# A Preliminary Study on the Potential of the New Red-Fleshed 'JB' Clone Apple for Cider Production
## 1 Introduction  
Apples are among the most widely consumed and produced fruits in the world's temperate zones. Most of the harvested fruit undergoes processing. Above all, concentrated apple juice is made, with a smaller share of natural juices, mousses, dried apples, and alcoholic beverages, among which cider is best known [1]. In Europe, \"cider\" refers to the fermented product, an alcoholic beverage with alcohol content of between 1.2 and 8.5% _v/v_[2]. In 2023, apples grown and harvested in Polish orchards accounted for up to 34% of the total apple production in the European Union. They were the most important fruit crop among fruit and vegetables [3]. All the cultivated cultivars of domestic apple trees belong to _Malus domestica_, a hybrid of _Malus sylvestris_ and _Malus sieversii_[4, 5]. Currently, there areabout 7500 cultivars worldwide, among which the more famous ones include the 'Golden Delicious', 'Gala', 'Idared', and 'Jonagold' [6]. Descriptive terminology based on specific fruit or juice characteristics is often used in relation to different apple cultivars. It takes into account sweetness and bitterness or sourness, among other factors. The best-known system for classifying apples in English-speaking countries is the Long Ashton Research Station (LARS) system, developed in England in the early 20 th century [4; 5; 7]. According to this system, apples are divided into four categories based on tannin concentration, which is determined by the Lowenthal method, and acidity. Other classification methods exist in France and Spain, for instance, apples are divided into six categories, but these systems are rarely used outside of their respective countries [4; 8]. Sour apples with low tannin and high acid contents include the 'Golden Harvey' and 'Granny Smith' cultivars. The 'Golden Delicious', 'Wickson', and 'Binet Rouge' cultivars are classified as sweet apples with low acid and tannin content. Bittersweet apples include, for example, 'Dabinett', 'Royal Jersey', and 'Muscadet de Dieppe', while bitter-sour cultivars include 'Stoke Red', 'Kingston Black', and 'Foxwhelp' [9]. Sweet apple cultivars are readily available in many regions, so it is common for elder makers to use them in production, blending them with less available cultivars characterized by greater bitterness. In traditional European-style ciders, at least 20% of all apples should be classified as bittersweet [8]. For apples that are not processed and are sold on the fresh market, characteristics such as sweetness, flavor, fruit size, skin color, and minor defects are essential. On the other hand, when selecting a cultivar of apples for cider, sugar content, tannin content, and acidity are taken into account, but attention is also paid to other important physicochemical characteristics, such as juice yield, pectin concentration, yeast assimilable nitrogen content, and aromatic volatile compound content [4; 5]. Sugars are key components in apples and, consequently, in apple juice. Apple juice typically contains between 9 and 15% sugar. However, some apple cultivars have a much higher sugar content; for example, the 'Golden Russet' cultivar has a sugar concentration of 23%. The dominant sugar in apples is fructose, while the other major sugars are sucrose and glucose, but the ratio between them can vary depending on the cultivar. The sugar content of apples can be negatively affected by drought, nutrient deficiencies, and extreme weather conditions (for example, very high and low temperatures) [10]. When apples are destined for fermentation purposes, such as cider production, the sugar content--which serves as the substrate for the synthesis of ethanol and carbon dioxide--is a key determinant of quality [1]. Another essential component in apples is organic acids, which influence the acidity, or taste, of the product.