Encapsulation of Lutein in Nanoemulsions Stabilized by Resveratrol and Maillard Conjugates

Abstract

Lutein is incorporated into foods as a natural yellow pigment and nutraceutical. The introduction of lutein into many foods and beverages, however, is problematic because of its strong hydrophobicity and poor chemical stability. In this research, lutein‐loaded nanoemulsions were prepared to overcome this problem. Casein‐dextran Maillard conjugates or physical complexes were utilized as emulsifiers, while either medium chain triglycerides (MCT) or grape seed oil (GSO) were used as carrier oils. The impact of resveratrol addition on nanoemulsion stability was also examined. The influence of storage temperature, pH, and CaCl2 concentration on the chemical and physical stability of the nanoemulsions was measured. The casein‐dextran conjugates were highly effective at improving the physical resistance of the nanoemulsions to environmental stresses, but had a detrimental effect on their color stability. Conversely, nanoemulsions prepared from casein‐dextran physical complexes were unstable around the protein's isoelectric point (pH 4.6), as well as upon addition of CaCl2. Incorporation of resveratrol and GSO into the nanoemulsions decreased lutein degradation and color fading at all temperatures. This study shows that casein‐dextran conjugates are highly effective at improving the physical stability of lutein‐loaded nanoemulsions, while resveratrol and GSO are effective at improving their chemical stability. Practical Application Lutein can be used by the food industry to create “clean label” and functional food products. The major challenges in incorporating lutein in foods are its poor chemical stability and its high hydrophobicity, which makes it difficult to incorporate. Emulsion‐based delivery systems assembled from natural ingredients may address these challenges. In this study, the impact of Maillard conjugates fabricated from caseinate and dextran, as well as resveratrol addition, on the formation and stability of lutein‐enriched nanoemulsions was determined. The information obtained from this study will help the formulation of more effective functional foods and beverage products.

Interface Compositions as Determinants of Resveratrol Stability in Nanoemulsion Delivery Systems

“…After 5 days of incubation at 25 °C, samples were centrifuged at 10,000× g (Beckman Instruments) for 15 min and the supernatant (0.05 mL) was diluted in 3.95 mL of DMSO. The unbound resveratrol was quantified by measuring the solution absorbance at 309 using a UV/vis model DU-530 spectrophotometer (Beckman Instruments) [ 21 ]. A solution of bovine casein or caprine casein in DMSO without resveratrol was used as a blank.…”

“…To evaluate the ability of the bovine and caprine caseins to bind resveratrol, mixtures of the casein solutions (2% w/w) dissolved in 5 mM phosphate buffer (pH 7.0) solution and resveratrol dissolved in ethanol (1.25% v/v), at a concentration of 500 µg/mL in the final mixture, were mixed using a magnetic stirrer at low speed for 30 min at 25 • C. The samples were then vortexed and incubated for 5 days at 25 • C. After 5 days of incubation at 25 • C, samples were centrifuged at 10,000× g (Beckman Instruments) for 15 min and the supernatant (0.05 mL) was diluted in 3.95 mL of DMSO. The unbound resveratrol was quantified by measuring the solution absorbance at 309 using a UV/vis model DU-530 spectrophotometer (Beckman Instruments) [21]. A solution of bovine casein or caprine casein in DMSO without resveratrol was used as a blank.…”

Recent Advances on Nanoparticle Based Strategies for Improving Carotenoid Stability and Biological Activity

“…Some other studies have also reported the development of carotenoid based NEs [ 82 , 83 , 84 ]. Comparatively, NEs are among the nanocarotenoid carriers most frequently used in pharmaceutical, food and chemical industries.…”

Improvement of Resveratrol Solubility by Complexation with Lactose Using Organic Solvent Spray Drying Technique

“…In recent studies, several solutions have been proposed and these methods include lipid nanocarriers or liposomes, nanoemulsions, nanocrystals, etc. These methods do contribute to the solubility of resveratrol [14][15][16][17]. However, it is undeniable that nanomaterials or liposomes have disadvantages, such as difficult and unstable preparation, and excipients (i.e., ethanol and propylene glycol) which are known to have recognized actions or effects are usually used in the preparation [18].…”