Food preservation by Larrea divaricata extract: participation of polyphenols.

The aim of this study was to evaluate the antioxidant and protease inhibitor capacities on eggs and milk protein of a nor-dihydroguaiaretic (NDGA)-standardized aqueous extract of Larrea divaricata (AE) and to analyze the participation of polyphenols as NDGA in these actions. NDGA was determined by high-performance liquid chromatography; flavonoids and polyphenols were quantified by spectrophotometric methods as well as inhibition of lipid peroxidation, proteinase inhibitor capacity, advanced glycation end products (AGES) formation, and inhibition of albumin denaturation. The extract protected food for oxidative damage by preventing malondialdehyde formation in egg yolk and by preventing AGE formation in completely cooked eggs, also impeded albumin denaturation, and casein hydrolysis induced by trypsin and heat. Polyphenols, especially flavonoids and NDGA, were involved in these actions.