Beta-lactoglobulin–polysaccharide complexes as nanovehicles for hydrophobic nutraceuticals in non-fat foods and clear beverages

For enrichment of non-fat clear drinks with hydrophobic nutraceuticals (HN), vitamin D2 (VD2), a model HN, was successfully entrapped within electrostatically stable nanoparticles ˜50–70 nm in size. The particles, having electrophoretic mobility more negative than −3 × 10−8 m2 V−1 s−1, comprised β-lactoglobulin (β-Lg) to which the HN was bound, and excess of a polyanionic polysaccharide (low methoxyl pectin), which provided electrostatic stability. As pectin concentration increased in 0.05% β-Lg solutions and pH 3.5–4.5, coacervation and turbidity first increased, but dropped beyond 0.01% pectin. The lowest turbidity, of about 0.035, was obtained at pH 4.25 and 0.05% pectin. As pH was increased from 3.5 to 4.25 the minimal particle size decreased and solutions became clearer. Optimal systems obtained were transparent, and may be suitable for enrichment of clear acid beverages. The nanocomplexes provided better protection to the vitamin against degradation than β-Lg alone, and stability was significantly better than that of unprotected vitamin dispersed in water.