## 4 Conclusions  
The study showed that the organoleptic and physical properties, as well as the chemical composition, of apple samples stored for 8 months under controlled atmospheric conditions changed. The total content of sugars and soluble solids was found to increase in the samples of apples stored in chamber I to VIII conditions. The highest increase in the total content of sugars was observed in apple samples of the 'Cortlend' cultivar stored in chamber III (3% of CO\({}_{2}\), 5% of O\({}_{2}\), and 92% of N\({}_{2}\)) conditions. The content of soluble solids increased in apple samples of 'Lodel' and 'Rubin' cultivars stored under chamber II (1% of CO\({}_{2}\), 5% of O\({}_{2}\), and 94% of N\({}_{2}\)) conditions. The study also showed a decrease in titratable acidity in apple samples of all cultivars stored in chamber I to VIII conditions.  
The values of C*, L*, a*, and b* co-ordinates of apple colors were evaluated. Maximum values of the red co-ordinate (a*) were found in apple samples of 'Alva', 'Lodel', and 'Sampion' cultivars stored in chamber VII (3% of CO\({}_{2}\), 10% of O\({}_{2}\), and 87% of N\({}_{2}\)) conditions. Apple samples of 'Alva', 'Lodel', and 'Noris' cultivars stored in chamber VI conditions (3% of CO\({}_{2}\), 1% of O\({}_{2}\), and 96% of N\({}_{2}\)) were found to have statistically significantly the lightest color, and their lightness was close to that of fresh fruit. We evaluated the parameters of the firmness of apple peel and flesh, and the changes in these parameters during storage in a controlled atmosphere of various compositions. The firmness of apple peel samples of the 'Sampion' cultivar stored in chamber I and III-VI conditions increased compared to that registered before storage. The firmness of the apple flesh of 'Auksis', 'Noris', 'Connel Red', and 'Lodel' cultivars also increased during storage in chamber III and VI conditions. We analyzed the strength of the correlation between the content of soluble solids and the changes in the firmness values of apples under storage conditions in chambers I to VIII. The content of soluble solids in apple samples under chamber I storage conditions (0.03% of CO\({}_{2}\), 21% of O\({}_{2}\), and 78.97% of N\({}_{2}\)) moderately strongly correlated (from r = \(-\)0.504 to r = \(-\)0.689) with the firmness values of apple samples stored under chamber I-VIII conditions. Under chamber VI (3% of CO\({}_{2}\), 10% of O\({}_{2}\), and 87% of N\({}_{2}\)) conditions, the content of soluble solids in apple samples weakly (from r = 0.262 to r = 0.282) or moderately strongly (from r = 0.326 to r = 0.418) positively correlated with the firmness values of apples under the storage conditions of chambers I-V and VII-VIII.  
The physical and organoleptic parameters of apples stored in a controlled atmosphere determined during the study are valuable and prove that under the studied conditions, it is possible to extend the time of the provision of apples to the consumers with minimal changes in their chemical composition and nutritional value.  
Conceptualization, V.J.; methodology, P.V.; formal analysis, A.B. and J.V.; investigation, A.B. and J.V.; resources, P.V. and J.V.; data curation, A.B. and J.V.; writing--original draft preparation, A.B.; writing--review and editing, M.L., P.V., J.V., and V.J.; visualization, A.B.; supervision, V.J. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
All datasets generated for this study are included in the article.  
The authors wish to thank the Lithuanian Research Centre for Agriculture and Forestry for the support of this study.  
The authors declare no conflict of interest.