Lutein, a natural pigment with diverse biological activities, exhibits low water solubility, stability, and bioavailability, necessitating encapsulation in suitable emulsions to enhance its utilization. In this study, enzymatic hydrolysates from Nannochloropsis oculata and soybean lecithin (SL) were utilized in grape seed oil emulsions to improve the delivery efficiency of lutein. The results indicated that enzymatic hydrolysates of N. oculata, derived from alkaline protease, papain, or a combination of both enzymes, exhibited emulsifying and antioxidant properties, which were further enhanced by complexation with SL. These complexes facilitated the formation of uniform emulsions characterized by reduced particle size and increased interfacial protein content, as evidenced by alterations in protein structure. Among the various formulations, the emulsion prepared with alkaline protease hydrolysate and its SL complex exhibited superior stability. Consequently, lutein-loaded grape seed oil emulsions were produced with particle sizes ranging from 281.44 to 321.86 nm, a polydispersity index of less than 0.3, and interfacial protein content between 4.95 and 5.16 mg. These SL-complex emulsions also demonstrated improved oxidative stability under accelerated testing conditions, as indicated by lower peroxide and malondialdehyde values. Following in vitro digestion, the bioavailability of lutein in SL-complex emulsion reached 25.35%-28.13%, surpassing that of non-emulsified oil-phase lutein, thereby underscoring the potential of this delivery system for enhancing lutein stability and absorption. The findings further emphasize the dual functionality of microalgal protein hydrolysates as natural emulsifiers and antioxidants, with their efficacy synergistically enhanced by phospholipid complexation.
Li et al. (Wed,) studied this question.