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B. R. HAMAKER, Whistler Center for Carbohydrate Research, Purdue Univ., Dept. of Food Science, 745 Agriculture Mall Dr., West Lafayette, IN 47907-2009 While glycemic response can be moderated by addition or replacement of existing starch with resistant starch, another approach to lowering glycemic response is to identify or design starch structures to have slowly digesting characteristics, or to alter food matrices such that digestion rate is slowed. Slowly digesting starch typically has a lower initial rate of digestion and then releases glucose for absorption throughout the small intestines. Other than the basis of how to create highly retrograded/resistant starch, relatively little is known regarding the molecular structural and interaction factors that might cause starches to be digested at slow rates. Yet, recent studies reveal more as to how starch structures could have a slow digesting characteristic, and other work on protein-starch associations during processing show how component interactions may slow starch digestion rate. Soluble fiber (e.g., b-glucans) has likewise been shown to reduce starch digestion rate principally through viscosity effect, yet other mechanisms may additionally explain the general effect of fiber on glycemic response in whole and processed foods. The talk will cover our current knowledge on methods to slow starch digestion from the perspective of accessibility of native and processed starch molecules to degradative enzymes. A short discussion will also be presented on the affect of food processing and manufacturing on glycemic response, in terms of changing food structure and matrices such that predicted low glycemic index foods or ingredients become higher in glycemic response. In particular, high temperature and high shear processes often result to increase accessibility of starch to amylases. In general, investigations into methods to moderate starch digestion profiles through altering starch structures or associated food matrices are relatively new, yet show promise as an alternative approach to develop foods with slow digesting characteristics for improved health.
Session 62, The broad impact of the glycemic response of foods
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