In Vitro Determination of the Glycemic Index

The use of sourdough as leavening agent, among other nutritional attributes, is preferable for making bread and other leavened baked goods with medium or low glycemic index (GI). In vitro methods mimicking in vivo human digestion are simple, reliable, accurate, and cost-effective to predict and estimate the glycemic response to a food. Here, we describe a procedure for starch hydrolysis—in vitro digestion. In the first part of the process, the native starch of the sample is broken down into D-glucose and determined. Then, the sample is subjected to an enzymatic treatment. The rate of starch hydrolysis is defined as the percentage of starch hydrolyzed at different time points, and the GI index may be predicted using a mathematical model. This process can be largely used in the evaluation of the predicted GI (pGI) in starchy products, where fermented cereals and legumes flour dough are most commonly used.