## 2 Characteristics of Apples
### Storage and Harvesting Conditions
Non-climacteric fruits produce only a small amount of ethylene during ripening, and the ageing process does not depend on its production. This group includes strawberries, grapes, watermelons, pineapples, or citrus. Both in the case of fruit and vegetables, technological processes taking place during production, such as peeling or cutting, also have an impact on the increased production of ethylene. Changes can be noticed in just a few minutes. In addition, there are reports of reduced ethylene production when storing climacteric fruits (e.g., apples) in an atmosphere with increased carbon dioxide CO2 and reduced oxygen O2 atmospheres [51]. [PERSON] et al. [52] studied the degradation of bioethylene under refrigeration conditions (3 \({}^{\circ}\)C) using a nanoparticle photocatalyst, TiO2. The authors showed that nanoparticles can increase the capture capacity due to the synergistic system of ethylene gas released from fruits and vegetables. There are reports of inducing or inhibiting the production of ethylene during various processes in plants. Unfortunately, too little information has been reported so far on the effect of melatonin on the quality of apples during storage. The research conducted by [PERSON] et al. [53] shows that melatonin delayed the ripening of apples by inhibiting the biosynthesis of ethylene. One of the varieties of packaging that controls the amount of oxygen and carbon dioxide between the packaging and the environment is the so-called \"smart films\". They are mainly used for fruit and vegetables, allowing for specific regulation of oxygen flow and controlling the ongoing respiration and ripening process. In addition, they make it possible to limit the development of undesirable anaerobic bacteria [54]. Intelligent packaging can also be used to monitor temperature changes or the generation of volatile amines and hydrogen sulphide during the shelf life of food products. Monitoring factors related to microbial growth, which is influenced by the formation of volatile compounds, temperature changes, and the presence of oxygen, is essential to ensure food safety and quality. With technological advances and the increasing demand for this type of packaging, the bakery industry is showing increasing interest in this type of packaging. The use of such packaging is associated with the possibility of adding antimicrobial and antioxidant compounds that can prevent the formation of undesirable flavours by microorganisms. Another great advantage is the possibility of adhesion of probiotics, which inhibit the growth of fungi [55]. Future research should also focus on recovering and extracting bioactive compounds from food processing waste while maintaining innovative \"green\" technologies. So far, there are too few studies and reports on using edible coatings and films produced from fruit processing waste for packaging fresh meat or poultry products. In addition, using nanotechnology is a promising solution to improve the functional properties of edible films and coatings. For example, edible coatings with 0.5% nano chitosan lowered the maximum ethylene production of apples and markedly eliminated the climacteric respiration peak. The coating slowed down the natural fruit ripening, thus enhancing the quality and storage life of the apple [56]. Therefore, future work should focus on the use of inexpensive and unmanaged waste to reduce the production costs of edible films and scale up production from a commercial scale while maintaining economic viability [57]. Due to growing demand and global concerns about food safety, nanotechnology is gaining interest as a solution to increase food supply. Expansive surface area and antimicrobial efficacy are versatile in traditional packaging and in integration with biopolymer matrices. Studies have shown that using an edible coating based on a nanoemulsion containing citrus essential oil and chitosan nanoparticles for packaging seafood extends its shelf life.