Tilia sp. Seed Oil—Composition, Antioxidant Activity and Potential Use

Abstract

Research on new, untapped seed oil sources is receiving increased attention. In this study, 18 different seed samples of Tilia cordata and Tilia platyphyllos from various locations in Slovenia were collected and oil was extracted. The compositions of triglyceride fatty acids and unsaponifiable compounds were determined using GC-MS, while antioxidant activity was evaluated using the DPPH method. The oil content in the seeds varied significantly, from 9.1% to 21.7%. Linoleic acid (50–60%) was found to be the predominant fatty acid, followed by oleic acid (18–22%) and palmitic acid (8–9%). Characteristic cyclopropene fatty acids (sterculic, dihydrosterculic and malvalic acids) were present in the average range of 4–8.4%. Antioxidant activity ranged from 8.9% to 65.5%, and was higher, on average, for T. platyphyllos. Higher antioxidant activity was closely correlated with higher γ-tocopherol contents. Statistically significant correlations were confirmed between antioxidant activity and γ-tocopherol, between Δ-tocopherol and phytol, between stigmasterol and β-sitosterol and between squalene and malvalic acid. Tilia oil may be of great interest for cosmetic and dermal preparations. It is, however, not considered a good source of dietary fatty acids due to the undesired, significant content of omega-6 fatty acids.