2.2.1. Papaya Harvest

One hundred papayas (*C. papaya* L. var. Maradol) were harvested from Tecoman, Colima, Mexico at maturation stage 1, defined as a yellow stripe near fruit apex (70%–80% of yellow surface) [16], and all fruits were similar in size and without any apparent physical damage.

### 2.2.2. Coating Preparation

Papaya edible coating was produced according to Escamilla-García et al. [17] with some modifications. One chitosan solution and one starch paste slurry were made in parallel. Chitosan (1% *w*/*v*) in lactic acid (0.5% *v*/*v*) was produced with constant agitation at 80 ◦C during 60 min; the starch paste slurry was prepared with 3.5% (*w*/*v*) oxidized starch in distilled water heated at 90 ◦C and stirred for 30 min. Starch:chitosan preparations were mixed in 3:1 (*w*/*w*) ratio and stirred for 5 min at room temperature; glycerol was added as plasticizer at chitosan:glycerol ratio of 1:1 (*w*/*w*), and stirred for 10 min. Previous experiments showed that a combination of 3.750 μg/mL of nisin and 0.0625 mg/mL of LAE were enough to inhibit coliforms, mesophilic bacteria, and yeasts, and thus were used as antimicrobial agents [18].

#### 2.2.3. Coating Application

Papayas were immersed in distilled water for 1 min to eliminate solid residues and impurities, followed by 1 min immersion in neutral electrolyzed water (NEW) developed at the Center for Research and Technological Development in Electrochemistry of Querétaro (CIDETEQ), at a concentration of 200 ppm total available chlorine. NEW is obtained by electrolysis of diluted NaCl solutions (0.1%–1% *w*/*v*) without the use of a membrane separating anode and cathode. Several studies have shown that highly oxidizing chlorine species are present in NEW, mainly hypochlorous acid, hypochlorite ions, chlorine dioxide, and ozone, which provide high bactericidal activity [19–21]. Oxidizing species are rapidly reduced during treatments, and there is no need for rinsing. Water was removed by drying at room temperature. Coating was applied on papaya peel using a sterile sponge (Figure 1), and properties of coated papayas were evaluated at 0, 5, 10, and 15 days of storage at room temperature. Uncoated papayas were used as control and were analyzed at the same storage times.

**Figure 1.** Coating application.

#### 2.2.4. Papayas Characterization

For papaya characterization, analyses of whole papayas (without peeling) were carried out to determine volatile compounds, wt % loss (dry basis, db), image analysis, color, and antimicrobial activity. Physicochemical parameters, such as % acidity (db), texture, vitamin C (db), pH, and soluble solids, were determined in papaya pulp.
