High pressure processing and retrogradation of potato starch: Influence on functional properties and gastro-small intestinal digestion in vitro

Abstract

A combined approach of high pressure processing (HHP) along with retrogradation was used to treat potato starch samples in order to influence their functional properties and kinetics of glucose release during gastro-small intestinal digestion in vitro. Native potato starch was treated at two levels of high hydrostatic pressure (400 MPa and 600 Mpa) and number of cycles (3 and 6) for 10 min and then subjected to retrogradation at 4 °C for 7 days. The granular starch samples treated at 400 MPa for 6 cycles showed higher peak and breakdown viscosities whereas peak time and final viscosity for the same samples treated for 3 cycles followed by retrogradation were higher than the native control sample. HHP in combination with retrogradation promoted an increase in the relative crystallinity whereas reduction in To and Tp was observed with an increase in the number of cycles at 400 MPa. The use of 3 cycles of 600 MPa led to significant changes in morphology of the granules, causing light eruptions on the surface of most granules, abrasions and major disruptions in some granules. After applying 6 cycles at 400 Mpa, a significant reduction was observed in starch hydrolysis (during gastro-small intestinal digestion in vitro) of the HHP-retrograded sample throughout the small intestinal phase, with a final reduction of 10–15% compared to the native and pressure-treated only sample.