Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1183980 | Food Chemistry | 2016 | 8 Pages |
•ALA-catechin conjugates were prepared by free radical grafting method.•Covalent ALA-catechin conjugates were confirmed by SDS–PAGE and ESI–MS.•The antioxidative properties of ALA were improved with catechin conjugation.•The BC retention in nanoemulsion was improved by ALA-catechin conjugates.
The goal of this study was to prepare and characterize α-lactalbumin (ALA)-catechin conjugates as a novel emulsifier in improving the retention of β-carotene (BC) in nanoemulsions via a free radical method. Covalent modification was observed and at least one catechin molecule was binding with ALA according to ESI–MS results. Far-UV CD indicated that the secondary structure of ALA was changed after conjugation. The Z-average particle diameters of nanoemulsions stabilized with ALA and ALA-catechin conjugates were 158.8 and 162.7 nm, respectively. The increase of mean particle size and the degradation of BC at 50 °C were both larger than at 25 °C during 30 days storage. BC retention stabilized with ALA-catechin conjugates was appreciably greater than ALA (control), which was attributed to the increase of ALA’s radicals-scavenging and free metal ion binding ability after grafting with catechin. The chemical antioxidant activities of ALA-catechin conjugates were increased with increasing concentrations from 0.1 to 1.0 mg/ml. In general, labile phytochemicals, like BC, can be protected against oxidation during storage by proteins-polyphenols conjugates without any side effects.