# 'Cavendish' banana crown rot control through sustained release of thymol by metal-organic frameworks (MOFs)

J. Zuniega, Joël Grabulos, Marc Lebrun, T. Aumond, C. Daniel, D.

Farrusseng, Pierre Brat

► To cite this version:

J. Zuniega, Joël Grabulos, Marc Lebrun, T. Aumond, C. Daniel, et al., 'Cavendish' banana crown rot control through sustained release of thymol by metal-organic frameworks (MOFs). Postharvest Biology and Technology, 2024, 217, pp.113119. 10.1016/j.postharvbio.2024.113119. hal-04676251

HAL Id: hal-04676251

https://hal.science/hal-04676251v1

Submitted on 23 Jul 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# ‘Cavendish’ banana crown rot control through sustained release of thymol by metal-organic frameworks (MOFs)

Johnrell Zuniega<sup>a,b,c,d</sup>, Joël Grabulos<sup>a</sup>, Marc Lebrun<sup>a</sup>, Thibaud Aumond<sup>e</sup>, Cécile Daniel<sup>e</sup>, David Farrusseng<sup>e,*</sup>, Pierre Brat<sup>a,**</sup>

<figure><img src="image_2.png" /></figure>

Check for
updates

## ARTICLE INFO

Keywords:

'Cavendish' banana fruit
Internal crown rot
MOFs
Phytotoxicity
Sustained release
Thymol vapor

## ABSTRACT

Crown rot is an economically important postharvest disease of ‘Cavendish’ banana fruit caused by a complex of phytopathogenic fungi including *Colletotrichum musae*. The sustained release of bioactive compounds, such as thymol, encapsulated in porous materials has been studied for applications in postharvest fruit treatments. The release concentrations of thymol in its vapor phase, its evolution, and its impact on fruit preservation, or damage, have rarely been reported. In this study, an 11-d *in vivo* assay at 14 °C clearly demonstrated the contrasting effects of thymol vapor on banana fruit internal crown rot and phytotoxicity. Thymol vapor achieved by sublimation reduced necrosis in the crown from 40 % to 4 %. However, it triggered phytotoxicity, which caused damage to the fruit peel. Metal-organic frameworks (MOFs), in this case ZIF-8, UiO-66-(COOH)₂ and zeolite 13X enabled the sustained and controlled release of thymol. When encapsulated in ZIF-8, thymol had a release rate approximately 200 times slower than its sublimation rate at 30 °C. Despite the slower release kinetics, thymol released from ZIF-8 achieved concentrations that reduced internal crown rot, to the same extent as thymol sublimation. Moreover, the controlled release minimized phytotoxicity.

## 1. Introduction

In the postharvest management of fresh produce, gaseous or vaporous bioactive compounds, such as antimicrobials, antioxidants, or plant growth regulators, are currently used for their ability to rapidly reach the produce surface through release systems (Chen et al., 2020). For example, chlorine dioxide (ClO₂) and sulfur dioxide (SO₂) gases are used to inhibit microbial growth (Zaitoon et al., 2022; Chen et al., 2020). However, these compounds are toxic industrial chemicals (TICs) and difficult to handle. Biocontrol agents derived from natural compounds are acknowledged as alternatives to these chemicals for postharvest disease control.

Thymol is a natural bioactive compound found in thyme (*Thymus vulgaris* L.). It exhibits antifungal properties against postharvest phyto-pathogenic fungi when applied in vapor form (Pinto et al., 2020). When applied in liquid form, it inhibits the growth of *Colletotrichum musae*, the

postharvest fungus that causes economically important postharvest diseases in banana fruit (Vilaplana et al., 2018).

Crown rot is considered as the main export postharvest disease that impacts ‘Cavendish’ banana [Musa acuminata (AAA Group)] fruit, the predominant export cultivar. It is caused by a fungal complex, including *C. musae* which is host specific to *Musa* species (Su et al., 2011). Among the fungi, *C. musae* is the most pathogenic, especially when inoculated alone, which triggers infection even with a small amount of inoculum to induce crown rot symptoms (Lassois and de Lapeyre de Bellaire, 2014). The fungi infect the crown through wounded tissues in the severed portions of the hand or fruit cluster. The symptoms begin to develop in the crown leading to subsequent softening and blackening of tissues where the clusters were cut from the bunch (Lassois and de Lapeyre de Bellaire, 2014).

Fruit intended for export typically undergo refrigerated sea shipment in a controlled atmosphere at low temperatures (14 °C, 90-95 % RH) for

<footnote><sup>a</sup> UMR QualiSud, Département PERSYST, CIRAD, Université de Montpellier, Avignon Université, Institut Agro, IRD, Université de La Réunion, Montpellier 34398, France</footnote>

<footnote><sup>b</sup> Institute of Crop Science, College of Agriculture and Food Science (CAFS), University of the Philippines Los Baños (UPLB), College, Laguna 4031, Philippines</footnote>

<footnote><sup>c</sup> Postharvest Horticulture Training and Research Center, CAFS, UPLB, College, Laguna 4031, Philippines</footnote>

<footnote><sup>d</sup> L'Institut Agro Montpellier, 34060, France</footnote>

<footnote><sup>e</sup> Université Claude Bernard Lyon 1, CNRS, IRCELYON - UMR 5256, Villeurbanne 69626, France</footnote>

<footnote>* Correspondence to: CNRS, IRCELYON - UMR 5256, Villeurbanne 69626, France.</footnote>

<footnote>** Correspondence to: CIRAD, UMR QualiSud, 73 rue Jean - François Breton, TA B95/16, Montpellier 34398, France.
E-mail addresses: david.farrusseng@ircelyon.univ-lyon1.fr (D. Farrusseng), pierre.brat@cirad.fr (P. Brat).</footnote>
a specific period depending on the target market. These shipping conditions effectively slow down fruit metabolism and fungal growth, thereby delaying crown rot development without causing physiological disorders (Lassois and de Lapeyre de Bellaire, 2014).

While these storage methods have proven effective, challenges may emerge when considering thymol as a complementary or alternative strategy for disease control. The evaporation of thymol solution to generate its vapor form is not practical for an extended period due to its high volatility (Li et al., 2022). Moreover, phytotoxicity appears as the main limitation of this approach, with the direct application of thymol causing fruit peel damage. Bordoh et al. (2020) reported that the liquid fraction of bioactive compounds at relatively high concentrations cause phytotoxicity.

To address the limitation of high volatility, nanoencapsulation has gained significant attention for the targeted delivery of active compounds (Yu et al., 2018). The approach involves incorporating the specific active ingredient of the compound in a nanocarrier, which can be a nanoporous support or encapsulant made from various materials, like nanoparticles (Boostani and Jafari, 2021). Notably, zeolites and Metal-Organic Frameworks (MOFs), characterized by their crystalline porous structures, have emerged as candidates for nanocarriers in drug or bioactive delivery systems, including postharvest applications in fruit (Nong et al., 2020; Chopra et al., 2017; Nagarajan, et al., 2021).

The release of bioactive compounds from nanocarriers is crucial for their biological activities. It is typically described through a concentration-time pattern called a release profile, where the profile means the release rate may not be constant but may change over time (Chen et al., 2020). Controlled release refers to the release of the compound under a specific rate and time (Boostani and Jafari, 2021). Specifically, sustained release is a release profile characterized by prolonged and relatively constant release at a fixed rate (McClements, 2014; Boostani and Jafari, 2021).

Thymol encapsulated in γ-CD-MOF exhibited slower release compared to crystalline thymol sublimation in the first 10 d (Li et al., 2022). In zeolite 4A, the thymol release was found to be complete within just a few hours (Cometa et al., 2022). While these studies reported the encapsulation and release percentages over specific time periods, there is limited information on the concentration of thymol released from MOFs as vapor, its evolution, and its effect on fruit preservation, and also damage, triggered by fruit exposure to high concentration.

Recent studies reported that the sustained release of thymol from MOFs reduced decay in cherry tomatoes, grapes and strawberries (Li et al., 2022; Min et al., 2021). To the best of our knowledge, the control of thymol vapor concentration for banana fruit preservation has not been studied. In a preliminary *in vitro* study, we investigated the sustained release of volatile thymol from MOFs, such as ZIF-8 and UiO-66-(COOH)₂, which slowed the growth of C. musae at 25 °C (Zuniega et al., 2024).

This study aimed to quantify concentration profiles of thymol release from nanocarriers and also its effect on the reduction of internal crown rot and phytotoxicity in ‘Cavendish’ banana fruit during simulated storage conditions, along with the potential inhibition of C. musae growth at 14 °C. To that end, we selected two MOFs whose synthesis had been upscaled, ZIF-8 and UiO-66-(COOH)₂, as well as the commercially available zeolite 13X.

## 2. Materials and methods

### 2.1. Experimental materials

Thymol in solid crystalline form was purchased from Sigma-Aldrich Chemicals Corporation. Three microporous solids with a cavity size in the nanometer range were studied (Table 1). ZIF-8 (Zeolitic Imidazolate Framework) and UiO-66-(COOH)₂ (University of Oslo) were synthesized by spray-drying (Carné-Sánchez et al., 2013) and precipitation (Khabzina et al., 2018), respectively. On the other hand, zeolite 13X (Na exchanged, FAU structure), was acquired from Sigma-Aldrich. Table 1 provides an overview of the key features of these porous solids.

Mature, green, defect-free and organic ‘Cavendish’ banana fruit initially harvested from commercial farms in Ivory Coast or Ghana, then packed in cardboard boxes, were procured from Compagnie Frui tière, Châteaurenard, France. The fruit were harvested at commercial maturity and at the green stage according to Ganry and Chillet (2008) harvest method. The C. musae fungal strain was from Ivory Coast.

### 2.2. Encapsulation of thymol in porous solids

The thymol@porous solid was obtained through vapor diffusion loading at 60±1 °C (Zuniega et al., 2024). One gram of thymol, as solid crystalline powder, was placed in a 200-mL glass container. One gram of porous solid contained in a cylindrical aluminum foil (length: 100 mm; diameter: 20 mm; thickness: 0.01 mm) was then carefully placed inside the glass container. The top of the aluminum foil was left open and the bottom did not touch the thymol solid crystals. The container was then sealed and heated to 60 °C for 16 h to facilitate thymol sublimation, which resulted in the accumulation of a high vapor phase concentration inside the container. The loading process occurred through the adsorption and diffusion of thymol in the porous supports taking advantage of the high concentration at relatively high temperature. The thymol@porous solid was then washed with ethanol for a few seconds to remove the oily thymol that was covering the powder surface. It was then dried at 30 °C for 4 h to remove the ethanol.

### 2.3. Sustained release measurement

The headspace gas was sampled at the same time as *in vitro* and *in vivo* assays. A pre-weighed thymol@porous solid, a 100-mL beaker filled with sterilized distilled water, and a C. musae PDA plate or a fruit cluster were placed inside a 5.5 L polypropylene container (280 mm×215 mm×110 mm), then kept at 14±1 °C for 11 d either tightly closed, or briefly opened for 2 min with or without ventilation (fanning).

The weight (mg) of thymol@porous solid¹ was computed following Eq. (1):

$$ \text{weight(mg)} = \left( \frac{\text{potential/desired weight of thymol}^2}{\% \text{ encapsulation}^3} \right) \times 100 \quad (1) $$

¹the porous solid loaded with thymol then placed inside each polypropylene container

²target weight of thymol (50 mg or 200 mg) loaded in the porous solid

<table><caption>**Table 1**

Key components and characteristics of the porous solids.</caption><thead><tr><th>Porous solids</th><th>Metal constituents</th><th>Organic linker</th><th>BET surface area (m<sup>2</sup> g<sup>-1</sup>)</th><th>Wettability</th><th>References</th></tr></thead><tbody><tr><td>ZIF-8</td><td>Zn</td><td>methylimidazolate</td><td>825</td><td>hydrophobic</td><td>Gholampour et al. (2017)</td></tr><tr><td>UiO-66-(COOH)<sub>2</sub></td><td>Zr</td><td>terephthalic acid</td><td>710</td><td>hydrophilic</td><td>Khabzina et al. (2018)</td></tr><tr><td>Zeolite 13X</td><td>Si, Al</td><td>n.a.</td><td>799</td><td>hydrophilic</td><td>Orsikowsky-Sanchez et al. (2021)</td></tr></tbody></table>
³encapsulation efficiency (wt%) considering the final weight of thymol@porous solid and initial weight of porous solid used during encapsulation

Samples were taken immediately after 24 h for the container, which was either tightly closed (only thymol in the headspace), or opened daily for 2 min with ventilation (headspace thymol flushed with fresh air by fanning). Otherwise, if the container remained closed for 3 d, it was opened for around 2 min (without any ventilation or fanning) before 1 h-sampling, then remained closed until the following day. Gas sampling and opening-closing of the container were repeated daily.

Thymol released from the porous solids was studied by SPME/GC/MS analysis. A solid phase microextraction (SPME) fiber [50/30 µm divinylbenzene (DVB)/carboxen (CAR)/polydimethylsiloxane (PDMS); Supelco, Bellafonte, USA] was exposed to the headspace for 1 h to trap the thymol at 14 °C, then re-exposed for 10 min at 20 °C in a 10-mL glass vial containing 1 µL of an internal standard. The fiber was then introduced into an Agilent gas chromatograph 6890 series equipped with a 60 m 0.25×0.25 DB5 analytical fused-silica column (J&W Scientific, Folsom, CA) coupled with a 5973A mass selective detector. The headspace gas was thermally desorbed at 250 °C for 1 min in split mode. The initial oven temperature was maintained at 100 °C, followed by an in-

and *Thielaviopsis paradoxa*. In this study, *C. musae* was used, since it is the most pathogenic and commonly isolated fungus of banana (*Lassois and de Lapeyre de Bellaire, 2014*).

### 2.5.1. *In vitro* assay

An *in vitro* assay was conducted to assess the inhibitory effect of volatile thymol against *C. musae*, and to analyze its sustained release at the same time. The controls involved crystalline thymol and no thymol.

The pre-weighed thymol@porous solid containing 50 mg of thymol and a 100-mL beaker filled with sterilized distilled water were positioned at opposite ends of the polypropylene container. A 10 µL conidial suspension (10⁶ conidia mL⁻¹) of a 7–10-d-old *C. musae* was pipetted into the PDA plate, then placed inverted in the middle of the container. A circular metal plate with side perforations was used to keep the PDA plate slightly raised. The container was then hermetically sealed and maintained at 14±1 °C for 11 d, with daily opening (without ventilation or fanning) and resealing after 3 d.

The diameter of the fungal colony (mm) was measured immediately after opening the container. Three PDA plates were measured per treatment with two diameter readings per PDA plate. Percent inhibition was calculated following Eq. (2):

$$ \text{inhibition}(\%) = \left( \frac{\text{mean diameter of treatment without thymol} - \text{mean diameter of the treatment}}{\text{mean diameter of treatment without thymol}} \right) \times 100 \quad (2) $$

crease to 250 °C at a rate of 10 °C min⁻¹, then held steady at 250 °C for 15 min. Helium served as the carrier gas with a flow rate of 1.0 mL min⁻¹. Duplicate samples were collected.

Thymol trapped on the fiber was quantified using a calibration curve established under the same sampling operating conditions using EI+ at 70 eV in SIM mode. Three serial dilutions of thymol dissolved in methanol were used against 1 µL of 3-heptanol standard solution (0.815 mg mL⁻¹) placed in a 10-mL glass vial. The quantity (µg 10 mL⁻¹) of thymol released was then determined using Agilent Mass-hunter Quantitative Analysis software version 11.1.

## 2.4. Desorption studies under controlled gas flow

### 2.4.1. Desorption followed by TGA

The desorption of thymol encapsulated in ZIF-8 was evaluated by thermogravimetric analysis (TGA) using a TGA/DSC 1 STARe System Mettler Toledo instrument. Around 10 mg of thymol@ZIF-8 was placed in a crucible. The instrument was maintained at 25 °C for 48 h under a constant air flow of 30 mL min⁻¹. Subsequently, the material was heated to 1000 °C with a heating rate of 0.5 °C min⁻¹ to evaluate the total amount of thymol encapsulated. Crystalline thymol was analyzed using the same method.

### 2.4.2. Desorption followed by FID

Around 20 mg of thymol@ZIF-8 was placed in a tubular cell (length: 8 cm; diameter: 5 mm) between quartz wool plugs. The cell was then positioned in a GC oven (Agilent gas chromatograph 6850 series) maintained at 30 °C with a constant flow of N₂ (68.3 mL min⁻¹) as the carrier gas. The concentration of thymol at the outlet of the cell when desorption occurred was quantified by a FID detector which was calibrated using propane.

## 2.5. *In vitro* and *in vivo* assays

The fungal pathogens predominantly associated with banana fruit crown rot are *C. musae*, *Lasiodiplodia theobromae*, *Fusarium verticillioides*,

### 2.5.2. *In vivo* assay

Green banana fruit were procured before ripening treatment at Compagnie Frui tière, Châteaurenard, France and immediately transported to the CIRAD laboratory in Montpellier, France. The fruit were sorted according to their being free from mechanical damage, early ripening, or onset of disease upon arrival in the laboratory. A fruit cluster with 4–5 fingers (800–1000 g) was used in duplicate per treatment.

A thin slice of the crown was removed from each cluster using a sharp knife. The latex was allowed to flow for 30 mins. The crown was then sterilized by dipping in 70 % ethanol and air dried for 30 mins. Fifty (50) µL of *C. musae* conidial suspension (10⁴ conidia mL⁻¹) was then deposited on the middle region of the crown surface. Once the droplet was completely dried, the cluster was placed inside the polypropylene container with a pre-weighed thymol@porous solid containing 50 mg or 200 mg of thymol and sterilized distilled water, the same as in the *in vitro* set-up. The container was then kept tightly closed and maintained at 14±1 °C for 11 d. This was done to simulate the low temperature storage conditions (14 °C, 90–95 % RH) during the 10–12-d sea shipment of fruit.

The headspace gas was sampled daily and the concentration (µg L⁻¹) of volatile thymol released was calculated. After 11-d storage, the crown of each cluster was cut in half, then the necrotic area was measured with reference to the internal crown surface. The calculation was based on the height and length of both the upper and lower ends of the necrotic area or crown surface. Internal crown rot expressed as percent necrosis was calculated according to Eq. (3):

$$ \text{necrosis}(\%) = \left( \frac{\text{necrotic area}}{\text{internal crown surface}} \right) \times 100 \quad (3) $$

Phytotoxicity was assessed visually, primarily revealed by black spots on the peel. Fruit weight loss (%) after 11-d storage was also determined using Eq. (4).
$$ \text{weight loss}(\%) = \left( \frac{\text{initial weight} - \text{final weight}}{\text{initial weight}} \right) \times 100 \quad (4) $$

## 2.6. Statistical analysis

The experiment was carried out in a completely randomized design (CRD). The data were calculated by mean ± standard deviation (X ± SD). Treatment means were subjected to a one-way ANOVA. The data were run through SAS® Studio. The significance level between treatment means was determined by the HSD test (p≤ 0.05). Percentage data were subjected to arcsine transformation prior to analysis.

# 3. Results

## 3.1. Sustained release of thymol from porous solids

Following encapsulation, MOFs and zeolite released thymol vapor molecules at defined rates under both in vitro and in vivo conditions over a specific duration at 14±1 °C. This study investigated how the initial weight of loaded thymol in porous solids, the temperature, and brief periods of ventilation (with fanning) affected thymol release concentrations.

### 3.1.1. Weight of loaded thymol (in vitro)

The release behavior of entrapped components can be influenced by the initial amount of the bioactive compound (Boostani and Jafari, 2021). Under undisrupted conditions with tightly closed containers, 220–270 µg L⁻¹ of volatile thymol was sublimated from crystalline thymol and loaded on porous solids after 24 h (Fig. 1A). The maximum concentration reached almost 700 µg L⁻¹. Crystalline thymol exhibited the highest release concentration compared to thymol released from porous solids. This was more evident during the later stages of the incubation period, particularly starting on the 6th day, followed by a marked difference of 150–250 µg L⁻¹ between the crystalline thymol and loaded porous solids on the 8th and 11th day.

On the other hand, MOFs or zeolite reduced the concentration of thymol by a third to a half after 4 d. Despite lower encapsulation efficiency compared to zeolite, ZIF-8 and UiO-66-(COOH)₂ both exhibited higher release concentrations when loaded with 50 mg of thymol. Increasing the loaded thymol from 50 mg to 200 mg did not result in a major difference in the release concentrations from either crystalline thymol or loaded porous solids. The fourfold increase in thymol weight only resulted in a 10–40% increase in the release concentrations (Fig. 1B). In contrast to the report of Boostani and Jafari (2021), there was no proportional relationship between the amount of loaded thymol

and the concentrations at which it was released.

### 3.1.2. Temperature (in vitro)

Under disrupted conditions with containers briefly opened (without ventilation), thymol crystal sublimation resulted in a maximum vapor concentration of 1030 µg L⁻¹ at 14 °C (data not shown). In the recent study by Zuniega et al. (2024), under the same conditions but at 25 °C, the concentration of thymol vapor from its crystalline form was measured at 2250 µg L⁻¹. This marked a 2-fold increase in the concentration due to the temperature rise from 14 °C to 25 °C.

Temperature is a major factor that influences the saturation pressure of thymol in the gas phase, which can be extrapolated from a thermodynamic mathematical model comprised of an Antoine equation with parameter coefficients provided by the National Institute of Standards and Technology (NIST) web application from the results of Stull (1947). The thymol concentrations at saturation pressure were estimated to be 218 µg L⁻¹ and 524 µg L⁻¹ at 14 °C and 25 °C, respectively. These extrapolated values were much lower than the measured vapor concentrations from crystalline thymol at the same temperatures in this study.

The temperatures of 14 °C and 25 °C fall below the lower temperature limit for the validity of the Antoine model, which is set at 60 °C and primarily applies to liquid-vapor thermodynamic equilibrium. However, thymol remains in its solid state at 14 °C and 25 °C since these temperatures are lower than its melting point (49–50 °C). Under the application conditions, a solid-vapor (sublimation) equilibrium was involved rather than a liquid-vapor (evaporation) equilibrium. Consequently, the estimated saturation pressures should be regarded as an approximation, or an indication of an order of magnitude rather than a hard number or precise value. However, the model may provide a fair estimation of temperature sensitivity. The extrapolated values aligned with the measurements in the in vivo assay at 14 °C.

Importantly, at 25 °C, ZIF-8 exhibited a maximum 2-fold decrease in concentration compared to crystalline thymol, with concentrations of 1230 µg L⁻¹ and 2250 µg L⁻¹, respectively (data not shown). Similarly, at 14 °C, ZIF-8 released thymol at a lower concentration of 870 µg L⁻¹ compared to sublimation from crystalline thymol (1030 µg L⁻¹). However, the difference between concentrations was not as substantial as that with a higher temperature. For both temperatures, UiO-66-(COOH)₂ demonstrated lower vapor concentrations than zeolite.

### 3.1.3. Presence of a fruit cluster in the container (in vivo)

The evolution of thymol concentrations over time under undisrupted conditions in the presence of banana fruit is shown in Fig. 2. The release pattern of volatile thymol was almost similar to that of the in vitro assay

<figure><img src="image_3.png" /><figcaption>Fig. 1. Concentration (µg L⁻¹) of thymol released from MOFs or zeolite during in vitro storage at 14 °C using (A) 50 mg or (B) 200 mg of loaded thymol in porous solids. The polypropylene containers were kept tightly closed for 11 d. Letters indicate HSD at a 5% level of significance. Each point represents the mean of two replicates.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>**Fig. 2.** Concentration (µg L⁻¹) of thymol released from MOFs or zeolite during *in vivo* storage at 14 °C using (A) 50 mg or (B) 200 mg of loaded thymol in porous solids. The polypropylene containers were kept tightly closed for 11 d. Letters indicate HSD at a 5 % level of significance. Each point represents the mean of two replicates.</figcaption></figure>

(Fig. 1A), with crystalline thymol having the highest release concentrations (Fig. 2A). Notably, there was a rapid release on the 1st day, followed by a relatively stable concentration maintained for 11 d. The main difference observed was that vapor concentration was reduced by more than half compared to the *in vitro* assay under the same conditions.

The release concentrations of volatile thymol did not exhibit a proportional increase despite a fourfold increase in the weight of loaded thymol (Fig. 2B). There was only a 10–30 % increase, even with an increased weight. These results followed similar trends to the *in vitro* assay under undisrupted conditions.

### 3.1.4. Daily ventilation (in vivo)

In contrast to the previous experiment involving brief air exposure (3.1.2), the container was subjected to ventilation using a fan for 2 min immediately after opening, to provide better air circulation within the container. This was carried out to simulate air flow or ventilation during the refrigerated transport of fruit, which are typically packed in polyethylene bags with perforations prior to placing in cardboard boxes.

The brief periods of ventilation induced by fanning resulted in thymol release concentrations ranging from 80 to 300 µg L⁻¹ (Fig. 3),

<figure><img src="image_5.png" /><figcaption>**Fig. 3.** Concentration (µg L⁻¹) of thymol released from MOFs or zeolite during *in vivo* storage at 14 °C using 50 mg of loaded thymol in porous solids. The polypropylene containers were opened daily for 11 d then flushed with fresh air by fanning for 2 min. Letters indicate HSD at a 5 % level of significance. Each point represents the mean of two replicates.</figcaption></figure>

which was almost similar to the release concentrations achieved when containers were tightly closed (Fig. 2). Consistently, crystalline thymol had higher release concentrations than loaded porous solids throughout the storage period.

### 3.2. Continuous monitoring of the release pattern in ZIF-8

Based on the *in vitro* and *in vivo* assays, it appeared that the vapor concentration of thymol reached plateaus in less than 24 h after release. The concentration plateaus were reached on the 1st day and after each subsequent day when complete flushing of the containers was achieved by ventilation. Hence, discriminating release patterns of loaded porous solids from the sublimation of crystalline thymol based on a daily sampling frequency was found to be difficult.

The sublimation and release pattern of thymol were measured continuously by TGA and FID at 25 °C and 30 °C, respectively. In both methods, a continuous flow of air (or N₂) was passed through the sample holder. The amount released was either measured by weighing the sample (TGA) or by integrating the concentration of the gas phase as a function of time (FID). While TGA measurements provide information over 48 h, the FID system allows higher sensitivity, but for a shorter duration.

The sublimation of crystalline thymol exhibited a constant and linear profile over time (Fig. 4), which was also observed by Li et al. (2022). Thymol sublimation was relatively fast due to its high volatility. The sublimation rate was measured as 11.1 µg h⁻¹ at a constant temperature of 25 °C. After 48 h, the temperature was increased to 200 °C to sublimate all thymol. In contrast, for thymol@ZIF-8, no measurable thymol release could be observed under the same conditions (below TGA sensitivity), although thermal desorption indicated an encapsulation efficiency or loading of 13 % (by weight).

The sublimation and release of thymol from ZIF-8 was followed by FID at 30 °C for 1000 min (16.6 h). FID sensitivity allowed the detection of low concentrations of thymol released by ZIF-8. Under these conditions, the total release of thymol was 200 times less when encapsulated in ZIF-8 compared to crystalline thymol (Fig. 5). The release pattern followed an exponential decay, with initially high concentrations released in the first few hours followed by a gradual decline. After 16 h, a plateau-like state was reached with a release concentration of 0.22 µg L⁻¹.

The vapor concentrations obtained by sublimation of crystalline thymol, as measured by TGA and FID, were of the same order of magnitude at 6.2 µg L⁻¹ and 44 µg L⁻¹, taking into account the temperature difference (25 and 30 °C, respectively), as well as the difference in cell geometry, masses, and flows.
<figure><img src="image_6.png" /><figcaption>Fig. 4. TGA measurements under 30 mL min⁻¹ air flow at 25 °C for 48 h then heating to 1000 °C (left: crystalline thymol; right: thymol@ZIF-8).</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Fig. 5. Thymol released (µg L⁻¹) by FID measurements under 68 mL min⁻¹ N₂ flow at 30 °C for 16.6 h (left: crystalline thymol; right: thymol@ZIF-8).</figcaption></figure>

Based on FID data, there was a more than 200-fold marked difference between the vapor phase concentrations of thymol loaded in ZIF-8 and the sublimation for crystalline thymol (0.2 µg L⁻¹ and 44 µg L⁻¹,

respectively). Notably, the encapsulation of thymol in ZIF-8 slowed down the release of the vapor phase, which then resulted in a much lower concentration compared to its sublimation. Unfortunately, TGA measurements on the release of thymol in UiO-66-(COOH)₂ and zeolite 13X were inconclusive due to the concomitant desorption of water also adsorbed in the pores.

### 3.3. *In vitro* assay

In this assay, the polypropylene container was briefly opened each day, without any fanning. Generally, incubation at 14 °C slowed down *C. musae* growth (Fig. 6). When combined with a low temperature, the volatile thymol released from its crystalline form proved to be more efficient than thymol loaded in porous solids starting on the 5th day of incubation, attaining a maximum inhibition of 17 % on the 7th day.

The volatile thymol released from porous solids, ranging from 360 to 870 µg L⁻¹ (data not shown), was insufficient to exert a maximum inhibitory effect against *C. musae* at 14 °C. For the porous solids, there was a higher percent inhibition in thymol released from ZIF-8 than UiO-66-(COOH)₂ and zeolite throughout the incubation period.

The inhibition was likely associated with the thymol vapor concentration, which was slightly lower for encapsulated thymol. Under these conditions without ventilation, there could have been an accumulation of thymol vapor to reach the state of thermodynamic equilibrium with the thymol adsorbed in the porous solids.

<figure><img src="image_8.png" /><figcaption>Fig. 6. Growth inhibition (%) of *C. musae* exposed to volatile thymol released from MOFs or zeolite (50 mg of loaded thymol in porous solids). No data is shown after 7 days as *C. musae* treated without thymol already reached its maximum growth on the PDA plate during this period. The polypropylene containers were briefly exposed to air for 2 min daily (without fanning) during incubation at 14 °C. Values are means ± SD. Each point represents the mean of three replicates.</figcaption></figure>
<table><caption>**Table 2**
Internal crown rot (% necrosis) after 11-d storageª at 14 °C.</caption><thead><tr><th rowspan="3">Treatment</th><th colspan="2">Internal crown rot (% necrosis)</th></tr><tr><th colspan="2">Wt (mg) of thymol loaded in porous solids per polypropylene container</th></tr><tr><th>50 mg</th><th>200 mg</th></tr></thead><tbody><tr><td>without thymol</td><td>41</td><td>43</td></tr><tr><td>crystalline thymol</td><td>4</td><td>13</td></tr><tr><td>thymol@ZIF-8</td><td>5</td><td>4</td></tr><tr><td>thymol@UiO-66-(COOH)<sub>2</sub></td><td>21</td><td>8</td></tr><tr><td>thymol@zeolite</td><td>13</td><td>20</td></tr></tbody></table>

## 3.4. *In vivo* assay

### 3.4.1. Reduction of internal crown rot

The effectiveness of volatile thymol for crown rot control was evident in this study. The sustained release from porous solids provided continuous exposure of the fruit to the antimicrobial properties of thymol. Low temperature storage contributed to the delay in crown rot development, as revealed by the inhibition of *C. musae* growth (Fig. 6).

Compared to fruit without thymol, internal crown rot was effectively reduced by volatile thymol released from its crystalline form and loaded porous solids (Table 2). Fruit treated with vapor sublimated from crystalline thymol achieved 4–13 % necrosis, which was 3–10 times less than for those treated without thymol.

Under undisrupted conditions with containers tightly closed, MOFs or zeolite were able to release 80–335 µg L⁻¹ of volatile thymol (Fig. 2). Despite having lower release concentrations than the crystalline form, the reduction was almost as effective as that with volatile thymol released from its pure form. The percent necrosis ranged from 4 % to 21 %, which was comparable to that of volatile thymol released from crystalline form.

For the porous solids, ZIF-8 was the most effective in reducing internal crown rot (4–5 % necrosis), particularly evident with a higher weight of loaded thymol (Table 2). The volatile thymol released from ZIF-8 ranged from 80 µg L⁻¹ to 280 µg L⁻¹, which was already sufficient to reduce internal crown rot from 40 % to 4 % when combined with a low temperature (Fig. 6).

The reduction in internal crown rot was associated with the calculated weight loss data (Table 3). Fruit exposed to volatile thymol from porous solids, or its crystalline form, had significantly lower weight loss compared to without thymol, with almost a 15-fold difference. This indicated less infection during storage, which was manifested as reduced necrosis in the internal crown surface.

### 3.4.2. Phytotoxicity

Direct application of the thymol liquid fraction causes undesirable effects, such as phytotoxicity which occurs as black spots on the fruit peel. In this study, slight phytotoxic effects were evident on the peel,

<table><caption>**Table 3**
Fruit weight loss (%) after 11-d storageª at 14 °C.</caption><thead><tr><th rowspan="3">Treatment</th><th colspan="2">Weight loss (%)</th></tr><tr><th colspan="2">Wt (mg) of thymol loaded in porous solids per polypropylene container</th></tr><tr><th>50 mg</th><th>200 mg</th></tr></thead><tbody><tr><td>without thymol</td><td>5.98±1.01</td><td>5.98±1.01</td></tr><tr><td>crystalline thymol</td><td>0.40±0.02</td><td>0.64±0.12</td></tr><tr><td>thymol@ZIF-8</td><td>0.52±0.07</td><td>0.45±0.02</td></tr><tr><td>thymol@UiO-66-(COOH)<sub>2</sub></td><td>0.55±0.13</td><td>0.59±0.07</td></tr><tr><td>thymol@zeolite</td><td>0.56±0.13</td><td>0.53±0.00</td></tr></tbody></table>

especially on the upper fruit surface exposed to the volatile thymol present in the container's headspace (Fig. 7). On the other hand, fruit without thymol did not exhibit any black spots.

Under undisrupted conditions, the controlled release of thymol from the porous solids minimized phytotoxic effects. The severity of phytotoxicity remained consistent regardless of the weight of thymol. The black spots were more noticeable on the peel surface close to the positioning of the thymol@porous solid inside the container. Moreover, the brief periods of ventilation introduced by fanning aggravated phytotoxicity, even with a lower weight of loaded thymol in the porous solids (data not shown).

## 4. Discussion

The sustained release of bioactive compounds, such as thymol, encapsulated in porous materials has been demonstrated in different systems (Lv et al., 2022) and studied for various applications including postharvest treatments of fruit (Li et al., 2022; Min et al., 2021). Generally, these studies reported encapsulation efficiencies (the amount of bioactive compounds loaded in the porous solids) and the release percentage over a given period of time. However, the concentration of a sustained release of thymol vapors, its evolution, and its effect on fruit preservation, or damage, have rarely been reported.

The time pattern of thymol vapor concentration is determined by the sublimation rate and, notably, its vapor saturation pressure at a given temperature. The minimal impact of increasing the weight of loaded thymol in the porous solids from 50 to 200 mg indicated that the total amount of thymol was not a relevant factor, but rather the equilibrium concentration in the vapor phase. This suggests that sustained release is controlled by adsorption-desorption thermodynamics and vapor phase equilibrium. At 14 °C, the estimated saturation vapor pressure of thymol is approximately 3.5 Pa (218 µg L⁻¹). However, this extrapolated value should be interpreted with caution because the parameter set of the Antoine model is only valid above 60 °C. Experimentally, the maximum vapor concentration was measured at 1030 µg L⁻¹ for crystalline thymol sublimation, which may therefore represent the thermodynamic equilibrium at 14 °C.

Encapsulation of thymol in the porous solids allowed a much slower release compared to thymol crystal sublimation. This indicates that nanoporous materials exhibit desirable properties for the sustained release of thymol. Measurements in the FID system showed a thymol sublimation rate of 2 × 10⁻⁴ mmol min⁻¹. However, after encapsulation in ZIF-8, the release rate dropped to 1 × 10⁻⁶ mmol min⁻¹ following 16.6 h of exposure to nitrogen flow. This marked a substantial 200-fold reduction in the release rate when thymol was encapsulated in ZIF-8. Although thymol desorption was slow, it was nevertheless fast enough to reach the saturation concentration in the gas phase in the container after 24 h. At this rate, about 200 µg of thymol could be released after 24 h under flow, which was a significant amount relative to the measured concentration inside the 5.5 L polypropylene container. Notably, the atmosphere inside the container was saturated with humidity, along with other vapors or gases emitted by the fruit, particularly CO₂. These vapors and gases could alter the thermodynamic equilibrium, which could then accelerate or reduce the thymol desorption rate.

The desorption studies followed by TGA on UiO-66-(COOH)₂ and zeolite 13X were influenced by humidity. When exposed to air flow, these porous solids loaded with thymol exhibited water desorption. In contrast, ZIF-8 is a highly hydrophobic MOF that does not adsorb moisture even under very high humidity conditions (Canivet et al., 2014). Consequently, no weight variation could be measured by TGA.

Nonetheless, it could be assumed that the release of thymol from UiO-66-(COOH)₂ and zeolite 13X was influenced by the adsorption and diffusion properties, which showed similar concentration levels and patterns in *in vitro* and *in vivo* assays. However, it is important to note that UiO-66-(COOH)₂ and zeolite 13X are much less effective in internal

<footnote>ª The containers were tightly closed during storage with no daily opening for brief air exposure or fanning.</footnote>

<footnote>ª The containers were tightly closed during storage with no daily opening for brief air exposure or fanning.</footnote>
<figure><img src="image_9.png" /><figcaption>Fig. 7. Fruit clusters after 11-d storage at 14 °C. Phytotoxicity symptoms occurred as black spots on the peel surface. The polypropylene containers were kept tightly closed during storage, with no daily opening for brief air exposure or fanning.</figcaption></figure>

crown rot reduction than ZIF-8. The discrepancy in performance between different nanoporous release systems clearly indicates that the kinetics of release and its evolution under *in vivo* conditions are key criteria.

The *in vivo* assays clearly demonstrated contrasting effects of thymol vapors on banana fruit preservation, particularly with regard to internal crown rot and phytotoxicity. While the maximum concentration of thymol released in the vapor phase through sublimation reduced internal crown rot, it also caused damage to the fruit peel in the form of phytotoxicity. Hence, a sustained release system capable of releasing thymol at concentrations that are sufficient to avoid phytotoxicity would be an ideal solution. This study indicates that an optimal concentration of thymol should be maintained to reduce internal crown rot while minimizing phytotoxic damage.

Under undisrupted conditions (*in vitro*), the thymol concentrations reached relatively high levels on the 1st day (200–400 µg L⁻¹), then increased up to the 5th to 7th day to a maximum of 600–700 µg L⁻¹, and then gradually decreasing thereafter while maintaining a high concentration. The daily brief ventilation of the polypropylene container (*in vivo*), aimed at flushing the thymol vapor with fresh air, did not alter the concentration pattern. This clearly indicated that thymol sublimation is rapid enough to achieve equilibrium. The equilibrium state achieved during the incubation or storage period possibly limited the thymol that the porous solids could retain or release to a specific level. Hence, interpreting the evolution pattern of thymol gas phase concentration for both *in vitro* and *in vivo* assays is complex due to variations in the design of the measurement.

This study demonstrated that prolonged exposure to a thymol concentration of 80–335 µg L⁻¹ is beneficial in reducing internal crown rot, with minimal phytotoxicity. Specifically, there was a significant reduction in necrosis from 40 % to 4 % with 80–280 µg L⁻¹ thymol released from ZIF-8. Besides the low temperature, which slowed down the growth of *C. musae*, ZIF-8 could have an indirect effect on the activity of the fungi. Shen et al. (2020) reported that MOF itself has antimicrobial properties due to the synergistic effects of the metal ions and organic ligands in the framework.

In the existing literature, there are no reports available on the use of volatile thymol released from porous solids such as MOFs for banana

crown rot control. The antifungal activity of the liquid fraction of thymol has effectively been demonstrated against anthracnose, also caused by *C. musae*, in organic banana fruit (Vilaplana et al., 2018). Similar to our study, Min et al. (2021) reported the potential application of volatile thymol released from PCN MOFs in reducing decay in grapes and strawberries after 7-d storage at 25 °C. Moreover, the controlled release of thymol from γ-CD-MOF reduced decay in cherry tomatoes after 15-d storage at 25 °C (Li et al., 2022).

Despite the reduction in internal crown rot, phytotoxicity was evident as scattered black spots on the fruit peel. Bordoh et al. (2020) reported that phytotoxicity results from tissue damage brought about by relatively high concentrations of the bioactive compound in its liquid form. However, in this study, there were minimal to no phytotoxic effects due to the presence of thymol in vapor form and its release at lower concentrations.

In association with the reduction in internal crown rot, thymol in its vapor phase also reduced fruit weight loss. This could be attributed to the reduced necrosis or infection caused by *C. musae*. Fruit weight loss is an important parameter for fruit quality assessment, as it is partly induced by fruit metabolism. The reduced weight loss of fruits treated with thymol released from porous solids was revealed by the significant reduction in internal crown rot compared to fruits without thymol. Similar studies in cherry tomatoes, grapes and strawberries reported that fruits treated with volatile thymol released from MOFs had lower weight loss due to reduced decay (Min et al., 2021; Li et al., 2022).

## 5. Conclusions

Thymol sublimated from its solid crystalline phase inhibited *C. musae* growth and also reduced internal crown rot at 14 °C. ZIF-8, UiO-66-(COOH)₂ and zeolite 13X enabled the controlled release of volatile thymol, which resulted in a lower release concentration compared to its sublimation. Specifically, the release of thymol when encapsulated in ZIF-8 was much slower than its sublimation rate. Under nitrogen flow at 30 °C, the release rate was approximately 200 times slower than the sublimation. Despite the slow release in ZIF-8, thymol concentrations reached 80–280 µg L⁻¹, which effectively reduced necrosis in the crown from 40 % to only 4–5 %. This was associated with incurred lower fruit
weight loss. Importantly, controlled release from nanoporous materials led to minimal phytotoxicity. The intriguing performance of ZIF-8 in encapsulation and sustained release deserves further research and engineering to achieve a practical, low-cost solution for postharvest fruit treatments.

### CRediT authorship contribution statement

**Johnrell Zuniega:** Writing – original draft, Visualization, Validation, Methodology, Investigation, Formal analysis, Data curation. **Joël Grabulos:** Supervision, Methodology, Formal analysis. **Marc Lebrun:** Supervision, Methodology, Formal analysis. **Dr Thibaud Aumond:** Methodology, Formal analysis, Data curation. **Cécile Daniel:** Methodology, Formal analysis, Data curation. **Dr David Farrusseng:** Writing – review & editing, Supervision, Methodology, Formal analysis. **Dr Pierre Brat:** Writing – review & editing, Supervision, Project administration, Methodology, Funding acquisition, Formal analysis.

### Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper

### Data Availability

Data will be made available on request.

### Acknowledgment

The study was supported by the Department of Science and Technology – Science Education Institute (DOST-SEI), Philippines and the French Embassy to the Philippines and Micronesia as part of J. Zuniega’s doctoral thesis under the DOST-PhilFrance Fellowship.

### Authorship confirmation

All listed authors have significantly contributed to the work and agreed with its content and submission. All authors have seen and approved the final version of the manuscript.

### References

* Boostani, S., Jafari, S.M., 2021. A comprehensive review on the controlled release of encapsulated food ingredients; fundamental concepts to design and applications. *Trends Food Sci. Technol.* 109, 303–321. https://doi.org/10.1016/j.tifs.2021.01.040.

* Bordoh, P.K., Ali, A., Dickinson, M., Siddiqui, Y., 2020. Antimicrobial effect of rhizome and medicinal herb extract in controlling postharvest anthracnose of dragon fruit and their possible phytotoxicity. *Sci. Hortic.* 265, 109249 https://doi.org/10.1016/j.scienta.2020.109249.

* Canivet, J., Bonnefoy, J., Daniel, C., Legrand, A., Coasne, B., David, F., 2014. Structure-property relationships of water adsorption in metal-organic frameworks. *N. J. Chem.* 38, 3102–3111. https://doi.org/10.1039/C4NJ00076E.

* Carné-Sánchez, A., Imaz, I., Cano-Sarabia, M., Maspoch, D., 2013. A spray-drying strategy for synthesis of nanoscale metal–organic frameworks and their assembly into hollow superstructures. *Nat. Chem.* 5, 203–211. https://doi.org/10.1038/nchem.1569.

* Chen, M., Chen, X., Ray, S., Yam, K., 2020. Stabilization and controlled release of gaseous/volatile compounds to improve safety and quality of fresh produce. *Trends Food Sci. Tech.* 95, 33–44. https://doi.org/10.1016/j.tifs.2019.11.005.

* Chopra, S., Dhumal, S., Abeli, P., Beaudry, R., Almenar, E., 2017. Metal-organic frameworks have utility in adsorption and release of ethylene and 1-methylcyclopropene in fresh produce packaging. *Postharvest Biol. Technol.* 130, 48–55. https://doi.org/10.1016/j.postharbio.2017.04.001.

* Cometa, S., Bonifacio, M.A., Bellissimo, A., Pinto, L., Petrella, A., De Vietro, N., Iannaccone, G., Baruzzi, F., De Giglio, E., 2022. A green approach to develop zeolite-thymol antimicrobial composites: analytical characterization and antimicrobial activity evaluation. *Heliyon* 8. https://doi.org/10.1016/j.heliyon.2022.e09551.

* Ganry, J., Chillet, M., 2008. Methodology to forecast the harvest date of banana bunches. *Fruits* 63, 371–373 https://doi.org/10.1051/fruits:2008036.

* Gholampour, N., Chaemchuen, S., Hu, Z.Y., Mousavi, B., Tendeloo, G.V., Verpoort, F., 2017. Simultaneous creation of metal nanoparticles in metal organic frameworks via spray drying technique. *Chem. Eng. J.* 322, 702–709. https://doi.org/10.1016/j.cej.2017.04.085.

* Khabzina, Y., Dhainaut, J., Ahlhelm, M., et al., 2018. Synthesis and shaping scale-up study of functionalized UiO-66 MOF for ammonia air purification filters. *Ind. Eng. Chem. Res.* 57, 8200–8208. https://doi.org/10.1021/acs.iecr.8b00808.

* Lassois, L., de Lapeyre de Bellaire, L., 2014. Crown rot disease of bananas. *Postharvest Decay: Control Strategies* (edited by S. Bautista-Baños). Academic Press, pp. 103–130.

* Li, Z., Sun, Y., Pan, X., Gao, T., He, T., Chen, C., Zhang, B., Fu, X., Huang, Q., 2022. Controlled release of thymol by cyclodextrin metal-organic frameworks for preservation of cherry tomatoes. *Foods* 11, 3818. https://doi.org/10.3390/foods11233818.

* Lv, M., Sun, D.-W., Huang, L., Pu, H., 2022. Precision release systems of food bioactive compounds based on metal-organic frameworks: synthesis, mechanisms, and recent applications. *CRI. Rev. Food Sci. Nutr.* 62, 3991–4009. https://doi.org/10.1080/10408398.2021.2004086.

* McClements, D.J., 2014. Nanoparticle- and Microparticle-based Delivery Systems: Encapsulation, Protection and Release of Active Compounds. CRC press.

* Min, T., Sun, X., Zhou, L., Du, H., Zhu, Z., Wen, Y., 2021. Electrospun pullulan/PVA nanofibers integrated with thymol-loaded porphyrin metal-organic framework for antibacterial food packaging. *Carbohydr. Polym.* 270, 118391 https://doi.org/10.1016/j.carbpol.2021.118391.

* Nagarajan, V., Kizhaeral, S., Subramanian, M., Rajendran, S., Ranjan, J., 2021. Encapsulation of a volatile biomolecule (hexanal) in cyclodextrin metal-organic frameworks for slow release and its effect on preservation of mangoes. ACS Food Sci. Technol. 1, 1936–1944. https://doi.org/10.1021/acsfoodscitech.1c00205.

* Nong, W., Liu, X., Wang, Q., Wu, J., Guan, Y., 2020. Metal-organic framework-based materials: synthesis, stability and applications in food safety and preservation. *ES Food Agrofor.* 1, 11–40. https://doi.org/10.30919/esfaf0001.

* Orsikowsky-Sanchez, A., Franke, C., Sachse, A., Ferrage, E., Petit, S., Brunet, J., Plantier, F., Miqueu, C., 2021. Gas porosimetry by gas adsorption as an efficient tool for the assessment of the shaping effect in commercial zeolites. *Nanomater* 11, 1205 https://doi.org/10.3390/nano11051205.

* Pinto, L., Bonifacio, M.A., De Giglio, E., Cometa, S., Logrieco, A.F., Baruzzi, F., 2020. Unravelling the antifungal effect of red thyme oil (*Thymus vulgaris* L.) compounds in vapor phase. *Molecules* 25, 4761. https://doi.org/10.3390/molecules25204761.

* Shen, M., Forghani, F., Kong, X., Liu, D., Ye, X., Chen, S., Ding, T., 2020. Antibacterial applications of metal-organic frameworks and their composites. *Compr. Rev. Food Sci. Food Saf.* 19, 1397–1419. https://doi.org/10.1111/1541-4337.12515.

* Stull, D.R., 1947. Vapor pressure of pure substances organic and inorganic compounds. *Ind. Eng. Chem. Res.* 39, 517–540. https://doi.org/10.1021/ie50448a022.

* Su, Y.Y., Noireung, P., Liu, F., Hyde, K.D., Moslem, M.A., Bahkali, A.H., Abd-Elsalam, K. A., Cai, L., 2011. Epitypification of *Colletotrichum musae*, the causative agent of banana anthracnose. *Mycoscience* 52, 376–382. https://doi.org/10.1007/s10267-011-0120-9.

* Vilaplana, R., Pazmiño, L., Valencia-Chamorro, Silvia, 2018. Control of anthracnose, caused by *Colletotrichum musae*, on postharvest organic banana by thyme oil. *Postharvest Biol. Technol.* 138, 56–63. https://doi.org/10.1016/j.postharbio.2017.12.008.

* Yu, H., Park, J.-Y., Kwon, C.W., Hong, S.-C., Park, K.-M., Chang, P.-S., 2018. An overview of nanotechnology in food science: Preparative methods, practical applications, and safety. *J. Chem. 2018* https://doi.org/10.1155/2018/5427978.

* Zaitoon, A., Luo, X., Lim, L.T., 2022. Triggered and controlled release of active gaseous/volatile compounds for active packaging applications of agri-food products: a review. *Compr. Rev. Food Sci. Food Saf.* 21, 541–579. https://doi.org/10.1111/1541-4337.12874.

* Zuniega, J.S., Grabulos, J., Lebrun, M., Aumond, T., Daniel, C., Brat, P., Farrusseng, D., 2024. Encapsulation of thymol and limonene in metal-organic frameworks for inhibition of *Colletotrichum musae* growth. *Int. J. Food Sci. Technol.* 59, 730–742. https://doi.org/10.1111/ijfs.16812.