Drying kinetics, chemical, and bioactive compounds of yellow sweet pepper as affected by processing conditions

Abstract

The effect of processing (pre-treatments and drying temperatures) on yellow sweet pepper was evaluated in terms of drying kinetics, physico-chemical (non-enzymatic browning index and color), and bioactive (carotenoids, ascorbic acid, phenolics, flavonoids and antioxidant activity) components. Drying at 60°C results in a significant increase in drying rate (540 min) and decrease in the moisture (6.36%) of the final product. All the pre-treatments enhanced the drying kinetics relative to the control sample. The Page model was found to be the best appropriate model for explaining the slices drying behavior. Drying temperature at 60°C showed the highest retention of phenolics (706.59 mg/100 g), flavonoids (363.41 mg/100 g) and antioxidant activity (178.13 nmol/L). Sample treated with combined pre-treatment retained maximum bioactive compounds. These results were also clearly justified by Principal Component Analysis. This study revealed that combined pre-treatment at 60°C lowered the drying time, better bioactive retention and best preservation of color. Practical applications Yellow sweet peppers are abundant in bioactive compounds, which have nutritional and medicinal importance. However, sweet pepper is highly perishable and not easy to store for long time. Drying is most preferable and economical method to improve shelf life of peppers. This study showed that higher drying rate, lower drying time, combined pre-treatment resulted in the good product quality.