## 2 Raw Material  
Apple pomace remains in high quantities after apple juice pressing and can be used in many industrial sectors as a raw material [15; 16; 17]. Apple juice is one of the most popular fruit juices in the human diet. Apple production in the world is constantly growing and currently amounts to over 90 million tons per year [18]. A similar volume applies to grapes, at approximately 85 million tons [18]. The largest producer of apples is China, providing nearly half of the world's total volume [19], followed by the USA, Turkey, and Poland, with production of approximately 4.2-4.5 million tons per year each [19]. Apple production in the EU is approximately 12.5 million tons per year. Apple production in Poland has increased by over 30% over the last decade, and in 2022 it amounted to over 4.2 million tons, which is one third of the production of the entire EU [20]. Most of the apples produced in Poland are used to manufacture apple juice, apple juice concentrate, cider, and other apple products [19]. Currently, the largest producers of apple juice concentrate are China, the USA, and Poland [18; 19]. After milling and pressing apples for juice, significant amounts of apple pomace remain (including peels, seed chambers, seeds, calyx, stems, and the rest of the tissue). Apple pomace constitutes approximately 25% of the weight of fresh fruit [17; 21]. Drying pomace is a common practice enabling storage. Wet apple pomace (just after juice pressing) can easily spoil during the fermentation and puttrefaction processes. Therefore, to enable storage, transportation, and further processing, apple pomace is dried. Large-sized drum dryers with adjustable rotation speeds are commonly used for this purpose. Because of the high temperature of exhaust gases and the flammability of dry pomace, a countercurrent flow of gases is used. The temperature of the drying gases entering the drum is 700-900 \({}^{\circ}\)C, and the temperature of the gases leaving the drum is 100-120 \({}^{\circ}\)C. The most common uses for dried apple pomace are in the production of bio-renewable fuel as pellets and the production of pectins [17; 21]. Apple pectin is a valuable by-product from both the point of view of food technology and human nutrition. Although most plant tissues contain pectin, the primary sources for industrial pectin production are citrus peels and apple pomace [17; 21]. This is because of the availability of large amounts of citrus peels and apple pomace remaining after juice production. Apple pomace also has traditional uses, such as composting or as animal feed for dairy cows, sheep, or horses [22; 23; 24]. The new use of dried apple pomace described here is its use in the industrial scale production of apple seed edible oil. The direct raw materials used for obtaining this oil are seeds separated from apple pomace [25; 26]. Like grapeseed oil, apple seed oil has the potential to become a valuable new by-product of apple juice and cider production. The new technological approach outlined here could increase production of apple seed oil. In the example of Poland, we provide the volume of apple pomace and the potential yield of apple seed oil below. In Poland, approximately 80% of harvested apples, i.e., approximately 3.4 million tons, are used to produce apple juice and apple juice concentrate [19]. This scale of production results in a significant volume of apple pomace remaining, approximately 850,000 tons per year. The drying of apple pomace causes its weight to be lost by approximately 40%. As a result, approximately 510,000 tons of dried pomace are produced each year. Dried pomace contains, on average, approximately 4-7% seeds (depending on variety), which can be used for the production of apple seed oil. The oil content in apple seeds, depending on the apple variety, is 15-22% [4; 7; 14]. This amount of pomace contains approximately 25,000 tons of seeds, from which it is possible to obtain, depending on the method, 3.5-5 million liters of oil per year [25].