The increase in soluble pectins at the expense of ionically (CDTA fraction) and covalently (Na2CO3 fraction) bound polyuronides is the main cell wall change taking place during the transition from green-unripe to red-ripe strawberry fruit. The chromatographic analysis of pectin fractions indicates that CDTA pectins were depolymerised in ripe fruit, but not Na2CO3 polyuronides. Additionally, the amount of Ara was notably reduced in both fractions at the ripe stage. The nanostructure of bound pectins has been analysed by AFM. The results obtained suggest a reduction of the structural complexity of pectins during fruit development. Thus, pectic chains displayed a lower number of branches and the number of pectin aggregates was reduced in the samples of red fruit. This set of chemical, biochemical and nanostructural changes of the pectin matrix during ripening could contribute to the pectin solubilisation process and to the modification of the cell wall physical properties, probably reducing its mechanical strength and, finally, leading to a reduction in fruit firmness.