Effects of different glutenin types on the physicochemical properties and in vitro digestion of cassava starch

Long-term consumption of rapidly digestible starches is a major factor associated with diabetes and other metabolic diseases. In this study, cassava starch (CS) was used to investigate interactions between starch and different forms of glutenin protein and the effect of these interactions on in vitro digestibility. First, CS and natural glutenin (Glu), glutenin hydrolysate (GPH), or citric acid modified glutenin (CA-Glu) were heat treated. The physicochemical properties and digestibility of CS were then measured using differential scanning calorimetry, Raman spectroscopy, X-ray diffraction, and in vitro digestion methods. The results showed that Glu, GPH and CA-Glu increased starch gelatinization enthalpy. Glu, GPH, and CA-Glu also enhanced the ordered structure of starch and starch - protein interactions. Further, in vitro digestion studies showed that the addition of glutenin reduced CS digestibility, wherein CA-Glu had the largest impact. These results have implications for reducing effects of the human diet on disease and warrant further study.