Hybrid Drying of Carrot Preliminary Processed with Ultrasonically Assisted Osmotic Dehydration

• Published in: Food technology and biotechnology Vol. 55; no. 2; pp. 197 - 205
• Main Authors: Mierzwa, Dominik, Kowalski, Stefan Jan, Kroehnke, Joanna
• Format: Journal Article
• Language: English
• Published: Croatia Sveuciliste U Zagrebu 01.04.2017; Sveuciliste u Zagrebu, Prehramheno-Biotehnoloski Fakultet; University of Zagreb Faculty of Food Technology and Biotechnology
• Subjects: Carrots; Consumption; Convective drying; Dehydration; Dewatering; Dried vegetables; dry product colour; Drying; Food quality; Fructose; Heat; hybrid drying; I.R. radiation; Infrared radiation; Kinetics; Mass transfer; Methods; Microwave radiation; microwaves; Moisture content; Neural networks; Nutritional aspects; Original Scientific Papers; Osmosis; osmotic dehydration; Physiological aspects; Pores; Porosity; Pretreatment; Product quality; Raw materials; Schedules; Ultrasonic imaging; Ultrasound; Water loss; Poland; microwaves; osmotic dehydration; dry product colour; ultrasound; hybrid drying
• ISSN: 1330-9862; 1334-2606
• DOI: 10.17113/ftb.55.02.17.4942

In this paper the kinetics of osmotic dehydration of carrot and the influence of this pretreatment on the post-drying processes and the quality of obtained products are analysed. Osmotic dehydration was carried out in the aqueous fructose solution in two different ways: with and without ultrasound assistance. In the first part of the research, the kinetics of osmotic dehydration was analysed on the basis of osmotic dewatering rate, water loss and solid gain. Next, the effective time of dehydration was determined and in the second part of research samples were initially dehydrated for 30 min and dried. Five different procedures of drying were established on the grounds of convective method enhanced with microwave and infrared radiation. The influence of osmotic dehydration on the drying kinetics and final product quality was analysed. It was found that it did not influence the drying kinetics significantly but positively affected the final product quality. Negligible influence on the drying kinetics was attributed to solid uptake, which may block the pores, hindering heat and mass transfer. It was also concluded that the application of microwave and/or infrared radiation during convective drying significantly influenced the kinetics of the final stage of drying. A proper combination of aforementioned techniques of hybrid drying allows reducing the drying time. Differences between the particular dehydration methods and drying schedules were discussed.