Application of far‐infrared radiation for sun‐dried chili pepper (Capsicum annum L.): drying characteristics and color during roasting.

BACKGROUND: Chili is hygroscopic and needs a fast‐drying method before feeding into pulverizers. The far‐infrared radiation (FIR) roasting technique provides various benefits, such as higher drying rates within a short duration, reduction of mycotoxins, and improvement in the textural quality of agricultural produce. In addition, thin‐layer modeling supports understanding the drying kinetics of agricultural produce. Therefore, the objective of this research was to study the thin‐layer drying characteristics and color of whole chili pod and its components (i.e. seeds, pedicel, and placenta) of sun‐dried chili during FIR roasting. The samples were dried at 7.76 μm (100 °C), 6.12 μm (200 °C), 5.056 μm (300 °C), and 4.30 μm (400 °C) by exposing them to FIR in a single layer and the drying kinetics were studied using the Midilli model. Further, the color variation during FIR roasting was studied. RESULTS: FIR roasting of chili pods and their components (i.e. seeds, pedicel, and placenta) shows a falling rate drying period at each wavelength. The moisture content decreased with decreasing FIR wavelength. The ∆E values for pods, pedicel, and placenta were increased during FIR roasting. The Midilli model results in R2 and root‐mean‐square error value ranges of 0.7563–1.000 and 5 × 10−8–0.1238 respectively for the current study. The Midilli model at 300 °C shows that the FIR has minor variation compared with other FIR temperatures. CONCLUSION: FIR technology can be implemented to roast chili pods and their components (i.e. seeds, pedicel, and placenta) within a short period. Further, the application of FIR for roasting purposes desirably increases the color variation. The Midilli model can effectively describe the drying kinetics of the chili pods and their components during FIR roasting. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]