Nanostructured lipid carriers (NLCs) stabilized by natural or synthetic emulsifiers for lutein delivery: Improved physicochemical stability, antioxidant activity, and bioaccessibility

This study investigated the impacts of individual emulsifiers on the physicochemical stability, antioxidant ability, and in vitro digestion behavior of lutein-loaded nanostructured lipid carriers (NLCs). NLCs particles stabilized by ethyl lauroyl arginate, rhamnolipid, or tea saponin were fabricated by high-pressure microfluidization method. Differential scanning calorimetry and X-ray diffraction results confirmed the regulatory effect of emulsifiers on the crystallization behavior of NLCs. NLCs stabilized by rhamnolipid presented higher encapsulation efficiency (94.73%) for lutein than those stabilized by tea saponin (90.39%) or ethyl lauroyl arginate (88.86%). Meanwhile, the stability of embedded lutein during storage or photothermal treatments was greatly enhanced. Individual emulsifiers, together with lutein, endowed NLCs with excellent antioxidant capacity. During in vitro digestion, rhamnolipid-stabilized NLCs showed the slowest release of free fatty acids (50.87%) and provided an optimal sustained release for lutein with relatively high bioaccessibility (23.01%).