Physical and chemical stability of β-carotene-enriched nanoemulsions: Influence of pH, ionic strength, temperature, and emulsifier type

• Published in: Food chemistry Vol. 132; no. 3; pp. 1221 - 1229
• Main Authors: Qian, Cheng, Decker, Eric Andrew, Xiao, Hang, McClements, David Julian
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-06-2012; Elsevier
• Subjects: Biological and medical sciences; Carotenoids; Degradation; Food additives; Food industries; Functional foods; Fundamental and applied biological sciences. Psychology; General aspects; Milk and cheese industries. Ice creams; Nanoemulsion; Nutraceuticals; Protein; Stability; β-Carotene; β-Lactoglobulin; Degradation; Carotenoids; Stability; Functional foods; β-Lactoglobulin; Nanoemulsion; Protein; β-Carotene; Nutraceuticals; Temperature; Carotene; Chemical stability; Food additive; Emulsifier; Milk protein; Health food; Ionic strength; Pigments; pH; Whey protein; Carotenoid
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2011.11.091

► The influence of temperature, pH, salt, and emulsifier type on β-carotene nanoemulsion stability was examined. ► β-Carotene degradation increased with increasing temperature and decreasing pH, but was largely unaffected by salt. ► Protein-stabilised emulsions aggregated at intermediate pH, high salt, and high storage temperatures. ► β-Carotene degradation was slower in protein-stabilised than in surfactant stabilised emulsions.
The enrichment of foods and beverages with carotenoids may reduce the incidences of certain chronic diseases. However, the use of carotenoids in foods is currently limited because of their poor water-solubility, high melting point, low bioavailability, and chemical instability. The potential of utilising oil-in-water (O/W) nanoemulsions stabilised by a globular protein (β-lactoglobulin) for encapsulating and protecting β-carotene was examined. The influence of temperature, pH, ionic strength, and emulsifier type on the physical and chemical stability of β-carotene enriched nanoemulsions was investigated. The rate of colour fading due to β-carotene degradation increased with increasing storage temperature (5–55°C), was faster at pH 3 than pH 4–8, and was largely independent of ionic strength (0–500mM of NaCl). β-Lactoglobulin-coated lipid droplets were unstable to aggregation at pH values close to the isoelectric point of the protein (pH 4 and 5), at high ionic strengths (NaCl >200mM, pH 7), and at elevated storage temperatures (55°C). β-Carotene degradation was considerably slower in β-lactoglobulin-stabilised nanoemulsions than in Tween 20-stabilised ones. These results provide useful information for facilitating the design of delivery systems to encapsulate and stabilise β-carotene for application within food, beverage, and pharmaceutical products.