Characterization of catechin-α-lactalbumin conjugates and the improvement in β-carotene retention in an oil-in-water nanoemulsion. (15th August 2016)

• Record Type: Journal Article
• Authors: Yi, Jiang; Fan, Yuting; Zhang, Yuzhu; Zhao, Liqing
• Is Part Of: Food chemistry. Volume 205(2016)
• Page Start: 73
• Page End: 80
• Publication Date: 2016-08-15
• Subjects: BC β-carotene -- ALA α-lactalbumin -- BLG β-lactoglobulin -- VAD vitamin A deficiency -- SDS–PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis -- CD circular dichroism -- ESI–MS electrospray Ionization–mass spectrometry -- HPLC high-performance liquid chromatography -- PDI polydispersity index; α-Lactalbumin -- Nano-encapsulation -- β-Carotene -- SDS–PAGE -- Chemical stability; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2016.03.005
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: 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. Abstract: 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.