Changes of Postharvest Nutritional Quality and Antioxidant Enzymes in ‘Haribhanga’ Mango by Aloe vera Gel with Chitosan and Coconut Oil Coating During Ambient Storage

Mature mango fruits were taken from an orchard near the Hajee Mohammad Danesh Science & Technology University, Dinajpur-5200, Bangladesh. Mangoes were picked when their skins (peel) turned yellow at the bottom and remained green at the top. These are the typical stages of harvest for local producers (75–82 days old). The color of the fruit at the harvest stage was assessed visually.

For coated and control treatment, 72 physiologically ripe and healthy fruits (12 in each treatment) were immersed in 1% sodium hypochlorite for 3 minutes. The following six treatments were randomly assigned to six batches of fruits: control (distilled water), 1.5% chitosan solution (CH) (w/v), Aloe vera gel (AV) (1 : 1, v/v), coconut oil (CO) (1 : 1, v/v), 1.5% chitosan + A. vera gel (CH + AV) (1 : 1, v/v), and coconut oil + A. vera gel (CO + AV) (1 : 1, v/v). The fruits were coated for 5 minutes and dried at room temperature for 2 hours. Fruits were then divided into four groups. The first group was not stored – 0 days, the second group – 5 days, the third – 10 days, and the fourth group – 15 days of storage at ambient temperature (25 ± 2 °C) and relative humidity of 80–85%. After that, fruit samples were evaluated every 5 days for up to 15 days. Most mango growers and merchants cannot afford to invest in a temperature-controlled storage facility. The average mango season temperature in Bangladesh is about 25–32 °C. Mangoes are typically stored in that condition by the growers. So, in this experiment, we stored mangoes at ambient conditions (25 ± 2 °C).

Chitosan solutions were prepared after Rhim et al. (1998) with some modifications. 1.5 g of chitosan powder was dissolved in a 1% solution of 100 ml of aqueous lactic acid (v/v) containing 1 ml of glycerin. The solution was harmonized by a magnetic stirrer at 25 °C for 4 hours and filtered through four layers of muslin cloth.

Leaves of A. vera were picked, and the parenchyma and outer layer were separated. The parenchyma was homogenized to create a mucilaginous gel and filtered to remove the fibrous materials (Song et al. 2013).

Chitosan and Aloe vera combined solutions were prepared by Vieira et al. (2016) with slight modifications. In brief, a combination of chitosan and Aloe vera solution (1 : 1, v/v) was mixed for 4 hours at room temperature in a magnetic stirrer.

Aloe vera gel and coconut oil (1 : 1, v/v) were combined in a beaker and placed in a hot water bath, where they melted and formed a transparent liquid.

The weight loss percentage was calculated by using the following standard procedure: Weight loss %=Initial fruit weight (g) − Fruit’s weight on the observation day (g)Initial fruit weight (g)×100. {\rm{Weight}}\,{{\rm loss }}\left( \% \right) = \frac{{{\rm{Initial}}\,{{\rm fruit}}\,{{\rm weight}}\;({\rm{g}}) - {\rm{ Fruit's}}\,{{\rm weight}}\,{{\rm on}}\,{{\rm the}}\,{{\rm observation}}\,{{\rm day}}\;({\rm{g}})}}{{{\rm{Initial}}\,{{\rm fruit}}\,{{\rm weight}}\;({\rm{g}})}} \times 100.

The subsequent formula used to determine decayed fruits: Decay (%)=Number decayed fruitsNumber initial fruits×100. {\rm{Decay}}\;{\rm{(}}\% ) = \frac{{{Number}}\,{{decayed}}\,{{fruits}}}{{{Number}}\,{{initial}}\,{{fruits}}} \times 100.

Fruit firmness was determined using an HP-200 Force gauge (Handpi, China) and expressed in kilograms per square centimeter. The fruit sample was penetrated using a round stainless-steel probe with a 2 mm diameter. Three measurements were taken, and the average firmness was estimated.

Ascorbic acid (AA) and titratable acidity (TA) were estimated by Islam et al. (2020). Total soluble solids (TSS) concentration was calculated as a percentage using a hand-held oil refractometer with a refractive index of 1.435–1.520 nD. A digital pH meter (HI 2211 pH/ORP, China) was used to monitor pH’.

A colorimeter BCM-110 BCM-200 (Biobase, China) was used to measure the color of mango skin at two locations on opposing sides of the fruits and expressed as L* (positive value: lightness, negative value: darkness), a* (negative: green, positive: red), and b* (negative: blue, positive: yellow) values.

According to Singleton and Rossi (1965), the total phenol content (TPC) of mango pulp was estimated with several modifications. Fruit pulp of 1 g was extracted with methanol (10 ml) and filtered using filter paper (Whatman No. 1). An aliquot (1 ml) was mixed with Folin–Ciocalteu reagents (0.5 ml) (Sigma Aldrich) and 7.5% (w/v) aqueous Na₂CO₃ solution (1 ml) was added. The volume was made up to 10 ml by adding distilled water. Samples were vortexed and kept in the dark at ambient temperature for 35 minutes, then centrifuged for 10 minutes at 4,000 rpm. An Elisa Microplate reader E-19, One Tech, China, was used to measure the absorbance at 765 nm against a blank. The TPC was expressed as milligrams of gallic acid equivalent (GAE) per 100 grams of fruit pulp.

Here, 1 g of pulp with 10 ml of methanol was integrated by a mortar and pestle and then filtered through filter paper (Whatman No. 1). Next, an extract of 0.1 ml with 1.9 ml of 2,2-diphenyl-1-picrylhydrazyl (DPPH) solution (0.3 mM) was placed in a Falcon tube, vortexed, and then kept in a dark area for 30 minutes. The standard curve was prepared using several concentrated Trolox solutions (0–1 μmol·g⁻¹). The absorbance was measured at 517 nm with a spectrophotometer (UV 1800, Shaanxi, China) against a blank, and the results were expressed as micromole Trolox equivalent (TE) per gram of fruit pulp (Hossain et al. 2021).

Mango fruits were stored in a sealed plastic container holding septa for 2 hours (the incubation period) at room temperature to assess respiration rate and ethylene production. Then, the gas was taken using a syringe from the container and inspected using a gas analyzer to determine the respiration rate (CO₂/O₂ gas analyzer, FELIX, F-950 Three Gas Analyzer, USA). The ethylene gas analyzer needle was put into the container's headspace throughout the septa, and then C₂H₄ was calculated in microliters. Finally, respiration and ethylene production were calculated using fruit weight and volume, the gas volume of the container, and incubation time. Results for rate of respiration and ethylene synthesis were given in milliliters of CO₂ per kilogram per hour and microliters of C₂H₄ per kilogram per hour, respectively (Nasrin et al. 2020).

The fruit pulp of 0.2 g was mixed in 3 ml of phosphate buffer (100 mM, pH 7, and 4% polyvinyl polypropylene) using a mortar and pestle and then centrifuged for 15 minutes at 12,000 rpm and aliquot stored at 4°C for further use.

According to Soliva et al. (2001), activity was evaluated with slight modifications. Shortly, 1,200 μL phosphate buffer solution (pH 7, 100 mM), 600 μL catechol (100 mM), and 600 μL enzyme extract were mixed. The absorbance was measured by a spectrophotometer (UV 1800, Shaanxi, China) at 410 nm for 2 minutes, and the activity was confirmed in units per milligram of fresh weight.

According to Aebi (1983), catalase (CAT) activity was improving with slight modifications. A reaction solution containing 700 μL K₂SO₄ buffers (50 mM, pH 7), 100 μL H₂O₂ (200 mM), and 100 μL EDTA (2.5 mM) was mixed with 100 μL enzyme extract. Absorbance changes were documented at 240 nm for 2 minutes using a spectrophotometer (UV 1800, Shaanxi, China). CAT activity was expressed in units per milligram of fresh weight.

Activity was assessed by adding 100 μL of enzyme extract, 100 μL of H₂O₂ (100 mM), 100 μL guaiacol (20 mM), 100 μL EDTA (2.5 mM), and 600 μL phosphate buffer (100 mM, pH 7). The absorbance was then measured with a spectrophotometer (UV 1800, Shaanxi, China) at 470 nm for 2 minutes, and the results were demonstrated in units per milligram of fresh weight (Chance & Maehly 1955).

The factorial arrangement was used in a completely randomized design with three replications (each replication contained four fruits) to analyze the data that had been collected. The experimental data were evaluated using analysis of variance (ANOVA). Variations resulted from the different coatings and storage times. All computations and calculations were done using the Statistical Tool for Agricultural Research (STAR, Version 2.0.1; IRRI, Laguna, Philippines). The LSD test calculated statistical differences between mean values (P ≤ 0.05). The principal component analysis (PCA) was used to identify potential relationships between variables using the R statistical program (version 4.3.1; R Core Team 2023).

As indicated in Figure 1A, all samples’ weight loss increased with storage progression, although the weight loss of control fruits was much higher than in other treatments. By the end of storage, CH + AV resulted in the minimum weight loss (9.8%), whereas control treatment resulted in the maximum weight loss (14.0%). The weight loss rates of the CH, AV, CO, and CO + AV gels were 10.8%, 10.9%, 13.8%, and 12.1%, respectively. The interaction between storage time and coating treatment greatly affected fruit firmness. Regardless of treatment, firmness steadily diminished throughout the storage period. The initial mango firmness value of 6.4 kg·cm⁻² decreased dramatically over 15 days of storage, reaching values of 2.3 kg·cm⁻², 2.1 kg·cm⁻², 2.8 kg·cm⁻², 1.8 kg·cm⁻², 3.3 kg·cm⁻², and 1.4 kg·cm⁻² for control, CH, AV, CO, CH + AV, and CO + AV, respectively (Fig. 1B).

Figure 1.

Fruit decay began between days 5 and 10 of storage in the control, AV, and CO + AV treatments. After 15 days, decay occurred in all treatments, the highest in control (over 16%) and CO (15.5%) and the lowest in CH + AV (8.4%) and CH (10%) (Fig. 1C).

Edible coatings and storage duration exhibited a substantial effect on mango ascorbic acid, TSS, TA, and pH (Table 1). The initial level of ascorbic acid was 28.2 mg·100 g⁻¹ and decreased significantly with storage time in all treatments. CH and CH + AV-coated mango retained the most ascorbic acid during storage – 22.33 and 21.40 mg·100 g⁻¹, compared to 16.11 mg·100 g⁻¹ in the control. The TSS content in mango fruits increased noticeably during storage, reaching the highest value (17.32%) after 15 days. Compared to the control, the mangoes coated with CH + AV displayed a reduced mean TSS (9.20%), statistically similar to the AV-coated fruits. Significant results were also obtained for the interactions between treatments and storage time. The fruits coated with CH + AV and the control had the lowest (11.7%) and highest (22.5%) TSS after 15 days of storage. The initial TA concentration (0.12%) was permanently reduced by half within the first five days of storage. The highest mean percentage of TA (0.14%) over the entire storage time was observed in fruits coated with CH + AV. The pH of the fruit increased with the storage time. Fruits treated with CO + AV had the lowest mean pH values (4.31) compared to control fruits (4.92).

Regardless of treatment, the skin brightness (L*) value indicated a diminishing tendency as storage time progressed (Fig. 2A). Control fruits had a significantly lower L* value compared to coated fruits throughout storage. Fruits coated with CH and CH + AV had higher L* values during storage. Their value after 15 days was 43.3 and 44.5 compared to L* 32.6 of control fruits. In the remaining treatments, the fruits had intermediate values. The a* values increased with storage time. After 15 days of storage, the CH + AV-coated fruits had the lowest (−3.2) a* value, whereas the control and the CO + V-coated fruits had the highest (−1.9) a* value (Fig. 2B). The b* values decreased consequently after 5 days of storage. Through all the storage, the value of the fruits coated with CH + AV had the highest b* values (Fig. 2C).

Figure 2.

TPC in mango fruits decreased significantly in all treatments during storage, and most significantly in control fruits (46.0 mg GAE·100 g⁻¹ FW) (Fig. 3A). The highest TPC was in fruits coated with CH + AV (94.8 mg GAE·100 g⁻¹ FW).

Figure 3.

The DPPH scavenging activity in all coated fruits and control progressively decreased with storage time. However, the rate of reduction was faster in control fruits. At the end of storage, the highest DPPH activity was observed in fruits coated with CH + AV, AV, and CH – 290.3 μmol·g⁻¹ FW, while in the noncoated control it was 105.5 μmol·g⁻¹ FW (Fig. 3B).

As seen in Figure 4A, the initial respiration rate was 17.4 ml CO₂·kg⁻¹·h⁻¹, which increased significantly during 5 days of storage before dropping. The highest value of 49.3 ml CO₂·kg⁻¹·h⁻¹was found in control fruit, and 21 ml CO₂·kg⁻¹·h⁻¹ in CH + AV-coated fruit, before a slight decrease or stabilization. Coated fruit released less ethylene than noncoated fruit during storage. Noncoated fruit showed the highest ethylene production, followed by CO-coated fruit (Fig 4B). It may be inferred that the coated treatments, independent of storage length, significantly delayed fruit ripening by suppressing ethylene production during storage. After 15 days of storage, fruit treated with CH + AV and CH had the lowest ethylene level (0.2 μl C₂H₄·kg⁻¹·h⁻¹) compared with control fruits (0.9 μl C₂H₄·kg⁻¹·h⁻¹) and CO-coated (0.7 μl C₂H₄·kg⁻¹·h⁻¹).

Figure 4.

PPO activity increased gradually during storage and was highest in noncoated and CO-coated fruit, followed by CO + AV (Fig. 5A). CAT activity increased over five days of storage in all treatments. An increase in CAT activity was observed in control and CO-coated fruit until the tenth day (Fig. 5B). POD enzyme activity also increased over time (Fig. 5C) and was highest in CH + AV-coated fruit, followed by AV-coated fruit. The only exception was noncoated fruit, in which POD activity decreased during the first five days of storage.

Figure 5.

PCA was applied to analyze several biochemical constraints and antioxidant enzymes to assess the effect of various treatments on postharvest mango fruit quality (Fig. 6). The data revealed that two principal components, PC1 and PC2, accounted for 87.8% of the overall variance. PC1 explained 79.3% of the variation in the dataset, whereas PC2 explained 8.5% of the variance. Positive correlations between PC1 and the firmness, ascorbic acid, titratable acidity, TPC, antioxidant activity, CAT and POD enzymes, b* and L* values were found. Conversely, there was a negative correlation of PC1 and weight loss, TSS, occurrence of decay, respiration, ethylene, PPO enzyme, and a* value of skin. Only TSS and b* value were positively correlated with PC2; in contrast, pH was strongly negatively correlated. The DPPH, CAT, ascorbic acid, and TPC exhibited a high positive correlation with CH and CH + AV treatments, but fruit firmness was strongly connected with AV. In contrast, TSS, weight loss, and respiration had stronger associations with the treatment of CO and CO + AV. The skin color (a*), ethylene production, PPO, and decay incidence exhibited positive correlations with control samples.

Figure 6.

Weight loss can be related to water loss from the cells of the fruit induced by respiration and transpiration processes. Water loss during postharvest storage is a serious issue, causing weight loss and changes in texture, appearance, and shriveling (Ncama et al. 2018). Edible coatings form semipermeable barriers that limit transpiration, respiration, and ethylene production (Falguera et al. 2011). AV improved the water retention capacity in tomatoes when combined with other edible coatings (Chauhan et al. 2015). Duan et al. (2019) reported that CH coating extended the shelf life of mango fruit and reduced weight loss without affecting the fruit's flavor, aroma, or digestibility. Our findings agree with Seyed et al. (2021), who found that CH + AV significantly slowed the weight loss of mango fruit during storage at room temperature. Shah and Hashmi (2020) found that applying CH + AV coating can enhance mango fruit weight reduction, similar to what we found.

Firmness is a crucial mango quality indicator for customers since it indicates the ripening phases of the fruit and is also predictive of the shelf life and quality of fresh fruit (Dotto et al. 2015). The fruit ripening stage is often accompanied by softening of the texture and modifications of the cell walls, which results in increased pectin solubility. As a result, the coating may preserve fruit firmness by lowering cell wall activity and degrading enzymes, for example, polygalacturonase (PG), pectin methylesterase (PME), and galactosidase (Rastegar & Atrash 2021). It is widely assumed that the effect of coatings on firmness preservation is primarily related to reducing enzyme activity, respiration, and metabolic activity; consequently, the ripening process is hampered by the limitation of gas exchange, moisture loss, and moisture movement from the fruit skin (Hassan et al. 2018). The chitosan coating effectively preserved mango firmness, corresponding with Cosme Silva et al. (2017) report. Our findings demonstrated that the CH coating alone or combined with AV successfully delayed mango fruit firmness, coinciding with Rastegar and Atrash (2021) results.

Ascorbic acid is one of the strongest antioxidants in fruit, scavenging reactive oxygen species (ROS) and free radicals during ripening (Fenech et al. 2018). L-ascorbic acid is converted into dehydroascorbic acid during oxidation, which may cause of the ascorbic acid's decline as storage time advances (Akram et al. 2017). In this experiment, the use of CH and AV, alone or in combination, can help reduce surface permeability to oxygen and carbon dioxide and regulate ascorbic acid losses in fruit. These results are in close agreement with those of Khalil et al. (2022), who found that the use of CH in the treatment of mango increased vitamin C content compared to other treatments, and Shah and Hashmi (2020), who found that mango fruit provided large amounts of vitamin C as a result of CH + AV coating.

The progressive increase in TSS during the fruit's postharvest storage might be caused by water loss, starch degradation into simple sugars, or cell wall polysaccharides being hydrolyzed (Seyed et al. 2021). Nevertheless, edible coatings can prevent drastic increases in TSS by restricting respiration and reducing the metabolic rate in the covered fruits (Dong & Wang 2018). Aloe vera alone or combined with chitosan had reduced TSS throughout mango storage, consistent with the findings of Yin et al. (2019) and Yu et al. (2021).

Fruit TA is progressively reduced with storage and a dramatic fall signals senescence (Shah & Hashmi 2020). The higher TA value in the coated fruits may be attributable to reduced gas exchange and, as a result, the fruit respiration rate, avoiding the oxidation of organic acids (Cosme Silva et al. 2017). Previous results showed that coating mango fruits with Aloe vera gel with chitosan increased TA content (Seyed et al. 2021). Regardless of treatment, TA decreased while pH increased during storage. The pH of strawberries increased after storage under greater control than in AV-coated fruit (Sogvar et al. 2016).

The color of the skin promotes consumer acceptance, which increases the market value of the fruit. Fruits are attractively bright and greenish when harvested. Still, the greenish hue progressively fades to yellowish or reddish yellow owing to the breakdown of chlorophyll pigment into carotenoids, anthocyanins, and xanthophyll. The findings of this study showed that the L* value gradually decreased in all treatments, while slowly degrading value in the coated fruits than in the control. In this study, all coated fruits prevented the loss of greenness (a*) during storage compared to the control. Previous research has shown that coated fruits may delay chlorophyll degradation, act as a barrier for gaseous exchange, and limit respiration rate, eventually extending shelf life with a skin greenness hue (Lo’ay & Taher 2018). Similarly, guava fruits covered with A. vera gel showed less chlorophyll loss during storage than the control (Rehman et al. 2020). In this regard, Seyed et al. (2021) discovered that the combination of AV with CH reduced fruit color change during storage compared to the control. Based on visual appearance, CH and AV-coated fruits had a superior skin color after 15 days of storage compared to control and other treatments.

The primary causes of mango fruit damage include postharvest diseases and fast ripening (Khaliq et al. 2019). In horticultural commodities, chitosan coating significantly reduced the frequency of disease-induced degradation of mango fruit while maintaining fruit quality (Hasan et al. 2020). Chitosan postharvest treatment is well-known for its antimicrobial activity (Basumatary et al. 2021). It can destroy the plasma membrane of pathogen spores, stifle mycelial development, and cause harm to the fungal cytoplasm (El Hadrami et al. 2010). Similarly, AV coating, single or combined with other treatments, can improve apricot shelf life quality by delaying microbial degradation (Nourozi & Sayyari 2020). In this study, with CH alone or combined with AV treatment, the frequency of deterioration in mango fruits during storage was significantly minimized.

Phenolic compounds that have the effect of fruit retaining their nutritional properties (color, flavor, astringency, acidity, and bitterness), which are continuously lost as the fruit ripens during storage. Phenols are secondary plant metabolites that scavenge ROS and in a result increase antioxidant capabilities (Swallah et al. 2020). Edible coatings play an essential role in phenolic component metabolism by modifying the environment surrounding the fruit and lowering rates of respiration and oxidation (Hassan et al. 2018). The findings of the current study are comparable to those of Seyed et al. (2021), who discovered that the use Aloe vera gel and chitosan coatings had a positive effect on the retention of phenolic components in mango during storage.

During fruit ripening and storage, ROS production increases, causing oxidative stress due to fruit degradation. Fruits can scavenge ROS through the enzymatic activities of CAT, superoxide dismutase, ascorbate peroxidase, and nonenzymatic antioxidant systems (phenolic substances, ascorbic acid, and glutathione). Our findings concerning superoxide dismutase are consistent with those of Shah and Hashmi (2020) and Seyed et al. (2021), who found that DPPH scavenging activity was enhanced in mango after post-harvest treatment with Aloe vera and chitosan. They further claimed that the enhanced DPPH scavenging activity could be attributed to the higher phenol content in mango treated with Aloe vera or chitosan. Similarly, the antioxidant activity of DPPH was retained during storage of banana fruit coated with Aloe vera (Khaliq et al. 2019). A similar tendency was found in guava fruits covered with Aloe vera, showing increased overall antioxidant levels (Rehman et al. 2020).

Due to their climacteric nature and short shelf life when kept at room temperature, mangoes have limited marketing opportunities in faraway places (Sousa et al. 2021). The shelf life of fruit can be extended by using edible coatings that limit gaseous exchange and slow down fruit respiration and the accompanying physiological processes. The outcomes of the current investigation are consistent with those of Chauhan et al. (2015), who reported that chitosan and Aloe vera seem to be plasticized polymers that restrict oxygen access while storing CO₂ in fruit tissues. Chitosan forms a thin layer on the fruit surface, acting as a barrier to gas and environment replacement, affecting respiration and maturation of the fruit (Ali et al. 2019).

Throughout the ripening process, ethylene synthesis increases. It is usually accepted that ethylene production during climacteric ripening results in signal transduction, which raises the expression of genes encoding enzymes that control ripening traits, including color, flavor, texture, and scent (Dautt-Castro et al. 2019). Ethylene production is also affected by fruit respiration rate, which was reduced by CH + AV treatment; thus, coated fruits may contain significantly less ethylene (Shah & Hashmi 2020). A similar pattern was found in oranges treated with guar gum and pea starch, which resulted in lower ethylene production (Saberi et al. 2018). This study confirmed that combination of A. vera gel and chitosan reduces ethylene production in mango fruit.

The expression of genes encoding enzymes involved in the antioxidant system of fruit, such as PPO, POD, and CAT, rises during ripening; also, endogenous defense against the formation of damaging ROS has been described (Lo’ay & EL-Ezz 2021; Yu et al. 2021). During the oxidation of phenolic compounds to quinones, the PPO enzyme causes browning of the tissues of most horticultural crops. As a result, PPO may be linked to browning (Rastegar et al. 2021). Coating treatments lowered PPO activity, which may have triggered defense-related enzymes and avoided mango fruit browning and prolonged storage (Adiletta et al. 2019). Endogenous CO₂, O₂, and ethylene from chitosan coating on fruit surfaces may have slowed PPO action and enzymatic browning (Romanazzi et al. 2018). This study discovered that coating treatments reduced PPO activity, which may have activated defense-related enzymes and increased fruit protection. These findings agree with earlier research published by Deng et al. (2015), who found that chitosan treatment reduces PPO activity and improves tomato quality during storage. Similarly, Molamohammadi et al. (2020) discovered that pistachio fruit coated with chitosan and salicylic acid had decreased PPO activity, which was caused by a reduction in the availability of gases, especially O₂ (Petriccione et al. 2015). Higher CAT activity helps with O₂ elimination and H₂O₂. Our findings are similar to those of Shah and Hashmi (2020), who observed that coating mango fruits with chitosan enhances CAT activity. Ali et al. (2019) stated that Aloe vera gel coating increases the CAT activity in litchi fruit under storage. Similar results have been published, showing that avocado fruit coated with Aloe vera increases CAT enzyme activity compared to control fruits (Khaliq et al. 2019). POD is a unique oxyradical detoxifying enzyme found in fruits that may aid in the reduction of oxidative damage (Xing et al. 2015). The above observations are nearly identical to those of Deng et al. (2015), who discovered that chitosan coatings enhance POD activity in oranges. Similarly, Xing et al. (2015) observed that a chitosan coating and cinnamon oil impacted the enhanced POD activity in jujube fruits, effectively encouraging fruit disease resistance throughout storage.