Glycosylation improves the functional characteristics of chlorogenic acid–lactoferrin conjugate

Abstract

In the present study, a chlorogenic acid (CA)-lactoferrin (LF) conjugate prepared via alkali treatment was glycoslated with glucose (Glc) or polydextrose (PD) by the Maillard reaction. Formation of the covalent CA-LF-Glc/PD ternary conjugates was confirmed by matrix-assisted laser desorption/ionization timeof-flight mass spectrometry (MALDI-TOF-MS), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and fluorescence analyses. The results showed that the grafting ratio between the CA-LF conjugate and Glc/PD was 40.50% for the CA-LF-Glc ternary conjugate and 11.72%for the CA-LF-PD ternary conjugate. Conjugating CA and Glc/PD onto LF changed the conformation of the protein, leading to a reduction in the a-helix content and an increase in the unordered structure. The thermal stability of the CA-LF conjugate was remarkably improved by the Maillard-type conjugation.According to AFM and DLS results, the ternary conjugates showed coarser structures and bigger particle sizes than their mixtures. The reducing power was increased from 206.91 mmol Trolox g À1 of CA-LF conjugate to 255.76 and 273.25 mmol Trolox g À1 sample, respectively, in CA-LF-Glc and CA-LF-PD ternary conjugates, indicating the glycosylation was an effective way to improve the antioxidant activity of the CA-LF conjugate. Moreover, the ternary conjugates were employed to encapsulate b-carotene as a model biologically active macromolecule, and they could enhance the physicochemical stability of bcarotene emulsions. This work presented a simple and general approach to the preparation of polyphenol-protein-polysaccharide conjugates that could be potentially employed as food-grade biomacromolecules in the food and pharmaceutical industries.

Covalent Bonding of Chlorogenic Acid Induces Structural Modifications on Sunflower Proteins

“…Covalentm odification of lactoferrin with CGA at same pH (pH 9) showed as imilari ncrease in overall absorbance of protein, accompanied by the appearance of as houldera t 324 nm, [36] thus it can be concludedt hat the increasing number of bound phenolic moleculesl ies behind this peak since the unboundp henols were removed by dialysis. To exclude the possibility of absorbance increased ue to attached polymerization products of CGA oxidation, the UV/Vis spectra of CGA was recorded both at pH 7( where it is not oxidized) and pH 9( where oxidation is expected).…”

Food‐Grade Covalent Complexes and Their Application as Nutraceutical Delivery Systems: A Review

“…In our recent studies, we have prepared protein–polyphenol–polysaccharide conjugates as multifunctional surface‐active ingredients (Liu and others , ). Ternary conjugates composed of lactoferrin, polydextrose, and chlorogenic acid were prepared via alkaline treatment and the Maillard reaction (Figure ).…”

Design and Testing of Dual-Targeted Gd3N@C80-Containing Glioblastoma Theranostics

“…Proteins absorb UV light at 280 and 200 nm, due to the absorption of aromatic amino acids and the absorption of peptide bonds, respectively. Several authors have reported UV-Vis signatures of Tf [36] and Lf (Figure 1 A of [37]) and both ligands have similar relatively higher absorption at 280 nm. As Tf and Lf are proteins of the same family with similar shape, similar absorbance signatures were anticipated around 280 nm in Tf-tagged and Lf-tagged as well as Tf+Lf-tagged formulations.…”