Effect of long-term storage on antioxidant activity of walnut cake

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Key words: 

antioxidant activity, polyphenols, walnut cake, food stability, shelf-life.

Summary

During the storage of food changes of content and activity of native antioxidants may be observed. These processes may have important impact on stability of lipid fraction so their direction and strength should be taken into account while predicting the shelf-life of products.  The aim of the study was to evaluate the changes in antioxidant activity of walnut cake during the one-year storage. The research material was walnut cake obtained during coldpressing of oil. The content of phenolic compounds and flavonoids was determined by spectrophotometric methods. Antioxidant activity was measured in FRAP test, in model linoleic acid – β-carotene emulsion and as DPPH radical scavenging capacity. The content of polyphenols in fresh walnut cake was equal to 85.1 mg of gallic acid per gram dry weight and flavonoids – 25.7 mg of quercetin per gram of dry weight. The highest antioxidant potential was maintained during the first 200 days of storage and then it systematically decreased. The results showed a strong positive correlation between the content of polyphenolic compounds and antioxidant activity upon storage.

mgr inż. Olga BIŃCZAK dr hab. inż. Urszula SAMOTYJA, prof. nadzw. UEP

Poznan University of Economics and Business Faculty of Commodity Science

Department of Food Commodity Science

al. Niepodległości 10, 61-875 Poznań, Poland tel. (+48) 61-856 90 45 e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.