Cut orientation and drying temperature effect on drying and rehydration kinetics of yacon (Smallanthus sonchifolius)

Yacon (Smallanthus sonchifolius) is commonly consumed fresh and is known for its nutritional and functional properties, however, this raw material still needs an added value that allows greater stability and availability. Against this, drying is a good processing alternative. This study aimed to evaluate for the first time the influence of temperature and the orientation of cut on drying and rehydration behavior of Yacon cylinders with longitudinal (L) and transversal (T) cut. Drying was performed at 50 and 60 °C and rehydration was performed with water at 30 °C. Drying and rehydration kinetics were described by the Page and Peleg models, respectively. As results, the effects of drying temperature are greater than the effects of the type of cut. The Page's model parameters indicated that the treatment with T cut dried at 60 °C was the treatment that dehydrated fast, while the water transfer during the process followed a super-diffusive mechanism. Regarding rehydration, the kinetics of water gain indicate that there was no difference between the rate of water gain among the treatments. However, the T cut samples dried at 50 °C presented a lower amount of water gained at the end of rehydration. In conclusion, the present work demonstrates the influence of temperature on accelerating water transfer as well as the non-isotropicity of food matrices. In addition, drying is presented as a good alternative for the processing of yacon, either in snacks or for subsequent processes such as making flour.