Chemical Characterization of Rosa canina L. Rosehip Seed: Application of Raman Spectroscopy and Gas Chromatography ^†

Rosehip seeds represent the food industry waste material, in the production of marmalade, jam, beverages, jelly, syrup, tea, etc. Agri-food wastes are rich in bioactive compounds and nutrients that can add value to different fields of agriculture and food production. The aim of this study was to assess the chemical composition of seeds from Rosa canina L. hips, with the focus on the seed oil fatty acid profile. In this respect, the analytical methods in situ Raman spectroscopy (RS) and gas chromatography (GC) were used. Fatty acids in the form of methyl esters (FAMEs) were analyzed by gas chromatography with a flame ionization detector (GC/FID). Raman spectra showed the presence of lipids, fatty acids, polyphenolics and saccharides (including cellulose) as the predominant classes of compounds in seeds. Bands at 1266, 1328, 1369 and 1655 cm⁻¹ were associated with lipids and unsaturated fatty acids (UFAs). The spectra also indicated cis isomers in the lipid fraction. Seeds contained 5.6% of oil, and GC analysis confirmed the presence of UFAs linoleic acid (ω-6) and α-linolenic acid (ω-3) (29.72 and 4.20%, respectively). Raman spectroscopy was applied as a fast and non-destructive analytical method for the chemical evaluation of rosehip seeds. The results of the GC analysis show that rosehip seeds are a good source of nutritionally valuable fatty acids that might be utilized in products specified as functional foods.