## 4 Discussion
### Study on Red Fruits and the Implementation of Cutting-Edge Edible Coating
#### 4.3.3 Application Technique for Applying an Edible Coating on Red Fruits
Each layer has a distinct function, such as avoiding the infiltration of pathogenic organisms into the fruit or restricting the oxygen supply [171; 185]. The efficacy of such connected multilayer coating is enhanced in comparison to typical edible coatings [105; 186]. The use of a multilayer coating technique to enhance the density of coating layers during the storage of fruits after harvest has been recorded for polysaccharides and charged polyelectrolytes that can form hydrogen and covalent bonds. Polysaccharides and charged polyelectrolytes have been shown to be effective in preserving fruits when using the multi-layer coating technique to enhance the integrity of the coatings [105; 187]. The efficacy of the multilayer coating technique in prolonging the storage duration of various types of fresh produce, such as strawberries, has been shown. The approach is ecologically sustainable as it minimizes the reliance on chemical preservatives and packing materials [188; 171]. The process of solution casting for the application of bio-coatings entails dissolving the biopolymer in an appropriate solvent and then putting it onto the surface of the fruit [189]. Solution casting is a technique used to produce independent films inside a Petri dish or a similar container. Dipping and spraying are the predominant techniques used to apply substances to fruits, with the solvent, often water, evaporating while the fruit undergoes drying. Prudent consideration should be given to the selection of the solvent for dissolving the biopolymer, as it must exhibit compatibility with both the biopolymer itself and the fruit or vegetable intended to be coated [171]. Upon the application of the solution onto the fruit surface, the solvent undergoes evaporation, resulting in the formation of a residual thin coating. The thickness of the coating may be controlled via adjusting the concentration of the biopolymer solution or the number of coating layers applied [175; 175; 189]. The advantage of solution casting lies in its simplicity, cost-effectiveness, and scalability for large-scale commercial manufacturing [190]. Furthermore, the thickness and homogeneity of the coating may vary depending on the application procedure, thereby affecting its efficacy [191]. Ultimately, solution casting is a very promising technique for acquiring bio-coatings that may effectively preserve fruits. This technology has the potential to enhance food quality and minimize food waste, as shown by recent studies conducted by [PERSON] et al. [192] and [PERSON] et al. [171]. Three-Dimensional Food Printing Method  
Three-dimensional food printing is the process of using a three-dimensional printer to sequentially place materials in layers, resulting in the creation of a food item with a distinct structure, texture, and, perhaps, nutritional composition [193]. The use of 3D printing technology has the potential to fabricate accurate and consistent edible coatings on fruits and vegetables, hence improving their durability and overall quality. This has the potential to be used for incorporating natural preservatives or antimicrobials into printed food, hence prolonging the freshness of perishable goods [171]. The use of 3D printing technology may contribute to the mitigation of food waste through enabling the production of edible items from fruits and vegetables that would otherwise be rejected due to their visual flaws. While it does not specifically preserve fresh food, it may effectively enhance the use of gathered fruits and vegetables. Although still in its early stages, 3D printing shows potential in producing biodegradable packaging for fruits and vegetables, particularly red fruits [171]. This might be devised to provide safeguarding and perhaps to integrate conservation methods (e.g., modified atmosphere packing) [194]. Cross-linking refers to the act of joining polymer chains together via covalent and non-covalent connections [105].