Extraction of Oil from Roman Nettle Seed by Cold Press and Evaluation of its Quality during Storage

• Published in: European journal of lipid science and technology 2023-01, Vol.125 (1), p.n/a
• Main Authors: Siabi, Shahla, Torbati, Mohammadali, Azadmard‐Damirchi, Sodeif, Naebi, Maryam, Savage, Geoffrey P.
• Format: Article
• Language: English
• Subjects: Caffeic acid; Carotenoids; Chlorophyll; cold press; Cold pressing; Fatty acids; moisture conditioning; Moisture content; Moisture effects; oil quality; Oils & fats; Phenolic compounds; Phenols; Phytosterols; Roman nettle seeds; Room temperature; Seeds; Storage; Tocopherol; Urtica pilulifera; Vitamin E; Water content
• ISSN: 1438-7697; 1438-9312
• DOI: 10.1002/ejlt.202200071

Roman nettle (Urtica pilulifera L.) is an annual plant whose seeds are rich in oil and valuable phytochemicals. In this study, oil from Roman nettle seeds is extracted by cold pressing and its quality is evaluated during storage at room temperature for up to 90 days. The seed moisture content is adjusted to 0%, 2.5%, 5%, 7.5%, and 10% (g 100 g−1) to evaluate its effect on oil extraction yield. The highest oil yield (31.5%) is found in the seeds containing 5% moisture. Acid and peroxide values increase with both moisture content increase and during storage. Moreover, an increase in seed moisture content decreases the oxidative stability (from 8.1 to 6.3 h), carotenoids (from 25 to 14 mg kg−1), chlorophylls (from 742 to 486 mg kg−1), and phenolic contents (from 134 to 97 (mg caffeic acid per kg oil)) of the extracted oils. Fatty acid profile and phytosterols are not significantly influenced (p > 0.05) by the moisture content of the seeds and storage. Total phenol contents and γ‐tocopherol levels increase during storage, but carotenoids, chlorophylls, and α‐tocopherol levels decrease. Based on overall composition and quality parameters, Roman nettle seed oil may have potential food applications. The moisture content of Roman nettle seeds is effective on the physicochemical characteristics of the extracted oil. Adjustment of the moisture content of the seeds prior to extraction improves the oil yield. The seeds containing 5% moisture content give the highest oil extraction yield (31.5%). Also, the quality of the extracted oil change during 90 days of storage.