TY - JOUR
T1 - Antioxidant and pro-oxidant activity of (-)-epigallocatechin-3-gallate in food emulsions
T2 - Influence of pH and phenolic concentration
AU - Zhou, Lisa
AU - Elias, Ryan J.
PY - 2013/6/1
Y1 - 2013/6/1
N2 - Polyphenols have been observed to exert both antioxidant and pro-oxidant activity in lipid foods, and factors that influence that net effect include both polyphenol concentration and matrix pH. In this study, the effects of concentration (1-500 μM) of a model polyphenol, (-)-epigallocatechin-3- gallate (EGCG), and matrix pH (2-7) on the net anti-/pro-oxidant activity of EGCG in flaxseed oil-in-water (o/w) emulsions were systematically evaluated. After 24 h, EGCG (5-100 μM) was observed to exhibit pro-oxidant activity in low pH (pH 2-4) emulsions, as determined by conjugated dienes (CDs) and thiobarbituric acid reactive substances (TBARSs) production. At the higher pH values studied (pH 5-7), lower CD and TBARS concentrations were detected in samples with 25-500 μM EGCG at 24 h. Overall, EGCG concentration and pH both played significant roles in determining net antioxidant or pro-oxidant effects, with the largest antioxidant and pro-oxidant effects observed at the higher EGCG concentrations (100-500 μM) tested.
AB - Polyphenols have been observed to exert both antioxidant and pro-oxidant activity in lipid foods, and factors that influence that net effect include both polyphenol concentration and matrix pH. In this study, the effects of concentration (1-500 μM) of a model polyphenol, (-)-epigallocatechin-3- gallate (EGCG), and matrix pH (2-7) on the net anti-/pro-oxidant activity of EGCG in flaxseed oil-in-water (o/w) emulsions were systematically evaluated. After 24 h, EGCG (5-100 μM) was observed to exhibit pro-oxidant activity in low pH (pH 2-4) emulsions, as determined by conjugated dienes (CDs) and thiobarbituric acid reactive substances (TBARSs) production. At the higher pH values studied (pH 5-7), lower CD and TBARS concentrations were detected in samples with 25-500 μM EGCG at 24 h. Overall, EGCG concentration and pH both played significant roles in determining net antioxidant or pro-oxidant effects, with the largest antioxidant and pro-oxidant effects observed at the higher EGCG concentrations (100-500 μM) tested.
UR - http://www.scopus.com/inward/record.url?scp=84873739095&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84873739095&partnerID=8YFLogxK
U2 - 10.1016/j.foodchem.2012.09.132
DO - 10.1016/j.foodchem.2012.09.132
M3 - Article
C2 - 23411273
AN - SCOPUS:84873739095
SN - 0308-8146
VL - 138
SP - 1503
EP - 1509
JO - Food Chemistry
JF - Food Chemistry
IS - 2-3
ER -