Impact of drying on the composition and organization tomato fruit cell walls: A biochemical and structural study

The cell walls are known to play an important role in the evolution of tomato quality during processing, but the mechanisms are not always clearly identified. The study investigated changes in cell wall polysaccharides in two tomato varieties, Terradou and H1311, following hot air drying at 45 °C for 18-20 h. Significant reductions in pectic sugars (rhamnose, uronic acid), pectin methyl esterification, and hemicellulose-related sugars (mannose, glucose, xylose) were observed, particularly in H1311, mirroring ripening processes and indicating enzyme activity during drying. Solid-state NMR revealed increase in cellulose crystallinity, especially in Terradou, along with reduced cell wall polysaccharide organization, reduced water content around pectin and increased cell wall interactions of pectin as the fruit dried. The correlations between sugar composition and structural dynamics suggest that mannan may play a key role in cellulose organization. The study highlights the role of fruit genetics and enzymatic breakdown in the drying process. It is hypothesized that preservation of hemicelluloses structure during drying helps maintain cell wall porosity, which may facilitate faster water migration.