Effect of chitosan-based edible coating on antioxidants, antioxidant enzyme system, and postharvest fruit quality of strawberries (Fragaria x aranassa Duch.)

Konjac glucomannan/microcapsule of thymol edible coating reduces okra pericarp browning by regulating antioxidant activity and ROS synthesis

Okra is susceptible to browning during storage. The effects of konjac glucomannan/microcapsule of thymol edible coating (TKL) on antioxidant activity and reactive oxygen (ROS) synthesis of okra during low-temperature storage were investigated. Thymol edible coating of thymol concentration 40 mg/mL (TKL40) had a regulatory effect on okra browning. After 14 days of storage, compared with the control group, the weight loss rate of TKL was reduced by 5.26 %, the hardness was increased by 24.14 %, and the L⁎ value was increased by 31 %. Moreover, TKL40 increased the scavenging capacity of okra for DPPH and ABTS free radicals, and activated catalase and superoxide dismutase activities by promoting the accumulation of total phenolics and flavonoids. TKL40 also reduced the cell membrane damage of okra during low-temperature storage by reducing the increase of malondialdehyde and H2O2 during okra storage. Meanwhile, it delayed the increase of relative conductivity and the production of O2.-, inhibited the activity of polyphenol oxidase in the late stage, so reduced the combination of polyphenol oxidase and phenolics to reduce the browning. Therefore, TKL40 reduces okra pericarp browning by regulating antioxidant activity and ROS synthesis.

Proline inhibits postharvest physiological deterioration of cassava by improving antioxidant capacity

Cassava (Manihot esculenta Crantz), a crucial global tuber crop, encounters significant economic losses attributed to postharvest physiological deterioration (PPD). The PPD phenomenon in cassava is closely related to the accumulation of reactive oxygen species (ROS), and amino acids play a pivotal role in regulating signaling pathways and eliminating ROS. In this study, the storage performance of eight cassava varieties were conducted. Cassava cultivar SC5 showed the best storage performance among the eight cassava varieties, but the edible cassava cultivar SC9 performed much worse. Comparative analysis of free amino acids was conducted in eight cassava varieties, revealing changes in proline, aspartic acid, histidine, glutamic acid, threonine, and serine. Exogenous supplementation of these six amino acids was performed to inhibit PPD of SC9. Proline was confirmed as the key amino acid for inhibiting PPD. Treatment with optimal exogenous proline of 5 g/L resulted in a 17.9% decrease in the deterioration rate compared to untreated cassava. Accompanied by a decrease in H2O2 content and an increase in catalase, superoxide dismutase and ascorbate peroxidase activity. Proline treatment proved to be an effective approach to alleviate cell oxidative damage, inhibit PPD in cassava, and prolong shelf life.

Emulsion-based edible chitosan film containing propolis extract to extend the shelf life of strawberries

In this study, propolis was first loaded into a conventional oil-in-water emulsion, which was combined with a chitosan film-forming solution to produce propolis emulsion-loaded film (PEF). Strawberries inoculated with Botrytis cinerea coated with PEF and blank emulsion-loaded films (BEF) were stored for 14 days at 4 °C. Compared to BEF, PEF showed superior mechanical and oxygen barrier properties, as well as antioxidant activities, but higher moisture permeability. PEF showed less oil agglomeration on the film surface after drying, as demonstrated by scanning electron microscopy (SEM) analysis. Compared to uncoated strawberries, coatings did not have a significant effect on weight loss or firmness during storage. In contrast, coated strawberries showed elevated total phenolics, anthocyanins, and ascorbic acid retention; however, PEF-coating yielded higher values. Moreover, the PEF coating resulted in a significantly lower reduction of organic acid and total soluble solids. Mold growth was visible in both uncoated and BEF-coated strawberries after 7 days of storage, while PEF-coated fruits showed no visible mold until the end of storage. Starting from day 4, PEF-coated fruits showed lower mold counts (~2 log CFU/g) than other samples. Therefore, the PEF prepared in this study has application potential for the preservation of fresh fruits.

Gum tragacanth, a novel edible coating, maintains biochemical quality, antioxidant capacity, and storage life in bell pepper fruits

Bell pepper fruits (Capsicum annuum L.) are prone to both physiological and pathological deterioration following harvest, primarily due to their high metabolic activity and water content. The storage of bell peppers presents several challenges, including weight loss, softening, alterations in fruit metabolites and color, increased decay, and a decline in marketability. The application of edible coatings (ECs) is one of the environmentally friendly technologies that improves many post-harvest quantitative and qualitative characteristics of products. This research investigated the impact of different levels of gum tragacanth (GT) coating (0, 0.25, 0.5, 1, and 2%) on the physiological and biochemical traits of stored bell pepper fruits (BPFs) (8 ± 1°C, 90-95% RH) for 28 days. The results showed the positive effect of coating treatments with higher concentrations of GT, up to 1%. Increasing the concentration of GT to 2% decreased the marketability and quality characteristics of fruits compared to 1% GT. After storage, the physiological weight loss of the fruits treated with 1% GT (10.46%) was lower than that of the uncoated fruits (18.92%). Furthermore, the coated fruits (1% GT) had more firmness, total phenol content, ascorbic acid, and titratable acidity content than uncoated fruits during storage. At the end of storage, the coated BPFs with 1% GT showed higher SOD (97.02 U g-1), CAT (24.38 U g-1) and POD (0.11 U g-1) activities and antioxidant capacity (81.74%) as compared to other treatments. Total soluble solids, total carbohydrates, total carotenoids, pH, malondialdehyde, and electrolyte leakage content increased in coated fruit during storage but were significantly lower than in uncoated fruits. Moreover, the samples coated with GT (1%) maintained good marketability (about 75%), while the marketability of the control (about 40%) was unacceptable. The study shows that GT (1%) coating can be a promising novel treatment option for increasing the storage quality of BPFs.

Enhancing Postharvest Quality and Shelf Life of Strawberries through Advanced Coating Technologies: A Comprehensive Investigation of Chitosan and Glycine Betaine Nanoparticle Treatments

The application of natural polymer-based coatings presents a viable approach to prolong the longevity of fruits and tissue damage. This study investigates the impact of treatments involving glycine betaine (GB), chitosan (CTS), and chitosan-coated glycine betaine nanoparticles (CTS-GB NPs) on preserving the quality and reducing decay in strawberry fruits. The fruits were subjected to treatments with GB (1 mM), CTS (0.1%), CTS-GB NPs (0.1%), or distilled water at 20 °C for 5 min, followed by storage at 4 °C for 12 days. The results indicate that CTS and CTS-GB NPs treatments resulted in the highest tissue firmness, total anthocyanin content, and ascorbate peroxidase activity, while exhibiting the lowest decay percentage and weight loss, as well as reduced malondialdehyde levels at the end of storage. GB, CTS, and CTS-GB NPs treatments demonstrated elevated catalase activity and antioxidant capacity, coupled with lower electrolyte leakage and hydrogen peroxide levels. These treatments did not significantly differ from each other but were markedly different from the control. The results substantiate that CTS and CTS-GB NPs treatments effectively preserve strawberry quality and extend storage life by bolstering antioxidant capacity and mitigating free radical damage.

Worldwide productivity and research trend on fruit quality: a bibliometric study

Introduction

As one of the important sources of food for human beings, fruits have been extensively studied. To better guide basic and applied research, it is urgent to conduct a systematic analysis of these studies based on extensive literature collection.

Methods

Based on the Web of Science Core Collection database, this study uses R language and CiteSpace to conduct bibliometric analysis and data mining on the literatures related to fruit quality from January 2013 to June 2023.

Results

The results indicated that among various fruits, tomatoes have been most frequently studied with special interests in photosynthesis, fruit development, and molecular breeding. The research direction primarily focused on fruit resistance and storage characteristics. Among the indicators related to fruit quality, antioxidant activity has the highest co-occurrence with other indicators of fruit quality, especially with nutrients such as anthocyanins, phenolic substances, sugars, and fruit firmness.

Discussion

Currently, adaptation to stress and antioxidant activity are recognized as prominent research focal points in this field. Fruit morphology, particularly fruit size, irrigation methods, application of molecular technology, and infection prevention, represent potential areas of interests in future research on fruit quality.

Effects of preharvest chitosan-Myrtus communis essential oil composite and postharvest nanocellulose on quality of strawberry

The objective of this study was to investigate the effects of preharvest chitosan-Myrtus communis essential oil composite (1.5 and 3.0 %) and postharvest nanocellulose (0.3 and 0.6 %) on the quality of strawberries. The gas chromatography-mass spectrometry (GC/MS) analysis led to identification of 32 compounds in the Myrtus communis essential oil. The study showed that using CHS-ES composite coating for foliar application could increase the lifespan of the fruit by up to 24 days. This is because it increases the levels of components, such as phenol content (TPC) total flavonoids content (TFC) vitamin C, firmness and SSC. It also enhances the effectiveness of enzymes such, as glutathione peroxidase (GSH POD) and polyphenol oxidase (PPO). The use of CHS-ES treatments reduced the weight loss of fruits between 50 and 80 %, which is very important from the commercial point of view and maintaining nutritional properties, marketability and appearance. The microscopic analysis further revealed that using CHS-ES composite + nanocellulose coating produced a more continuous and uniform surface than the control. In general, this method is both safe and environmentally friendly while also proving to be effective, in preserving and enhancing the quality of strawberries.

Hermetia illucens, an innovative and sustainable source of chitosan-based coating for postharvest preservation of strawberries

The ability of chitosan produced from pupal exuviae of Hermetia illucens to retard the decay of the local strawberry (Fragaria x ananassa) cultivar Melissa was investigated for the first time in this paper. The results demonstrated the effectiveness of insect chitosan compared to the commercial polymer in preserving and enhancing, at the same time, some physicochemical parameters (weight loss, pH and soluble solids content) and nutraceutical properties (total polyphenol content, total flavonoid content and total antioxidant activity) of strawberries stored at RT, 4°C and at mixed storage conditions (4°C + RT). Moreover, chitosan from H. illucens was also effective in reducing fungal decay and improving fruit shelf life. The obtained results confirm that insect chitosan, particularly deriving from H. illucens pupal exuviae, can be a viable alternative to crustacean one in safeguarding postharvest fruits.

Recent advances in the preservation of postharvest fruits using edible films and coatings: A comprehensive review

In recent years, there has been considerable growth in the creation of edible films and coatings, which is predicted to have a major impact on fruit quality in the coming years. Consumers want fresh fruits that are pesticide-free, good quality, high nutritional value, and a long shelf life. The use of edible coatings and films on fruits is an environmentally dependable approach to a creative solution to this problem. The application, recent trends, and views of coatings and edible films, as well as their impact on fruit quality, are presented in this article, along with a knowledge of their key roles and benefits. According to numerous studies, natural polymers are highly suited for use as packaging material for fresh fruits and can often be a viable alternative to synthetic chemicals. Plasticisers, surfactants, cross-linkers, antimicrobial agents, functional additives, nanoparticles, and fruit and vegetable residues can be used to alter the properties of edible coatings.

Understanding the effects of chitosan, chia mucilage, levan based composite coatings on the shelf life of sweet cherry

Sweet cherry (Prunus avium L.) fruits are prone to quality and quantity loss in shelf-life conditions and cold storage due to their short post-harvest life. Until now efforts have been made to extend the shelf life of the sweet cherry. However, an efficient and commercially scalable process remains elusive. To contribute to this challenge, here in this study, biobased composite coatings consisting of chitosan, mucilage, and levan, were applied on sweet cherry fruits and tested for postharvest parameters in both market and cold storage conditions. Results demonstrated that the shelf life of sweet cherries can be extended until the 30^th day while retaining important post-harvest properties like decreased weight loss, fungal deterioration, increased stem removal force, total flavonoid, l-ascorbic acid, and oxalic acid. Given the cost-effectiveness of the polymers used, the findings of this study indicate the feasibility of extending the shelf-life of sweet cherries on a larger scale.

Physicochemical characteristics, antioxidant potential, and shelf stability of developed roselle-fig fruit bar

Fruit bars are prepared by combining different ingredients which are wholesome and nutrient rich. The current study was designed to develop roselle-fig (different proportions) fruit bars and further investigate their physicochemical characteristics and antioxidant potential. Moreover, the prepared fruit bars were scrutinized for microbial and sensory characteristics to assess the appropriateness of ingredients during storage (up to 90 days). It was observed that there was gradual increase in moisture content with the passage of time, while ash, fat, fiber, and protein contents did not change significantly during storage. The pH and total soluble solid contents of these fruit bars during storage were 3.54-4.07 and 1.71-1.86 Brix, respectively. According to the mean values for sensory evaluation, T ₂ was preferred over other treatments. The bars received an acceptable sensory evaluation, demonstrating that they were suitable for 90 days of storage. Phytochemical quantities significantly increased in subsequent treatments, but decreased during storage in all the treatments. Similar trend was observed regarding total antioxidant and DPPH radical scavenging activities. The mineral contents increased significantly among the treatments. The microbial analysis of fruit bars exposed that the fruit were microbiologically safe. Hence, on the basis of the results obtained in this study, it may be concluded that the developed roselle-fig fruit bar would be acceptable and nutritious regarding physicochemical characteristics, microbiological quality, and antioxidant potential.

Chitosan and chitooligosaccharide regulated reactive oxygen species homeostasis at wounds of pear fruit during healing

Both chitosan (CTS) and chitooligosaccharide (COS) can promote fruit healing. However, whether the two chemicals regulate reactive oxygen species (ROS) homeostasis during wound healing of pear fruit remains unknown. In this study, the wounded pear fruit (Pyrus bretschneideri cv. Dongguo) was treated with a 1 g L^-1 CTS and COS. We found CTS and COS treatments increased NADPH oxidase and superoxide dismutase activities, and promoted O₂^.- and H₂O₂ production at wounds. CTS and COS also enhanced the activities of catalase, peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, and elevated the levels of ascorbic acid and glutathione. In addition, the two chemicals improved antioxidant capacity in vitro and maintained cell membrane integrity at fruit wounds during healing. Taken together, CTS and COS can regulate ROS homeostasis at wounds of pear fruit during healing by scavenging excessive H₂O₂ and improving antioxidant capacity. Overall, the COS demonstrated superior performance over the CTS.

The combined application of Arabic gum coating and γ-aminobutyric acid mitigates chilling injury and maintains eating quality of 'Kinnow' mandarin fruits

Low temperature storage of citrus generally extends the storage potential but leads to chilling injury appearance on the rind of fruits. The said physiological disorder has been found associated with changes in the metabolism of cell walls and other attributes. In this work, the influence of Arabic gum [AG (10 %)] and γ-amminobutyric acid [GABA (10 mmol L^-1)] either alone or in combined form was studied on fruits of 'Kinnow' mandarin during storage at 5 ± 1 °C for 60 days. The results exhibited that the combined AG + GABA treatment significantly suppressed weight loss (5.13 %), chilling injury (CI) symptoms (2.41 score), incidence of disease (13.33 %), respiration rate [(4.81 μmol kg^-1 h^-1) RPR] and ethylene production [(0.86 nmol kg^-1 h^-1) EPR]. In addition, AG + GABA application reduced relative electrolyte (37.89 %) leakage (REL), malondialdehyde [(25.99 nmol kg^-1) MDA], superoxide anion [(15.23 nmol min^-1 kg^-1) O₂^•-] and hydrogen peroxide [(27.08 nmol kg^-1) H₂O₂] along with lower lipoxygenase [(23.81 U mg^-1 protein) LOX] and phospholipase D [(14.07 U mg^-1 protein) PLD] enzyme activities compared with control. The AG + GABA treated 'Kinnow' group showed higher glutamate decarboxylase [(43.18 U mg^-1 protein) GAD] and lower GABA transaminase [(15.93 U mg^-1 protein) GABA-T] activity having higher endogenous GABA (42.02 mg kg^-1) content. The fruits treated with AG + GABA exhibited higher cell walls (CW) components such as Na₂CO₃-soluble pectin [(6.55 g kg^-1) NCSP], chelate-soluble pectin [(7.13 g kg^-1) CSP] and protopectin [(11.03 g kg^-1) PRP] concentrations along with lower water-soluble pectin [(10.64 g kg^-1) WSP] compared to control. In addition, 'Kinnow' fruits treated with AG + GABA showed higher firmness (8.63 N) and lower activities of CW degrading such as cellulase [(11.23 U mg^-1 protein) CX], polygalacturonase [(22.59 U mg^-1 protein) PG], pectin methylesterase [(15.61 U mg^-1 protein) PME] and β-galactosidase [(20.64 U mg^-1 protein) β-Gal] enzymes. The activity of catalase [(41.56 U mg^-1 protein) CAT], ascorbate peroxidase [(55.57 U mg^-1 protein) APX], superoxide dismutase [(52.93 U mg^-1 protein) SOD] and peroxidase [(31.02 U mg^-1 protein) POD] was also higher in combined treatment. In addition, AG + GABA treated fruits showed better biochemical and sensory attributes than the control. So, combined AG + GABA could be used for CI mitigation and storage life prolongation of 'Kinnow' fruits.

Application of Whey Protein-Based Emulsion Coating Treatment in Fresh-Cut Apple Preservation

Fresh-cut fruit requires an edible and water-resistant coating to remain fresh. This article investigated the effects of transglutaminase (TGase) and sunflower oil on the water-resistant characteristics, mechanical properties, and microstructure of a whey protein-based film. The whey protein-based emulsion coating’s preservation effect on fresh-cut apples was confirmed. According to the findings, sunflower oil (added at 1.5% w/w) could interact with β-lactoglobulin, α-lactoglobulin dimer, and β-lactoglobulin dimer to form emulsion droplets that are evenly dispersed throughout the protein film. This effect, combined with the covalent cross-linking of TGase, significantly improves the films’ microstructure, mechanical properties, and water resistance. However, too much and unevenly distributed sunflower oil (add 3% w/w) partially prevented the covalent cross-linking of TGase, reducing the elongation at the break of the composite film. In the fresh-cut apple storage experiment, the whey protein-based emulsion coating treatment significantly reduced the weight loss rate and browning index of fresh-cut apples by 26.55% and 46.39%, respectively. This was accomplished by the coating treatment significantly inhibiting the respiration rate increase, PPO and CAT activity enhancement, H2O2 production, and MDA accumulation. This research provides practical, technical, and theoretical guidance for the preservation of fresh-cut fruit.

Effect of Edible Coating Enriched with Natural Antioxidant Extract and Bergamot Essential Oil on the Shelf Life of Strawberries

In this study, the effects of the application of edible coatings on the shelf life of the strawberry were evaluated, with the aim of extending the fruit's availability and shelf life while preserving its qualitative characteristics. In particular, the application of edible coatings enriched with a natural antioxidant to strawberries was evaluated for their physicochemical, microbial, and structural properties, during a storage period (up to 14 days) at refrigerated temperature. The experimental plan provided the formulation for edible coatings enriched with different concentrations of a natural antioxidant extract obtained from bergamot (Citrus bergamia Risso) pomace (1, 2.5, and 5%), bergamot essential oil (0.1% v/v and 0.2% v/v), and a synthetic antioxidant, butylated hydroxytoluene (BHT, 100 ppm). Moreover, a control test with untreated strawberries was considered. The enriched gum Arabic coatings provided good results related to the preservation of the qualitative parameters of the strawberries. The samples coated with the antioxidant extract (2.5%, sample D) and bergamot essential oil (0.1%, sample F) showed the best maintenance of the qualitative parameters after 14 days, showing lower decay rates (36% D and 27% F), good acceptability by consumers (between 5 and 6), and good retention of ascorbic acid (>30 mg 100 g^-1).

Preharvest Application of Commercial Products Based on Chitosan, Phosphoric Acid Plus Micronutrients, and Orange Essential Oil on Postharvest Quality and Gray Mold Infections of Strawberry

Strawberry is a perishable fruit with a limited shelf life after harvest due to deterioration of quality and the development of gray mold, Rhizopus rot and other minor diseases. In this study, the effectiveness of commercial compounds based on chitosan, phosphoric acid plus micronutrients, and sweet orange essential oil (EO) in reducing decay and optimizing the quality of strawberries was analyzed. The plant canopy of a greenhouse crop was sprayed once and strawberry fruit were harvested three days later. Gray mold infections were evaluated after chilled storage for seven days at 4 ± 0.5 °C followed by five days shelf life. The qualitative parameters were recorded at harvest (initial day) and after three days of storage at room temperature (RT, 20 °C) or after cold storage and shelf life (CS, 4 °C). The application of sweet orange EO increased the antioxidant and flavonoid content at harvest, while a decrease was reported following three days of storage at RT. At the same time, increased ethylene production and weight loss were observed during CS three days after harvesting. Chitosan treatment maintained the harvest fruit quality and was effective in the control of postharvest decay. Our results suggest that the investigated natural compounds could improve strawberry quality after harvest. Since chitosan performed best in terms of maintaining quality and reducing postharvest decay, it could be considered as a good substitute for chemical-synthetic fungicides for the preservation of strawberry postharvest gray mold.

The Effect of Chitosan on Plant Physiology, Wound Response, and Fruit Quality of Tomato

In agriculture, chitosan has become popular as a metabolic enhancer; however, no deep information has been obtained yet regarding its mechanisms on vegetative tissues. This work was conducted to test the impact of chitosan applied at different plant growth stages on plant development, physiology, and response to wounding as well as fruit shape and composition. Five concentrations of chitosan were tested on tomato. The most effective chitosan doses that increased leaf number, leaf area, plant biomass, and stomatal conductance were 0.75 and 1 mg mL^-1. Chitosan (1 mg mL^-1) applied as foliar spray increased the levels of jasmonoyl-isoleucine and abscisic acid in wounded roots. The application of this dose at vegetative and flowering stages increased chlorophyll fluorescence (Fv/Fm) values, whereas application at the fruit maturation stage reduced the Fv/Fm values. This decline was positively correlated with fruit shape and negatively correlated with the pH and the content of soluble sugars, lycopene, total flavonoids, and nitrogen in fruits. Moreover, the levels of primary metabolites derived from glycolysis, such as inositol phosphate, lactic acid, and ascorbic acid, increased in response to treatment of plants with 1 mg mL^-1- chitosan. Thus, chitosan application affects various plant processes by influencing stomata aperture, cell division and expansion, fruit maturation, mineral assimilation, and defense responses.

Quality characteristics of strawberry fruit following a combined treatment of laser sterilization and guava leaf-based chitosan nanoparticle coating

Background

Strawberry fruit is a rich source of antioxidants that are beneficial for human health. However, the rapid decline of strawberries dramatically reduces the shelf life and raises postharvest losses. To develop an efficient and ecological approach for maintaining the quality, strawberries (Fragaria x ananassa, cv. Festival) were treated with 0.5% chitosan coating (0.5% Ch), guava leaf-based chitosan nanoparticles coating (Gl-ChNps), and a combination treatment of 1.3 mW/cm2 laser light followed by Gl-ChNps coating (combined treatment), then stored for 12 days at 10 °C and 85–90% RH. The untreated fruit served as a control.

Results

Semi-spherical particles with an average size of 21.92 nm, a monodisperse nature, and high solution stability were formed. The findings revealed that the combined treatment completely suppressed fungal decay compared to 50% decay in control, and significantly reduced weight loss percentage to 4.68% compared to 27.35% in control. In accordance, the combined treatment had the maximum anthocyanin content and vitamin C, at 42 and 81.1 mg/100 g, respectively. The results showed that treated strawberries had less change in color, total soluble solids, titratable acidity, and pH during storage than untreated strawberries, which exhibited higher chemical changes.

Conclusions

The edible film of chitosan nanoparticles acted as a semi-permeable barrier that modified and restricted gas exchange, reduced water loss, and delayed fruit senescence. In addition, the combination of laser light with chitosan nanoparticles has been shown to control the pathogens and retain the freshness of strawberries.

Graphical Abstract

Potential of nanochitosan coating combined with walnut green husk to improve the preservation of rainbow trout (Oncorhynchus mykiss) during refrigerated storage

The present study evaluated the potential of nanochitosan coating enriched with ethanol-water extract of the walnut green husk (WGHE) on spoilage and rancidity of rainbow trout (Oncorhynchus mykiss) during six-day refrigerated storage. Hence, we have considered fresh trout fillets without any treatment as control (C), immersed in 2% solution of chitosan nanoparticles (CN), combination with 1.5% and 3% WGHE with nanochitosan coating (CN + WGHE 1.5 and CN + WGHE3), for physicochemical, microbial and sensorial assays. The highest levels and total volatile nitrogen were observed after day 6 in C, while the lowest was found in CN + WGHE3 groups. Thiobarbituric acid reactive substance (TBARS) and peroxide value of untreated fillets on day 6 of the study were significantly higher than NC + WGHE3 with 0.08 mg/g and 3.27 mEq/kg, respectively. The total microbial population was: C ˃ CN ˃ CN + WGHE 1.5 > CN + WGHE3, which expresses the effect of the extract on the total microbial population. Overall, the combination of WGHE with CN increased the extract's efficiency in reducing peroxide value, TBARS, and total volatile nitrogen and delayed the pH increase, improving the overall acceptability of rainbow trout fillets stored in refrigerated conditions.

Post-harvest chitosan treatment suppresses oxidative stress by regulating reactive oxygen species metabolism in wounded apples

Mechanical wound on fruit triggers the formation of reactive oxygen species (ROS) that weaken cell walls, resulting in post-harvest losses. This mechanism can be controlled by using fruit preservatives to stimulate fruit antioxidant enzyme activities for the detoxification of ROS. Chitosan is a safe and environmentally friendly preservative that modulates ROS in whole fruits and plant cells, but the effects of chitosan on the ROS metabolism of mechanically wounded apples during storage are unknown. Our study focused on exploring the effects of post-harvest chitosan treatment on ROS production, cell membrane integrity, and enzymatic and non-enzymatic antioxidant systems at fruit wounds during storage. Apple fruits (cv. Fuji) were artificially wounded, treated with 2.5% (w/v) chitosan, and stored at room temperature (21-25°C, RH = 81-85%) for 7 days. Non-wounded apples were used as healthy controls. The results showed that chitosan treatment stimulated the activities of NADPH oxidase and superoxide dismutase and increased the formation of superoxide anions and hydrogen peroxide in fruit wounds. However, malondialdehyde, lipoxygenase, and membrane permeability, which are direct biomarkers to evaluate lipid peroxidation and membrane integrity, were significantly decreased in the wounded fruits after chitosan treatment compared to the wounded control fruits. Antioxidant enzymes, such as peroxidase and catalase activities, were induced by chitosan at fruit wounds. In addition, ascorbate-glutathione cycle-related enzymes; ascorbate peroxide, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase and the content of substrates, mainly ascorbic acid, dehydroascorbate, reduced glutathione, and glutathione, were increased at fruit wounds by chitosan compared to the wounded control fruits. Our results show that wounding stimulated the production of ROS or oxidative stress. However, treatment with chitosan triggered antioxidant systems to scavenge ROS and prevent loss of fruit membrane integrity. Therefore, chitosan promises to be a favorable preservative in inducing tolerance to stress and maintaining fruit quality.

Evaluating the Efficacy of Gum Arabic-Zinc Oxide Nanoparticles Composite Coating on Shelf-Life Extension of Mandarins (cv. Kinnow)

Restricted postharvest application of synthetic fungicides in maintaining the quality of citrus fruits has led to a search for alternative postharvest treatments. This study evaluated the efficacy of gum arabic (GA) enriched with green synthesized zinc oxide nanoparticles (ZnO-NPs) in maintaining the postharvest quality of mandarin (cv. Kinnow). ZnO-NPs were synthesized using Bidens pilosa leaf extract and incorporated into GA (2% w/v) at 0, 0.25, 0.5, and 1% to form composite coatings: GA, GA + ZnO-NP 0.25%, GA + ZnO-NP 0.5% and GA + ZnO-NP 1%, respectively. Fruit were dipped for 3 min in the respective coatings, with untreated fruit used as control. Fruit were air-dried, packed in commercial cartons, and stored at 5 ± 1°C and 90 ± 5% relative humidity (RH) for 40 days and observed at 10 days intervals, plus 5 days at 20 ± 5°C and 65 ± 5% RH to determine the incidence of physiological disorders. GA + ZnO-NP showed promise as an alternative postharvest treatment for controlling postharvest physiological disorders associated with 'Kinnow' mandarin. For instance, GA + ZnO-NP 0.5% markedly minimized weight loss (9.2%), electrolyte leakage (43.8%) and chilling injury incidence (5.4%) compared to control (weight loss; 33.3%, electrolyte leakage; 90.3% and chilling injury incidence; 41.5%) at the end of the storage. GA + ZnO-NP 1% significantly alleviated rind pitting, with 13.2% incidence compared to 45.2% rind pitting incidence in the control fruit. This was due to significantly higher phytochemical and antioxidant capacity and reduced antioxidant enzyme degradation in coated fruit than in control. In conclusion, gum arabic coating enriched with ZnO-NPs at concentrations between 0.5 and 1% is recommended as a viable option to maintain the quality of 'Kinnow' mandarin fruit during cold storage.

Protective, Biostimulating, and Eliciting Effects of Chitosan and Its Derivatives on Crop Plants

Chitosan is a biodegradable and biocompatible polysaccharide obtained by partial deacetylation of chitin. This polymer has been gaining increasing popularity due to its natural origin, favorable physicochemical properties, and multidirectional bioactivity. In agriculture, the greatest hopes are raised by the possibility of using chitosan as a biostimulant, a plant protection product, an elicitor, or an agent to increase the storage stability of plant raw materials. The most important properties of chitosan include induction of plant defense mechanisms and regulation of metabolic processes. Additionally, it has antifungal, antibacterial, antiviral, and antioxidant activity. The effectiveness of chitosan interactions is determined by its origin, deacetylation degree and acetylation pattern, molecular weight, type of chemical modifications, pH, concentration, and solubility. There is a need to conduct research on alternative sources of chitosan, extraction methods, optimization of physicochemical properties, and commercial implementation of scientific progress outcomes in this field. Moreover, studies are necessary to assess the bioactivity and toxicity of chitosan nanoparticles and chitosan conjugates with other substances and to evaluate the consequences of the large-scale use thereof. This review presents the unique properties of chitosan and its derivatives that have the greatest importance for plant production and yield quality as well as the benefits and limitations of their application.

Effects of Gum Arabic Coatings Enriched with Lemongrass Essential Oil and Pomegranate Peel Extract on Quality Maintenance of Pomegranate Whole Fruit and Arils

The effects of gum arabic coatings combined with lemongrass oil and/or pomegranate peel extract on freshly harvested mature 'Wonderful' pomegranate fruit were studied. Fruit were coated with gum arabic (GA) (1.5% w/v) alone or enriched with lemongrass oil (LM) (0.1% v/v) and/or pomegranate peel extract (PP) (1% w/v). Fruit were packed into standard open top ventilated cartons (dimensions: 0.40 m long, 0.30 m wide and 0.12 m high), and stored for 6 weeks at 5 ± 1 °C (90% RH). Evaluations were made every 2 weeks of cold storage and after 5 d of shelf life (20 °C and 65% RH). Fruit coated with GA + PP (4.09%) and GA + PP + LM (4.21%) coatings recorded the least cumulative weight loss compared to the uncoated control (9.87%). After 6 weeks, uncoated control and GA + PP + LM recorded the highest (24.55 mg CO2Kg-1h-1) and lowest (10.76 mg CO2Kg-1h-1) respiration rate, respectively. Coating treatments reduced the incidence of decay and treatments GA + LM + PP and GA + PP recorded the highest total flavonoid content between 2 and 6 weeks of storage. The findings suggest that GA coatings with/without LM and PP can be a beneficial postharvest treatment for 'Wonderful' pomegranates to reduce weight loss and decay development during cold storage.

Effects of polysaccharide-based coatings on postharvest storage life of grape: measuring the changes in nutritional, antioxidant and phenolic compounds

In this study, the effect of postharvest coating of chitosan (CH) 1.0%, gum ghatti (GG) 1.0% and combine of each other, on nutritional properties, phenolic compounds and antioxidant capacity of ‘Rishbaba’ grape (Vitis vinifera L.) was evaluated during 60 days of cold storage. Coating with 1.0% CH solely or in combined with 1.0% GG caused a considerable retain in grape berries phenolic acids compared to uncounted samples after the 60th day. Moreover, flavanols and flavan-3-ols content were found to be highest in fruits treated with CH and GG complex. At the end of storage, the highest concentrations of delphinidin, cyanidin, pelargonidin and malvidin were found in grapes coated with CH in combined with GG. The highest antioxidant capacity and the lowest polyphenol oxidase activity were related to samples treated with CH and GG complex. Also, the combination effects of CH and GG at 1.0% were the most efficient for soluble sugars and polyamines accumulation. The CH + GG complex had the best result on prohibiting grape fungal decay. The results showed a research increase of this complex that these are a strong potential strategy to produce coatings for improving the postharvest quality of fruits and could be considered as a good solution to preserve many components of them.

Quality Attributes of Chitosan-Coated Cornelian Cherry (Cornus mas L.) Fruits under Different Storage Temperatures

Temperature is the dominant environmental stimulus that influences the postharvest quality, visual appearance, and nutritional content of fruits. Temperature hastens fruit ripening and senescence by the impact on respiration rate and the acceleration of metabolic reactions. This study was conducted to select the optimized temperature for preserving the quality-related traits and antioxidant potential of cornelian cherry fruits after harvest. The fruits were treated with 1% chitosan and then kept under 0, 5, 10, and 21 °C for 21 days. The results revealed that fruits kept under lower than room temperature (21 °C) better retained antioxidant capacity and had higher levels of phenolics, flavonoids, and anthocyanins and even higher antioxidant enzyme activity, hence attaining prolonged postharvest life. Considering the quantity attributes and the shelf life, the temperature of choice was 0 °C. Zero temperature was also the best to keep the antioxidant capacity of cornelian cherry fruits. Overall, the results showed that low temperature and chitosan pretreatment provide an efficient method for maintaining the nutritional quality and antioxidant capacity of cornelian cherry fruits during storage time.

Use of metabolomics data analysis to identify fruit quality markers enhanced by the application of an aminopolysaccharide

Chitosan is a biostimulator that has a great effect either on plant physiology, productivity, or fruit quality. However, the metabolic mechanism regulated by chitosan still remains unknown. Untargeted metabolomics analysis, using LC-MS/MS mass spectrometry, was used to investigate fruit quality markers. Thus, this study was focused on the identification of untargeted metabolites of tomato fruits produced under the application of five doses of chitosan at different concentrations (0, 0.25, 0.50, 0.75, and 1 mg ml-1) that was extracted from Parapenaeus longirostris shrimp shells. The identification was carried out using two ion modes (ESI-/ESI+), a web application "Metfamily" to analyze signals, and reference libraries. The analysis of data using partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) showed that chitosan application, especially 0.75 mg ml-1, had a clear and remarkable effect regarding the number of metabolite families identified in both ion modes. This treatment has increased the relative abundance of many metabolites that belong to anthocyanins decorated with sugars, terpenoids, phenylpropanoids, acylsugars, glucosinolates, folates, galactolipids, fatty acids, and phospholipids. Thus, these results showed that chitosan application increased the quality of tomato fruits due to its involvement in the regulation of many metabolic pathways that might be responsible for enhancing the nutritional characteristics as well as the defense of fruits.

Chitosan-Phenylalanine Nanoparticles (Cs-Phe Nps) Extend the Postharvest Life of Persimmon (Diospyros kaki) Fruits under Chilling Stress

There are high levels of damage imposed on persimmon fruit postharvest, especially after storing it in cold storage, which causes chilling injury (CI). To reduce this stress on the fruit, the conventional way is to use chemical treatments. Since there is a limitation in the use of chemical materials, it is necessary to apply non-harmful treatments to decrease chilling injury and maintain the quality of persimmon in cold storage. The aim of this study is to investigate the effects of chitosan-loaded phenylalanine nanoparticles (Cs-Phe NPs) (2.5 and 5 mM) on physiochemical and quality factors of persimmon (Diospyros kaki) during 45 days of storage at 4 °C (38 °F) and evaluate the impact of Cs-Phe NPs on the preserving quality in order to reduce the chilling injury of this fruit. The experiment was conducted using a completely randomized design with three replications. Treatments were applied at 15, 30, and 45 days after storage at 4 °C with ≥90% relative humidity. The size of Cs-Phe NPs was less than 100 nm, approximately. The results showed that application of 5 mM of Cs-Phe NPs delayed the negative effects of chilling stress and enhanced antioxidant capacity, firmness, and total soluble solids of persimmon fruit. Lower H2O2 and malonaldehyde (MDA) accumulation along with higher soluble tannin and total carotenoid accumulation in persimmon fruit treated with 5 mM Cs-Phe NPs was also observed. Fruit coated using Cs-Phe NPs in both concentrations (2.5 and 5 mM) showed the highest antioxidant enzyme activity for superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and the lowest for polyphenol oxidase (PPO) and chilling injury during storage. According to our results, 5 mM of Cs-Phe NPs could be considered as the best treatment under chilling-stress conditions.

Effect of Chitosan–Pullulan Composite Edible Coating Functionalized with Pomegranate Peel Extract on the Shelf Life of Mango (Mangifera indica)

The polysaccharide based composite biomaterial (coating) used in preserving fruits and vegetables during storage is attracting increased attention as it is biodegradable material that prolongs shelf life. In the present investigation, chitosan–pullulan (50:50) composite edible coating was prepared with pomegranate peel extract (0.02 g/mL) as an active antioxidant agent. The effect of treatment with pomegranate peel extract enriched chitosan–pullulan composite edible coating on the shelf life of mango fruits during 18 days of storage period at room (23 °C) and cold (4 °C) temperature was evaluated. Results of the present study demonstrated that the application of chitosan–pullulan composite edible coating significantly (p ≤  0.05) influences the storage life of mango fruits at both storage temperatures. The chitosan–pullulan composite edible coating reduced the physiological loss in weight (PLW), and maintained total soluble solids (TSS), acidity and pH of coated mango fruits as compared to the control. In addition, fruit sensory quality such as freshness, color, taste and texture were also retained by the treatment. Furthermore, sustained firmness, phenolic content and antioxidant activity confirmed the effectiveness of the pomegranate peel extract enriched chitosan–pullulan composite edible coating on mango fruits. The phenolic, flavonoid and antioxidant activity of coated fruits were retained by pomegranate peel rich edible coating. Therefore, the chitosan–pullulan (50:50) combination with pomegranate peel extract can be used as an alternative preservation method to prolong the shelf life of mango fruits at room and cold storage conditions. However, more in-depth studies are required at farm and transit level without affecting the postharvest quality of mango fruits, providing more revenue for farmers and minimizing postharvest losses.

Effect of gum Arabic, xanthan and carrageenan coatings containing antimicrobial agent on postharvest quality of strawberry: Assessing the physicochemical, enzyme activity and bioactive properties

Effect of edible coatings of gum Arabic, carrageenan and xanthan gum containing lemon grass essential oil 1% w/v on postharvest quality of strawberry was studied under refrigeration for a period of 12 days. Results showed all the three coatings maintained fruit quality parameters during storage compared to control. Among all the coatings, carrageenan coated fruits showed delayed weight loss (10.1 to 8%), decay percentage (78.42 to 14.29%), retained ascorbic acid (0.15 to 0.27 g kg^-1), antioxidant activity (18.17 to 25.85%), firmness (9.07 to 12.43 N), L* (32.38 to 40.42), a* (16.08 to 17.22) and b* (27.36 to 33.54). Carrageenan gum also showed lowest cellulase activity (0.03 units h^-1 mg protein^-1), pectin methylesterase activity (1.13 A620 min^-1 mg protein^-1) and β-galactosidase activity (0.51 μmol min^-1 mg protein^-1), while showed maximum reduction in polygalacturonase activity (0.07 units h^-1 mg protein^-1) at the end of storage. Carrageenan gum was found effective in retention of anthocyanins and phenolic compounds during storage. Coatings loaded with antimicrobial agent inhibited psychrophilic bacteria, yeast and mold growth. It is concluded that carrageenan gum could better retain strawberry quality up to 12 days under refrigeration.

Chitosan as a Coating for Biocontrol in Postharvest Products: A Bibliometric Review

The aim of this work was to carry out a systematic literature review focused on the scientific production, trends, and characteristics of a knowledge domain of high worldwide importance, namely, the use of chitosan as a coating for postharvest disease biocontrol in fruits and vegetables, which are generated mainly by fungi and bacteria such as Aspergillus niger, Rhizopus stolonifera, and Botrytis cinerea. For this, the analysis of 875 published documents in the Scopus database was performed for the years 2011 to 2021. The information of the keywords' co-occurrence was visualized and studied using the free access VOSviewer software to show the trend of the topic in general. The study showed a research increase of the chitosan and nanoparticle chitosan coating applications to diminish the postharvest damage by microorganisms (fungi and bacteria), as well as the improvement of the shelf life and quality of the products.

Potentials of polysaccharides, lipids and proteins in biodegradable food packaging applications

Bio-based packaging materials are gaining importance due to their biodegradability, sustainability and environmental friendliness. To control the food quality and improve the food safety standards, proteins polysaccharide and lipid-based packaging films are enriched with bioactive and functional substances. However, poor permeability and mechanical characteristics are the challenging areas in their commercialization. Scientists and researchers are using a combination of techniques i.e. hydrogels, crosslinking, etc. to improve the intermolecular forces between different components of the film formulation to counter these challenges More recently, biodegradable packaging materials, sometimes edible, are also used for the delivery of functional ingredients which reveals their potential for drug delivery to counter the nutrient deficiency problems. This study highlights the potentials of bio-based materials i.e. proteins, polysaccharides, lipids, etc. to develop biodegradable packaging materials. It also explores the additives used to improve the physicochemical and mechanical properties of biodegradable packaging materials. Furthermore, it highlights the novel trends in biodegradable packaging from a food safety and quality point of view.

Combined treatments of chitosan and sodium silicate to inhibit Alternaria alternata pathogens of postharvest winter jujube

Alternaria alternata is a pathogenic fungus that infects jujube fruit and leads to serious economic losses. In this paper, the antifungal activity of chitosan combined with sodium silicate against A. alternata in vitro and in vivo was investigated, and the possible antimicrobial mechanisms were explored. Results showed that the spore germination and colony expansion of A. alternata were significantly inhibited by chitosan. Chitosan treatment induced the leakages of intercellular electrolytes, nucleic acids, and soluble protein of A. alternata. Meanwhile, chitosan damaged the cell morphology and membrane integrity of A. alternata. The combination of chitosan and sodium silicate was more effective than chitosan alone. In addition, the effect of chitosan and sodium silicate could significantly decrease natural rot rate and delay lesion expansion of winter jujube. Collectively, chitosan combined with sodium silicate had the potential to control postharvest diseases of fruit caused by A. alternata.

Controlling Fusarium oxysporum Tomato Fruit Rot under Tropical Condition Using Both Chitosan and Vanillin

Tomato Lycopersicon esculentum Mill. is one of the most cultivated and widely consumed vegetables in the world. However, it is very susceptible to the infection initiated by Fusariumoxysporum fruit rot, which shortens post-harvest life and thus reduces market value. This disease can be regulated appropriately by the application of synthetic fungicides. However, chemical fungicides constitute a serious health risk, and have harmful environment effects and increase disease resistance, even when microbes are dead. Hence, to overcome this problem, chitosan and vanillin, which have antimicrobial bioactive properties against the growth of microorganisms, could be an alternative to disease control, while maintaining fruit quality and prolonging shelf life. The aim of this research was to evaluate the antimicrobial activity of chitosan and vanillin towards the inoculate pathogen and to investigate the effect of chitosan and vanillin coating in vivo on Fusarium oxysporum fruit rot and defense-related enzymes (PAL, PPO and POD). Chitosan and vanillin in aqueous solutions, i.e., 0.5% chitosan + 10 mM vanillin, 1% chitosan + 10 mM vanillin, 1.5% chitosan + 10 mM vanillin, 0.5% chitosan + 15 mM vanillin, 1% chitosan + 15 mM vanillin and 1.5% chitosan + 15 mM vanillin, were used as edible coatings on tomatoes stored at 26 ± 2 °C and 60 ± 5 relative humidity. The result revealed 1.5% chitosan + 15 mM vanillin was able to control disease incidence by 70.84% and severity by 70%. These combinations of coatings were also able to retain phenylalanine ammonia-lyase (PAL), peroxidase activity (POD), and polyphenol oxidase (PPO) enzyme activities as well as prolong shelf life of tomatoes up to 15 days.

Regulatory influences of methyl jasmonate and calcium chloride on chilling injury of banana fruit during cold storage and ripening

Fruit quality is preserved through cold storage, but climacteric fruits are prone to chilling injury (CI) which limits their shelf life and marketability. Two postharvest treatments, 1 mM methyl jasmonate (MeJA) and 4% (wt/vol) calcium chloride (Ca2+), were separately used to investigate their influences on chilling injury (CI) incidence and fruit quality in unpacked banana cultivar "Grand Nain" during cold storage and subsequent ripening. Banana fruits were dipped for 2 min in aqueous emulsions containing 1% Tween-80-used here as a surfactant with untreated fruits being used as control. Fruits were stored at 10 ± 2 or optimal 14 ± 2°C temperature and relative humidity 85%-90% for a 20-day cold storage period and then removed from cold storage at 5, 10, 15, and 20 days followed by ripening at 22 ± 2°C. Treatments with MeJA or Ca2+ significantly reduced CI in banana fruit during cold storage and subsequent ripening temperature. Untreated controls exhibited increased CI, weight loss, and decreased hue angle, as well as firmness. In contrast, the aforementioned changes were considerably delayed after treatments with MeJA or Ca2+. Application of MeJA or Ca2+ also increased total phenolic compound contents and maintenance of total antioxidant activity throughout cold storage and during ripening periods as compared to that of the control. These findings indicate that coating bananas with 1 mM MeJA or 4% (wt/vol) Ca2+ can improve the postharvest quality and shelf life of fruits, and it can ameliorate chilling injury during cold storage and at ripening temperature.

Elicitation of Stress-Induced Phenolic Metabolites for Antimicrobial Applications against Foodborne Human Bacterial Pathogens

Foodborne bacterial pathogens in consumed foods are major food safety concerns worldwide, leading to serious illness and even death. An exciting strategy is to use novel phenolic compounds against bacterial pathogens based on recruiting the inducible metabolic responses of plant endogenous protective defense against biotic and abiotic stresses. Such stress-inducible phenolic metabolites have high potential to reduce bacterial contamination, and particularly improve safety of plant foods. The stimulation of plant protective response by inducing biosynthesis of stress-inducible phenolics with antimicrobial properties is among the safe and effective strategies that can be targeted for plant food safety and human gut health benefits. Metabolically driven elicitation with physical, chemical, and microbial elicitors has shown significant improvement in the biosynthesis of phenolic metabolites with antimicrobial properties in food and medicinal plants. Using the above rationale, this review focuses on current advances and relevance of metabolically driven elicitation strategies to enhance antimicrobial phenolics in plant food models for bacterial-linked food safety applications. Additionally, the specific objective of this review is to explore the potential role of redox-linked pentose phosphate pathway (PPP) regulation for enhancing biosynthesis of stress-inducible antibacterial phenolics in elicited plants, which are relevant for wider food safety and human health benefits.

Bioactive edible film based on Konjac glucomannan and probiotic Lactobacillus plantarum strains: Physicochemical properties and shelf life of fresh-cut kiwis

This study investigates the efficacy of Lactobacillus plantarum strains (L. plantarum LP3, L. plantarum AF1, and L. plantarum LU5) incorporated into a Konjac-based edible coating in order to prevent fungi growth and retain physicochemical characteristics of fresh-cut kiwis kept at 4 °C for 5 days. For this purpose, probiotic survivability, fungi counts, decay percentage, color changes, titratable acidity (TA), total soluble solids (TSS), ascorbic acid content, chlorophyll amount, total phenolics, and DPPH radical scavenging of fresh-cut kiwis were evaluated. Results indicated that the population of L. plantarum strains in all treated groups retained at sufficient amounts of probiotic consumption (above 6 and 7 log CFU/g) at the end of the storage period and L. plantarum LP3 had the highest viability in comparison to other strains. The incorporation of L. plantarum in Konjac coatings markedly reduced the amount of decay and color changes and maintained the chlorophyll and ascorbic acid contents of fresh-cut kiwis compared to control samples. After 5 days of storage, total phenol content and the DPPH antiradical activities of coated kiwi slices treated with probiotics were observed about 1.2 and 10.23 g/kg compared to the pure Konjac-coated (0.84 and 7.6 g/kg) and Konjac-uncoated samples (0.44 and 4.1 g/kg), respectively. No significant difference in TSS and TA of various treatments was detected. Coated kiwi slices loaded with probiotics had higher overall acceptability compared to Konjac-coated and control samples. In addition, probiotic treatment significantly reduced mold and yeast counts compared to the control group. PRACTICAL APPLICATIONS: Recently, edible films have received more consideration as a promising method to enhance the shelf life of fresh-cut fruit. The presence of probiotics in edible films reduces the growth of spoilage microorganisms and improves consumer health. Our findings encourage the application of edible coating incorporated with L. plantarum to design multifunctional foods and preserve the qualities of fresh-cut kiwifruit.

Application of Gum Arabic and Methyl Cellulose Coatings Enriched with Thyme Oil to Maintain Quality and Extend Shelf Life of "Acco" Pomegranate Arils

The effects of gum arabic (GA; 1.5% w/v) and methyl cellulose (MC; 1% w/v) enriched with thyme oil (TO; 0.25 and 0.5% v/v) on the quality of "Acco" pomegranate arils were studied. Coating treatments, namely, MC, MC + TO0.5%, MC + TO0.25%, GA, GA + TO0.5% and GA + TO0.25% were applied on arils by dipping, and evaluations were made on physicochemical and microbiological quality, phytochemicals and antioxidant capacity of arils stored (5 ± 1 °C, 95 ± 2% RH) for 16 days. Dipping arils in GA or MC, both containing TO (0.5% v/v) significantly (p < 0.0001) reduced weight loss and enhanced antioxidant activity (FRAP) (p = 0.0014). However, dipping arils in GA combined with TO (0.25% v/v) had the highest influence on reducing aril respiration rate compared with other treatments. Overall, results showed that application of coatings (GA + TO0.5% and GA + TO0.25%) reduced total yeast and mould and total plate counts and maintained quality up to 8 days of storage. These findings suggest that either GA + TO0.5% or GA + TO0.25% coatings have the capability to extend storage life of "Acco" pomegranate arils.