61A-46 |
Moist heat processing affects susceptibility of starch to digestion in some common dietary carbohydrate sources |
L. L. NIBA, Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, 319 Wallace Hall, Blacksburg, VA 24060 Starch resistance to digestion has nutritional and health implications. Lower starch digestibility is purported to be beneficial in diseases such as type II diabetes and colorectal cancer. There is need therefore to establish the factors that influence dietary starch susceptibility to digestion. The objective of this study was to determine the effects of moist heat processing and storage temperature on starch digestibility of common dietary carbohydrate sources. Maize flour, potato flour, cocoyam flour, farina, plantain flour, yam (Dioscorea spp.) flour and rice flour were assayed for starch digestibility by an established enzymic procedure. These were then either autoclaved, microwaved or parboiled, then freeze-dried. The freeze-dried samples were stored for ten days either below freezing or at room temperature. Parameters assessed were readily digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). RDS levels among flours ranged from 1.01 g/100g in rice flour to 8.16 g/100g in cocoyam flour. Autoclaving increased RDS levels in most flours, while microwaving greatly reduced RDS. Storage at room temperature reduced RDS content. Slowly digestible starch levels ranged from for 2.40 g/100g in farina to 22.21 g/100g in maize flour. SDS levels varied but were increased by autoclaving and reduced by microwaving for most samples. Storage at room temperature resulted in lower SDS. Resistant starch levels ranged from 18.1 g/100g in plantain flour to 37.1 g/100g in farina. Autoclaving reduced RS in some flours, but increased in others. Parboiling and frozen storage increased RS levels in most flours. It was concluded that moist heat processing and post-process storage temperature influence starch susceptibility to enzymic digestion. This however, varies depending on the plant source. This information will be useful in developing food processing and storage procedures that modify starch resistance to digestion in order to optimize its nutritional quality and enhance its physiological benefits.
Session 61A, Carbohydrate
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