Diabetics are recommended to eat a balanced diet containing normal amounts of carbohydrates, preferably those with a low glycemic index. For solid foods, this can be achieved by choosing whole-grain, fiber-rich products. For (sterilized) liquid products, such as meal replacers, the choices for carbohydrate sources are restricted due to technological limitations. Starches usually have a high glycemic index after sterilization in liquids, whereas low glycemic sugars and sugar replacers can only be used in limited amounts. Using an in vitro digestion assay, we identified a resistant starch (RS) source [modified high amylose starch (mHAS)] that might enable the production of a sterilized liquid product with a low glycemic index. Heating mHAS for 4-5 min in liquid increased the slowly digestible starch (SDS) fraction at the expense of the RS portion. The effect was temperature dependent and reached its maximum above 120 degrees C. Heating at 130 degrees C significantly reduced the RS fraction from 49 to 22%. The product remained stable for at least several months when stored at 4 degrees C. To investigate whether a higher SDS fraction would result in a lower postprandial glycemic response, the sterilized mHAS solution was compared with rapidly digestible maltodextrin. Male Wistar rats received an i.g. bolus of 2.0 g available carbohydrate/kg body weight. Ingestion of heat-treated mHAS resulted in a significant attenuation of the postprandial plasma glucose and insulin responses compared with maltodextrin. mHAS appears to be a starch source which, after sterilization in a liquid product, acquires slow-release properties. The long-term stability of mHAS solutions indicates that this may provide a suitable carbohydrate source for low glycemic index liquid products for inclusion in a diabetes-specific diet.