Assessment of pretreatments on drying kinetics and quality characteristics of thin-layer dried red pepper

Abstract

In this study, the effect of pretreatments (hot water blanching, microwave blanching, and ohmic heating) on the drying kinetics and quality characteristics of red pepper, dried at 60 and 70 °C, was investigated. The drying times varied between 205–290 min, depending on the pretreatment and temperature applied. The drying rate also changed based on the pretreatment and the falling rate period was observed. Four mathematical models were fitted to experimental data and the logarithmic model was found to be the best for all of the samples. Effective moisture diffusivity values obtained from Fick’s second law of diffusion ranged from 6.11 × 10–10 to 9.31 × 10–10 m2 s–1. The total phenolic contents, antioxidant capacities, and red pigment amounts of the dried peppers varied between 6.95 and 9.45 mg GAE g–1dry matter (DM), 2610.43 and 4463.96 mmol AEAC 100 g–1DM, and 184 and 443mg 100 g–1DM, respectively. Rehydration ability of pretreated samples was similar to or slightly lower than that of the untreated samples. As a result, it can be suggested that ohmic heating before drying at a temperature of 70 °C could be a promising alternative pretreatment to decrease drying time and produce high-quality dried red pepper.

A comparative study of electrical and conventional pre-treatments for quality assessment of hot air dried green bell pepper

“…The blanching of the peppers was performed in OH chamber, which consists of a rectangular plexiglass and two stainless steel electrodes. The system of OH chamber was described previously by İncedayi (2020). The distance between electrodes was set at 14 cm.…”

“…Model validation was also performed to determine the suitable model. For this purpose, the averages of two data sets were used to build the model (İncedayi, 2020) and the validation was achieved by applying nonlinear regression method by using the third data set. Model parameters were calculated using equations as follows: N: the number of observations…”

“…The Fick's second diffusion equation was used for calculation of the effective diffusivity according to İncedayi (2020).…”

Nutritional Analysis of Red-Purple and White-Fleshed Pitaya (Hylocereus) Species

“…The previous studies conducted with horticultural plants indicated that biochemical and volatile content greatly varied among cultivars, geographical conditions, growing conditions, etc. [79][80][81][82][83][84][85][86][87][88][89][90][91][92].…”

Mathematical modeling and drying characteristics of thin layer drying of bitter gourd in evacuated tube solar dryer-without heat pipe

“…Further drying proceed, the drying rate was gradually slow down due to low moisture present in the samples as well as low solar intensity at the end of the day. Decreasing moisture content increases the reduction in mass of the product which restricted the heat penetration in the dried layer resulting reduction in drying rate [17].…”