Formulation and stability assessment of ergocalciferol loaded oil-in-water nanoemulsions: Insights of emulsifiers effect on stabilization mechanism.
Journal:
Food research international (Ottawa, Ont.)
Published Date:
Oct 18, 2016
Abstract
In the study, we investigated the effect of emulsifiers with different stabilizing mechanisms on the formulation and stability of ergocalciferol loaded oil-in-water (O/W) emulsions. O/W emulsion stabilized by modified lecithin (ML; electrostatic stabilization), sodium caseinate (SC; electrosteric stabilization) or decaglycerol monooleate (MO-7S; steric stabilization) were formulated using high-pressure homogenization. The Sauter mean diameter (d) of emulsions produced by ML, SC and MO-7S were 126±1, 127±4 and 138±3nm, respectively. The stability of resulting emulsions was evaluated when they exposed to different environmental stresses and during 30days of storage at 25 and 55°C. Results showed that the emulsions prepared by MO-7S or ML were stable against a wide range of pH (2-8), while SC-stabilized emulsions showed instability with extensive droplet aggregation at pH4 or and 5. Only ML-stabilized emulsions showed droplet growth due to coalescence when treated at high NaCl concentration (300-500mM). In the absence of glucose, SC-stabilized O/W emulsions showed better freeze-thaw stability, in comparison to those formed with ML or MO-7S emulsifiers. The emulsion produced by ML was found to be stable to droplet aggregation at heating temperatures (80-120°C) for 1h. All the O/W emulsions stored at 25°C showed good physical and chemical stability. However, the chemical stability of ergocalciferol in emulsion system decreased in order of ML>MO-7S≫SC during storage at 55°C for a period of 30days. These findings provide valuable information for the development of nanoemulsion-based delivery system applied in food and beverage products.
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