Ultrasound as pretreatment for drying garlic slices in microwave and convective dryer
- 104 Downloads
The effects of ultrasound pretreatment (US) before hot air drying (HAD) and microwave drying (MWD) of garlic slices were investigated. For this aim ultrasonic bath at 30 °C for 30 min (35 kHz), microwave oven at 540 W power and tray dryer at 60 °C and with 1.0 m/s air flow rate were used to reach the final moisture content of 5%. Drying rate increased in the US + HAD and the US + MWD groups by 19.30% and 13.82% respectively in comparison with control groups. The effective moisture diffusivity (Deff) of garlic slices were calculated from Fick’s diffusion model for the HAD, US + HAD, MWD and the US + MWD groups as 1.420 × 10−10, 1.826 × 10−10, 1.177 × 10−8, 1.363 × 10−8 m2/s respectively. The rehydration rates increased, and bulk densities were decreased in the US + HAD and the US + MWD compared to the control groups. The color values were significantly affected after ultrasound pretreatment. Redness, and yellowness increased most in the US + HAD group.
KeywordsGarlic slices Ultrasound pretreatment Drying Rehydration rate Color
Compliance with ethical standards
Conflict of interest
The authors declare they they have no conflict of interest.
- Afolabi IS. Moisture migration and bulk nutrients interaction in a drying food systems: a review. Food Nutr. Sci. 5: 692–714 (2014)Google Scholar
- AOAC. Official Methods of Analysis. 17th ed. Association of Official Analytical Chemists. Gaithersburg, MD, USA (1990)Google Scholar
- Cemeroğlu B. Meyve Sebze İşleme Teknolojisi, 2. cilt. ISBN 975-98578-2-0 (2004)Google Scholar
- Datta AK. Heat and mass transfer in the microwave processing of food. Chem. Eng. Process. 86: 47–53 (1990)Google Scholar
- Fernandes FAN, Rodrigues S. Application of ultrasound and ultrasound-assisted osmotic dehydration in drying of fruits. Dry. Technol. 26: 509–1516 (2008)Google Scholar
- Hill MJ. The microwave palaeointensity technique and its application to lava. PhD thesis, University of Liverpool, England (2000)Google Scholar
- Içier F, Yıldız H, Eroğlu S, Sabancı S, Eroğlu E. Effect of electrical and ultrasonic pre-treatments during osmotic dehydration of quince slices. Acad. Food J. 1: 60–69 (2013)Google Scholar
- Rasouli M, Seiiedlou S, Ghasemzadeh HR, Nalbandi H. Convective drying of garlic (Allium sativum L.): part I: drying kinetics, mathematical modeling and change in color. Aust. J. Crop Sci. 5: 1707–1714 (2011)Google Scholar