## 3 Results and Discussion
### Changes in Organoleptic Characteristics of Apple before and after Storage in CA
#### 3.2.1 Changes in Apple Peel Color
found that, after 5 months of storage in controlled atmosphere chambers, the red co-ordinate (a*) in 'Sampion' apple peel varied from 10 NBS to 53 NBS, and the yellow co-ordinate (b*) from 5 NBS to 43 NBS, which confirms the results obtained in our study [50]. [PERSON] et al. pointed out that, recently, consumers tend to choose light red apples more often, while dark red apples are becoming less popular [51]. Researchers studied color changes in apples, which are determined by the pigments in the apple skin. [PERSON] and [PERSON] found that the color of apple skin is determined by the ratio of the qualitative and quantitative composition of anthocyanins and flavonoids. When anthocyanins predominate, apple skin tends to have pink hues, while the predominance of flavonoids gives apple skin yellowish shades [52; 53]. The dark red color of apples is determined by the ratio of the quantitative composition of anthocyanins to chlorophyll. Apples with a higher content of chlorophyll than anthocyanins in the skin have a dark red color, while a light red color of the apple skin means that the content of anthocyanins is higher than that of chlorophyll [30]. In a study conducted in 2008, [PERSON] et al. found that anthocyanin content strongly correlated with red (a*) and yellow (b*) co-ordinate values [5]. [PERSON] et al., in their study, found that red-fleshed apple samples expressed higher levels of MdMYB10 promoters responsible for anthocyanin synthesis than white-fleshed apple samples did [54]. There is evidence in scientific literature that apples show a change in color during storage due to browning, which reduces the quality and commercial value of the apples [50]. Based on the color values of lightness (L*) and chroma (saturation) (C*) co-ordinates, we evaluated color changes in apple samples under controlled atmosphere storage conditions. The analysis of apple color saturation showed that apple samples of 'Alva' (46.90 NBS), 'Lodel' (47.44 NBS), 'Noris' (45.33 NBS), and 'Sampion' (46.16 NBS) cultivars stored in Chamber VI conditions had statistically significantly the purest color (Figure 2, Panel a). The most mixed color was found in apple samples of 'Ligol' (35.31 NBS), 'Rubin' (38.98 NBS), and 'Spartan' (18.35 NBS) cultivars stored under chamber V conditions (Figure 2, Panel a). Figure 1: Variability of co-ordinates measured in NBS units in apple peel before and after storage in CA: (**a**) redness (a*) co-ordinate; (**b**) yellowness (b*) co-ordinate. The peel color of apple samples of 'Alva' (44.92 NBS), 'Lodel' (44.47 NBS), and 'Noris' (43.09 NBS) cultivars was found to be statistically significantly brightest under chamber VI conditions, and its brightness was close to that of fresh fruit (Figure 2, Panel b). Peel color of apple samples of 'Ligol' (32.38 NBS), 'Rubin' (33.24 NBS), and 'Spartan' (24.95 NBS) cultivars stored under chamber V conditions was the darkest and the furthest away from that of fresh apples (Figure 2, Panel b). The lightness index (L*) describes the degree of freshness of the fruit, and the lower the L* value, the darker the fruit, the more prone they are to turning brown, and the further their condition is from that of the fresh fruit [34]. [PERSON] 2002 et al. pointed out that apples of the 'Sampion' cultivar ranged in brightness (L*) from 40 to 70 NBS when stored for 5 months in controlled atmosphere chambers, as confirmed by the results obtained in our study [50]. [PERSON] et al. found that the lightness index (L*) values for 'Granny Smith' (56.90 NBS) and 'Golden Delicious' (60.42 NBS) cultivars were higher than those for 'Pink Lady' (49.02 NBS) and 'Starkrimon' (41.54 NBS) cultivars [29]. Our results confirm that non-red apples of different cultivars had higher values of the lightness index (L*) and lower co-ordinates of redness (a*) and yellowness (b*) compared to samples of red apples. In 2012, [PERSON] et al. found that the anthocyanin content was inversely proportional to the lightness index (L*) [55].