Structural changes and calcium bioaccessibility of calcium fortified milk containing CaCO loaded solid-in-oil-in-water emulsion during simulated in vitro digestion.

BACKGROUND

In most regions around the globe, average dietary calcium intake is relatively low. Consumers increasingly supplement calcium with milk. However, commercial high-calcium milk has the problem of low calcium bioaccessibility. This study was to explore calcium fortified milk containing calcium carbonate (CaCO ) loaded solid-in-oil-in-water emulsion as a potential novel calcium fortified milk with higher calcium bioaccessibility.

RESULTS

The CaCO loaded solid-in-oil-in-water (S/O/W) emulsion with good physical stability (zeta potential -33.34 ± 0.96 mV, mean particle size 4.49 ± 0.02 μm) and high calcium bioaccessibility (32.34%) was prepared when the concentration of xanthan gum was 4 g L . Furthermore, the physicochemical properties and gastrointestinal fate of calcium fortified milk (calcium contents, 1.25 mg mL , 1.35 mg mL , and 1.45 mg mL ) with different proportions of CaCO loaded S/O/W emulsion and pure milk were investigated. The calcium fortified milk (calcium content, 1.25 mg mL ) with a small amount of CaCO loaded S/O/W emulsion did not significantly affect the physicochemical properties of pure milk and had similar rheological properties and higher calcium bioaccessibility to commercial high-calcium milk. Excessive calcium ion (Ca ) weakens the electrostatic interaction of milk sample system and causes aggregation of colloidal particles, which was attributed to more insoluble calcium soap formation.

CONCLUSION

This study showed that the S/O/W emulsion delivery system improved the dispersion stability and bioaccessibility of CaCO . These findings contribute to the development of calcium fortified milk with improved physicochemical properties and higher calcium bioaccessibility. © 2023 Society of Chemical Industry.