Laboratory demonstrations show that the approach blocks certain digestive enzymes from reaching the potato starch as quickly, leading to a more controlled release of dietary glucose.
“There is a perception that potato foods are unhealthy because eating a large amount of some potato foods can cause a rapid increase in blood sugar, which is a risk for people with diabetes or those who want to control body weight,” said Amy Lin, PhD, the study’s principal investigator and lead of the Food Carbohydrate Program of the Singapore Institute of Food and Biotechnology Innovation (SIFBI) at A*STAR. “Our team revealed that toggling the accessibility of two digestion enzymes — α-amylase and mucosal α-glucosidase — in the small intestine is a successful strategy to make dietary glucose slowly and continuously release from potatoes.”
This process causes a reaction with pectin, a water-soluble fibre in potatoes, creating a gelling structure that acts as a barrier between starch granules and digestive enzymes. This protective layer is porous, and the processing method allows the size of the pores to be controlled to moderate how quickly α-amylase is able to penetrate the potato parenchyma cells and degrade starch to small molecules. Converting starch molecules to glucose relies on mucosal α-glucosidase, which is too big to penetrate those pores. Therefore, the elevation of dietary glucose of processed potatoes depends on the how quickly small starch molecules leach out of parenchyma cells and are digested by mucosal α-glucosidase.