Analysis of polyphenols in agri-food wastes

Abstract

This work is enrolled to a valuation project of wastes from agri-food industries. It is particularly based on the polyphenols recuperation. Polyphenols are natural antioxidants presents in fruits, vegetables, cereals and beverages. These compounds act against reactive oxygen species which produce processes of oxidation in our body. Several studies confirm that antioxidant from vegetal origin are related to the prevention of cardiovascular and neurological diseases, cancer and aging-related disorders. Research in this field has increased significantly in the recent years due to the beneficious effects that these compounds cause to health. There are two main strategies of analysis of the total content of polyphenols in food products: the first one is based on the determination of the antioxidant capacity; the second one is based on the analysis of the total content of polyphenols by liquid chromatography. In the project, Folin-Ciocalteu, trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays were evaluated and compared with the results obtained with liquid chromatography with UV detection. The results of Folin-Ciocalteu and TEAC methods show an appropriate correlation, even with the existent controversy with the equivalence of the values obtained with each assay. Finally, a very good correlation between both methods and HPLC data was observed. Wastes from winery, olive oil and black grape were the samples with most concentration of polyphenols