title: Real-time color change monitoring of apple slices using image processing during intermittent microwave convective drying.
abstract: An intermittent microwave convective drying method combined with a real-time computer vision technique was employed to detect the effect of drying parameters on color properties of apple slices. The experiments were performed at air temperature of 40 to 80℃, air velocities of 1-2 m/s, microwave powers of 200-600 W, and pulse ratios (PRs) of 2-6. Drying rate and drying time varied from 0.014 to 0.000001 min-1and 27 to 244 min, respectively. The normalized lightness values had ascending and descending parabolic trends with decrease in product moisture content. With descending dimensionless moisture content, redness, yellowness, color change, hue angle, and chroma were enlarged. The normalized redness values changed from -4 to 3. Models relating drying parameters with drying time, drying rate, and lightness were obtained and found to be significant (P < 0.01). Results indicated that microwave power and PRs had more influence on lightness and color change than other parameters.
authors.affiliation: Faculty of Agricultural Engineering and Technology, Department of Agricultural Machinery Engineering, University of Tehran, Karaj, Iran.
authors.forename: Nahid
authors.initials: N
authors.lastname: Aghilinategh
authors.affiliation: Faculty of Agricultural Engineering and Technology, Department of Agricultural Machinery Engineering, University of Tehran, Karaj, Iran shahinrafiee@ut.ac.ir.
authors.forename: Shahin
authors.initials: S
authors.lastname: Rafiee
authors.affiliation: Faculty of Agricultural Engineering and Technology, Department of Agricultural Machinery Engineering, University of Tehran, Karaj, Iran.
authors.forename: Soleiman
authors.initials: S
authors.lastname: Hosseinpour
authors.affiliation: Faculty of Agricultural Engineering and Technology, Department of Agricultural Machinery Engineering, University of Tehran, Karaj, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Omid
authors.affiliation: Faculty of Agricultural Engineering and Technology, Department of Agricultural Machinery Engineering, University of Tehran, Karaj, Iran.
authors.forename: Seyed Saeid
authors.initials: SS
authors.lastname: Mohtasebi
mesh_terms: D003116:Color; D003890:Desiccation / Q000379:methods*; D005511:Food Handling; D006358:Hot Temperature; D007091:Image Processing, Computer-Assisted; D027845:Malus / Q000737:chemistry*; D008872:Microwaves; D008962:Models, Theoretical
keywords: Apple slices; color properties; computer vision system; intermittent microwave convective drying; online monitoring