Rising methods and leavening agents used in the production of bread do not impact the glycaemic index.

Abstract

The aim of this study was to compare the glycaemic index of breads produced using different rising methods and leavening agents. Eleven bread varieties were selected based on method of production, and divided between three groups of ten participants (mean +/- SD age 30.0 +/- 10.7 years and BMI 22.9 +/- 2.8). Standard glycaemic index testing protocol was implemented after an overnight fast, using glucose as the reference food, and collecting blood samples over a two-hour period. Glycemic index was calculated using the usual method. Additionally, incremental area under the curve data were log transformed and glycaemic index was calculated using regression analysis. Mean glycaemic index values of the breads in ascending order were as follows: Swiss Rye; 60, Long oat; 68, Sourdough+oats; 71, Long rye; 76, Short oat; 77, Short whole meal; 78, Long whole meal; 80, Sourdough; 82, Short rye; 82, Yeast; 88, and Desem; 92. There were significant differences in mean glycaemic index values between Swiss Rye and Yeast (p = 0.010), Swiss Rye and Desem (p = 0.007) and Sourdough+oats and Desem (p = 0.043). The rising method and leavening agents used in this study did not impact on the glycaemic index of the breads tested. Other factors, such as increased bread density, and the addition of whole grains may be required to produce bread with a low glycaemic index.