Main content area

Stability of astaxanthin-loaded nanostructured lipid carriers as affected by pH, ionic strength, heat treatment, simulated gastric juice and freeze–thawing

Tamjidi, Fardin, Shahedi, Mohammad, Varshosaz, Jaleh, Nasirpour, Ali
Journal of food science and technology 2017 v.54 no.10 pp. 3132-3141
EDTA (chelating agent), alpha-tocopherol, antioxidants, astaxanthin, cryoprotectants, gastric juice, glycerol, heat, heat treatment, ionic strength, lipids, pH, polysorbates, sodium chloride, zeta potential
Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear/opaque food systems. In this study, the influence of pH, ionic strength, thermal treatment, simulated gastric juice (SGJ), and freeze–thawing on the stability of astaxanthin-loaded NLCs (Ax-NLCs) was examined. Ax-NLCs (containing α-tocopherol and ethylenediaminetetraacetic acid as antioxidants) were stabilized with Tween 80 and lecithin (Z-average size: 94 nm), and studied for the above mentioned purpose. The size of Ax-NLCs increased at low pH values (≤5), high NaCl concentrations (≥50 mM), and slightly at SGJ, mainly because of decreasing the ζ-potential. Moreover, thermal treatment at 80/90 °C led to an increase in Ax-NLCs size. Glycerol was found as an appropriate cryoprotectant for preventing aggregation of Ax-NLCs during freeze–thawing. pH, ionic strength, heat and SGJ had no drastic effects on the chemical stability of astaxanthin in NLCs. These results have valuable implications for the utilization of food-grade NLCs.