Loss factor and moisture diffusivity property estimation of lentil crop during microwave processing

Area of Science:

• Materials Science
• Chemical Engineering
• Food Science

Background:

• Accurate characterization of loss factor and moisture diffusivity is crucial for understanding material behavior during microwave processing.
• Direct measurement of these properties can be challenging due to equipment limitations.

Purpose of the Study:

• To develop an alternative, model-based procedure for determining material loss factor and moisture diffusivity.
• To investigate the influence of temperature and moisture content on these microwave properties.

Main Methods:

• Utilized a combined optimization approach and numerical solution of heat and mass transfer equations.
• Estimated model coefficients by minimizing the error between experimental and predicted surface temperature and moisture content.
• Employed differential scanning calorimetry and Fourier transform mid-infrared spectroscopy to analyze starch structure changes.

Main Results:

• Developed predictive models for loss factor and moisture diffusivity based on temperature and moisture content.
• Observed arithmetic growth in moisture diffusivity and a general increase in loss factor with microwave processing.
• Identified transition points in property trends around 50% moisture content, linked to starch gelatinization.

Conclusions:

• The proposed modeling approach offers a viable alternative for characterizing microwave material properties.
• Starch gelatinization significantly impacts material properties and microwave energy absorption.
• Microwave processing, especially at 50% moisture content, induces substantial alterations in starch structure.