Using mid-infrared spectroscopy combined with chemometrics to determine digested starch and maltose concentration during in-vitro digestion of starches

Starch digestion is typically evaluated using in-vitro techniques. During and after the in-vitro digestion, samples are collected (gastric and intestinal phases) at allotted time intervals where starch digestion is quantified through the analysis of sugars using routine chemical and enzymatic analysis. This paper reports the use of mid-infrared (MIR) spectroscopy as rapid method to measure the concentration of maltose and % digested starch during the digestion of rice and potato starch, maize starch namely Gelose 50 (50% amylose), Gelose 80 (80% amylose) and pregelatinized corn starch collected at different time points (5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 90, 105 and 120 min) from two in-vitro digestion experiments. Two types of samples, turbid and supernatant were also evaluated. The coefficient of determination (R2) and the standard error in cross-validation (SECV) ranged between 0.74 to 0.93 and 163 to 360 μg mL−1 for the prediction of the concentration of maltose. The use of turbid samples showed a better predictive ability when compared with the regression models developed using the supernatant samples. This method showed potential to significantly decrease the time and effort associated to determining maltose concentration and % digested starch during in-vitro digestion.