Comparison of Ultrasound-Assisted and Conventional Extraction for the Quality Characteristics of Strawberry Seed Oils from Different Varieties

In this study, the effects of ultrasound-assisted extraction (UAE) and conventional extraction (CE) on the quality characteristics of seed oils obtained from two strawberry cultivars, “Albion” and “Rubygem,” were investigated. The physical properties of the fruits and seeds were determined prior to oil extraction. The extracted oils were evaluated in terms of oil yield, free fatty acid (FFA), peroxide value (PV), color parameters, total phenolic content (TFC), tocopherol content, and sterol composition. Oil yields for “Albion” and “Rubygem” were 10.41% and 13.20%, respectively, with the CE method, and these values increased with UAE. In “Albion,” UAE reduced FFA from 0.94% to 0.65% and decreased the peroxide value from 16.4 to 15.4 meq O₂/kg. Similarly, in “Rubygem,” FFA decreased from 1.12% to 0.84%, while PV declined from 18.2 to 16.94 meq O₂/kg. Total phenolic content ranged between 1.23 and 1.85 mg GAE/100 g in CE samples and was higher in UAE treated oils. Color analysis demonstrated cultivar-dependent differences; “Albion” oils were lighter in appearance, whereas “Rubygem” oils exhibited more intense red and yellow hues. Sterol analysis revealed that β-sitosterol was the predominant sterol in all samples, whereas brassicasterol was not detected. Some minor sterols were cultivar-dependent. Overall, UAE improved oil yield and enhanced the principal quality parameters of strawberry seed oils compared to the conventional method.