## 3 Results and Discussion  
### Changes in Chemical Composition Before and after Storage in CA  
#### 3.1.1 Variability of the Composition of Sugars, Sucrose, and Ascorbic Acid  
The shape, size, color tone, and other characteristics of the quality of apples are important factors of their market value. Apples of attractive color, optimal size, and intact surface are likely to be selected first [34], while their organoleptic properties, such as taste, smell, and texture, determine whether the apples will be bought again [3; 31]. The sweet or sour taste of apples is one of the main organoleptic properties that determine thesatisfaction of the consumers' taste and the consumption of these fruit in the diet [31; 33]. [PERSON] and [PERSON] argued that the sweet taste of the fruit is determined by the complex of sugars and soluble solids in the apples. The sugars found in apples are sucrose, glucose, fructose, and sorbitol, and the complex of soluble solids consists of sugars and organic acids. These groups of organic substances determine the particularities of sweet or sour flavors of the apples [32; 33]. We did not find any published research findings on the organoleptic properties of apples grown in Lithuania that were used in our study. In order to preserve good commercial values and a quality product for a longer period of time, it is important to study the changes in organoleptic properties (sweetness and acidity) in apples stored in a controlled atmosphere of various compositions. Changes in total sugar and sucrose levels were detected during the experiment. Before the storage, the total sugar content in the samples of different apple cultivars varied from 9.15 to 11.14%, and sucrose content ranged from 2.00 to 3.24% (Table 2). The highest total amount of sugars (11.14%) was found in apple samples of the 'Rubin' cultivar, and the highest sucrose content (3.24%) was found in samples of the 'Sampion' cultivar (Table 2). Similar results for 'Fuji' apples were obtained by [PERSON] et al. in their study, where they found that the total sugar content in samples of 'Fuji' apples may exceed 20.00% [39]. The samples of the studied apple cultivars stored for 8 months in the conditions of chambers I-VIII demonstrated a general upward trend of sugar content (Table 2). The largest increase in total sugar content (from 9.42% to 14.16%) was found in apple samples of the 'Cortlend' cultivar stored in chamber III conditions (Table 2). The smallest change in total sugar content (from 10.74 to 12.19%) was found in apple samples of the 'Sampion' cultivar stored in chamber VI conditions (Table 2). Studies by [PERSON] and [PERSON] showed that the total sugar content in apple samples increased during storage and ranged from 9.67 to 12.47% [40]. The increase in the total sugar content in apple samples during storage is explained by the ripening process of the fruit and the hydrolysis of starch molecules [40]. An upward trend of sucrose content was found in apple samples of the studied cultivars stored in the conditions of chambers I, II, and IV (Table 2). The largest increase in sucrose content (from 2.07 to 3.74%) was observed in apple samples of the 'Ligol' cultivar stored in chamber II conditions (Table 2). Significant reductions in sucrose content were observed in apple samples of 'Auksis', 'Connel Red', 'Lodel', 'Rubin', 'Sampion', and 'Spartan' cultivars stored in chamber VIII conditions (Table 2). [PERSON] et al. stated that the sucrose content in apple samples decreases during storage because sucrose decomposes into fructose and glucose, which explains the upward trend in sugar content during apple storage [41]. Ascorbic acid found in apple samples has strong antioxidant properties. Ascorbic acid, as a powerful antioxidant, protects DNA, proteins, lipids, and other macromolecular structures from the damaging effects of free radicals [42]. Ascorbic acid found in apple samples is used not only for the prevention of various chronic diseases, such as cancer [42], but also for assessing the quality of apples [40].