Dihydroquercetin as an antioxidant

Summary Dihydroquercetin, a white crystalline pentahydroxy‐flavanone, occurring in large quantities in Douglas fir and Jeffrey pine barks, was found to be an effective antioxidant for lard, cottonseed oil, and butter oil. This compound imparts no taste and color to fats and oils and, like quercetin, appears to be nontoxic. It was found that 0.03% quercetin was slightly more effective than 0.03% dihydroquercetin as an inhibitor of rancidity in lard. The presence of a small amount of citric acid increased markedly the antioxidant effect of dihydroquercetin on lard. The pentaacetate, pentapropionate, and the pentabenzoate esters of dihydroquercetin showed no antioxidant activity.