## 3 Results and Discussion
### Light Transmission Rate and Transparency  
Food quality is highly dependent on protection from UV rays. Oxidation changes the taste of food, reduces its nutritional value, and creates toxic compounds, all of which  
Figure 2: FT-IR transmission spectra of edible films and their composites with gelatin concentration of 6.9 \(w/w\) (indicated by blue and violet colors), papaya concentration of 8:10 \(w/w\) (indicated by green and brownish-yellow colors), and soy protein concentration 2:4 \(w/w\) (indicated by black and red colors) in the range of 4000–500 cm\({}^{-1}\).  
can make food sources less satisfactory or unsuitable to shoppers. Oxygen produced by the ultraviolet irradiation of the sun is a rapid cause of lipid oxidation. Even at very low temperatures, the oxidation rate is greatly increased and the quality of food processed and stored is deteriorated [39]. The UV screening capacity of food packaging film is desirable to prevent the oxidation of UV light. Biopolymer films have been utilized to stay away from food quality deterioration due to physical compound changes or synthetic responses. As of late, gelatin has been utilized because of its great barrier properties [40]. Different parts can likewise be added, for example, soy protein into the biopolymer network to upgrade the usefulness, quality, stability, and safety of packaging food sources [41].  
The properties of the film to block ultraviolet (UV) and visible light (Vis) were measured, and the blocking properties of the film were measured at different wavelengths (200 to 800 nm) using dual-beam UV-VIS spectroscopy. They are represented by low transmittances between 200 and 350 nm and 400 and 800 nm, respectively. The results of UV-VIS spectroscopic analysis are shown in Figure 3. UV transmittance is appreciated as it increases the shelf life of packaged foods. High transparency of the container in the visible area is required since it allows the consumer to visually verify the condition of the product. The figures show the transmission spectrum in the spectral range from 280 to 600 nm. Papaya film had a higher transmittance in the visible region (660 nm) than in the UV region (280 nm) because papaya has properties of being a natural UV barrier. The addition of soy protein to the film significantly affected and reduced the UV transmission of the film (280 nm). The G/PP/SP-2 film lowered the transmittance of the film to UV light (280 nm). The combination of glycerol and gelatin reduced the transmittance. The transmittance of the G/PP-2 film sample is the highest, which means that the papaya does not have the same high UV protection properties as it does for the VIS region [34].  
Film transparency is vital in foodstuffs, as it affects light-sensitive products. The transparency of edible films is a significant tactile part of edible films and coatings that must be accepted by consumers [42]. The transparency of the film was confirmed at a wavelength of 500 cm\({}^{-1}\). Film G/PP-2 had higher transparency compared to other films, and film G/PP/SP-2 had lower transparency (Table 2 and Figure 4). The higher rate of the G/PP/SP2 film delamination was primarily responsible for the lower transparency.  
Figure 3: Transmittance spectra of edible films (black line indicates G/PP-2 film, blue line indicates G-2 film, and red line indicates G/PP/SP-2 film).  
Higher DSP concentrations increase particle size and compactness while decreasing film transparency [43]. Apple starch films incorporated with ellagic acid have quite similar transparencies [44]. The structure of the polymer and the bonding that develops during film formation determines its transparency. In addition, the film on the airside is more glossy, darker, and rougher than the film on the carrier side [45].