Apart from parameters of physicochemical properties that are indicators of fruit quality directly, atomic force microscopy (AFM), a powerful nanotechnology tool for examining food structure and molecule at nanostructure level is useful in obtaining qualitative and quantitative information of produce quality and safety. It has been applied on characterising nanostructure of fruit pectins wa- ter-soluble pectin (WSP), chelate-soluble pectin (CSP) and sodium carbonate-soluble pectin (SSP)