Effects of pretreatment on air impingement drying characteristics and product color for line pepper

The purpose of this paper was to investigate the effects of different pre-treatments on air impingement drying characteristics and product color of line pepper. The experimental results demonstrated that pre-treatments had important effects on drying characteristics and color. It was found that the drilling hole pre-treatment could significantly decrease the drying time, improve drying rate and reduce red pigment loss as well as browning. Color protection was achieved by blanching line peppers at 90℃ for 3 min in hot water. It was discovered that hot water blanching pre-treatment could extend drying time. Application of 110℃ superheated steam blanching for 3 min could prevent browning. For all pre-drying treatments, the total drying occurred in the deceleration period.