Influence of an O/W emulsion on the gelatinization, retrogradation and digestibility of rice starch with varying amylose contents

The present study aimed to explore the effects of oil-in-water emulsion on the gelatinization, retrogradation, and digestibility of indica rice starch (IRS), japonica rice starch (JRS), and glutinous rice starch (GRS). With the emulsion, the three types of starch granules exhibited limited swelling and increased gelatinization enthalpy during heating, and changed the peak viscosity and final storage modulus of starch gelatinization. After being refrigerated at 4 °C, the emulsion changed the firmness of starch gel, reduced the water migration, and increased the water-holding capacity of the three starch gels. X-ray diffraction and scanning electron microscopy revealed that the emulsion could delay the retrogradation of the three types of starches, and the inhibitory effect was related to the content of amylose. The results of in vitro digestion showed that the emulsion significantly increased the slowly digestible starch and resistant starch contents in the three types of starch. These findings indicated that the emulsion could inhibit the gelatinization and retrogradation properties, as well as delay the digestion of different types of starch, providing a theoretical basis for expanding the application of the emulsion in starch foods.