Comparative Effects of Three Different Drying Methods on Drying Kinetics and Quality of Jerusalem Artichoke (Helianthus tuberosus L.)

Mid-infrared-assisted freeze drying (MIR-FD) of Jerusalem artichoke cubes were attempted and their performance (processing time, energy consumption, color, water activity, hardness and rehydration) was compared with single-stage freeze dried (FD, control) samples. Two mathematical models could be used to describe the drying curves. It was aimed to improve the drying parameters and product quality of MIR-FD dried material. The effect of mid-infrared pre-drying (MIR) on drying rates of Jerusalem artichoke cubes was examined at different infrared intensity (3 and 6 kW/m−2). The values of drying rate considerably changed when the infrared intensity and pre-drying time was increased from 3 to 6 kW/m−2 and from 4 to 5 min. The MIR-FD hybrid drying mode took 15–40% lesser time compared to FD dried samples. Therefore, MIR-FD drying is an effective and economical method. MIR application had a significant (P < 0.05) effect on the color of the final product. The FD resulted in a product with significantly lower firmness and slightly higher water uptake (P < 0.05) than samples dried in the MIR-FD. Hybrid drying gave better results – all of the quality parameters – over MIR alone. Practical Applications The Jerusalem artichoke (Helianthus tuberosus L) is available in fresh and processed forms (powder, chips and soft drinks), the Jerusalem artichoke is rich in inulin, sugars, protein, macro and micro elements. Freeze- and mid-infrared drying have been industrially applied in the drying of foodstuffs and pharmaceutical products. The aim of this article is to examine the effectiveness of freeze drying (FD) enhanced with two-stage mid-infrared-freeze drying. The application of the mid-infrared-freeze drying (MIR-FD) produces a fast drying rate and higher drying quality. Our research work confirmed that MIR-FD is a good alternative instead of the FD. The development of new drying possibility for vegetables with good physical, chemical properties may be of interest in regard to the market supply (food supplement, functional food, etc.).