This study investigated the cellular and molecular mechanisms responsible for surface hardening in carrot slices during catalytic infrared (CIR) dry-blanching. Results showed that rapid dehydration induced by CIR leads to water redistribution, loss of cell membrane integrity, and disruption of ionic balance. Morphological analysis revealed evident shrinkage and deformation of surface cells, reflecting a collapse of tissue structure. Within the cell wall, CIR treatment promoted polysaccharide reorganization and the selective accumulation of alcohol-insoluble residues (AIR) and hemicellulose in the outer layer. Pectin structure was reorganized with increases in water-soluble pectin (WSP) and chelator-soluble pectin (CSP), while a decline in sodium carbonate-soluble pectin (NSP) was observed. Molecular analysis showed enhanced crosslinking of pectin networks in the hardened surface. Collectively, these findings demonstrate that CIR blanching induces surface crust formation through coupled processes of water migration, membrane rupture, and polysaccharide reorganization, providing new insight into the texture control of infrared-processed fruits and vegetables. • Multiscale perspectives explained mechanisms behind surface crusting in CIR blanching. • CIR blanching induced rapid water migration, triggering surface cell collapse and shrinkage. • Cell membrane damage enhanced permeability and ion leakage, affecting tissue integrity. • Cell wall polysaccharides redistributed and restructured, reinforcing surface hardness.
Wu et al. (Fri,) studied this question.