*3.7. Relationship among Fruit Characteristics*

Correlation analysis was applied for investigating the interdependence of the guava characteristics (Figure 7). The results indicated that weight loss, decay, TSS, TSS/acid, total sugar, antioxidant, and rot had a negative relationship to firmness. This strong relationship revealed that greater guava had lesser antioxidant activity, which agrees with the resulted relationship for blackberries [41,42]. Strong positive correlations were found between firmness and acidity, V.C, and total chlorophyl. The marketable percentage was positively linked to firmness, acidity, V.C. and total chlorophyl; thus, these indicators could be used to forecast other results. Meanwhile, marketable percentage was negatively correlated with weight loss, decay, TSS, TSS/acid, total sugar, antioxidant, and rot, verifying that some physicochemical changes could cause lower acceptance by the consumers, and consequently create lesser marketability. PCA was utilized to discover the connection among the variables. Thus, PCA was utilized to discover the relationships among parameters in different treatments. PCA analysis revealed that the first principal component (PC1) and the second principal component (PC2) were 82.5 and 17.5%, respectively, with the accumulative variance contribution rate of 99% (>75–85%). PC1 was positively associated with the variables: VC, pectin, acidity, sugars, antioxidants, weight loss, firm, and decay area. PC2 was positively associated with the variables of TSS, phenolics, carotene, and chlorophyl. Furthermore, locations of the combined GA with natural extracts and the functional and freshness properties were close, showing the impact of GA-natural extracts on the quality of guava during the cold storage.

**Figure 7.** PCA analysis of the different treatments with different parameters.

### **4. Discussion**

Edible coatings have barrier features that decrease a fruits' surface permeability to oxygen and carbon dioxide, resulting in a change in internal gas composition that reduces oxidative metabolism and increases the fruit's shelf life [43]. We proposed that coating fruits with GA would result in significant differences, and increase the fruit shelf-life [20,44].

Water exchange between the interior and exterior atmospheres is believed to be the primary cause of fruit weight loss and decay percentage, resulting in a low marketable percentage during cold storage. With the advancement of cold storage, the growth in transpiration ratio, ethylene making, and the cellular interruption of fruits resulted in a rise in the physiological failure of weight and decay prevalence, and a reduction in saleable guavas [45–47].

Consequently, the use of GA can decrease the gases exchange among orange fruits and the environment by accumulating carbon dioxide in fruits with low O2-availability for respiration and, as a result, inhibit respiratory enzymes. Furthermore, GA coating can close openings in the peel. Furthermore, the coating can impede the fungi growth in a wide range of horticultural products [48]. This application improved membrane integrity, postponed fruit senescence, and reduced transpiration and respiration [49]. However, coating alters the atmosphere and inhibits the gaseous exchange of the fruit, which prevents ascorbic acid oxidation by limiting the entry of oxygen into the fruit's interior [50]. The lower TSS values in treated samples compared with the controls could be attributed to the conversion of organic acids to sugars via gluconeogenesis and the solubilization of cell wall ingredients by galactosidases and glucosidases found in guava fruit [51].

These findings are matched with those obtained by [25]; they indicate that guava fruits coated with 10% GA showed a significant reduction in weight loss (%) and a delay in the change in firmness, titratable acidity, soluble solid concentration color, maintaining the sensory quality during storage at room temperature, as compared with the uncoated control fruit of banana and papaya fruits, as well as Khaliq, Mohamed, Ali, Ding and Ghazali [23] in 'Choke Anan' mangoes, who reported that treated fruits with edible GA coatings had significantly higher firmness than uncoated fruits during cold storage. Moreover, in avocado fruit (Maluma), the application of GA at 10 or 15% + Moringa leaf extracts maintained higher firmness than other treatments [33]. A similar effect was found in mass loss, with fruit covered with the previously stated coatings showing minimal change. It may be argued that the prevention of moisture loss was the primary reason why coated fruit remained firmer than uncoated fruit. This theory is supported by [29], who found that moisture loss is not only associated with mass loss, but also fruit softening.

Cactus pear extracts and henna leaf extracts significantly decreased weight loss, compared with the control, during cold storage in both seasons. The antimicrobial and antifungal properties of henna leaf extract, as well as its antioxidant activity, contribute to its promising effect in delaying fruit weight loss and decay percentage. In addition, prickly pear has antimicrobial and antioxidant properties.

Lawsone makes up about 0.5 to 1.5 percent of the ingredients in henna. The main constituent responsible for the plant's dyeing properties is lawsone (2-dihydroxynaphthoquinone). Henna, on the other hand, contains mannitol, tannic acid, mucilage, and gallic acid. These substances are present in henna as a mixture. The antimicrobial activity could be attributed to many free hydroxyls that can combine with carbohydrates and proteins in the bacterial cell wall. They may become entangled with enzyme sites, proformance them inactive [52]. When compared with alcoholic and oily extracts, water extracts had no antibacterial activity. This could be due to a lack of solvent properties, which are key in antibacterial effectiveness.

Phenolic compounds are antioxidants that act as protective mechanisms in fruit. TPC content has a defense mechanism against plant pathogen invasion and plays an important role in plant resistance [2,53]. Furthermore, trapping the lipid alkoxyl radicals, antioxidants and phenols could significantly reduce reactive oxygen species (ROS) and prevent lipid peroxidation in plant tissue [2,54,55]. Maintaining TPC and increasing TAA could be attributed to postharvest treatments' ability to scavenge excess ROS and, as a result, reduce oxidative damage to the fruits [23,56,57].

Hence, the use of GA can reduce gas exchange among orange fruits and the environment by accumulating carbon dioxide in the fruits, resulting in low availability of O2 for respiration and, as a result, the reticence of respiratory enzymes. Furthermore, GA-coating can plug openings in the peel. Furthermore, a coating can prevent the growth of fungi in a variety of horticultural products [48].

### **5. Conclusions**

Overall, our findings indicated that both postharvest applications "cactus pear stem (10%), moringa (10%), and henna leaf (3%) extracts incorporated with gum Arabic (10%)" and their combinations had a positive impact on the quality characteristics of 'Maamoura' guavas during cold storage. The combined treatments of 10% GA + 10% moringa leaf extract were the most effective coating for fresh guava after long periods of cold storage. These applications significantly reduced weight loss, decay and *Rhizopus* rot infection (%), while also increasing marketable percentage, and delaying fruit softening during cold storage. Furthermore, these applications delayed color development by significantly retaining total chlorophyll content, maintaining fruit content in vitamin C and acidity, and slowing the accumulation of fruit contents in TSS and TSS/acid ratios compared with untreated fruits during the cold-storage period. Finally, compared with the control, these

applications significantly increased the shelf-life period at ambient conditions after the end of the cold-storage period.

**Author Contributions:** Conceptualization, M.F.M.A., M.S.G., A.M.E.B. and L.A.A.; methodology, M.F., A.R.M., M.H.M., H.M.A.E.G. and A.M.R.A.A.; software, H.M.A.E.G. and K.H.A.H.; validation, S.F.E.-G., M.S.G., A.M.E.B. and M.H.M. formal analysis, S.F.E.-G.; investigation, M.H.M. and H.M.A.E.G.; data curation, K.H.A.H.; writing—original draft preparation, S.F.E.-G., M.S.G., A.M.E.B., M.F.M.A. and K.H.A.H.; writing—review and editing, S.F.E.-G., M.S.G., A.M.E.B., M.F.M.A., M.F., A.R.M., A.M.R.A.A. and H.A.S.A.; funding acquisition, M.F.M.A., M.A.A., D.M.H. and L.A.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors extend their appreciation to King Saud University for supporting this work. Researchers Supporting Project under project number (RSP-2021/406), King Saud University, Riyadh, Saudi Arabia.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Relevant data applicable to this research are within the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
