Cuticular constituents and their effects on water loss in fruit of Canarium album (Lour.) Raeusch

The cuticle layer covering the surface of the fruit acts as a crucial barrier to regulate water loss and preserve the texture. This study comprehensively investigated the morphological characteristics, cutin matrix depolymerization, and wax content and their effects on transpiration in Chinese olive fruit. Microscopic examination revealed that the surface of the fruit had fissured wax layers, sparse lenticels, and a delicate cuticle covering the epidermal cells. We developed a simple and efficient powder extraction method to decompose cutin polymers, especially from partially depolymerized cutin matrices and epidermal peels, from which cuticular membranes cannot be isolated. The analysis revealed a cutin monomer content of approximately 4.85 g m −2 , predominantly comprising C16–9/10,16-dihydroxy fatty acids (51.4 %) and phenols (19.5 %). The fruit waxes (8.11 g m −2 ) were predominantly composed of pentacyclic triterpenoids, constituting approximately 88 %, with a small amount of very-long-chain aliphatic compounds. The water loss rate from Chinese olive fruit was 4.75 × 10 −3 g m −2 s −1 , resulting in a permeability of 19.6 × 10 −5 m s −1 , which is higher than that reported for many other fruit. The reduced efficiency of the transpiration barrier may largely be attributed to the chemical composition and spatial arrangement of the cuticle. The findings of this study provide a basis for mitigating the dehydration process and developing appropriate preservation strategies for Chinese olive fruit.