European Food Research and Technology

, Volume 245, Issue 3, pp 607–616 | Cite as

Antioxidant properties, profile of polyphenolic compounds and tocopherol content in various walnut (Juglans regia L.) varieties

  • Karolina PyciaEmail author
  • Ireneusz Kapusta
  • Grażyna Jaworska
  • Anna Jankowska
Original Paper


The aim of this work was to characterize antioxidant properties, establish the profile of polyphenolic compounds and evaluate the content of tocopherols in walnut fruits. The research material consisted of eleven walnut varieties which were examined for dry matter content, fats and minerals content. Their antioxidant capacity was determined by the ABTS, DPPD and FRAP assays. The profile of polyphenolic compounds was established by means of ultra-high performance liquid chromatography coupled with a mass detector (UPLC–PDA–ESI–MS). In addition, tocopherols (α, β, γ and δ) were quantified using high-pressure liquid chromatography (HPLC). Walnut fruits differed significantly in terms of their physicochemical parameters, antioxidant properties and the content of bioactive compounds. Walnuts of the Lake cultivar exhibited the strongest antioxidant potential, while those of the U02 had the highest content of total polyphenols (2.07 g/100 g). Phenolic acids, among which gallic acid, protocatechuic acid, syringic acid, and genistinic acid were identified, dominated in the polyphenol profile. In turn, the spectrum of tocopherols contained four isoforms: α, β, γ and δ. In the examined walnuts, the total tocopherol content ranged from 19.83 mg/kg (U17) to 126.00 mg/kg (Lake) and β- and δ-tocopherols were present in major quantities.


Walnuts Antioxidant properties Polyphenols Tocopherols 


Compliance with ethical standards

Conflict of interest

The authors have declared no conflict of interests.

Compliance with ethics requirements

This article does not contain any studies with human and animal subjects.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Karolina Pycia
    • 1
    Email author
  • Ireneusz Kapusta
    • 1
  • Grażyna Jaworska
    • 1
  • Anna Jankowska
    • 2
  1. 1.Department of Food Technology and Human Nutrition, Faculty of Biology and AgricultureUniversity of RzeszowRzeszowPoland
  2. 2.Commercial Walnut-Tree Nurseries Anna JankowskaPrzeworskPoland

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