## 3 Results and Discussion
### Quality Prediction Test
#### 3.2.1 Flotation Test  
Direct Flotation Test  
In Figure 5A,B, mango slices dried at 40 \({}^{\circ}\)C show a shorter rising time 98.55 s and thus higher activity rate 0.69 mm s\({}^{-1}\) compared to those dried at 60 \({}^{\circ}\)C (189 s, 0.44 mm s\({}^{-1}\)) and 80 \({}^{\circ}\)C (1199.15 s, 0.05 mm s\({}^{-1}\)), respectively. Therefore, it can be assumed that more catalase is retained in the dried mango slices when dried at a low temperature of 40 \({}^{\circ}\)C. An earlier study supports this assumption, where [PERSON] et al. [7] reported that the catalase degradation rate accelerated 3.84-fold during drying at 60 \({}^{\circ}\)C and 10.58-fold at 80 \({}^{\circ}\)C, compared to 40 \({}^{\circ}\)C.  
Although this is a rapid and direct approach to differentiate between samples dried at 40 \({}^{\circ}\)C, 60 \({}^{\circ}\)C and 80 \({}^{\circ}\)C, there are certain limitations inherent in this method. This test is not suitable for fresh mango samples as they have a high moisture content, and the flesh of fresh mango can easily mix with the H\({}_{2}\)O\({}_{2}\) solution. In addition, the pieces cut from the mango slices dried at 40 \({}^{\circ}\)C, 60 \({}^{\circ}\)C and 80 \({}^{\circ}\)C had different densities, as shown in Figure 5C. The density of the samples dried at 80 \({}^{\circ}\)C was higher (0.83 \(\pm\) 0.02 g cm\({}^{-3}\)) compared to those dried at 60 \({}^{\circ}\)C (0.76 \(\pm\) 0.03 g cm\({}^{-3}\)) and 40 \({}^{\circ}\)C (0.74 \(\pm\) 0.06 g cm\({}^{-3}\)), which may interfere with the flotation time. The increase in density at higher drying temperatures 80 \({}^{\circ}\)C could be due to excessive shrinkage [38]. Furthermore, it was noticed that air was trapped in some of the dried samples during hot-air convective drying, which could be due to the speed of air diffusion, water evaporation, change in pore size, rapture and dislocation of cells or splitting of the tissue [39]. Air entrapment in the dried samples could also influence the flotation time. The surface alterations of dried mango, as illustrated in Figure 5D, could be another factor affecting the flotation time. The mango slices dried at 40 \({}^{\circ}\)C retained a more porous matrix with larger and randomly distributed pores, while those dried at 60 \({}^{\circ}\)C and 80 \({}^{\circ}\)C had a hard surface with mostly filled pores. [PERSON] et al. [40] reported that during drying at temperatures below 50 \({}^{\circ}\)C, the cells remain intact, and water movement from the intracellular to intercellular space occurs only through microcapillaries and at a very slow rate. As a result, minimal deformation was observed. In contrast, when subjected to higher drying temperatures, the surface of samples was dried more quickly, causing it to become stiffer (case hardening) [15]. During the flotation test with direct-dried mango, the mango with a well-preserved porous structure may aid the rapid substrate diffusion and influence the floating time by reacting immediately with the available catalase. The results of the indirect flotation test in Figure 6A,B show a significant difference between the disc rising time and the activity rate of mango slices dried at 40 \({}^{\circ}\)C (60.10 s, 0.89 mm s\({}^{-1}\)) compared to 60 \({}^{\circ}\)C (543.13 s, 0.11 mm s\({}^{-1}\)) and 80 \({}^{\circ}\)C (2403 s, 0.02 mm s\({}^{-1}\)), respectively. This is particularly true for the extracted samples with more catalase units; they have a short disc rising time and a high activity rate [29]. Therefore, the catalase extracts obtained from mango slices dried at 40 \({}^{\circ}\)C exhibited a short disc rising time and high activity rate, closer to the fresh samples due to the higher retention of catalase activity 11.24 units mL\({}^{-1}\), as shown in Figure 6C. However, higher drying temperatures have a negative effect on the residual catalase activity [7] and consequently, the rising time of the disc increased, and the activity rate decreased.