Morphology, profile and role of chelate-soluble pectin on tomato properties during ripening

To illustrate the role of chelate-soluble pectin (CSP) on fruit properties, neutral sugar composition and morphology of CSP from two tomato cultivars (‘Dongsheng’ and ‘Geruisi’) at two ripening stages (turning and light-red) were investigated by high-performance liquid chromatography (HPLC) and atomic force microscopy (AFM), respectively. Physicochemical properties and firmness of the tomatoes were determined as well. The percentage of wide CSP chains was reduced and the large CSP polymers were found degraded more with lower firmness during ripening. The proportion of galacturonic acid (GalUA) and rhamnose (Rham) increased during tomato ripening in both cultivars. The proportion of xylose (Xyl) and arabinose (Ara) increased in ‘Dongsheng’ tomatoes while decreased in ‘Geruisi’. The results indicate that the morphology and neutral sugar composition of CSP were closely related with firmness of tomatoes.