Effects of Different Modified Atmosphere Packages on Storage Quality of Peppermint and Establishment of Respiration Rate Model of Peppermint Preservation

To extend the post-harvest storage duration of peppermint and predict the post-harvest respiration rate of peppermint, peppermint was subjected to modified atmosphere packaging conditions with different packaging materials (PE, OPP1.8/PE3.5, OPP1.8/4.5, OPP2.3/PE4.5, HDPE), various O₂ concentrations (3%~7%), and different CO₂ concentrations (5%~15%). Parameters including weight loss rate, relative electrical conductivity, color difference, sensory evaluation, vitamin C content, total chlorophyll content, and total colony count were measured. Response surface optimization experiments were conducted with O₂, CO₂, and packaging materials as factors to determine the optimal gas ratios and packaging materials for post-harvest preservation of peppermint. On this basis, the volatile compounds and surface fungal diversity of peppermint were studied. The proportions of O₂ and CO₂ inside the optimal packaging materials for peppermint were measured by using the closed space system. Based on this, a model equation was obtained using the permeation system method and numerically simulated. Matlab software was used to calculate the respiration rate at equilibrium, and a regression analysis was performed using a quadratic polynomial model. High-throughput sequencing was used to sequence and analyze peppermint samples from the optimal, worst, and control treatment groups, comparing changes in the proportion of dominant microbial communities. The results showed that the optimal gas composition and packaging material were 3.5% O₂+9.4% CO₂ and HDPE, which extended the freshness period of peppermint from 7~9 days to 10~12 days. It could inhibit the increase of linalool and other alcohols during peppermint storage, reduce the volatilization of D-carvone and other ketones, and delay the senescence of peppermint. Based on these experiments, a more accurate quadratic respiration rate model for peppermint under controlled atmosphere packaging was established, which effectively inhibited the growth of decay-causing microorganisms such as Ascomycota and Mycetes in peppermint.