## 2 Materials and Methods  
### Oil Samples  
Oil samples were obtained from seeds of purslane (_Portulaca olearacea_ L.), cucurbit (_Cucurbita maxima_ L. [PERSON]), luffa (_Luffa aegyptia_ Mill.) and linsseed (_Linum usitatsimum_ L.). In particular, purslane and pumpkin oils were obtained from seeds harvested from plants cultivated at the experimental farm of the University of the Thessaly in the growing period of spring-autumn 2020. Purslane plants were cultivated following the agronomic practices previously described by [PERSON] et al. [11]. In brief, seeds were sown directly in soil on June 1 2020 and harvested approximately two months later and when most of the plants reached fully maturity (3 August 2020). A base dressing with 100 kg/ha of N-P-K was applied, while plants were irrigated via a sprinkler irrigation system at regular intervals. Plant distances were 30 cm \(\times\) 5 cm, between and within the rows, respectively, while the dimensions of the experimental plots were 3 m \(\times\) 3 m (n = 3). No pesticides, fungicides, or herbicides were applied during the growing period, since no certified agrochemicals are available for the species. Weed control was implemented with hand hoeing. Plants were cut at 5-10 cm above ground with a scythe and seeds were removed from fruit after shaking and sieving. After harvesting, seeds were stored at dry conditions until oil extraction.  
Similarly, pumpkin seeds were sown directly in soil in single rows on 27 July 2020, and fruit was harvested on 7 December 2020. Plant distances were 1.5 m within each row and 2.5 m between the rows, while three rows (n = 3) of 50 m long were used (33 plants per row and 100 plants in total). A base dressing with 250 kg per hectare of 12-11-18 (N-P-K) fertilizer (YaraMila Complex, Yara Hellas S.A., Greece) was applied before sowing, while during the growing period plants were fertigated with ammonium nitrate (34.5% nitrogen at 40 kg per hectare; Idealfer, Gavriel S.A., Greece) and calcium nitrate (15.5-0-0 +26% CaO at 50 kg per hectare; Haifa-Cal, Haifa Group, Greece). Plants were irrigated via drip irrigation system at regular intervals. Pests and diseases management was carried according to best practice guides, while for weed control mulching with plastic film on sowing lines was applied. After the harvest, fruit were dissected and seeds were removed from the pulp, washed with distilled water, and left to dry at room temperature. After drying, seeds were stored at dry conditions until oil extraction.  
Linseed and luffa seed oils were obtained from local retail shops and from Giachanas--Cold Presseed Seeds S.A. (Evros, Greece). In particular, three different samples of linseed and one sample of luffa seed oil were studied, namely linseed oil 1 (Chemco Linseed Oil; Syndesmos S.A., Greece), linseed oil 2 (Giachanas--Cold Presseed Soils S.A.), linseed oil 3 (Organic flaxseed oil; Biotuscany srl., Italy), and luffa seed oil (Giachanas--Cold Presseed Oils S.A.). All commercially available seed oils were extracted via cold pressing, as indicated on the product label.  
For purslane and pumpkin seed oils (Purslane oil and Pumpkin oil, respectively), extraction was carried out via cold pressing according to the methodology and the conditions previously described by the authors [10; 11]. Both oils were extracted by Giachanas--Cold Pressed Soils S.A., while the cold press was a Henan 6 YL-160 screw oil press (Henan VIC Machinery Co. Ltd.; Henan, China) [11].  
After extraction, oils were stored at room temperature at dry and dark conditions in amber screw top glass vials until further analyses.