Phytochemical composition, oxidative stability, and antioxidant behavior of roasted expeller-pressed oils from butternut squash and pumpkin seeds

Tocmo, R. ORCID: https://orcid.org/0009-0007-4850-977X and Padilla-Zakour, O. (2026) Phytochemical composition, oxidative stability, and antioxidant behavior of roasted expeller-pressed oils from butternut squash and pumpkin seeds. Journal of Food Processing and Preservation, 2026 (1). ISSN 1745-4549 doi: 10.1155/jfpp/6576717

Abstract/Summary

Seed oils are increasingly valued for their nutritional quality and natural antioxidant content, yet their oxidative stability remains a critical quality concern. This study evaluated the phytochemical composition, antioxidant capacity, and oxidative stability of roasted butternut squash (Cucurbita moschata) (BSO) and pumpkin (Cucurbita pepo) seed oils (PSO). Major antioxidants, including tocopherols, tocotrienols, carotenoids, and phenolic compounds, were quantified, and antioxidant capacity was assessed. Oxidative stability indices were monitored during both accelerated storage and 20-week storage studies. Both oils were rich in γ-tocopherol and exhibited comparable oxygen radical absorbance capacity (ORAC) and total phenolic values. Five phenolic compounds were identified, including luteolin, tyrosol, vanillin, vanillic acid, and trans-cinnamic acid. Fatty acid analysis revealed that both oils were rich in unsaturated fatty acids, predominantly linoleic acid (57.14% in BSO and 48.54% in PSO) and oleic acid (18.34% in BSO and 33.38% in PSO), with relatively low levels of saturated fatty acids. Oxidation progressed slowly under dark storage, with peroxide and TBARS values remaining below the 20meq O2/kg regulatory limit for unrefined oils, indicating high intrinsic stability. Light exposure significantly accelerated oxidation, particularly in clear (90% UV light transmission) and emerald green bottles (60% UV light transmission), while amber bottles provided effective protection. Tocopherols and carotenoids showed progressive depletion during storage, displaying strong inverse correlations with oxidation indices. Total phenolic content measured by the Folin–Ciocalteu method, a nonspecific measure of total phenolics, remained stable over the 20-week storage. These findings demonstrate that roasted BSO and PSO possess favorable oxidative stability when appropriately packaged and stored below a temperature of 30°C and highlight their potential as value-added, antioxidant-rich specialty oils for functional food applications.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/129757
Identification Number/DOI	10.1155/jfpp/6576717
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Food Microbial Sciences Research Group
Publisher	Wiley
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