sprouts

radish

microwave drying

infrared drying

antioxidants

polyphenols

rehydration

In the latest years people’s attention focus on the consumption of products characterised by abundance in bioactive compounds. One of the products rich in the bioactive compounds is radish sprouts, which are generally consumed raw or slightly cooked. However, in recent years the problems connected with foodborne illness in sprouts were noticed. One of the possibilities to resist this problem is to use drying as the traditional method used for food preservation. Moreover, the set up right parameters of the process and methods of drying might influence on the sensory quality of plant products. During drying the water decrease because of evaporation and water activity reduce and inhibition of microbial activity occurs. Furthermore, the enzymatic and chemical reactions rate reduce what has influenced the quality of the food matrix. Thus, the aim of presented work was to assess the nutritional and quality losses such as DPPH scavenging activity, total phenolic compounds content, colour and rehydration properties, of the dried radish sprouts obtained by different drying techniques (convective drying – CD, microwave-assisted convective drying – MV-CD and infrared-assisted convective drying – IR-CD). In the case of convect- ive drying, process was carried out with the air velocity of 1 m·s ^–1 and at the temperature of 60°C. In infrared-assisted convective drying was used the power of infrared emitter equal 7.875 kW·m ^–2 , and air velocity equal to 1 m·s ^–1 . For microwave-assisted convective drying the starting microwave power was equal to 200 W, the air velocity was 1 m·s ^–1 in the temperature of 30°C. The DPPH scavenging activity and total phenolic compounds content were measured using spectrophotometric methods. The colour was measured in CIE L*a*b* system and rehydration properties were express as the soluble solids loss ratio and relative water content. After the drying process, the loss of total phenolic content and antioxidant capacity were observed. However, the methods of drying not differentiate the antioxidant capacity and the total phenolic content was significantly higher when infrared-assisted convective drying was applied. The colour after drying was altered and differences between the dried samples were noticed. Moreover, the analysis of rehydration properties shows that the fastest kinetics of water absorption was characteristic for infrared assisted convective dried sprouts. On the research basis, it can be indicated that analysed drying methods allow shaping the final quality of dried radish sprouts allowing to manufacture of products characterised by certain properties.