Lipid composition and functional properties of quinoa (Amarilla Sacaca) seed oil: impact of cultivation in a hyper-arid Saharan environment on yield, fatty acids, and antioxidant capacity

Introduction: Quinoa (Chenopodium quinoa Willd.), a nutrient-dense “golden grain” from South America, is valued for its resilience to abiotic stresses, making it a strategic crop for arid regions. While its protein quality is well-established, the composition and bioactivity of oil from varieties grown under extreme hyper-arid conditions, such as those in the Algerian Sahara, remain unexplored. This study provides the first comprehensive characterization of the oil from Quinoa (Amarilla Sacaca) cultivated in this unique environment. Methods: Quinoa seeds of the Amarilla Sacaca variety, harvested from the hyperarid Ouargla region of Algeria, were processed to extract oil via Soxhlet method using n-hexane. The oil was characterized for its physicochemical properties (acid, peroxide, iodine, and saponification values, etc.) and bioactive phytochemical content (total phenolics, flavonoids, carotenoids) using standard AOAC and spectrophotometric methods. The fatty acid profile and minor lipophilic compounds were analyzed by GC-MS. Antioxidant activity was evaluated using three complementary in vitro assays: DPPH radical scavenging, β-carotene bleaching inhibition, and nitric oxide (NO) radical scavenging. Results: The extracted oil yield was 3.98%. It was rich in bioactive compounds, with a total phenolic content of 467.78 ± 11.38 μg GAE/g, total flavonoids of 209.90 ± 8.83 μg RE/g, and total carotenoids of 7.88 ± 0.12 mg/kg. The fatty acid profile was dominated by unsaturated fatty acids (87.22%), with linoleic acid (C18:2 n-6, 51.33%) and an unusually high concentration of petroselaidic acid (C18:1 n-6t, 33.44%) as the major constituents. Squalene (1.01%) and 2,4-di-tert-butylphenol (0.83%) were identified as significant minor bioactive components. The oil demonstrated potent, multi-mechanistic antioxidant activity (IC50 values: DPPH = 45.67 μg/mL; β-carotene bleaching = 38.05 μg/mL; NO scavenging = 26.57 μg/mL), which was strongly correlated with its phytochemical content (r > 0.85, p < 0.001). Discussion and conclusion: The extreme arid conditions appear to induce a trade-off, suppressing oil yield while significantly enhancing the accumulation of bioactive phytochemicals. This results in a functionally superior oil with a unique fatty acid fingerprint and exceptional antioxidant capacity, surpassing that of pure α-tocopherol in some assays. The high squalene content positions it as a sustainable, plant-based alternative for nutraceutical and cosmetic applications. These findings highlight Saharan Quinoa oil as a high-value specialty product, supporting sustainable development goals (SDGs 2, 3, 9, 12) and offering a pathway for the integrated valorization of resilient crops within a circular bio-economy framework.