Physicochemical characteristics of cold-pressed oil from different varieties of hemp (Cannabis sativa L.)

This project aimed to evaluate the physicochemical properties of cold-pressed hemp seed oil obtained from four different cultivars of Cannabis sativa L. grown in Poland. The seeds were pressed using a cold-press screw system under controlled conditions, and the oils were analyzed using standard laboratory methods to determine a broad range of quality parameters relevant to edible oil evaluation. The experimental procedures included measurements of seed moisture content and oil yield, which varied among cultivars. The acid value (AV) and peroxide value (PV) were determined through titration methods, showing that all oils complied with quality limits set for unrefined edible oils (AV < 4.0 mg KOH/g, PV < 15 meq O₂/kg). The oxidative stability of the oils was assessed using the Rancimat method at 90 °C, indicating relatively short induction times due to high unsaturation. Secondary oxidation products were evaluated by measuring the p-anisidine value (p-AnV). Fatty acid composition was determined, revealing high proportions of polyunsaturated fatty acids (PUFAs), including linoleic (C18:2) and α-linolenic acid (C18:3), with favorable n6:n3 ratios (~3:1). Additionally, the oils were characterized for total phenolic (Folin–Ciocalteu method) and flavonoid content, antioxidant acivity (using DPPH radicals), and chlorophyll content. The results confirmed that cold-pressed hemp seed oil is a valuable nutritional product, and that varietal differences significantly influence its physicochemical profile. These findings may support future development of hemp-based oils for functional or high-quality culinary applications.