Pressure moisture treatment (PMT) of starch, a new physical modification method

Abstract

Effect of pressure level on the physicochemical properties of pressure moisture treated (PMT) starch was investigated. Native starches (corn, potato, rice, tapioca) were equilibrated to water contents of 25% (MCDB) and pressurized at 350, 450, 550 MPa for 10 min at 25 °C, which is called pressure moisture treatment (PMT). PMT starches showed lower equilibrium moisture content compared with native starches at the same relative humidity. Broader amylopectin melting transition temperature with higher end temperature and melting enthalpy were observed in PMT starches. PMT decreased solubility and swelling power. In RVA pasting properties, PMT increased pasting temperature but decreased peak viscosity, break down, set back and final viscosity, which is similar to cross-linked starch. PMT increased RS and SDS contents but decreased RDS content compared with native starch. Consequently, PMT starches exhibited distinctively different properties compared with native starch, suggesting the possibility of PMT as a new physical starch modification method. • Pressure can be used instead of heat for physical starch modification. • Pressure moisture treatment (PMT) changed physicochemical properties of starch. • PMT starches revealed similar properties to cross-linked starch. • The first evidence of PMT as a new physical starch modification method.