The effect of soy addition on the satiety , glycemic index , and insulinemic index of a soft pretzel

The contribution of calories from nutrient-poor snack foods is rising in many Western diets, possibly contributing to the increasing prevalence of obesity and diabetes. Soy offers unique potential to provide high quality protein, dietary fiber, and phytochemicals to snack foods to produce a more healthful nutritional profile. In this study, 27.3% of wheat flour was replaced with soy ingredients in a soft pretzel in order to observe the changes in the product‟s satiety, glycemic index (GI), and insulinemic index (II). First, the soy pretzel was tested for consumer acceptability by 51 untrained sensory panelists on a 9-point hedonic scale. Second, in a crossover trial, 20 healthy adults consumed soy and traditional pretzels (1000 kJ or 239 kcal each) after an overnight fast. They reported their levels of satiety on a 10 cm visual analogy scale (VAS) for 2 hrs postprandially. Third, 12 healthy, non-diabetic subjects consumed soy or traditional pretzels (50 ± 2 g available carbohydrates) to determine the GI and II of both products. Blood glucose and insulin responses were monitored for 2 hrs after consumption and compared to a glucose reference. It was found that the consumer-acceptable soy soft pretzel has a lower GI than its 2 traditional counterpart [39.1±20.4 (mean±SD) for soy and 66.4±15.3 for wheat, p=0.002]. On the other hand, soy addition did not statistically affect II (p=0.15), or satiety (p=0.91). In conclusion, a soy pretzel formulation with 27.3% of wheat flour replaced by soy ingredients leads to attenuated postprandial glycemia without significantly affecting insulinemia or satiety in healthy adults.