3.1.1. Decay

As for the storage period, regardless of the treatments, the obtained results showed that the incidence of fruit decay appeared after 14 days of cold storage, followed by a consistent increase with increasing the storage period up to 28 days (Tables 1 and 2, Figure 1). Data also indicated that all treatments significantly decreased the decay incidence of mango fruits during the two seasons of the study. The chitosan treatment did not significantly differ from the combined treatment in both seasons. The incidence of decay was higher in the control mango fruits than in the other treatments. The control fruit had an 8.9% decay incidence after 14 days of storage, but the HW treatment, chitosan, and the combination treatments had no decay incidence (Table 1). In the first season, at the end of the storage date, the control treatment had a decay incidence of 30.20%, followed by the HW-treated samples (19.35%), while the chitosan and combined treatments were only 3.6 and 2.4%, respectively (Table 1). A significant interaction effect between the treatments and the storage period on the percentage of fruit decay was obtained in both seasons. Data revealed that the fruit decay percentage was least with all treatments, especially when those treatments were accompanied by the shortest storage period in comparison with the same treatments accompanied by the longest storage period.

**Table 1.** Effect of hot water treatment and chitosan coating on postharvest decay (%) of mango fruits during storage at 13 ± 0.5 ◦C and 85%–90% relative humidity (RH) for 28 days during 2020 season.


Means followed by the same letters within treatments, storage period, and their interactions in 2020 season are not significantly different at level *p* ≤ 0.05.

**Table 2.** Effect of hot water treatment and chitosan coating on postharvest decay (%) of mango fruits during storage at 13 ± 0.5 ◦C and 85%–90% relative humidity (RH) for 28 days during 2021 season.


Means followed by the same letters within treatments, storage period, and their interactions in 2021 season are not significantly different at level *p* ≤ 0.05.

**Figure 1.** Visual appearance of mango fruit after 7 days (**A**) and 21 days (**B**) of storage at 13 ± 0.5 ◦C and 85%–90% relative humidity.

### 3.1.2. Weight Loss

The percentage of mango fruit weight loss increased dramatically when the storage duration was extended to 28 days (Figure 2A and Table 3). All treatments considerably decreased weight loss of 'Kent' mango fruits during cold storage when compared to untreated control fruits (Figure 2A and Table 3). Fruit treated with chitosan or the combined treatment (Figure 2A) lost less weight (4.13% and 5.16%, respectively) than the control or the HW-treated fruit (6.80% and 6.16%, respectively). As for the interaction effect, data showed that all the treatments at the same storage period decreased weight loss.

**Figure 2.** Effect of hot water treatment and chitosan coating on weight loss (**A**), fruit firmness (**B**), and total soluble solids (T.S.S) (**C**) of mango fruits during storage at 13 ± 0.5 ◦C and 85%–90% relative humidity (RH) for 28 days during 2020 and 2021 seasons. Values are means ± SE from three replicates. Statistical analysis was performed using LSD test.

**Table 3.** Results of the analysis of variance with mean square testing the effects of treatments (T), storage period (S), and their interactions on fruit firmness (N), weight loss (%), TSS (%), acidity (%), vitamin C (mg/100 g FW), color index (h◦), peroxidase activity (units/mg FW), catalase activity (units/mg FW), and MSI (%) during 2020 and 2021 seasons.


ns, \*, \*\*, \*\*\* nonsignificant, or significant at *p* = 0.05, 0.01, and 0.001, respectively.

### 3.1.3. Firmness

Data presented in Table 3 and Figure 2B reflected the reduction in fruit firmness with the progress of the storage period for all treatments. However, after 7 days of storage, the control fruits and the fruits treated with HW softened faster than the other treatments. At the end of storage, the control fruit and the fruit treated with HW showed low values of 11.48 and 12.53 N, respectively, whereas the combined-treated fruits and the chitosantreated fruits showed a high fruit firmness value of 14. 96 and 19.84 N, respectively. Data also showed that there was a significant interaction between the treatments and the storage period for mango fruit firmness in both seasons. The ripening of mango fruits leads to a loss in firmness with the progress of the storage period.

### 3.1.4. Total Soluble Solids (TSS) and Titratable Acidity (TA)

Total soluble solids and titratable acidity, as well as a comparison of the means over the storage period for both experimental seasons, are shown in Figures 2C and 3A and Table 3. TSS increase in all treatments over time, while TA decreased over the fruit's storage period, which is a climacteric fruit feature during the ripening process. At the end of the storage period, all postharvest treatments significantly increased TSS and decreased TA compared to the control treatment. In both seasons, fruits treated with chitosan had the lowest TSS values (13.57 and 12.97, respectively) and the highest TA values (0.79 and 0.77, respectively).

**Figure 3.** Effect of hot water treatment and chitosan coating on acidity (**A**), color index (**B**), and vitamin C (**C**) of mango fruits during storage at 13 ± 0.5 ◦C and 85%–90% relative humidity (RH) for 28 days during 2020 and 2021 seasons. Values are means ± SE from three replicates. Statistical analysis was performed using LSD test.
