Effect of ball‐mill treatment on physical properties and molecular change of maize starch granule was investigated. Ball‐mill treatment was done by rotary type mill, and species of maize starch are normal, waxy and high amylose (amylo). Running time of the treatment is 0–320 h. Starch granules loss smoothness on surface and became rough, even though their changing speed was different among the three species. But, they retained whole figure and size after 320 h treatment in the all cases. Amylase susceptivity and water absorption activity were measured. Structural change of starch components was compared among the three species with X‐ray diffraction, DSC and GPC. High Performance An‐ion Exchange Chromatography (HPAEC) pattern of debranched sample treated with ball‐mill for 320 h showed that formation of very short chain in amylopectin is little. 13C solid‐NMR spectra suggest that disruption of molecules of amylopectin and amylose with ball‐mill might occur at their glycosidic linkage. However, very slight radical was observed by Electron Spin Resonance spectroscopy (ESR) in the case of 320 h sample.

Molecular change of potato starch granule by ball‐mill treatment was investigated. Starch granule still retained its whole figure after 320h, treatment, but its surface changed extremely rough. Water absorption activity extremely increased by 10h treatment. Amylase susceptivity of starch increased according to treatment time. X‐ray diffraction pattern lost its peak and enthalpy on DSC decreased 70% after 20h treatment. Iodine color reaction value decreased 30% and λ max shifted hypso‐chromic 15nm in the both cases of debranched and non‐debranched samples after 20h treatment, and this indicates amylose was also degraded by the treatment. However, the peak of amylose decreased 10% and the peak of amylopectin decreased 10% on each GPC of branched and non‐debranched samples after 20h treatment. GPC (Toyopearl HW‐65) of 320h treated sample shows only one peak, but its debranched sample shows similar pattern to that of non‐treated sample on HPAEC. 13C‐solid state NMR spectra suggest that total disruption frequency is fairly low after long this treatment.

Introduction of fatty acid into maize starch granule by ultra high pressure treatment (UHPT) was investigated. Starches are normal, waxy and amylo‐species. They were treated by ball‐mill before UHPT. Fatty acids are linoleic, oleic and oleic‐stearic acid mixtures. Removal of oil on granule surface was done with 50% ethanol. The incorporated amount of fatty acids and tendency of effect of ball‐mill time on the fatty acid amount are different among the three starch species. Fatty acid introduction to amylose and amylopectin helices was also investigated after washing with chloroform‐methanol‐water mixture. The introduced fatty acid amount to amylostarch is the largest among three species. It is proved that the less double bond in fatty acid, the more fatty acid introduced to starch. The peak at 13.6° (2T) on X‐ray diffraction pattern of starch samples treated by UHP becomes large and their Tp on DSC becomes low as increase of introduced fatty acid.

A combination treatment (dry‐heat and glucoamylase) was applied on potato starch granules. Many inner granules in the granules after the treatments were observed by SEM. The inner granule located near edge of ellipsoid of granule was partially degraded X‐ray diffraction pattern of starch granules did not change before and after the treatments in spite of over 50% loss by amylase digestion. GPC and iodine reaction of the sample showed the treatments brought about fairly large degradation of both amylopectin and amylose components, but GPC of debranched sample after the combination treatments showed amylose was thoroughly degraded while peaks pattern of amylopectin did not change. Small size granules were more susceptible than large size granules by the treatments.

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