2.2.1. Decayed Fruit Percentage

Decay due to browning skin, shriveling, and diseases were recorded and estimated based on the initial number of fruits in each sample and reported as a percentage.

### 2.2.2. Fruit Firmness

Fruit firmness was measured using an Effegi pressure tester (Effegi, 48011 Alfonsine, Alfonsine, Italy) connected to a flat probe (8 mm diameter). At the equator of the fruit, the skins were removed in four pieces and four independent measurements were recorded for each fruit.

### 2.2.3. Weight Loss Percentage

Weight loss was assessed by weighing ten labeled treated fruits at 7-day intervals during the storage. The percentage of weight loss was assessed by the following equation:

$$\% \text{ Weight loss} \,\% = \frac{\text{The initial weight} - \text{fruit weight at examining date}}{\text{The initial weight}} \times 100$$

### 2.2.4. Fruit Content of Total Soluble Solids (TSS) and Titratable Acidity (TA)

For each treatment, four fruit pulp samples were squeezed out, and the resulting juice was used to measure the TSS percentage using a hand refractometer (Atago, Japan), and the titratable acidity in grams of citric acid per 100 mL of fruit juice [29].

### 2.2.5. Vitamin C

Vitamin C was determined by oxidizing ascorbic acid with 2,6-dichlorophenol endophenoldye and the results were reported in mg/100 g on a fresh weight basis [30].

### 2.2.6. Fruit Color Index

Flesh color was measured using a Minolta Chroma Meter CR-200 (Minolta Co. Ltd., Osaka, Japan). Flesh color measurements were expressed as hue angle chromaticity values (h◦). Four readings were obtained at different points on each mango fruit for each data observation [31,32].

### 2.2.7. Defense-Related Enzymes Activities

The peroxidase activity of *M. indica* kernels was determined using a colorimetric test based on the initial increase in absorbance at 420 nm in the presence of a constant volume of hydrogen peroxide and a crude extract of pyrogallol. POD activity was expressed as U/g FW, where one unit of peroxidase activity was defined as the amount of extract that caused a 0.001 per minute change in absorbance at 420 nm [33].

Catalase (CAT) activity was measured using the method of Beers and Sizer [34], with certain modifications. The reaction mixture consisted of 0.2 crude extracted from 50 mM sodium phosphate buffer (pH 7.0) and 150 mL of 20 mM of H2O2. The action of CAT on hydrogen peroxide caused a decrease in absorbance at 240 nm. The change in absorbance per minute was defined as one unit of CAT.

### 2.2.8. Membrane Stability Index Percentage (MSI)

Ion leakage from fruit peels was assessed in peel discs using the method described by Sairam et al. [35], with modification, and was represented as a percentage of membrane stability index (MSI). For each replicate/treatment, 3 g of wash disks were randomly selected and placed in 30 mL of deionized water at room temperature on a shaker for 4 h. Before boiling (C1), a digital conductivity meter (Orion 150A +, Thermo Electron Corporation, Colorado, CO, USA) was used to check the conductivity. The same disk was placed in a boiling water bath (100 ◦C) for 30 min to release all electrolytes, cooled to 22 ± 2 ◦C in running water, and boiled to measure conductivity (C2). MSI was calculated as a percentage using the following formula: [1 − (C1/C2)] × 100. Fruit softening or the appearance of chilling injury signs indicated the termination of the trial.
