Effects of amylose and amylopectin molecular structures on the emulsification performance of starch nanoparticles

Starch nanoparticles have increasing applications as emulsion stabilizers in functional foods and drug delivery. The effects of amylose and amylopectin molecular structures on the emulsification performance of starch nanoparticles obtained from anti-solvent precipitation are explored here. From size-exclusion chromatography results, ten different starch nanoparticles with distinct molecular structures possessed a molecular size ranging from 63 nm to 111 nm. Rice-starch nanoparticles showed near-neutral wettability (contact angle 90.25°) with 100 % emulsifying stability index (ESI). Correlation analysis indicated that the maximum size of the amylopectin component was positively associated with ESI, while the amount of amylopectin long chains and the lengths of amylose short chains negatively correlated with ESI. Mechanistic reasons for these observations are put forward. These findings can help design new emulsifiers using starch nanoparticles, and development of "clean-label" (i.e. having relatively few ingredients, "natural" ingredients, and few synthetic additives) food emulsions.