# Commercial Hemp Seed Oils: A Multimethological Characterization
## 1 Introduction  
_Cannabis sativa_ L. is an annual plant belonging to the family of Cannabinaceae, widely spread in all five continents. Although its name is frequently associated with drugs of abuse (marijuana), due to the presence of psychotropic \(\Delta^{9}\)-tetrahydrocamabinol (THC) [1], the recent evidence of _Cannabis sativa_L. cultivars characterized by low amounts of \(\Delta^{9}\)-THC (known as industrial hemp) raised a growing interest toward this plant in different fields, including pharmaceutical, food, and cosmetic sectors. In Europe, hemp cultivars with an amount of \(\Delta^{9}\)-THC lower than 0.2% (in dry matter basis) are allowed for cultivation, and are reported in the EU approved list [2]. Among the different parts of the plant, hemp seeds are the only one to be authorized for food applications [3], as cannabinoids are present mainly due to cross-contamination during harvesting and processing [4]. Since ancient times, hemp seeds were consumed in the human diet; however, they were replaced by other seeds and used as feed materials for all animal species. Only in recent times the discovery of hemp seeds' high nutritional value led to a revaluation of this source for human consumption. Literature regarding the investigation of hemp seeds' composition has increased, making them an emerging source for value-added functional food ingredients and nutraceuticals [5; 6]. Hemp seeds are consumed shelled in salad dressings, and in the production of snack bars, or they can be cold pressed to obtain edible hemp seed oil, and the residual cake is grinded to have a fiber-rich flour used in processed food (such as bread, biscuits, and pasta). The high nutritional value lies in the presence of secondary metabolites and the characteristic fatty acids profile, which stands out for the higher levels of polyunsaturated fatty acids (PUFAs) with respect to saturated ones. The two essential fatty acids, linoleic acid (C18:2 \(\omega\)-6) and \(\alpha\)-linolenic acid (C18:3 \(\omega\)-3), account for more than 50% and 15-25% respectively, resulting in a perfect balanced 3:1 ratio \(\omega\)-6:\(\omega\)-3, optimal for healthy human nutrition [5]. Moreover, the presence of secondary metabolites such as phenolic compounds and tocopherols [7; 8; 9; 10; 11], with antioxidant properties, improves the health benefits and helps to prevent the PUFA oxidation process, improving hemp seed oil shelf-life. Some studies recommend a dietary intake of hemp seed oils [12; 13; 14], nowadays largely present in the markets of different countries (Canada, the European Union, Australia, and China) [15]. It is important to underline that a specific regulation concerning the analytical parameters for the quality assessment of hemp seed oils is still lacking, although the increasing interest towards hemp food products for human consumption has prompted few countries to issue guidelines about the acceptable level of \(\Delta^{9}\)-THC in hemp seeds, hempseed oil, or processed food [4; 16; 17; 18]. Indeed, some studies discuss the development of a proper analytical procedure for the detection of cannabinoids levels and ratio in hemp seeds and hempseed oils [4; 19; 20; 21; 22]. However, a plethora of different factors could influence the oil quality, such as the area of cultivation [23; 24], the type of cultivars [25], the origin of seeds [26], agronomic practices, and extraction processing [27; 28] that usually indicate the cold pressing as the preferred method to preserve the \(\omega\)-3:\(\omega\)-6 ratio [11]. Moreover, the price of commercial hempseed oil ranges from 20 to 100 \(\xi\)/L, making it an expensive food product sold on the market without any quality assurance. Taking into account the variability in composition and the price, quality parameters need to be established in order to both valorize products and preserve consumer safety and awareness. Hemp seed oils are sold as food, and labeled accordingly [29].