Arrowroot starch was steam-treated (ST) by subjecting to pressure steaming at 1.03 bar for 15 min, after preconditioning the moisture content in the samples to 15, 25 and 30%. A control sample (9.8% H 2 O) without any added moisture was also treated in a similar way. The steam-treated samples and the unmodified sample were analysed for apparent and soluble amyloses (expressed as blue value), intrinsic viscosity, swelling and solubility at 90°C, and cold water solubles. The thermal decomposition pattern of the samples was studied on a differential thermal analyser (DTA) and the X-ray diffraction pattern on a Philips X-ray diffractometer. The enzyme susceptibility of the unmodified and steam-treated samples was examined with reference to α-amylase. In general, steam-treated samples showed appreciable changes in the above properties compared to the unmodified one, as well as to the sample steam-treated without any added moisture.

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