Improving solubility and stability of β-carotene by microencapsulation in soluble complexes formed with whey protein and OSA-modified starch

In this study, a soluble complex formed between 0.5% (w/v) heated whey protein isolate (HWPI) and 5% (w/v) octenyl succinic anhydride (OSA)-modified starch at pH 4.5 was used to encapsulate ?-carotene for improving its solubility and stability. The apparent aqueous solubility of ?-carotene was increased markedly (264.05 ? 72.53 ?g/mL) after encapsulation in the soluble complex. Transmission electron microscopy and scanning electron microscopy were used to evaluate the effect of the encapsulation of ?-carotene on the structure of the soluble complex. Fourier transform infrared spectroscopy showed that the characteristic peaks of ?-carotene disappeared in the soluble complex, suggesting that ?-carotene may have been encapsulated into the soluble complex via hydrophobic interactions. X-ray diffraction indicated that the ?-carotene was in an amorphous form within the soluble complex. An accelerated stability test showed that the soluble complex could effectively improve the chemical stability of ?-carotene during long-term storage under low pH conditions.