Intermittent and continuous infrared drying of sweet potatoes

POLAT A., Taskin O., Izli N.

HEAT AND MASS TRANSFER, vol.58, no.10, pp.1709-1721, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 10
  • Publication Date: 2022
  • Doi Number: 10.1007/s00231-022-03212-3
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chimica, Compendex, INSPEC
  • Page Numbers: pp.1709-1721
  • Bursa Uludag University Affiliated: Yes


In this study, the influence of the intermittent and continuous infrared drying methods on color, microstructure analysis on images obtained using scanning electron microscopy (SEM), thermal analysis, shrinkage and rehydration ratios of sweet potato samples was investigated. In addition, the drying curves were determined and the experimental drying data were modeled using eight different mathematical thin layer drying models. The three different watt values (300, 400 and 500 W) and three different intermittent ratios (PR = 1, 2 and 3) were used in the drying process. The time for the products to reach the final moisture content varied between 70 and 340 min, depending on the infrared watt power and intermittent values. The Midilli et al. model is assumed to represent the intermittent and continuous infrared behavior of the sweet potato samples in thin layers compared to the other models. The lowest L* (color lightness) value (60.11 +/- 1.44) was measured in the samples dried with 500 W PR = 1 application. Deteriorations and burns were observed in the microstructure of the dried products due to the increase in infrared wattage and decrease in the intermittent values. The average product temperature reached the highest 139.5 degrees C with 500 W PR = 1 and the lowest 61.6 degrees C with 300 W PR = 3 applications. As a result, it has been determined that the infrared drying method can be an alternative method in terms of developing quality products in sweet potato drying.