Investigating the relationship between volatile components and differentially expressed proteins in broccoli heads during storage in high CO2 atmospheres

Broccoli heads usually age by yellowing or producing an off-flavor after harvesting and during storage under improper conditions. However, the reasons for the off-flavor are complex, and the factors affecting the development of this characteristic is unclear. This study aimed to investigate the relationship between off-flavor compounds and differentially expressed proteins in a controlled O2/CO2 atmosphere using headspace GC–MS fingerprinting and an iTRAQ-based quantitative proteomic approach. Results demonstrated that a suitably controlled O2/CO2 atmosphere increased the energy production efficiency, improved stress resistance, and markedly extended the shelf life of broccoli heads. However, treatment with an excessively high CO2 proportion promoted glycolysis and fermentation, reduced energy generation efficiency, altered sulfur-component metabolism, and promoted the accumulation of an offensive odor in broccoli heads. This study provides a foundation for understanding the metabolic mechanisms responsible for off-flavor and highlights potential control measures under high CO2 conditions.