Influence of guar gum and chitosan enriched with lemon peel essential oil coatings on the quality of pears

Abstract Pear is a typically climacteric fruit and highly perishable with a low shelf life owing to extreme metabolic activity after harvesting. The present study aimed to reduce weight loss and improve the firmness of pear during storage. The lemon peel essential oil (LPEO) has gained considerable attention due to being the richest source of bioactive compounds that behaved as a natural antioxidant agent, being cost‐effective, and being generally recognized as safe. Edible coatings equipped with a natural antioxidant agent and renewable biopolymers have gained more research fame owing to their involvement in the direction of biodegradability and food safety. In this work, edible skin coating materials (ESCMs) embedded by chitosan (1%) and guar gum (2%) were fabricated, and afterward, five concentrations of LPEO (1, 1.5, 2, 2.5, and 3.0%) were incorporated individually into the ESCMs. Findings revealed that LPEO–ESCMs significantly reduced the weight loss and improved the firmness of pear up to 45 days of storage at 4 ± 2°C. Furthermore, the LPEO–ESCMs have enhanced the antioxidant capacity, antibacterial efficiency, and malondialdehyde level of pear during storage time. It was concluded that 3% of LPEO–ESCMs improved the overall acceptability of pear fruits. Taken together, the novel insights of guar gum and chitosan‐based ESCMs entrapped with LPEO will remain a subject of research interest for researchers in the future.


| INTRODUC TI ON
The consumers' interest regarding the consumption of fruits has been increasing extensively because these are well renowned to be one of the significant pillars of a healthy diet (Maringgal et al., 2020).
However, the postharvest losses resulting in the deterioration of the quality and quantity of the fruits are key problems that are faced in the modern era (Nair et al., 2020). These losses are likely due to poor handling and storage or unsuitable packaging, promoting microbial, and fungal infections. As a novel plant, pear fruit (Pyrus communis L) is a member of the Rosaceae family and has become very popular among the consumers due to its good taste, thin peel, crisp flesh, and low caloric contents, and an excellent source of vitamin C and dietary fiber (Lindo-García, . Many researchers revealed that the pear fruit is vulnerable to enzymatic browning and oxidative instability, leading to spoilage during cold storage Sharma & Rao, 2015). After harvesting, the respiration rate and ripening process led to significant changes in the color, firmness, flavor, acidity, and total soluble solids of pear fruits (Lindo-García, Muñoz, et al., 2020). Therefore, some persuasive mechanisms have been developed to preserve pear fruits without affecting the nutritive value and sensory attributes (Lindo-García et al., 2019). Over the years, several storage techniques have been established to prolong the lifetime of fruits, including modified atmosphere packaging (MAP) and controlled atmosphere (CA). The MAP and CA storage research on CO 2 and O 2 injury have investigated to increase ethylene production rate and flavor problem due to anaerobic respiration (Lindo-García et al., 2019). Thus, an edible coating is a modified atmosphere technique that has exhibited excellent findings for enhancing the quality of the fruits (Guimaraes et al., 2018).
Evidence-based results exhibited that edible coating could function as a barrier on the fruit's surface, extending the shelf life by modifying the internal gas atmosphere, slowing down the ripening process, and reducing water losses (Maringgal et al., 2020). Recommended renewable biopolymers that are being used in the development of edible coatings are polysaccharides, lipids, and proteins (Garavand et al., 2020).
Among the aforementioned biopolymers, polysaccharides are known to be potent candidates used to improve the quality of fresh fruits (Barclay et al., 2019). As polysaccharides have numerous benefits over artificial polymers due to their biodegradable, biocompatible, and renewable characteristics and compliance to environmentally friendly modifications Usman et al., 2021;Zhao et al., 2020). Moreover, edible coatings prepared from polysaccharide sources not only enhance the fruit quality but also provide strong protection against undesirable factors such as heat, moisture contents, and enzymatic degradation. Guar gum is a galactomannan comprising of a mannose [(1 → 4)-linked β-D-mannopyranose] backbone with galactose side groups [(1 → 6)-linked α-D-galactopyranose]. It is obtained from the endosperm of the plant Cyamopsis tetragonoloba which belongs to the Leguminosae family. Chitosan is also one of the considerable natural polymers that have utilized for the shelflife extension of fruits under a range of different storage conditions (Garavand et al., 2020). The abovementioned organic polymers have commonly been used to inhibit the growth of different food-related microbes such as Escherichia coli, Bacillus subtilis, and Staphylococcus aureus by retarding their growth (Jawad et al., 2017). Moreover, these have been suggested for film formation and coatings due to high water-soluble capacity, easy solubility in organic acids, high molecular weight, and long polymeric chains (Li et al., 2016). Recently, chitosanbased coatings enriched with ascorbic acid and procyanidin markedly improved the antioxidant activity of mango (up to 24 days at 15 ± 2°C with 85%-90% relative humidity [RH]) and fresh blueberries (at 4°C for 14 days), respectively (Mannozzi et al., 2018). Likewise, pullulan, calcium chloride, and chitosan have been used to preserve the whole pear for 30 days at 0 ± 1°C, by enhancing the total antioxidant activity significantly. Similarly, authors have found that the best pear coating is 2% chitosan and 1% pullulan as it provides an insulating barrier to the surface of the pear and improves the environment around the fruit. Furthermore, the researchers have preserved mango (Silva et al., 2017) and guava (Silva et al., 2018) fruits with chitosan solution, which have slowed down the water losses, respiratory rate, climacteric peak, firmness quality, and skin color by interjecting the degradation of chlorophyll up to 20 days and 96 h, respectively, at 25 ± 2°C and 85 ± 3% RH. Conclusively, the results indicated that the edible chitosan coating effectively improved fruit quality by starch degradation and mitochondrial respiration reduction. Gum and ginseng extract coatings were prepared in 2018 to preserve the quality of sweetened cherry for up to 8 days, at 20°C (Dong & Wang, 2018).
Findings revealed that the organic polymer coating can delay the production of malondialdehyde. Furthermore, the mechanism also markedly eradicates weight loss, slows down respiration rate, delays the changes in ascorbic acid and anthocyanins, and maintains the membrane integrity throughout the storage period. However, efforts have been made to introduce novel natural protecting materials, for example, essential oils were used to maintain fresh fruits' safety and quality (Azarakhsh et al., 2014). An earlier research investigated the effects of a minimum inhibitory concentration of pectin-and alginatebased edible coatings enhanced with eugenol and citral or their mixture (Guerreiro et al., 2016). According to that study, both pectin-and alginate-based coatings preserved fresh-cut 'Bravo de' Esmolfe' apples. However, the insight of chitosan-and guar gum-based edible coatings and their antimicrobial and antioxidant agent like lemon peel essential oil (LPEO) remains to be investigated. Therefore, the present study was designed to inhibit the growth of microbes and provides a suitable environment around pear fruits using ESCMs enriched with LPEO; however, the storability of the pear was explored.

K E Y W O R D S
chitosan, edible coatings, guar gum, lemon peel essential oil, pear | 2445 IFTIKHAR eT Al.

| MATERIALS AND METHODS
The healthy and undamaged pear fruits were harvested in early August and stored at 6-8°C with 85 ± 5% RH in the cold storage chamber. A skinning machine was used for peeling. The fruit was processed in two parts: peel and pulp, leading to freezing by liquid nitrogen at −80°C. Before the experiment, the samples were grounded (IKA ® -WERKE MF 10 basic S1 (1000 W, 50/60 Hz) microfine grinder drive equipped with a 0.5 mm sieve was used for cryogenic grinding) into powder form. The chemicals with 95% purity used in the experiments were purchased from Sigma-Aldrich Pvt.

| Extraction of LPEO
The lemon was obtained from Ayub Agriculture Research Institute (AARI), Faisalabad, Pakistan. In the round-bottomed flask, 100 g lemon peel was pulverized and steeped in water. LPEO were extracted by hydrodistillation (400 ml of distilled water) for up to 4 h with an industrial Clavenger device at the boiling range of water and atmospheric pressure. The Clevenger device consisted of a 1000-ml round-bottomed flask (Isolab), reflux condenser (Norm Cam), and a volatile determination tube. Ground glass connector was connected to every object. The essential oil is measured on Clevenger equipment after the extraction time has passed. Until the quality assessment analysis, the LPEO was placed at refrigeration temperature (4 ± 1°C). The following equation was used to compute the production of lemon oil: Y = V W × 100; where Y is the production of LPEO in percentage (v/w), V is the LPEO acquired (ml), and W is the quantity of lemon peels (g). The findings were obtained for the various extraction times of 60, 120, 180, and 240 min for lemon peel. The average yield of LPEO was 3.5%; however, it depends on the extraction conditions such as extraction time, water-to-material ratio, and extraction power (Dao et al., 2021).

| Preparation of ESCMs solutions enriched with LPEO
Edible skin coating materials, adding the LPEO, were formulated as defined by Azevedo et al. (2014). Moreover, the preparation of chitosan solution (100 ml) was formed by liquefying chitosan (w/v) in a 1.5% acetic acid (0.5 ml acetic acid/100 ml deionized H 2 O) solution at 25°C for 3.5 h and incorporating 1.28% glycerol (w/v) to the mixture while heating the solution on a hot plate. In the case of guar gum solution (100 ml), 2% of guar gum (w/v) and 0.64% of glycerol (w/v) were added into distilled water and heated the solution into a water bath up to 70°C for 30 min as described by Mehyar et al. (2011), with minor modification. After cooling (25°C), the mixture was incorporated into the chitosan solution and mixed well until it was homogeneous. Then, the solution was autoclaved at 121°C for 15 min in a glass bottle. Lastly, the LPEO was dissolved in ESCMs solution, and the concentration of guar gum, chitosan, and LPEO used in each treatment has exhibited in Table 1.

| Analysis of LPEO-ESCMs solution
Titratable acidity (TA), pH, and viscosity have a particular impact on fruits' quality. The pH of the LPEO-ESCMs solution was determined using a digital meter (Mettler FE20, Mettler-Toledo). The pH meter was calibrated through buffer solutions before utilization for experiments. The acidity of LPEO-ESCMs solution was measured using the following formula: where 'V' is the titer volume of NaOH, and 'm' is the weight of LPEO-ESCMs solution (ml). The viscosity of the LPEO-ESCMs solution was evaluated as described by Lin and Zhao (2007).

| LPEO-ESCMs treatments
The whole fresh pear was sorted into comprehensive arbitrary groups, cleaned from dirt, debris, or any other particles by 50 ppm TA B L E 1 Treatment plan for pear fruit coating sodium hypochlorite solution, and then washed with distilled water.
Afterward, the washed fresh pear was dried at room temperature through hygienic air by adopting the methodology of de Aquino et al. (2015). The pear was coated with chitosan and guar gum (ESCMs) encapsulating five different concentrations (1, 1.5, 2, 2.5, and 3.0%) of LPEO, while the control sample was placed in the distilled water (Table 1). After dipping the pears, they were dried on the nylon sheet. Moreover, 1920 healthy and uniform pears were picked and divided into six treatments, and every treatment contained 320 pears. There were three replications in treatment, and each replication comprises of 106 pears. The corrugated three-ply fiberboard boxes were utilized to pack the pears using 5% perforation with paper lining and then the packed pears boxes were kept into a cold storage chamber (at 4 ± 2°C and up to 95% RH for 45 days). The antioxidant capacity, microbiological analysis, and physicochemical changes in pear fruits were explored at 15, 30, and 45 days of storage.

| pH of coated pear fruits
The digital pH meter was used to measure the pH value of coated and uncoated pear as documented by Tiwari et al. (2008). Before evaluation, the digital pH meter was calibrated with two buffer solutions: acidic solution (with pH 4.0) and basic solution (with pH 7.0).

| Total soluble solids and organic acid content of coated pear fruits
Total soluble solid and malic acid contents were obtained from fresh-frozen tissue of pear as presented by Nath et al. (2012). TSS content was measured by diluting 2 g of pear flesh tissue in 62.5% (v/v) aqueous methanol solvent and kept in a thermostatic water bath for 10 min at 60°C and blending the mixture using vortex every 3 min to avoid layering. Afterward, the sample was centrifuged at 24,000 g for 12 min at 18°C. The supernatants of every treatment were obtained and utilized for enzyme-attached spectrophotometric measurement of sucrose (β-fructokinase), fructose, and glucose (hexokinase/phosphoglucose and isomerase) via commercial kits (BioSystem SA). In malic acid measurement, 2 g of frozen flesh tissue was dissolved in 5 ml distilled water, the treatments were slightly shaken for 8 min at 25°C, and then, centrifuged at 24,000 g for 6 min at 18°C. The resultant supernatant was found and used for enzymecoupled spectrophotometric measurement (L-malate dehydrogenase) of malic acid through commercial kits (BioSystem SA).

| Weight loss of coated pear fruits
The determination of weight loss was an important parameter to check the pear quality during the entire storage. The weight loss (%) was calculated using an MS6002TS balance (Mettler-Toledo GmbH) by difference between the initial weight of pear and final weight of pear (at every storage interval) as per the method described by Kaur et al. (2019).

| Firmness of coated pear fruits
The pear fruits firmness was calculated from the flesh of the pear, after removal of a thin part of the skin, at the equatorial area of the pear through a Fruit Texture Analyzer (Güss Manufacture Ltd) with an 8-mm-diameter probe as presented by Dong and Wang (2018).
The trigger edge was fixed at 1 N, while the calculating speed and distance were 10 mm/s and 8.9 mm, respectively.

| Antioxidant capacity and malondialdehyde (MDA) contents
The antioxidant activity of control and coated pears was studied by using the 2,2-diphenyl-1-picryl-hydrazyle (DPPH) test as per the procedure of Usman et al. (2020). Each sample (1 g) of pear fruit extract was mixed in 3.0 ml of ethanol, and centrifuged at 4°C for 15 min with the 12,000 g rpm, for analyzing DPPH. Then, the 3.9 ml DPPH-ethanol mixer, 0.1 ml supernatant, and 0.009 ml distilled water were vigorously mixed and shaken before keeping it in darkness for 30 min. Afterward, the absorbance was determined at a wavelength of 515 nm against a blank reference of ethanol without DPPH using a spectrophotometer (U-2900, Hitachi). The antioxidant activity was measured by calculating the percentage of DPPH radical scavenging ability using an equation as mentioned below: A c and A s represent the absorbance of the control (a mixture having 0.009 ml distilled water instead of sample supernatant) and sample, respectively, after 30 min of incubation.
Malondialdehyde is a method to estimate the lipid oxidation progress, which was performed as presented by Martínez-Solano et al. (2005) using the thiobarbituric acid reactive substrates (TBARS). The absorbance was measured using a spectrophotometer (U-2900, Hitachi) with a wavelength of 532 nm. The outcomes were exhibited as nmol/kg/s.

| Microbiological analysis
The total viable count (TVC) of both the control sample and coated pear was estimated using a normal saline solution (NSS) and nutrient agar media by following the procedure of Sharma and Rao (2015). The NSS was prepared using an 8.5 g/L of sodium chloride (NaCl) and diluted in the melted sample and autoclaved at 121°C for 15 min. The nutrient agar media were made using 100 ml of distilled water dissolved in 2.8 g of agar, leading to autoclaved at 121°C for 15 min. The six test tubes were labeled (i.e., 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , and 10 -6 ) and the 9 ml of NSS has been poured into each test tubes. The 1 ml sample was poured into the first test tube (10 -1 ), and then the 1 ml sample was poured into the second test tube. A total of six dilutions were made in the same way. The nutrient agar media were poured into the Petri dish to solidify. Then, 1 ml sample from each dilution with a sterilized pipette was plated on Petri plates using a steak plate method. An inoculate was spread over an agar plate by using a sterilized glass spreader and was incubated at 37°C for 24 h. The colonies were counted using a colony counter in the Petri dishes; the average number of colony sizes was ranging from 30 to 300. TVC was calculated after the multiplication of the obtained count with reciprocal of selected dilution and expressed as colony forming units (log cfu/g).

| Data analysis
The research was performed out in 2020 and 2021 and arranged with a completely randomized design (factorial) using three replicates. Results were joined for the homogeneity of variance of 2 years of studies. Outcomes were evaluated by two-way analysis of variance (ANOVA) and averages were differentiated through the least significant test. The variable findings among treatments were considered statistically significant at p ≤ .05 level of significance with a statistical software SAS (version 9.3 for Windows). Study outcomes were shown as mean ± standard error.

| Compositional analysis of fresh pear
The moisture, crude protein, crude fat, crude fiber, ash, total sugar, and mineral contents were found to be 80.41 ± 1.45% 5.4 ± 0.65%, 1.02 ± 0.13%, 4.9 ± 0.67%, 0.77 ± 0.10%, 6.3 ± 0.59, and 1.2 ± 0.23%, respectively ( Table 2). The results were in agreement with the findings of Palma et al. (2015). The minor difference in the results could be due to the different growth conditions, harvesting practices, and postharvest conditions, or variations in climate, maturity, and soil conditions.

| Physicochemical analysis of LPEO
Lemon peel essential oil is a rich source of bioactive compounds such as tannins, phenolic acids, anthocyanins, and flavonoids. Thus, it has excellent antioxidant capacity and nutritional value that can improve the quality of final products. However, the physicochemical analysis of LPEO has been designed before application with ESCMs.
Therefore, it is essential to evaluate the FFAs, refractive index, peroxide value, p-anisidine value, saponification value, and the specific gravity of LPEO (Table 3). The FFAs were formed by the breakdown of triglycerides through hydrolysis (Shewfelt & Del Rosario, 2000).
The FFAs were exclusively prone to oxidation, which resulted in off-flavor of essential oil during storage.  (Ferhat et al., 2006). The specific gravity of LPEO was found to be 0.82 ± 0.023. The specific gravity of LPEO was found to be 0.82 ± 0.023. The findings of specific gravity (0.84) were very close, as presented by Ahmad et al. (2006). The peroxide index is the most common parameter used to predict lipid peroxidation (Kamal et al., 2011). The LPEO was exhibited in the range 5.56 ± 0.57 mEqO 2 /kg, which was similar to the results of Olabanji et al. (2016) who observed the peroxide value of LPEO of about 5.25 mEqO 2 /kg.

| Physicochemical analysis of ESCMs
The TA and pH of ESCMs solution were found in the range 0.22 ± 0.004% (malic acid) and 3.6, respectively (

| pH and Titratable acidity
Evidence-based results have shown that the average pH of coated pear was increased from 3.50 to 4.58 at 0 to 45 days of storage interval, respectively. However, the pH value has to be controlled using a different treatment of LPEO-ESCMs. It was noted that 3% of LPEO prominently reduced the pH of pear fruit as expressed in Figure 1d. Wang et al. (2007)

| Weight loss
Weight loss in fresh fruits and vegetables is a critical attribute regarding economic losses. The weight loss in pear fruits is due to variation in metabolic activities, such as respiration rate, the activity of fruit softening enzymes, and transpiration of water during the entire storage time (Cheng et al., 2009). As mentioned above, the study agreed with Singh et al. (2009) and Zheng et al. (2017) for plum and kiwi fruits, respectively. In our study, a substantial increase in weight loss was noticed in pear fruits with the increase in the cold storage duration from 0 to 45 days regardless of the given treatments as shown in Figure 1b. However, the LPEO-ESCMs reduced the weight loss compared with untreated pear fruits during the whole storage. The lowest weight loss (3.28%) was noted in the coated pear with 3% of LPEO-ESCMs, whereas the highest weight loss (7.06%) was observed in the untreated pear. This study's results were similar to the findings of Medeiros et al. (2012) that reduced the weight loss in pear fruits by the application of calcium-based coating material. A correlation study found that the relationship between mass loss and fruit firmness was the opposite (Adhikary et al., 2021). Additionally, edible coatings are believed to reduce weight loss owing to their semipermeable membrane barrier properties (Gol et al., 2013;Valero et al., 2013), as proved in a variety of fruits, such as sweet cherry, pepper, litchi, peach, and apricot (Ayranci & Tunc, 2003). Furthermore, discrepancies in the ability to inhibit weight loss have been linked to the varying water vapor permeability of the polysaccharides employed to formulate the edible coating (Vargas et al., 2008). As per certain experts (Serrano et al., 2008), adding glycerol into the coating as a plasticizer improved the weight retention of particular fruits. This could be because fresh-cut fruit is considerably more prone to water loss than whole fruit, and the polysaccharides seem to be more permeable to water-than lipid-based coatings.

| Pear firmness
The level of fruit maturity and rate of ripening process can be easily determined by assessing fruit's firmness. Firmness is directly connected to fruit texture, consumer acceptance in esteem to crispiness, and storability of fruit. Findings have revealed that the LPEO-ESCMs noticeably affected the firmness of pear fruits at each storage interval. The firmness of pear fruits was reduced from 71.12% to 64.62% regardless of LPEO-ESCMs treatments during the whole storage time (Figure 1c). However, the pear softening rate was much lower in LPEO-ESCMs compared to the untreated pear. The variation in pear firmness to variable LPEO treatments was practically significant and high in 45-day storage ahead in contrast to 30 days, where 1%, 1.5%, 2%, 2.5%, and 3% LPEO exhibited similar results. The outcomes were comparable as per the discussion of Dave et al. (2017). Finally, we can conclude that fruit firmness had an inverse relationship with storability. It is also established that the fruit firmness could be triggered due to the activity of fruit-softening enzymes. Therefore, the fruit firmness can be maintained by reducing the activity of polygalacturonase, cellulose, hemicellulose, and pectin methylesterase (Kaur et al., 2019). Contrarily, the softening of fresh-cut apples was noted after application of edible coatings with essential oils, and caused the acid hydrolysis of pectic acid in fresh-cut apple cell wall due to the low pH of film-forming solutions of edible coatings containing essential oils (Raybaudi-Massilia et al., 2008). Additionally, it has been claimed that such textural degradation may be produced by the essential oils penetrating the fruit's cell tissue causing structural alterations (Salvia-Trujillo et al., 2015).  T0  T1  T2  T3  T4  T5 (a) (c)

| Total soluble solid contents
The Total soluble solid contents (TSSC) is the best eating quality of pear fruits and consumer acceptability during storage. The TSSC has been increased in fruits using carbohydrate synthesis, which accelerated the ripening of fruits (Nath et al., 2012). In this study, the TSSC contents augmented throughout the storage irrespective of treatments with the rapid rate in untreated pear fruits compared with LPEO-ESCMs pear as expressed in Figure 2b.

| Antioxidant capacity
The free radicals' theory of aging is very common in the scientific literature, which has been produced due to oxidative stress. Secondly, the degradation of polyphenols in pear fruits may had occurred due to the direct oxidation by polyphenols oxidases along with different oxidation. The findings of the current research explained the effect of LPEO, which has been a rich source of bioactive compounds.

| MDA level
The off-flavor or rancid flavor is a prevalent challenge in the postharvest produces during storage. Recently, Lindo-García et al. (2019) have proven that the softening and ripening of 'Blanquilla' pear fruits are linked to oxidative stress, leading to higher MDA levels and increasing the climacteric rate. Moreover, they were also illustrated that the ethylene production in off-tree ripened 'Conference' pear due to the softening and increase in lipid peroxidation (MDA level

| Microbiological analysis
Fresh and cold storage fruits and vegetables are prone to microbial contamination. The detection of spoilage in fresh fruits and vegetables might be possible when the microbial level reached above 7 logs CFU/g (Sharma & Rao, 2015). The microbial load of treated pear fruits was increased irrespective of varying treatments from 2.01 to 7.49 log CFU/g at 0 to 45 days of storage ( Figure 2c). However, the microbial count of uncoated pear fruits was higher than coated pear fruits. Moreover, the TVC was observed as 7.14 log CFU/g and 3.22 log CFU/g for untreated pear fruit (0% LPEO-ESCMs) and treated pear fruit with 3% LPEO-ESCMs, respectively. The findings depicted that the rate of bacterial growth in coated pear fruits was minimum than uncoated pear fruits.
The research indicates that the primary goal of incorporating essential oils and/or their components into edible coatings is to serve as antioxidant and antibacterial regulators. As per Azarakhsh et al. (2014), an alginate-based coating optimized formulation with lemongrass oil drastically decreased total microbes, yeast, and mold counts in coated fresh-cut pineapple samples when compared to the control group, and the same effect was observed for 'Fuji' apples infused with carnaubashellac wax comprising of lemongrass oil (Jo et al., 2014). According to Raybaudi-Massilia et al. (2008), an alginate coating alone did not significantly lower psychrophilic aerobic bacteria, yeast, or mold counts on fresh-cut 'Fuji' apples. It can be concluded that the LPEO has an antibacterial effect and is a potential candidate to reduce the microbial load of fruits throughout the storage period.

| Sensory evaluation
It was quite interesting that the effect of LPEO-ESCMs regarding sensorial characteristics was noticeable in climacteric fruit rather than in non-climacteric ones (Adhikary et al., 2021). The inclusive sensory attributes are imperative for the measurement of fruits' storability. The overall sensory quality of pear was decreased during each storage interval irrespective of all treatments as shown in Figure 3. However, the color, taste, texture, flavor, and overall acceptability scores were improved using 3% LPEO-ESCMs, which followed close linearity with the treated pear with 1%, 1.5%, 2%, and 2.5% LPEO of up to 45 days of storage at refrigerated temperature. The control pear revealed the maximum overall acceptability on the first day of storage which decreased steadily. On the contrary, the inclusion of lemon grass for up to 0.3% (w/v) in alginatebased coating did not impact on the sensory attribute of treated fresh-cut pineapples (Azarakhsh et al., 2014). However, the incorporation of 0.5% (w/v) lemongrass markedly improved the sensory properties of coated fruits. In another study, the sensory characteristics have also improved by chitosan-based coatings enriched with essential oil (Perdones et al., 2012). This meant the addition of essential oil can modify the sensory profile of fresh-cut fruits during storage, but the concentration of essential oil is important to induce the overall differences in the sensory attributes, and 3% LPEO concentration changed the general sensory quality attributes. ripening-related changes, including soluble solids content, antioxidant activity, firmness score, and TA level. Besides, it also reduced weight loss, microbial load, and respiration rate of treated pear fruits than untreated pear. Therefore, based on these results, it was concluded that the LPEO-ESCMs utilization is a great leap forward to alleviate storability and retain the quality of pear fruits. However, the best combination of coatings was incorporated with the high concentration of essential oil (3%), which is not adequate for the larger scale, considering that the costs of essential oils are expensive. Keeping in view, the research gaps were identified on a correlation analysis of pear fruits' enzymes activity and pear fruits' firmness and mass loss. Furthermore, more information is required on a biotechnological intervention about the gene expression by the application of LPEO-ESCMs.

ACK N OWLED G M ENTS
We are grateful to all the postgraduate students and faculty members who contributed to the sensory evaluation of the samples.

CO N FLI C T O F I NTE R E S T
The authors declare no conflict of interests.

CO M PE TI N G I NTER E S T
The authors confirm that they have no known competing financial interests or personal relationships that could have appeared to influence the manuscript.

CO N S E NT TO PA RTI CI PATE
All authors extend consent to participate as coauthors.

DATA AVA I L A B I L I T Y S TAT E M E N T
The dataset supporting the conclusions of this article is included within the article.