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Enzymatic grafting of gallate ester onto chitosan: evaluation of antioxidant and antibacterial activities
Author(s) -
ItzincabMejía Lidia,
LópezLuna Alberto,
Gimeno Miquel,
Shirai Keiko,
Bárzana Eduardo
Publication year - 2013
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12181
Subject(s) - chitosan , antioxidant , chemistry , nuclear chemistry , propyl gallate , gallate , antibacterial activity , grafting , minimum inhibitory concentration , dpph , antimicrobial , polyphenol , organic chemistry , bacteria , biology , genetics , polymer
Summary The antioxidant octyl gallate ( OG ) has been successfully grafted onto chitosan by means of horseradish peroxidase biocatalyst. The maximum gallate incorporation onto chitosan determined by 1 H NMR spectroscopy was up to 16 molar%. The resulting materials displayed antioxidant capacities with DPPH radical inhibition percentage up to 23% upon the assay conditions. The grafting of the antioxidant on chitosan enhanced its antimicrobial activity. Minimal inhibitory concentration ( MIC ) for E scherichia coli was 0.5 g L −1 . The native medium molecular weight chitosan alone or grafted with the lowest OG incorporation (ca. 11 molar%) attained 100% inhibition of E . coli , whereas lower inhibition was observed for all other materials 50.7–68.9% corresponding a reduction in the counts from 10.6 to 5.23–3.30 Log CFU mL −1 . The inhibition of L isteria monocytogenes was significantly higher (59.8–100%) than that with the G ram negative bacterium reaching the MIC at 0.25 g L −1 with a reduction in the counts from 12.6 Log CFU mL −1 to 5.06–0 Log CFU mL −1 .