Role of the plum cuticle layer in influencing fruit texture and permeation during the salting process

‘Tuogu’ and ‘Bingtang’ plums display unique textural responses to salt curing, manifesting in volume reduction, surface wrinkling, and alterations in color and texture, alongside ongoing material exchange. Over a seven-day salting period, ‘Tuogu’ plums lost 14.9 % of their moisture, compared to ‘Bingtang’ plums' 24.8 %, with salt permeability rates of 5.0 % and 5.2 %, respectively. Cuticle analysis revealed that the dominant component of the cutin monomers in both fruits was fatty acids, accounting for over 90 %, while the wax composition was predominantly very long-chain alkanes and triterpenoids, also constituting over 90 %. ‘Tuogu’ plums, with their rich waxes and dense, thick cuticle, showed enhanced barrier properties against material exchange, whereas ‘Bingtang’ plums, with their abundant cutin monomers, exhibited increased elasticity and material exchange capacity.