Characterization of a Novel Resistant-Starch and Its Effects on Postprandial Plasma-Glucose and Insulin Responses

Objectives of this study were to understand the physicochemical properties of a novel resistant starch (RS) made by complexing high-amylose maize starch VII (HA7) with palmitic acid (PA), and its effects on reducing postprandial plasma-glucose and insulin responses. The HA7 starch was heat-treated and debranched using isoamylase (ISO) to enhance the starch-lipid complex formation. The RS content of the HA7 starch debranched with ISO and complexed with PA (HA7+ISO+PA) was 52.7% determined using AOAC Method 991.43 for dietary fiber, which was greater than that of the HA7 control (35.4%). The increase in the RS content of the HA7+ISO+PA sample was attributed to the formation of retrograded debranched-starch and starch-lipid complex. The postprandial plasma-glucose and insulin responses of 20 male human-subjects after ingesting bread made from 60% (dry basis) HA7+ISO+PA were reduced to 55 and 43%, respectively, when compared with those after ingesting control white bread (as 100%) containing the same amount of total carbohydrates. The results suggested that the HA7+ISO+PA can be used for the interventions of insulin resistance and metabolic syndrome, including diabetes and obesity.