Date of Graduation

12-2013

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor

Sun-Ok Lee

Committee Member

Ya-Jane Wang

Second Committee Member

Craig Coon

Abstract

Diabetes and obesity are chronic illnesses increasing at dramatic rates in the U.S. and around the world. Research has looked to prevent or control diabetes and obesity through functional ingredients such as healthy-dietary carbohydrates to control blood glucose levels. Starch is a principle carbohydrate, which influences blood glucose levels, and measuring starch digestibility fractions can help predict the glucose response in the body. The objectives of this study were to investigate the functional starch content of parboiled brown rice flour and grain sorghum flour, and measure the effects on postprandial plasma glucose and insulin levels of 14 and 10 healthy men after consuming a parboiled brown rice flour pudding and grain sorghum flour muffin, respectively. For control treatments, a standard 50g glucose solution served as the parboiled brown rice flour pudding control, and a wheat flour muffin was compared to the grain sorghum muffin. Initial flour materials and final food products were analyzed for total starch (TS) content as well as the starch digestibility fractions: rapidly-digestible starch (RDS), slowly-digestible starch (SDS), and resistant starch (RS). Using a randomized-crossover design, male subjects consumed treatments during respective studies within a one-week washout period, and glucose and insulin levels were observed at 15 minutes before and at 0, 15, 30, 45, 60, 75, 90, 120, 180 minutes after consumption in addition the incremental Area Under the Curve (iAUC) was calculated. Significant reductions of the mean glucose responses were observed after the consumption of parboiled brown rice pudding at 6 intervals and mean glucose iAUC responses also significantly lowered (P<0.05). Mean plasma insulin responses also reduced in a similar trend. The grain sorghum study observed mean glucose responses significantly reduced at 5 intervals and the mean insulin responses reduced at 6 intervals (P<0.05). Mean plasma glucose iAUC responses reduced significantly an average of 26% and mean plasma insulin iAUC significantly reduced an average 55% (P<0.05). Results suggest parboiled brown rice flour or grain sorghum flour would be a good functional ingredient to assist in managing blood glucose levels and additional research of slowly-digestible and resistant starches may help in the prevention of diabetes and obesity.