gamma-Oryzanol nanoemulsions produced by a low-energy emulsification method: an evaluation of process parameters and physicochemical stability

摘要

gamma-Oryzanol is a natural antioxidant and nutraceutical compound, which makes it a good candidate for nutraceuticals, food supplements and pharmaceutical preparations. However, the incorporation of gamma-oryzanol into aqueous formulations is rather difficult and its bioavailability can be severely decreased because of its water-insoluble property. In this study,gamma-oryzanol-enriched nanoemulsion based fish oil and medium-chain triglyceride as carrier oils were proposed. The main objective was to optimize process parameters to form stable nanoemulsions and evaluate their physicochemical stability. The formulations of stable gamma-oryzanol nanoemulsions were composed of 10% mixed carrier oils (weight ratio of fish oil to medium-chain triglyceride = 3 : 7) and 10% mixed surfactants (weight ratio of Tween 80 to Span 20 = 3 : 1). The nanoemulsions were stable at a broad pH range of 2-7 and high salt concentrations (= 0.8 mol L-1) and sucrose levels (= 16%). The nanoemulsions were much more stable at heating temperatures below 50 degrees C than at elevated heating temperatures (60 and 70 degrees C). The nanoemulsions maintained their physical stability at various storage temperatures (5-37 degrees C) for 18 days. Nanoemulsions at 5 and 23 degrees C had lower peroxide values and anisidine values than those at an elevated storage temperature (37 degrees C). These results demonstrate that the low-energy emulsification method can produce gamma-oryzanol-enriched nanoemulsions using fish oil and medium-chain triglyceride as carrier oils, and provide useful information for producing bioactive lipids-loaded nanoemulsions for food systems, personal care and pharmaceutical products.