# A Preliminary Study on the Potential of the New Red-Fleshed 'JB' Clone Apple for Cider Production
## 3 Results and Discussion
Cider production typically utilizes raw materials with acidities ranging from 4.5 to 7.5 g malic acid/L, with the lower value being characteristic of English-style ciders and the higher one being typical of sparkling North American ciders [35]. Given this, the cultivar under study appears to have potential for use in cider production, especially since suitable methods for reducing acidity are available. [PERSON] et al. [36] determined the total acidity of three naturally cloudy apple juices available on the market, which were 4.8, 3.7, and 2.2 g of malic acid/L for juices 1, 2, and 3, respectively. These values vary but remain relatively low. As the authors noted, the last juice, with 2.2 g/L, approaches the lower limit of quality requirements for this type of product. The red-fleshed clone studied had 1.8 times the acidity of the first juice analyzed in their article, indicating greater potential for processing. Similar results were obtained by [PERSON] et al. [14] who reported that apples of the 'JB' clone had the highest malic acid content. In addition, the value of this indicator was almost three times higher than that of the commonly grown apple cultivars. [PERSON] and [PERSON] [32], performing a physicochemical analysis of 26 fresh juices from different apple cultivars, determined the malic acid content using a chromatographic method. The highest malic acid content was recorded in juice from the Boskoop cultivar (8.9 g/L), and the lowest in juice pressed from Florina apples (1.4 g/L). The average malic acid content was 5.1 g/L. Thus, it can be concluded that the red-fleshed cultivar had a similar malic acid content (0.12 g/L lower) to the Boskoop cultivar and was significantly different from the average reported by the authors. [PERSON] et al. [33] subjected juice from various fruits to high-performance liquid chromatography (HPLC) analysis to determine the content of eight acids, including malic acid. Their findings showed that the average malic acid content in 12 juices from different apple cultivars was 474.04 mg/100 mL (4.7 g/L). Malic acid accounted for an average of 82.91% of all acids identified. During the analysis of most red-fleshed cultivars, the determination of the exact acid profile was not performed; instead, all acids were expressed in terms of malic acid, which is the most abundant in these fruits, as also shown by the authors of the discussed article (malic acid accounted for 82.91%). If they had reported all acids as a sum, they would still have obtained a result much lower than that of the cultivar analyzed in this paper, demonstrating its very high total acidity. [PERSON] et al. [14], while studying the acidity of the apple fruit of the 'JB' clone and the Chopin cultivar, found that it was almost three times higher than that of fruit commonly grown in Poland. In summary, juice from the 'JB' clone is characterized by exceptionally high overall acidity compared to other apple juices. However, it is possible to find cultivars similar in this respect, such as the Boskoop cultivar. Fruits with such high acidity are better suited for processing than direct consumption. The high malic acid content can protect the product from microbial spoilage, thus eliminating the need to add other acids during food production. The content of polyphenols in the red-fleshed apple must was 307.28 \(\pm\) 1.29 mg/L, expressed as chlorogenic acid (Table 2). Literature data indicate that industrial apple cultivars have a polyphenol content of up to 2700 mg/kg. However, many countries use commercially available cultivars with a polyphenol content of approximately 1022 mg/kg for cider production. As a result of the processes carried out, especially during the raw material treatment, the content of polyphenols is significantly reduced. Only 30% of the phenolic compounds in the fruit remain in apple must, which is linked to browning reactions caused by the activity of the polyphenol oxidase (PPO) enzyme [37]. [PERSON] et al. [38] performed an HPLC analysis of apple juices regarding polyphenol content.