title: Native and thermally modified protein-polyphenol coassemblies: lactoferrin-based nanoparticles and submicrometer particles as protective vehicles for (-)-epigallocatechin-3-gallate.
abstract: The interactions between native, thermally modified lactoferrin (LF) and (-)-epigallocatechin-3-gallate (EGCG) at pH 3.5, 5.0, and 6.5 were investigated. Turbidity, particle size, and charge of LF-EGCG complexes were mainly dominated by pH value and secondary structure of protein. At pH 3.5 and 5.0, LF-EGCG complexes were nanoparticles which had high ζ-potential, small size, and soluble state. At pH 6.5, they were submicrometer particles which exhibited low ζ-potential, large size, and insoluble state. The infrared spectra of freeze-dried LF-EGCG complexes showed that they were different from LF and EGCG alone. Far-UV CD results indicated that heat denaturation might irreversibly alter the secondary structure of LF and EGCG induced a progressive increase in the proportion of α-helix structure at the cost of β-sheet and unordered coil structure of LF at pH 3.5, 5.0, and 6.5. EGCG exhibited a strong affinity for native LF but a weak affinity for thermally modified LF at pH 5.0 and 6.5. An inverse result was observed at pH 3.5. These results could have potential for the development of food formulations based on LF as a carrier of bioactive compounds.
authors.affiliation: Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University , Beijing 100083, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Chenqi
authors.initials: C
authors.lastname: Xu
authors.forename: Fuguo
authors.initials: F
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.forename: Yanxiang
authors.initials: Y
authors.lastname: Gao
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D004355:Drug Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D011485:Protein Binding; D017433:Protein Structure, Secondary
chemical_list: D004337:Drug Carriers; D002392:Catechin; C045651:epigallocatechin gallate; D007781:Lactoferrin
keywords: (−)-epigallocatechin-3-gallate; nanoparticle; submicrometer particle; thermally modified lactoferrin