Exploring the impact of respiration on pectin metabolism through a quantitative respiratory system created by equilibrium modified atmosphere packaging with adjustable gas-conductor materials.

Pectin metabolism plays a critical role in the softening and quality deterioration of postharvest pepper fruits. While respiratory inhibition influences pectin metabolism, its quantitative effects on respiration intensity and pectin composition remains insufficiently underexplored. This study addresses this gap by employing a quantitative respiration system integrated with gas-conductor materials to regulate the storage atmosphere, reducing respiration from 7.1 to 9.7 mg CO₂∙kg-1∙h-1 to 1.9-5.1 mg CO₂∙kg-1∙h-1. This intervention mitigated fruit softening, increasing final hardness (23.4 N to 38.8 N) and springiness (0.61 to 0.75). It also suppressed phenotypic changes, reducing weight loss and total soluble solids, while preserving total phenols, flavonoids, and ascorbic acid content. Moreover, EMAP suppressed pectin metabolism, increasing water-soluble pectin (WSP), decreasing chelate-soluble pectin (CSP), altering monosaccharide compositions especially glucose, galactose, and galactonic acid, and reducing the activities of pectin-degrading enzymes, particularly PL and β-Gal. Correlation analysis revealed positive associations between texture properties and CSP levels, as well as monosaccharide components. These findings reveal the link between respiratory inhibition and pectin metabolism, providing insights for enhancing postharvest storage strategies and extending the shelf life of the peppers.