BACKGROUND Flavor plays a critical role in defining sensory and consumer acceptance of dried pepper, and it can be affected by temperature and moisture content during hot air drying (HAD). Thus, headspace‐gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS) was used to analyze changes in volatile compounds of pepper during the HAD process with different drying temperatures. RESULTS A total of 45 volatile flavor compounds were identified, including 11 esters, 11 aldehydes, nine alcohols, five ketones, three furans, three acids, two pyrazines, and one ether. The results showed that with the loss of moisture during drying, aldehydes and alcohols decreased, esters initially increased and then decreased. However, propyl acetate, 2,3‐butanediol, 2‐acetylfuran, and 2‐methylpyrazine increased. Moreover, drying temperature was closely related to the change of volatile flavor compounds. Aldehydes, alcohols, and some other volatile flavor compounds (methyl salicylate, ethyl acetate, 2‐methylpyrazine, dipropyl disulfide) decreased with an increase of temperature (60–80 °C) at the same moisture content, while high temperature could promote the formation of ethyl octanoate, methyl octanoate, benzaldehyde, furfurol, acetal, 5‐methylfurfural, and 2‐acetylfuran. Based on principal components analysis and heat map clustering analysis, peppers dried at 70 or 80 °C presented similar composition, and the loss of volatile flavor compounds was more than samples died at 60 °C during the HAD process. CONCLUSION Overall, the flavor quality of peppers dried at 60 °C was better than that of other treatments during the HAD process. HS‐GC‐IMS was a reliable and effective means of analyzing volatile flavor compounds in peppers during the drying process. © 2020 Society of Chemical Industry

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The cuticle plays an important role for the quality of pepper fruit. However, the molecular mechanism of cuticle formation in pepper fruit remains unclear. Our results showed that the wax was continuously accumulated during pepper development, while the cutin monomer first increased and then decreased. Hexadecanoic acid and 10,16-hydroxyhexadecanoic acid were the main components of wax and cutin, respectively. Combined with transcriptome and proteome, the formation patterns of wax and cutin polyester network for pepper cuticle was proposed. The 18 pairs of consistent expression genes and proteins involved in cuticle formation were revealed. Meanwhile, 12 key genes were screened from fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, fatty acid elongation, cutin, suberine, and wax biosynthesis, glycerolipid metabolism, and transport pathway. This study would provide important candidate genes and theoretical basis for the molecular mechanism of cuticle formation, which is essential for the breeding of peppers.