigate different engineering parameters that most strongly influence the rate and uniformity of IR heating. The mode was verified by comparison of the predicted temperature profiles with experimental data for tomatoes with three dimensions. Uniformity of temperature distribution at tomato surface was quantified by the surface-averaged temperature and the derived temperature uniformity index. The predicted temperatures agreed well with experimental data (r2>0.9). Simulation results illustrated that IR heating induced a dramatic temperature increase on the tomato surface which extended to 0.6 mm beneath (>90°C) during a 60 s heating period, whereas interior temperature at the tomato center remained low (<30°C). Sensitivity analysis suggested that strategies to enhance IR heating rate and uniformity could be implemented through varying emissive power, adjusting the distance between emitters, and presorting tomatoes according to size. The developed model is an effective design tool for better understanding the complex IR radiation in developing the innovative IR dry-peeling process.