The K-RAPRS method was designed to more closely mimic the human small intestine by reducing the incubation period to 4 hours. This is different to K-RSTAR which requires an incubation time of 16 hours.
Recent studies on the hydrolysis of newly developed resistant starch materials such as phosphate crosslinked starch (RS4) indicated that these incubation conditions are an essential requirement to obtain meaningful physiologically relevant values for RS.
Both K-RAPRS and K-RSTAR have a detection limit of 2-100% per weight of sample. K-RSTAR will remain available as this kit is widely. However for samples containing high levels of RS4 the K-RAPRS method may be more suitable.