Thermal stability and in vitro digestive behavior of Pickering emulsion stabilized by high-amylose starch nanocrystals

Abstract

In this study, high-amylose starch (HAS) was processed using sulfuric acid-ultrasonic cross-linking to produce high-amylose starch nanocrystals (HASNC). These nanocrystals were used to stabilize Pickering emulsions and assess their effectiveness in encapsulating β-carotene. Normal starch nanocrystals (NSNC) were prepared similarly for comparison. The HASNC retained key HAS properties, such as heat and enzyme resistance, providing several advantages to HASNC-stabilized emulsions. First, after exposure to 100 °C heat and in vitro tests simulating the mouth and stomach, the HASNC-stabilized emulsions demonstrated significantly greater stability and higher β-carotene retention compared to the NSNC-stabilized emulsions. This enhanced stability is attributed to the lower gelatinization degree and increased resistance to α-amylase hydrolysis of HASNC, which provides stronger steric stabilization of the oil droplets. Second, during in vitro small intestine tests, the greater enzyme resistance of HASNC allowed for the formation of a denser barrier around the oil droplets, effectively preventing lipase and bile salts from contacting the oil droplets. This led to a reduced rate and extent of lipid digestion and facilitated a sustained-release effect. Consequently, HASNC, as a starch-based emulsifier, show great potential as an effective delivery system for the sustained release of bioactive compounds.