Study of the phenolic profile of a grape pomace powder and its impact on delaying corn oil oxidation

The grape pomace, the main by-product from the winemaking industry, contains many bioactive substances that must be valorized. The aim of this study was to assess the total phenolic content (TPC), phenolics profile by using HPLC and the antioxidant activity (AOA). The results showed a TPC of 38.86 +/- 5.22 g gallic acid equivalent (GAE)/kg while an AOA of 247.84 +/- 18.65 mu mol Trolox equivalent (TE)/g. Epicatechins were the most representative phenolic compound, according to the HPLC analysis. Then, the grape pomace powder (GPP) was tested in the Rancimat equipment as a natural antioxidant for delaying the corn oil oxidation. Results showed statistically significant differences between the corn oil treated with GP and the control, so the GPP could be a promising natural antioxidant to tackle the oxidation vulnerability of corn oil.