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Composition and oxidative stability of silflower (Silphium integrifolium) seed oil and its potential as a new source of squalene
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  • Hong-Sik Hwang,
  • Sean Liu,
  • Jill Winkler-Moser,
  • Mukti Singh,
  • David Van Tassel
Hong-Sik Hwang

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Sean Liu
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Jill Winkler-Moser
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Mukti Singh
USDA Agricultural Research Service
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David Van Tassel
The Land Institute
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Silphium integrifolium Michx. (silflower), a perennial plant, is of great interest as a potential new oilseed crop due to its long, strong, deep, extensive root systems, which can prevent erosion, capture dissolved nitrogen, and out-compete weeds eliminating the need for frequent irrigation and herbicide uses. In this study, oil was extracted from unhulled silflower seeds, and its composition and oxidative stability were evaluated. The oil content in unhulled silflower seeds was 15.2 % (w/w), and its fatty acid composition was similar to that of sunflower oil. The level of total polar compounds (TPC) in the oil was 12.3 % (w/w), and the content of total phenolics was 1.12 mg gallic acid equivalent (GAE)/g oil. Noteworthily, 4.89 % squalene was isolated from silflower oil indicating its potential application as an alternative source of squalene. Silflower oil had lower oxidative stability as indicated by the oxidative stability index (OSI) at 110 °C and thermogravimetric analysis (TGA), presumably due to its high level of chlorophyll (1002.8 mg/Kg). Even after a typical refining process involving degumming, alkali refining, and bleaching with Fuller’s earth, silflower oil contained 725.5 mg/kg chlorophyll, and its oxidative stability was not improved. Further treatments with bleaching agents including bentonite, sepiolite, and Tonsil® lowered the chlorophyll level to 4.2, 474.5, and 38.5 mg/kg, respectively, and some aspects of oxidative stability were improved and better than those of refined sunflower oil. This study presents the potential of silflower oil as new edible oil and a great plant source of squalene.
31 Jul 2023Submitted to Journal of the American Oil Chemists' Society
31 Jul 2023Submission Checks Completed
31 Jul 2023Assigned to Editor
01 Aug 2023Review(s) Completed, Editorial Evaluation Pending
15 Aug 2023Reviewer(s) Assigned
01 Nov 2023Editorial Decision: Revise Minor
13 Nov 20231st Revision Received
13 Nov 2023Submission Checks Completed
13 Nov 2023Assigned to Editor
13 Nov 2023Review(s) Completed, Editorial Evaluation Pending
20 Nov 2023Reviewer(s) Assigned