Abstract: A lutein-enriched nanoemulsion stabilized by sodium caseinate was constructed by high-pressure homogenization, and its 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging capacity and oxygen radical absorbance capacity (ORAC) were investigated. The effects of environmental conditions on lutein stability and free radical scavenging capacity in the nanoemulsion were evaluated. The free radical scavenging capacity of lutein was improved significantly by incorporation into the emulsion system (P < 0.05). In addition, the free radical scavenging activity and lutein content of the nanoemulsion decreased to varying degrees when exposed to pH 2.0 as well as 50 and 100 mmol/L NaCl, but increased significantly after condensation treatment (P < 0.05); in contrast, thermal treatment (60, 80, 100 ℃) had little impact on the two parameters.

Key words: lutein, nanoemulsion, free radical scavenging capacity, stability