Structural, emulsifying and curcumin-embedded properties of arachin nanoparticles induced by ultrasound and heat

Abstract

Different types of arachin (one of the major globulins in peanut proteins) nanoparticles were prepared by ultrasound (US) and heat treatments, respectively. The results showed that short-term US treatment induced large nanoparticles (named US200 and US500, ∼267 nm) that maintained a compact globular structure; long-term US treatment induced small nanoparticles (named US500L, ∼197 nm) with a moderately unfolded structure; heat treatment induced medium-sized nanoparticles with an unfolded structure. The large nanoparticles had significantly lower surface hydrophobicity, β-sheet content, and λmax but higher enthalpy of denaturation (ΔH) than other nanoparticles. US500L and US500 exhibited the highest emulsifying activity and stability indices, respectively. As for curcumin-embedded properties, both US and heat treatments enhanced the curcumin encapsulation efficiency (from 88.53 to 94.08-97.88%) and load amount (from 1.77 to 1.88-1.96 μg/mg) of arachin. However, only curcumin in large nanoparticles was effectively protected from damage by heat and light. In simulated digestion tests, curcumin in US500L and heat-induced nanoparticles showed higher stability and bioavailability, which was mainly attributed to the slower digestion of these nanocomplexes. We have established a simple method for the preparation of arachin nanoparticles by US and the nanoparticles have potential applications in the food industry due to their favorable bifunctional properties.