Fresh apple slice preservation driven by molecular hydrogen.

Abstract

During 8-day cold storage (4°C, 85% relative humidity), fresh-cut apple slices exhibited progressive surface browning and physiological deterioration that correlated with declining endogenous hydrogen gas (H2) levels. To clarify whether exogenous H2 supply could counteract these changes, modified atmosphere packaging (MAP) containing 0.01%, 0.1%, or 1% H2 was evaluated. Among the concentrations tested, 0.1% H2-MAP partially restored H2 homeostasis and most effectively retarded browning and water loss. Sensory quality, nutritional content, and antioxidant capacity were all better maintained compared with controls. Non-targeted metabolomics combined with molecular analyses revealed marked upregulation of flavonoid biosynthesis via the phenylpropanoid pathway under positive ion mode detection. These findings indicate that H2-MAP represents a promising approach for extending the shelf life and maintaining the quality of fresh-cut fruit products.

Mechanism

Exogenous H2 supply activates the phenylpropanoid metabolic pathway, upregulating flavonoid biosynthesis, which sustains antioxidant capacity and suppresses enzymatic browning and physiological deterioration in fresh-cut apple tissue.