Amount, stability, and digestibility of carbohydrates after the extrusion process: Impact on the glycemic index of flours commonly consumed in Chile

Flours from wheat, corn, lentils, and rice are essential for the formulation of various high-consumption foods in the Chilean population. The extrusion process is widely used by the food industry to generate properties that allow for the instant re-constitution of flours. However, this technological process affects the nutritional properties of the carbohydrates (CHO) in the food ingredient, including quantity, stability, and digestibility; characteristics that directly impact the glycemic response of individuals and the glycemic index of foods. This review analyzes the effect of extrusion on the nutritional properties of CHO in foods made from commonly consumed flours in Chile. Factors such as temperature, and to a lesser extent, humidity, and speed used in the extrusion process, along with the origin of the grain used, determine the healthy properties of CHO in extruded flours. The utility of adjusting the mentioned variables in the extrusion process would allow for the standardization of industrial scaling in the production of extruded foods that would positively impact the starch hydrolysis rate and glycemic index of wheat, corn, lentil, or rice flours, and foods formulated from them.