A Mathematical Model for Color Changes in Red Pepper during Far Infrared Drying

Abstract

Purpose:The color changes in red pepper during far infrared drying were studied in order to establish a color change model. Methods:The far infrared drying experiments of red pepper were conducted at two temperature levels of 60, 70℃ and two air velocity levels of 0.6 and 0.8 m/s. The results were compared with the hot-air drying method. The surface color changes parameters of red pepper were measured qualitatively based on L (lightness), a (redness), b (yellowness) and total color changes (ΔE). The goodness of fit of model was estimated using the coefficient of determination (R 2 ), the root mean square error (RMSE), the mean relative percent error (P) and the reduced chi-square (χ 2 ). Results: The results show that an increase in drying temperature and air velocity resulted in a decrease in drying time, the values of L (lightness) and a (redness) decreased with drying time during far infrared drying. The developed model showed higher R 2 values and lower RMSE, P and χ 2 values. Conclusions: The model in this study could be beneficial to describe the color changes of red pepper by far infrared drying.

Drying characteristics and quality of red ginseng using far-infrared rays

“…The drying rate was represented by the moisture ratio. The moisture content that was measured at each drying time point was converted into the moisture ratio by using the following equations [10] , [11] : where M t indicates moisture content at any drying time point and M e , M 0 , M m , and M f indicate equilibrium, initial, middle, and final moisture contents, respectively.…”

Feasibility of a chromameter and chemometric techniques to discriminate pure and mixed organic and conventional red pepper powders: A pilot study

“…Similarly,Cao et al, (2016) found lower L, a, and b values in the dried red peppers (sun, infrared, and hot-air drying) as compared to the fresh ones. Also,Ning et al, (2012) andPinar et al (2021) reported a reduction in the L value in red pepper after drying. These variations could be tied to the drying method and drying parameters.…”