# Out and Out Processed Products--Technology, Composition, Nutritional Value, and Health
## 3 Oat in Food Technology  
Oat grains are popularly used in various branches of the food industry (Table 3) [48]. One of the most popular oat products is oat flakes, often eaten as a breakfast cereal. Oat flakes are made from cleaned oat grain, in which lipolytic enzymes have been inactivated [49]. Typically, two types of oat flakes are produced: ordinary oat flakes (flaked directly after the process of grain cleaning and inactivation of lipases) and instant oat flakes (subjected additionally to hydrothermal treatment, and thus not requiring further processing/boiling before consumption) [50]. Oat flakes are also used as one of the components of cereal/fruit/nuts mixtures (muesli) or are processed into granola (oat flakes with sugar, oil, and nuts or fruits, subjected to the baking process) [51; 52]. Oat grain flour is another popular oat product. Even though it is characterized by worse technological parameters compared to wheat flour, it is often used as an additive in the production of bread due to the large amount of previously discussed health-promoting substances in its composition [53; 54]. In addition, oat flour has a very low glycemic index, unlike the popular wheat or rye flours, so it can be used in the production of bread for diabetics [55]. Oat grains certified as gluten-free are also broadly used to produce bread suitable for people suffering from celiac disease [56]. Oat groats, produced from oat grains in de-hulling and polishing processes, can be a substitute for such products as rice, pasta, or potatoes [57; 58]. Another application of oat grains in the food industry is the production of sprouts. The sprouts are obtained as a result of the grain germination process and are intended to be consumed as a whole--as a sprout with germinating grain [59]. The sprouts are characterized by high enzymatic activity and contain a set of nutritionally important ingredients, such as vitamins (A, B, C, and E) and minerals (i.e., fluorine, iron, zinc, copper, calcium, and iodine). In addition, spotted grains contain substances that can improve the taste and smell of food products [60; 61; 62; 63]. Oat malls should be mentioned as another important application of oat grains [64]. Malt is produced by controlled soaking, germination, drying, and degermination of grains, primarily barley, but some mathhouses produce malt from oat grains, which gives some types of beer unusual organoleptic characteristics. Such practices became popular in the 21 st century, due to the so-called 'beer revolution', which significantly impacted the brewing industry [65; 66; 67; 68]. Oat flakes are also used in the brewing industry due to the fact that beers brewed with the use of oat malt possess a certain creaminess, particularly well-received in dark beers or necessary for beer styles such as 'oatmeal stout' [69; 70]. It is important to mention that with the growing popularity of vegan and vegetarian diets, the demand for protein concentrates made from plant-derived substrates has also increased [71]. One of the most popular sources of protein for the production of these food products is soybeans; however, oat grains have also found application in this branch of industry, especially in the region of Europe where soybeans, due to the climate, are not so popularly grown [14; 72; 73; 74]. There is no way to omit here one of the other key food products for vegans and vegetarians, popularly made from oat grains, which are plant-based milk substitutes [75]. Oat'milk' is made from crushed oat flakes or flour, which are subjected to hydrothermal processes and the action of \(\beta\)-amylase. Due to the increased content of maltose and dextrins, a drink with a degree of sweetness similar to lactose is obtained [76]. Oat grains are suitable for making oat drinks, but can also be used to make fermented products from plant-based drinks, such as oat 'yoghurts' [77]. It is also popular to use oat bran (a by-product of hulled oat milling) as an addition to desserts, milk, yogurt, or other food products in order to increase their fiber content [78; 79].