Optimization of vacuum drying characteristics of red and green cherry pepper paste using response surface methodology: a comparative study

Fresh red and green cherry peppers were dehydrated under vacuum at a plate temperature: of 50 – 70 °C and bed thickness: of 3 – 7 mm for the production of cherry pepper flakes and the process was optimized using the response surface methodology (RSM). Plate temperature and bed thickness were considered as dependent variables for responses, including vitamin C, capsaicin, and total colour change, of the dehydrated cherry pepper flakes to carry out vacuum drying experiment. Optimum vacuum drying conditions for the production of quality red cherry pepper flakes were found as 60.97 °C for plate temperature and 6.4 mm of bed thickness and 59.8 °C (≈ 60 °C) plate temperature and 5.74 mm (≈ 6 mm) bed thickness for green cherry pepper flakes. The modelling of vacuum drying characteristics of red and green cherry pepper paste was done for the production of cherry pepper flakes. Midilli model was found to be the best-fit model for both types of cherry pepper paste based on statistical parameters (R2 = 1.0, χ2 = 0.007, RMSE= 0.001). The independent variables had a significant effect (p < 0.01) on effective moisture diffusivity (1.87 x 10–10 8.9–9 x 10–10 m2/s). 27.761 kJ/mol (red) and 36.465 kJ/mol (Green) were the activation energy.