title: Functionalization of chitosan by a free radical reaction: Characterization, antioxidant and antibacterial potential.
abstract: Chitosan was functionalized with epigallocatechin gallate (EGCG) by a free radical-induced grafting procedure, which was carried out by a redox pair (ascorbic acid/hydrogen peroxide) as the radical initiator. The successful preparation of EGCG grafted-chitosan was verified by spectroscopic (UV, FTIR and XPS) and thermal (DSC and TGA) analyses. The degree of grafting of phenolic compounds onto the chitosan was determined by the Folin-Ciocalteu procedure. Additionally, the biological activities (antioxidant and antibacterial) of pure EGCG, blank chitosan and EGCG grafted-chitosan were evaluated. The spectroscopic and thermal results indicate chitosan functionalization with EGCG; the EGCG content was 25.8mg/g of EGCG grafted-chitosan. The antibacterial activity of the EGCG grafted-chitosan was increased compared to pure EGCG or blank chitosan against S. aureus and Pseudomonas sp. (p<0.05). Additionally, EGCG grafted-chitosan showed higher antioxidant activity than blank chitosan. These results indicate that EGCG grafted-chitosan might be useful in active food packaging.
authors.affiliation: Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora, México; Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Moreno-Vásquez
authors.affiliation: Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora, México; Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: Emma Lucía
authors.initials: EL
authors.lastname: Valenzuela-Buitimea
authors.affiliation: Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: Maribel
authors.initials: M
authors.lastname: Plascencia-Jatomea
authors.affiliation: Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: José Carmelo
authors.initials: JC
authors.lastname: Encinas-Encinas
authors.affiliation: Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez-Félix
authors.affiliation: Centro de Investigación en Química Aplicada, Saltillo, Coahuila, México.
authors.forename: Saúl
authors.initials: S
authors.lastname: Sánchez-Valdes
authors.affiliation: Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: Ema Carina
authors.initials: EC
authors.lastname: Rosas-Burgos
authors.affiliation: Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora, México.
authors.forename: Víctor Manuel
authors.initials: VM
authors.lastname: Ocaño-Higuera
authors.affiliation: Departamento de Ciencias Químico Biológicas, Universidad de Sonora, Hermosillo, Sonora, México. Electronic address: abril@guayacan.uson.mx.
authors.forename: Abril Zoraida
authors.initials: AZ
authors.lastname: Graciano-Verdugo
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D000975:Antioxidants; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D005609:Free Radicals; D011549:Pseudomonas / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D005609:Free Radicals; D002392:Catechin; D048271:Chitosan; C045651:epigallocatechin gallate
keywords: 2,2-Diphenyl-1-picrylhydrazyl radical (DPPH) (PubChem CID: 74358); 2,2′-Azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) (PubChem CID: 5815211); 6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) (PubChem CID: 40634); Acetic acid (PubChem CID: 176); Antibacterial; Antioxidant; Ascorbic acid (PubChem CID: 54670067); Chitosan (PubChem CID: 71853); Epigallocatechin gallate; Epigallocatechin gallate (EGCG) (PubChem CID: 44134699); Folin-Ciocalteu reagent (PubChem CID: 452323); Grafting; Hydrogen peroxide (H(2)O(2)) (PubChem CID: 784); Modified chitosan; Sodium carbonate (PubChem CID: 10340)