An emerging pretreatment technology for reducing postharvest loss of vegetables-a case study of red pepper (Capsicum annuum L.) drying

Drying and pretreatment play key roles in reducing postharvest losses and improving food security. High humidity hot air impingement blanching (HHAIB) was employed in the present work to pretreat red peppers and its effects on natural micro flora, quality and drying characteristics of red pepper were evaluated. Results showed that the aerobic bacteria were decreased to1.72 log CFU/g; meanwhile, the mold and yeast populations were under the detection limit (<1.0 log CFU/g) after blanching for 30 s. Moreover, HHAIB treatment enhanced the drying rate, and the drying time was reduced by 14%-29% compared to the untreated samples. Weibull model precisely described the drying behavior of red pepper. HHAIB treatment (within 30 s) caused the decreases in ascorbic acid contents. At the same time, there was no significant (p > 0.05) effect on the surface color and natural pigment contents. The findings indicate that HHAIB pretreatment is a promising technique for increasing red pepper microbial safety and drying rate.