title: Combined infrared-vacuum drying of pumpkin slices.
abstract: Infrared-vacuum dehydration characteristics of pumpkin (Cucurbita moschata) were evaluated in a combined dryer system. The effects of drying parameters, infrared radiation power (204-272 W), system pressure (5-15 kPa), slice thickness (5 and 7 mm) and time (0-220 min) on the drying kinetics and characteristics of pumpkin slices were investigated. The vacuum pressure, lamp power and slice had significant effect on the drying kinetics and various qualities of the dried pumpkin. Moisture ratios were fitted to 10 different mathematical equations using nonlinear regression analysis. The quadratic equation satisfactorily described the drying behavior of pumpkin slices with the highest r value and the lowest SE values. The effective moisture diffusivity increased with power and ranged between 0.71 and 2.86 × 10(-9) m(2)/s. With increasing in infrared radiation power from 204 to 272 W, β-carotene content of dried pumpkins decreased from 30.04 to 24.55 mg/100 g. The rise in infrared power has a negative effect on the color changes (ΔE). The optimum condition was determined as power, 238W, pressure, 5 kPa and slice thickness, 5mm. These conditions resulted into dried pumpkin slices with maximum B-carotene retention.
authors.affiliation: Department of Food Science and Technology, Science and Research branch, Islamic Azad University, Tehran, Iran.
authors.forename: Seyyed Hossein Hosseini
authors.initials: SH
authors.lastname: Ghaboos
authors.affiliation: Department of Food Science and Technology, Science and Research branch, Islamic Azad University, Tehran, Iran.
authors.forename: Seyed Mahdi Seyedain
authors.initials: SM
authors.lastname: Ardabili
authors.affiliation: Faculty of Food Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Kashaninejad
authors.affiliation: Department of Food Science and Technology, Science and Research branch, Islamic Azad University, Tehran, Iran.
authors.forename: Gholamhassan
authors.initials: G
authors.lastname: Asadi
authors.affiliation: Faculty of Food Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
authors.forename: Mehran
authors.initials: M
authors.lastname: Aalami
keywords: Image processing; Infrared-vacuum drying; Pumpkin; β-carotene