# A Preliminary Study on the Potential of the New Red-Fleshed 'JB' Clone Apple for Cider Production
## 1 Introduction
The primary organic acid found in apples is malic acid (90-95%, equivalent to 3-5 g/L); other acids include quinic acid (approximately 4%, or 0.2-0.5 mg/L) and citric acid (about 1.5%, or 0.05-0.07 mg/L), as well as ascorbic acid, shikimic acid, maleic acid, succinic acid, and tartaric acid, which may be present in trace amounts [11]. The acidity of apples depends mainly on the cultivar and the treatments used during cultivation. Mixing different apple cultivars during cider production allows producers to achieve the desired acid concentration and appropriate pH [4; 5]. Polyphenols are important compounds found in apples [12]. They contribute to their characteristic color. In addition, tannins, which are a subgroup of polyphenols, are responsible for the bitter and astringent taste of these fruits [11]. There are five main groups of polyphenic compounds in apples: flavanols (procyanidins, catechin, and epicatechin), phenolic acids (primarily chlorogenic acid), flavonoids (quercetin and glycosides), dihydrohalcones, and anthocyanins (cyanidin glycosides) [13]. The total polyphenol content in apple juice ranges from 70 to 8000 mg of gallic acid per liter. Most apple cultivars,however, have polyphenol contents below 1600 mg/L [14]. Cider production begins with pressing apple juice. During fruit crushing and juice pressing, only a portion of the phenolic compounds are extracted [15]. This is mainly due to the rejection of the peel and seeds, which are rich in various phenolic compounds [16; 17]. The above information indicates that the content of biologically active substances in apples depends on the cultivar, degree of maturity, fruit part, and geographic area. According to [PERSON] et al. [14], fruits may contain more monosaccharides and fewer organic acids during dry and warm summers. Additionally, their antioxidant profile is altered under these conditions. Higher air temperatures and lack of rainfall before apple ripening can act as stress factors, leading to an increase in the polyphenol contents of apple flesh and skin. However, these authors [14] noted that there are cultivars, such as clone 'JB', which have an average fruit acidity nearly three times higher than that of the commonly grown apple cultivars in Poland (as observed in a three-year study). Since clone 'JB' is relatively new, research on this clone remains limited. A key characteristic of this cultivar is its significantly higher content of antioxidant compounds compared to other cultivars. On the other hand, the 'JB' clone has been shown to have a very short storage life [18]. Nevertheless, given its above-average acidity and high polyphenol and flavonoid content, its potential for processing should be considered. In traditional cider production, cultivars classified as bittersweet or bitter-sour are highly desirable [8]. The 'JB' clone perfectly meets these criteria, especially since it possesses the unique trait of red flesh, which would significantly enhance the color of the cider. Given this, this study aimed to evaluate the processing potential of the new 'JB' apple clone bred at the Warsaw University of Life Sciences, mainly for juice and original cider production.