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ANTIOXIDANT ACTIVITY COMPARISON OF THOMPSON GRAPE POMACE EXTRACT, ROSEMARY AND TOCOPHEROLS IN SOYBEAN OIL
Author(s) -
GÁMEZMEZA NOHEMI,
NORIEGARODRÍGUEZ JUAN ANTONIO,
LEYVACARRILLO LILIA,
ORTEGAGARCÍA JESUS,
BRINGASALVARADO LORENA,
GARCÍA HUGO SERGIO,
MEDINAJUÁREZ LUIS ANGEL
Publication year - 2009
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2008.00285.x
Subject(s) - pomace , citric acid , chemistry , antioxidant , food science , phenols , soybean oil , biochemistry
The effect of natural antioxidants was tested by oxidative stability index (OSI) in refined soybean oil (RSO) using Rancimat method. Phenolic compounds of Thompson grape pomace were extracted with 95:5 (v : v) ethanol : water. The antioxidant activity of grape pomace extract (GPE) obtained was compared with those of rosemary extract (RE), and tocopherols mix (TM) known as covi‐ox T‐70. The synergistic effect of citric acid was also evaluated. Results showed a total phenols content of 17.39 mg ( + )‐catechin equivalents per g of GPE. Thompson GPE at 0.3 and 0.5% (w/w) exhibited greater antioxidant activity than TM. RSO containing GPE or RE at 0.5% (w/w) showed an OSI higher than 48 h at 110C. Citric acid did not show synergistic effect with GPE. However, a synergistic effect for TM at 0.02% (w/w) with citric acid at 1.0% (w/w) was observed. Citric acid at 2.0% (w/w) with RE at all concentrations tested also displayed synergism.PRACTICAL APPLICATIONS Synthetic antioxidants are widely used in the food industry to delay fat oxidation; however, their utilization has been questioned due to toxicology concerns. Researchers have recognized the need to identify new natural antioxidants to use as additives. In this study, we measured total phenolics content of Thompson grape pomace extract (GPE) and found that the antioxidant activity of this extract was stronger than tocopherols from soybean oil. We propose that GPE can have applications as a food antioxidant.