Please use this identifier to cite or link to this item: https://hdl.handle.net/11499/46351
Title: Comparison of the Oil Quality of Light and Dark Walnuts under Different Storage Conditions
Authors: Yildiz, Aysun Yurdunuseven
Karaca, Hakan
Keywords: pellicle color
darkening
ground walnut
storage condition
lipid oxidation
Juglans-Regia L.
Fatty-Acid Profile
Oxidative Stability
Antioxidant Activity
Kernels
Tocopherols
Temperature
Polyphenol
Attributes
Atmosphere
Publisher: Japan Oil Chemists Soc
Abstract: The skin of the walnut kernels can get dark during the pre- and post-harvest stages of the production. Dark kernels are less palatable for most consumers but are still edible and maybe preferable, especially in the ground form, for industrial use. In this study, we investigated the differences between oil oxidation indexes, fatty acid and tocopherol compositions of the oils, total polyphenol contents and antioxidant capacities of the extracts of light and dark walnuts. In addition, we evaluated the effects of packaging under nitrogen and vacuum-packaging techniques and storage temperature on these characteristics of both light and dark walnuts during storage for 6 months. Peroxide values and free fatty acid contents of all samples were higher at the end of storage compared to initial values, being more noticeable at 20 degrees C than at 4 degrees C. Increases in the free fatty acid contents were quite higher in dark walnuts than the light ones (6.1 and 3.1 fold, respectively) and the highest values of conjugated diene and peroxide were determined in the samples packaged under air and stored at 20 degrees C. Dark walnuts had lower total phenolic, alpha- and gamma-tocopherol contents and antioxidant activities compared to the light ones. Total phenolic and tocopherol contents decreased over time. We conclude that due to the antioxidant compounds in the fruit, oxidation parameters of dark walnuts are still acceptable at the end of 6-month storage even in the packages with air and at non-refrigerated conditions.
URI: https://doi.org/10.5650/jos.ess20266
http://acikerisim.pau.edu.tr:8080/xmlui/handle/11499/46351
ISSN: 1345-8957
1347-3352
Appears in Collections:Mühendislik Fakültesi Koleksiyonu
PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

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