Effect of varying combinations of pre-treatment and drying methods on the quality of chili pepper product

This work was to develop a processing strategy that simultaneously optimizes the drying time and quality of dried products. The fresh chili pepper was assigned into eight groups, being hot-air drying, CaCl 2 + hot-air drying, freezing + hot-air drying, CaCl 2 + freezing + hot-air drying, vacuum drying, CaCl 2 + vacuum drying, freezing + vacuum drying, and CaCl 2 + freezing + vacuum drying (Ca × FVD). Results showed that Ca × FVD had relatively better drying performance with moderate drying rate, rehydration capacity (1.31), water-holding capacity (3.66), and the largest expansion force (4.00 mL/g). Swebull2 was determined as the optimal model to predict the drying process of chili pepper. The dried chili pepper from Ca × FVD group maintained the color quality (L* = 43.43, a* = 38.90, b* = 23.73, and ΔE = 4.26) similar to the fresh samples and alleviated the loss of nutrients. The flavor of Ca × FVD product was featured by baking and nutty. Metabolomics analyses revealed that Ca × FVD could exert positive influences mainly via maintaining cell integrity, inhibiting oxidation and regulating Maillard reaction. All data suggest Ca × FVD has the potential to be a workable approach for manufacturing high-quality dried chili pepper. • Effect of pre-treatment and drying methods on the chili pepper quality was evaluated. • Soaking with 30 g/hg CaCl 2 + pre-freezing + vacuum drying was the optimal strategy. • Dried chili pepper exhibited similar quality traits to the fresh fruit. • This work provides an idea for producing dried chili pepper with high quality traits.