Comparative analysis of the biochemical composition of fruit tissues in representatives of the Malus sect....

This research represents the first comprehensive biochemical analysis of mature fruits from apple trees of the Chloromeles section, specifically examining Malus coronaria, Malus ioensis, Malus × platycarpa and Malus × soulardii. The experimental investigations revealed distinctive compositional characteristics in lipids, carbohydrates, flavonoids, and chlorophylls that markedly differentiate these species from other representatives of the genus Malus. Specifically, our research revealed the absence of procyanidin B1 and a high content of chlorogenic acid, accompanied by remarkably low quantities of cinnamic acid and its derivatives. Linoleic acid represented approximately 50% of the total fatty acid profile, which is substantially lower compared to the lipid content commonly observed in domesticated apple varieties. Conversely, the linolenic acid concentration was significantly higher. Fructose levels in fruit tissues of the Chloromeles section ranged from 15% in M. ioensis to 50% in M. coronaria, the section's largest fruiting species. Additionally, the analysis revealed the presence of transport sugars and highly etherified protopectins. Unlike other Malus, the Chloromeles section mature fruits exhibited high chlorophyll and low carotenoid contents. These pigments were present in both the peel and pulp tissues. The observed composition, including elevated transport sugar and protopectin levels, is typically associated with fruits at early ripening stages. This may contribute to the suboptimal flavor development, despite the presence of a relatively high total soluble sugar content.