# Investigation of Oil Extracted from Roasted and Unroasted Oats with Use of Chemometrics
## 1 Introduction  
Oats (_Avena sativa_ L.) are one of the crops that have been grown and consumed worldwide since ancient times; they are considered highly valuable due to their nutritional properties, e.g., fibre content [1] and high amount of healthy fats [2]. Oat grains are an essential source of protein, minerals, and oil [3]. _Avena sativa_ L. is a grass that grows up to 1.5 m tall, with tufts or solitary culms, an erect or bent base, and a smooth texture. The leaves are unarticulated, green, and have spherical sheaths on the back. Seed size is commonly around 30,000 seeds per kilogramme of crop, although it can vary depending on the cultivar [3]. Wild oats (_Avena fatua_) and common oats (_Avena sativa_) look similar, but wild oats are not being used for grain production. Oats have been grown for over 2000 years in various parts of the world. They are typically grown in temperate regions and require less summer heat than other cereals like wheat, rye, or barley. Oats are also more rain-resistant, making them particularly significant in areas with cool, wet summers. Oats are a perennial plant that can be cultivated either in autumn (harvested in late summer) or in spring (harvested in early autumn) [4]. The common _Avena sativa_ L. is the most important cultivated oat, and it is also the most unusual compared with other cereal grains due to the storage of high amounts of oil in the endosperm, which can be up to 90% of the total grain oil [5]. The lipid fraction of the oat grain determines its energy content in considerable measure and significantly impacts nutritional quality via the fatty acid composition [6]. Roasting is a typical food processing operation involving dry heating where hot air covers the food, cooking it evenly on all sides [7]. The temperature applied should be at least 140 \({}^{\circ}\)C. The oven uses a combination of convection, conduction, and radiation to heat the food product. However, the impact of each heat transfer mechanism may vary at different stages of the process. Roasting is a crucial method for food processing that significantly enhances the taste, aroma, tenderness, colour, and crispiness of various foods, such as seeds, nuts, grains, and plant leaves. This thermal process involves heating the product to a temperature lower than its melting point. Roasting and other heating methods can enhance food's digestibility, palatability, and bioavailability by modifying the food matrix through physicochemical and structural changes. Roasting is a cooking method for all sorts of foods that convert macro-nutrients into a more digestible form (the bigger molecules, e.g., polymers, are converted into smaller ones, e.g., simple sugars). The process reduces water activity, improves shelf-life, and changes antioxidant and functional properties, leading to better consumer acceptance [8]. The roasting process is commonly defined as \"The process of cooking foodstuffs on an open fire or in an oven\". This does not differ much from the scientific definition. However, the roasting conditions must be mentioned, e.g., temperature or gaseous flow inside the oven. This process can also modify the profile of phenolic compounds, sometimes enhancing their antioxidant capacity and improving their health benefits [9]. Roasting has a positive effect on the oil properties. Roasting enhances the extraction yield of oil in oilseeds [10]. Dry roasting exhibits a significant impact on the physicochemical characteristics of peanut oil [11]. In this paper, we have discussed how roasting affects the oil properties. For this reason, roasting on hemp seed and its effect on its oil was discussed in the Results Section [12], and how roasting affects oils' acid and peroxide values was discussed in the Results Section and cited in [13; 14; 15; 16]. The oxidative stability determines the shelf life of roasted seeds and nuts as well as manufactured products containing roasted seeds and nuts [17].