Conservation of 'Palmer' mango with an edible coating of hydroxypropyl methylcellulose and beeswax

A comprehensive study on the potential of edible coatings with polysaccharides, polyphenol, and lipids for mushroom preservation

Edible coatings have been widely explored as packaging substitutes. Application of edible coatings on mushrooms remains under-explored, due to its highly porous nature, with limited benefits to date. Herein, we thoroughly benchmark six polysaccharides, one polyphenol (lignin derivative), and three lipids as edible coatings for mushrooms, namely Agaricus bisporus. The study cross-correlates the dynamics of browning and weight retention, uniquely evaluated in three storage conditions. It was shown that polysaccharide and polyphenol coatings provided notable anti-browning (46 % and 44 % reduction by alginate and pectin respectively) and limited improvements in water retention (e.g., 10 % reduction by alginate and pectin), whereas lipids were found to outstandingly reduce both the mushroom's browning (80 % and 74 % reduction by coconut oil and wax respectively) and maintains weight (169 % and 149 % improvement by wax and coconut oil respectively) in ambient conditions after two days of storage. Scanning electron microscopy was used to explore the film forming potential of the coatings, revealing inadequate surface coverage by polysaccharides and polyphenol. Beyond the benchmarking provided herein, we expect that the analytical and experimental framework provided herein can help fast-track developments of highly efficient edible coating formulations.

Quality Preservation and Shelf-Life Extension of Prickly Pear (Opuntia ficus-indica L. Mill) Using Edible Coatings

Prickly pear consumption is increasing across the world due to its rich variety of nutrients and bioactive compounds. Yet, it is a seasonal and highly perishable fruit, and the application of edible coatings emerges as an alternative to extend its shelf life. In this work, the effects of alginate, starch, chitosan, and pectin as coatings on the physicochemical, bioactive, microbiological, and textural properties of two prickly pear varieties (orange and red), kept under refrigeration (5 ± 2 °C) were evaluated for 6 weeks. Coatings proved to be helpful in the maintenance of the fruits' color and textural properties, especially when pectin was applied. Overall, starch and chitosan can be considered the most effective coatings in preserving the quality of prickly pears among the options studied. A lower weight loss (8-10%) in fruits was achieved when starch and chitosan were applied, while in control fruits (without coating), the loss was 18-23%. Starch and chitosan also contributed to preserving the bioactivity of red fruits and showed good results in the preservation of total phenolic content in the orange fruits. In addition, starch and chitosan coatings also presented the best performance for the reduction of microbial contamination (both yeasts and molds and total mesophilic aerobic microorganisms). These findings highlight the role of edible coatings in preserving prickly pears, for a longer period, meeting consumers' demand for fresh fruit.

Natural biopolymers in edible coatings: Applications in food preservation

Edible coatings are revolutionizing food preservation by offering a sustainable and effective solution to key industry challenges. Made from natural biopolymers such as proteins, polysaccharides, and lipids, these coatings form a thin, edible layer on food surfaces. This barrier reduces moisture loss, protects against oxidative damage, and limits microbial growth, thereby extending shelf life while preserving food quality. Enhanced with natural additives like essential oils and antioxidants, these coatings offer antimicrobial benefits and contribute to health. Applications span from fresh produce, where they control respiration and moisture, to meat, dairy, and bakery products, maintaining sensory and nutritional properties. Innovations in coating technologies-such as composite materials, nano-emulsions, and bio-nanocomposites-are improving their mechanical strength, barrier properties, and compatibility with other preservation methods like modified atmosphere packaging. Although challenges remain in cost, consumer acceptance, and regulation, edible coatings represent a significant stride towards sustainable food systems and reduced dependence on synthetic packaging.

A novel edible biocomposite coating based on alginate from the brown seaweed Dictyota mertensii loaded with beeswax nanoparticles extends the shelf life of yellow passion fruit

In this study, an edible biocomposite coating of alginate extracted from the brown seaweed Dictyota mertensii was loaded with beeswax nanoparticles (BDMAB) to extend the shelf life of yellow passion fruit (Passiflora edulis f. flavicarpa). The films were characterized by morphology, moisture content, contact angle, water vapor permeability, solubility, and optical and mechanical properties. Using a 4 × 6 factorial design, coated fruit was evaluated during six storage intervals (0, 2, 4, 6, 8, 10 days) at 22.5 ± 0.5 °C and 65 ± 5 % RH, focusing on respiration rate, weight loss, peel thickness and color, pulp yield and color, soluble solids, titratable acidity, ascorbic acid, phenolics, antioxidant capacity, and sensory acceptance. The BDMAB coating, composed of 67.9 % (w/w) ADM (bleached), 5 % (w/w) glycerol, 8.5 % (w/w) beeswax, and 18.6 % (w/w) Tween 80, significantly (p < 0.05) reduced the respiration rate, minimized weight loss, and preserved quality attributes, such as acidity, ascorbic acid, phenols, and antioxidant capacity. A 3-day extension in shelf life was inferred based on the climacteric peak delay of BDMAB-coated fruits compared with the control. Sensory analysis confirmed the acceptance of BDMAB coating. Therefore, BDMAB biocomposite coatings have great potential for preserving yellow passion fruit and promoting sustainability and conservation.

Maintenance of postharvest quality of 'Palmer' mango coated with biodegradable coatings based on cassava starch and emulsion of lemongrass essential oil

This study aimed to evaluate the effect of applying oxidized cassava starch-based edible coatings with addition of lemongrass essential oil emulsion on 'Palmer' mangoes stored under refrigeration. A completely randomized design was used, arranged in a 5 × 3 factorial scheme, with five types of coatings and three evaluation times. The evaluated postharvest quality parameters consisted of weight loss, pulp and peel firmness, biochemical transformations related to pigments, and pulp and peel coloration of mango. The application of edible coatings with a 0.9 % EO concentration resulted in delayed fruit ripening, evidenced mainly by a 7.25 % reduction in weight loss, a 29.23 % increase in soluble solids content, and a 24.15 % decrease in total chlorophyll, when compared to uncoated fruits, which showed 19.8 %, 48.66 %, and 82.00 %, respectively, over the storage period. This effect was also evident in the angle Hue (°h) measurement, with uncoated fruits showing a decrease of 32.2 %. The antimicrobial effect and absence of anthracnose symptoms were observed in the fruits in which the coating with 0.9 % EO was applied. Therefore, biodegradable coating with the addition of 0.9 % emulsion EO, can be used as postharvest treatments for maintenance quality of 'Palmer' mangoes during refrigerated storage.

Starch-based films affected by the addition of collagen from Prochilodus magdalenae residues and HPMC: Application in Andean blackberry (Rubus glaucus Benth) coatings

Starch-based films offer the advantages of biodegradability, edibility, barrier properties, flexibility, and adaptability. This study compared the physicochemical properties of starch-based films by adding raw fish collagen and hydroxypropylmethylcellulose (HPMC). The tensile properties were evaluated, and the interaction with water was analyzed. Barrier properties, such as water vapor and oxygen permeability, were examined, and optical properties, such as gloss and good internal transmittance, were evaluated. The films were evaluated as coatings on Andean blackberries (Rubus glaucus Benth) for 2 weeks at 85% RH and 25°C. The results showed that the inclusion of collagen caused a reduction in the tensile strength and elastic modulus of the films. Also, the formulation with the highest collagen concentration (F7) exhibited the lowest weight loss and water vapor permeability, also it had the highest collagen concentration and showed the highest reduction in Xw and WAC, with values of 0.048 and 0.65 g water/g dry film, respectively. According to analyzing the optical properties, F1 presented the highest bright-ness and transmittance values, with 18GU and 82 nm values, respectively. In general, the films and coatings are alternatives to traditional packaging materials to prolong the shelf life of these fruits.

Preparation and application of hydroxypropyl methylcellulose blended with beeswax and essential oil edible coating to enhance the shelf life of sweet cherries

The study involved preparing and applying edible nano-emulsion coatings containing hydroxypropyl methylcellulose (HPMC), beeswax (BW), and essential oils (thyme, cinnamon, clove, and peppermint) onto sweet cherries. The application was conducted at 4 °C, and the coated cherries were stored for 36 days. This research examines synthesized nano-emulsions physicochemical properties and antibacterial and antifungal activities (C1, C2, and C3). Additionally, it evaluates the quality parameters of control and coated sweet cherry samples. The features of the three edible coatings were assessed, and the findings from the zeta sizer, zeta potential, FTIR, and SEM analyses were deemed satisfactory. It was observed that the application of nano-emulsion coating C1 yielded positive results in maintaining quality attributes such as total suspended solids (TSS), total solids (TS), color, weight loss, respiration rate, firmness, total phenolic contents, and sensory evaluations. Nano-emulsion coating C1 demonstrated efficacy as an antibacterial and antifungal agent against foodborne pathogens E. coli and A. niger, respectively. The current research results are promising and applicable in food industries. The implications suggest that composite nano-emulsion, specifically nano-emulsion edible coatings, can be extensively and effectively used to preserve the quality and shelf life of fruits and vegetables. Furthermore, the environmental waste from conventional food packaging will be minimized using edible packaging applications.

Recent Highlights in Sustainable Bio-Based Edible Films and Coatings for Fruit and Vegetable Applications

The present review paper focuses on recent developments in edible films and coatings made of base compounds from biological sources, namely plants, animals, algae, and microorganisms. These sources include by-products, residues, and wastes from agro-food industries and sea products that contribute to sustainability concerns. Chitosan, derived from animal biological sources, such as crustacean exoskeletons, has been the most studied base compound over the past three years. Polysaccharides typically constitute no more than 3-5% of the film/coating base solution, with some exceptions, like Arabic gum. Proteins and lipids may be present in higher concentrations, such as zein and beeswax. This review also discusses the enrichment of these bio-based films and coatings with various functional and/or bioactive compounds to confer or enhance their functionalities, such as antimicrobial, antioxidant, and anti-enzymatic properties, as well as physical properties. Whenever possible, a comparative analysis among different formulations was performed. The results of the applications of these edible films and coatings to fruit and vegetable products are also described, including shelf life extension, inhibition of microbial growth, and prevention of oxidation. This review also explores novel types of packaging, such as active and intelligent packaging. The potential health benefits of edible films and coatings, as well as the biodegradability of films, are also discussed. Finally, this review addresses recent innovations in the edible films and coatings industry, including the use of nanotechnologies, aerogels, and probiotics, and provides future perspectives and the challenges that the sector is facing.

Potential application of bee products in food industry: An exploratory review

Over the past eight years, bee products such as wax, honey, propolis, and pollen have generated intense curiosity about their potential food uses; to explore these possibilities, this review examines the nutritional benefits and notable characteristics of each product related to the food industry. While all offer distinct advantages, there are challenges to overcome, including the risk of honey contamination. Indeed, honey has excellent potential as a healthier alternative to sugar, while propolis's remarkable antibacterial and antioxidant properties can be enhanced through microencapsulation. Pollen is a versatile food with multiple applications in various products. In addition, the addition of beeswax to oleogels and its use as a coating demonstrate significant improvements in the quality and preservation of environmentally sustainable foods over time. This study demonstrates that bee products and apitherapy are essential for sustainable future food and innovative medical treatments.

Layer by layer application of chitosan and carboxymethyl cellulose coatings delays ripening of mango fruit by suppressing cell wall polysaccharides disassembly

Mango is a climacteric fruit that ripens quickly after harvest due to its climacteric nature. Edible coatings have been reported to delay the ripening of various harvested fruit. The efficacy of the applied edible coatings could be improved by using in combination as a layer-by-layer (LBL) approach. So, the influence of LBL application of chitosan (CH) and carboxymethyl cellulose (CMC) was studied on mangoes during postharvest storage at 15 °C for 20 days. Mangoes were coated with monolayers of CH (1 % w/v) and CMC (1 % w/v) as well as LBL application of CH and CMC and were compared with control. The treatment of mangoes with CH and CMC-based LBL treatment resulted in lower decay percentage and weight loss along with higher total chlorophyll pigments and suppressed total carotenoid accumulation. The LBL application of CH and CMC showed lower activity of chlorophyll degrading such as chlorophyllase (CPS), pheophytinase (Phe), Mg-dechalatase (MGD) and chlorophyll degrading peroxidase (Chl-POD) enzymes as well as reduced changes in b*, a* and L* along with a suppressed increase in ethylene (EP) and CO2 production (CPR) rates having higher antioxidant such as catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) enzymes activity. In addition, mangoes coated with LBL treatment of CH and CMC exhibited lower water-soluble pectin (WSP) and higher protopectin (PP) having higher concentrations of chelate soluble (CSP) and sodium carbonate-soluble pectin (SCP). Similarly, LBL-coated mangoes showed significantly higher hemicellulose (HCLS) and cellulose (CLS) contents in contrast with control. It was observed that mangoes coated with CH and CMC-based LBL coating exhibited higher flesh firmness and showed suppressed cellulase (CS), pectin methylesterase (PME), polygalacturonase (PG) and β-galactosidase (β-Gal) enzymes activity. The concentrations of total soluble solids and ripening index were markedly lower and titratable acidity was higher in the LBL-based coating treatment in comparison with control. In conclusion, LBL treatment based on CH and CMC coatings could be used for the delay of ripening and softening of harvested mangoes.

The reduce of water vapor permeability of polysaccharide-based films in food packaging: A comprehensive review

Polysaccharide-based films are favored in the food packaging industry because of their advantages of green and safe characters, as well as natural degradability, but due to the structural defects of polysaccharides, they also have the disadvantages of high water vapor permeability (WVP), which greatly limits their application in the food packaging industry. To break the limitation, numerous methods, e.g., physical and/or chemical methods, have been employed. This review mainly elaborates the up-to-date research status of the application of polysaccharide-based films (PBFs) in food packaging area, including various films from cellulose and its derivatives, starch, chitosan, pectin, alginate, pullulan and so on, while the methods of reducing the WVP of PBFs, mainly divided into physical and chemical methods, are summarized, as well as the discussions about the existing problems and development trends of PBFs. In the end, suggestions about the future development of WVP of PBFs are presented.

Effect of coating using beeswax and sodium nitroprusside on chlorophyll stability and quality factors of lime during cold storage

Lime (Citrus floridana) is a quickly perishable fruit, limiting its shelf life because of reduced chlorophyll content and post-harvest quality under different storage conditions. To increase chlorophyll stability as well as other quality factors of limes, they were coated with beeswax in 0.1 wt.% and sodium nitroprusside in three various concentrations (0.1, 0.2, and 0.4 mM) at 25 °C for 3 min and then stored at 8 °C for 60 days. In this research, changes in weight loss, juice content, firmness (F), chlorophyll, chlorophyllase activity, polyphenol oxidase activity, color, total acidity (titratable acidity), ascorbic acid (ASA) and sensory evaluation were studied. During storage at low temperatures, BW surface coating (0.1%) alone, sodium nitroprusside alone, and also in combination with each other and a double layer were effective in maintaining chlorophyll and the qualitative characteristics of limes. In our observations, the best treatment was the treatment where the limes were coated by beeswax enriched by sodium nitroprusside coating. This treatment contained the highest content of lime juice and the highest chlorophyll plus the lowest activity of chlorophyllase and polyphenol oxidase, while the amount of green color was maintained to a large extent. As a result, it is possible to use beeswax enriched by sodium nitroprusside coating method to maintain the quality and chlorophyll of cold-stored lime fruits.

Harnessing the metabolic modulatory and antioxidant power of 1-(3-Phenyl-Propyl) cyclopropane and melatonin in maintaining mango fruit quality and prolongation storage life

BACKGROUND

The aim of this study was to compare and investigate the effects of 1-(3-phenyl-propyl) cyclopropene (PPCP) and melatonin (MT) as anti-ethylene agents on postharvest senescence, quality, chilling tolerance, and antioxidant metabolism in the mango fruit cv. "Keitt". The study involved exposing the fruit to 20 μL L- 1 PPCP or 200 μM MT, in addition to a control group of untreated fruit, before storing them at 5 ± 1 °C for 28 d. The findings revealed that the treatments with PPCP and MT were effective in reducing chilling injury and preserving fruit quality when compared to the control group.

RESULTS

The use of 20 μL L- 1 PPCP was an effective treatment in terms of mitigating chilling injury and preserving fruit quality for 28 d. This was attributed to the decrease in metabolic activity, specifically the respiration rate and the production of ethylene, which led to the maintenance of fruit firmness and bioactive compounds, energy metabolism, and antioxidant activity, such as ascorbic acid, total flavonoids, trolox equivalent antioxidant capacity, dehydroascorbate reductase, glutathione reductase activity, ATP, and ATPase activity. The study also found that the MT treatment at 200 μM was effective in reducing chilling injury and weight loss and improving membrane stability. Additionally, it led to a decrease in malondialdehyde content and electrolyte leakage, and the maintenance of fruit quality in terms of firmness, peel and pulp colour values for mango peel and pulp total carotenoid content, as well as phenylalanine ammonia lyase and tyrosine ammonia lyase activity. These findings indicate that PPCP and MT have the potential to be efficient treatments in maintaining mango quality and minimizing post-harvest losses.

CONCLUSION

The utilisation of treatments with 20 μL L- 1 of PPCP or 200 μM MT was found to effectively preserve the postharvest quality parameters, in terms of bioactive compounds, energy metabolism, and antioxidant activity, of mangoes cv. "Keitt" that were stored at 5 ± 1 °C for 28 d.

Exogenous glutathione maintains the postharvest quality of mango fruit by modulating the ascorbate-glutathione cycle

Background

Mango fruit is prone to decay after harvest and premature senescence, which significantly lowers its quality and commercial value.

Methods

The mango fruit (Mangifera indica L.cv. Guixiang) was treated with 0 (control), 2, 5, and 8 mM of reduced glutathione (GSH) after harvest. The fruit was stored at 25 ± 1 °C for 12 days to observe the changes in the antioxidant capacity and postharvest quality.

Results

Compared with the control, the 5 mM GSH treatment significantly decreased the weight loss by 44.0% and 24.4%, total soluble solids content by 25.1% and 4.5%, and soluble sugar content by 19.0% and 27.0%. Conversely, the 5 mM GSH treatment increased the firmness by 25.9% and 30.7% on days 4 and 8, respectively, and the titratable acidity content by 115.1% on day 8. Additionally, the 5 mM GSH treatment decreased the malondialdehyde and hydrogen peroxide contents and improved the antioxidant capacity of mango fruit by increasing the superoxide dismutase and peroxidase activities and upregulating the expression of the encoding genes. Meanwhile, the higher levels of monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase enzyme activities and gene expressions accelerated the AsA-GSH cycle, thereby increasing the accumulation of AsA and GSH and maintaining the redox balance.

Conclusions

Overall, the experimental results suggest that 5 mM GSH maintains high antioxidant capacity and postharvest quality of mangoes and can use as an effective preservation technique for postharvest mangoes.

Opuntia ficus indica mucilage coatings regulate cell wall softening enzymes and delay the ripening of banana fruit stored at retail conditions

Rapid ripening and softening due to cell wall polysaccharide degradation and disassembly pose major challenges in extending fruit storability. This study aimed to examine the efficacy of Opuntia ficus indica mucilage (OFIM) edible coating in minimizing softening in bananas under retail conditions. Mucilage was extracted from freshly harvested prickly pear cladodes and dried into a powder. Phenolic compounds in OFIM powder were quantified using liquid chromatography-mass spectrometry (LC-MS). OFIM concentrations (1, 2 and 3 % (w/v)) were prepared, and their physicochemical properties were examined. The prepared coatings were applied to harvested banana fruit by dipping and stored at room temperature for 12 days. During the experiment, several parameters were measured, including fruit weight loss, total soluble solids (TSS), titratable acidity (TA), peel color, pulp firmness, ethylene production, respiration rate, ion leakage, malondialdehyde (MDA) content, total chlorophyll and carotenoids, chlorophyll-degrading enzymes, protopectin content and water-soluble pectin (WSP) and softening-related enzymes in the peel. Results showed that mucilage treatments effectively delayed cell wall and chlorophyll degradation, as well as carotenoid accumulation, thus inhibiting ripening-associated processes compared to control fruit. OFIM-treated fruit exhibited significantly higher firmness, chlorophyll content, and TA, lower TSS content, ethylene production, respiration rate, MDA concentration, ion leakage and protopectin content than uncoated fruit. This suggests that OFIM edible coating has the potential to maintain quality and extend the shelf life of bananas by suppressing softening enzymes during storage.

Green Management of Postharvest Anthracnose Caused by Colletotrichum gloeosporioides

Fruits and vegetables are constantly affected by postharvest diseases, of which anthracnose is one of the most severe and is caused by diverse Colletotrichum species, mainly C. gloeosporioides. In the last few decades, chemical fungicides have been the primary approach to anthracnose control. However, recent trends and regulations have sought to limit the use of these substances. Greener management includes a group of sustainable alternatives that use natural substances and microorganisms to control postharvest fungi. This comprehensive review of contemporary research presents various sustainable alternatives to C. gloeosporioides postharvest control in vitro and in situ, ranging from the use of biopolymers, essential oils, and antagonistic microorganisms to cultivar resistance. Strategies such as encapsulation, biofilms, coatings, compounds secreted, antibiotics, and lytic enzyme production by microorganisms are revised. Finally, the potential effects of climate change on C. gloeosporioides and anthracnose disease are explored. Greener management can provide a possible replacement for the conventional approach of using chemical fungicides for anthracnose postharvest control. It presents diverse methodologies that are not mutually exclusive and can be in tune with the needs and interests of new consumers and the environment. Overall, developing or using these alternatives has strong potential for improving sustainability and addressing the challenges generated by climate change.

Beeswax: A review on the recent progress in the development of superhydrophobic films/coatings and their applications in fruits preservation

Recently, the design and fabrication of bio-inspired superhydrophobic materials using natural lipid additives such as beeswax (BW) have aroused great attention in food packaging as they can minimize the transfer rate of water molecules and have effective moisture barriers. This review discusses the recent progress in the design and fabrication of BW-containing edible films/coatings (e.g., emulsion and blend films, bilayer materials, bionanocomposites, and antimicrobial materials) and their potential applications on the postharvest life and quality attributes of various fruits. Incorporation of BW into polysaccharides- and proteins-based emulsion films effectively improved their hydrophobicity, water vapor, and UV/visible light barrier properties, as well as the film tensile properties. The addition of nanoparticles to BW-based polymeric matrices often results in improved physico-mechanical properties. BW coatings have been also applied to prolong the shelf-life of various climacteric fruits, however, optimization of the wax concentration can be further investigated to develop targeted food storage systems.

Application of Polysaccharide-Based Edible Coatings on Fruits and Vegetables: Improvement of Food Quality and Bioactivities

Most foods derived from plant origin are very nutritious but highly perishable products. Nowadays, the food industry is focusing on the development of efficient preservation strategies as viable alternatives to traditional packaging and chemical treatments. Hence, polysaccharide-based edible coatings have been proposed because of their properties of controlled release of food additives and the protection of sensitive compounds in coated foods. Thus, this technology has allowed for improving the quality parameters and extends the shelf life of fruits and vegetables through positive effects on enzyme activities, physicochemical characteristics (e.g., color, pH, firmness, weight, soluble solids), microbial load, and nutritional and sensory properties of coated foods. Additionally, some bioactive compounds have been incorporated into polysaccharide-based edible coatings, showing remarkable antioxidant and antimicrobial properties. Thus, polysaccharide-based edible coatings incorporated with bioactive compounds can be used not only as an efficient preservation strategy but also may play a vital role in human health when consumed with the food. The main objective of this review is to provide a comprehensive overview of materials commonly used in the preparation of polysaccharide-based edible coatings, including the main bioactive compounds that can be incorporated into edible coatings, which have shown specific bioactivities.

Chitosan and other edible coatings to extend shelf life, manage postharvest decay, and reduce loss and waste of fresh fruits and vegetables

Fresh fruits and vegetables contain high percentage of water and continue metabolic activity after being harvested, resulting in ripening, increased sensitivity to decay-causing fungi, and consequent loss and waste. Edible coatings are prepared from naturally occurring renewable sources and can contribute to reducing waste, respecting environment, and consumer health. Chitosan and other edible coatings form a thin layer surrounding fresh produce that acts as a protective agent, extending shelf life, and have the potential to control their ripening process and maintain nutritional properties of the coated product. This review discusses recent research on the application of chitosan and other edible coatings to prevent fungal decay, keep the quality, and reduce fresh product waste.

Metabolomics insights into the potential of encapsulated essential oils as multifunctional food additives

Growing consumer concern about foodborne disease outbreaks and health risks associated with chemical additives has propelled the usage of essential oils (EOs) as novel food additives, but are limited by instability. In this regard, a series of EOs nano/micro-capsules have been widely used to enhance their stability and improve food quality. However, classical food quality assessment methods are insufficient to fully characterize the effects of encapsulated EOs on food properties, including physical, biochemical, organoleptic, and microbial changes. Recently, the rapid development of high-throughput sequencing is accelerating the application of metabolomics in food safety and quality analysis. This review seeks to present the most recent achievements in the application of non-targeted metabolomics to identify and quantify the overall metabolite profile associated with food quality, which can guide the development of emerging food preservation technologies. The scientific findings confirm that metabolomics opens up exciting prospects for biomarker screening in food preservation and contributes to an in-depth understanding of the mechanisms of action (MoA) of EOs. Future research should focus on constructing food quality assessment criteria based on multi-omics technologies, which will drive the standardization and commercialization of EOs for food industry applications.

Recent advances in polysaccharide-based edible coatings for preservation of fruits and vegetables: A review

Harvested fruits and vegetables are prone to decay and quality deterioration during storage. Although traditional packaging and chemical treatments are effective, they are harmful to the environment and human health. Hence, higher requirements for food preservation technology are increasingly proposed. Nontoxic, renewable, degradable, and edible packaging for fruits and vegetables has become a research hotspot in recent years. Chitosan, alginate, cellulose, pectin, starch, and other polysaccharides as coating materials have been widely used. Compared with traditional plastic packaging and chemical treatment, these coatings exhibited a better preservation effect and higher safety. In this paper, the preservation mechanism of fruits and vegetables by edible coatings treatment was described, and the research on edible coatings used in fruits and vegetables was summarized. The effects polysaccharide-based edible coatings on physicochemical quality and antimicrobial effect of fruits and vegetables were reviewed.

The molecular mechanism on suppression of climacteric fruit ripening with postharvest wax coating treatment via transcriptome

Wax coating is an important means to maintain fruit quality and extend fruit shelf life, especially for climacteric fruits, such as apples (Malus domestica). Here, we found that wax coating could inhibit ethylene production, chlorophyll degradation, and carotenoid synthesis, but the molecular mechanism remains unclear. The regulatory mechanism of wax coating on apple fruit ripening was determined by subjecting wax-treated apple fruits to transcriptome analysis. RNA-seq revealed that 1,137 and 1,398 genes were upregulated and downregulated, respectively. These differentially expressed genes (DEGs) were shown to be related to plant hormones, such as ethylene, auxin, abscisic acid, and gibberellin, as well as genes involved in chlorophyll degradation and carotenoid biosynthesis. Moreover, we found that some genes related to the wax synthesis process also showed differential expression after the wax coating treatment. Among the DEGs obtained from RNA-seq analysis, 15 were validated by quantitative RT-PCR, confirming the results from RNA-seq analysis. RNA-seq and qRT-PCR of pear (Pyrus ussuriensis) showed similar changes after wax treatment. Our data suggest that wax coating treatment inhibits fruit ripening through ethylene synthesis and signal transduction, chlorophyll metabolism, and carotenoid synthesis pathways and that waxing inhibits endogenous wax production. These results provide new insights into the inhibition of fruit ripening by wax coating.

Carboxymethyl cellulose coating delays ripening of harvested mango fruits by regulating softening enzymes activities

The effect of carboxymethyl cellulose [(1%) CMC] was evaluated on mango fruits under storage at 20 ± 1 °C for 20 days. The CMC coating noticeably reduced weight loss and disease incidence. Application of CMC delayed climacteric peak of ethylene and respiration rate with significantly reduced relative ion leakage, malondialdehyde, superoxide anion and hydrogen peroxide content. The treated mangoes showed significantly lower L*, a*, b* and total carotenoids. The CMC treatment reduced the increase in cellulase, pectin methylesterase and polygalacturonase activity that delayed softening of mango fruits. In addition, activities of peroxidase, catalase, ascorbate peroxidase and superoxide dismutase were substantially higher in CMC-treated mango fruits. The treated fruits showed significantly lower soluble solids and higher titratable acidity which thereby reduced the ripening index of mangoes. In conclusion, CMC treatment could be considered a potential pre-storage treatment to delay postharvest ripening and to conserve the eating quality of ambient stored mango fruits.

Antifungal activity and molecular mechanisms of mulberrin derivatives against Colletotrichum gloeosporioides for mango storage

In this work, by using high throughput virtual screening and bioactivity assays, this work revealed that three natural compounds, mulberrin (Mul) exhibiting the highest anti-CYP51 activity, isoxanthohumol and (s)-isopsoralen markedly inhibited 14α-demethylase (a pivotal biosynthetic enzyme involved in the biosynthesis of ergosterol) in Colletotrichum gloeosporioides. Results of computational biology analysis demonstrated that, among the three inhibitors bound to the catalytic pocket of CYP51, Mul showed a closer distance with heme in CYP51 and a stronger binding free energy with CYP51. In vitro tests, Mul demonstrated excellent anti-Colletotrichum gloeosporioides activity by inhibiting CYP51 activity. Notably, Mul treatment decreased the bioactivity of CYP51, thereby increasing cell membrane permeability and cell death. Moreover, Mul treatment significantly prolonged the preservation period of fruits. These results suggest that Mul suppresses anthracnose in postharvest mango by inhibiting the growth of Colletotrichum gloeosporioides and can be used as a potential natural preserving agent.

Potential of engineered nanostructured biopolymer based coatings for perishable fruits with Coronavirus safety perspectives

Fresh fruits are prioritized needs in order to fulfill the required health benefits for human beings. However, some essential fruits are highly perishable with very short shelf-life during storage because of microbial growth and infections. Thus improvement of fruits shelf-life is a serious concern for their proper utlization without generation of huge amount of fruit-waste. Among various methods employed in extension of fruits shelf-life, design and fabrication of edible nanocoatings with antimicrobial activities have attracted considerable interest because of their enormous potential, novel functions, eco-friendly nature and good durability. In recent years, scientific communities have payed increased attention in the development of advanced antimicrobial edible coatings to prolong the postharvest shelf-life of fruits using hydrocolloids. In this review, we attempted to highlight the technical breakthrough and recent advancements in development of edible fruit coating by the application of various types of agro-industrial residues and different active nanomaterials incorporated into the coatings and their effects on shelf-life of perishable fruits. Improvements in highly desired functions such as antioxidant/antimicrobial activities and mechanical properties of edible coating to significantly control the gases (O2/CO2) permeation by the incorporation of nanoscale natural materials as well as metal nanoparticles are reviewed and discussed. In addition, by compiling recent knowledge, advantages of coatings on fruits for nutritional security during COVID-19 pandemic are also summarized along with the scientific challenges and insights for future developments in fabrication of engineered nanocoatings.

Influence of Nano-Silica/Chitosan Film Coating on the Quality of ‘Tommy Atkins’ Mango

In this study, we assessed the coating of ‘Tommy Atkins’ mangoes with films containing chitosan and nano-silicon dioxide in terms of the effects on fruit parameters as an indicator of quality. After coating, the fruits were first stored at 13 ± 1 °C and 90–95% RH for 30 days, and then at 20 ± 2 °C and 70–75% RH for 5 days, which corresponds to the marketing period. The results showed that coating treatments significantly decreased the fruits’ weight loss and decay percentage compared to the uncoated control samples over the storage period. Additionally, all coated treatments delayed skin degreening, reduced endogenous ethylene production, suppressed respiration rate, and maintained the firmness, compared to untreated control fruit. Titratable acidity and vitamin C significantly decreased in all samples during storage, but this decrease was less pronounced in the coated fruits. Furthermore, coating can delay the increments in total soluble solids and total sugars while maintaining total phenolics, and high antioxidant content of fruits, thereby extending the effective length of the marketing period of treated fruits compared to the control. It was shown that the coating combination of 2% chitosan plus 1% nano-silicon dioxide was the most successful in maintaining the mango’s quality under cold storage and during marketing.

Synthesis and characterization of chitosan/montmorillonite nanocomposites for application as edible coating

Edible coating can improve fruits shelf life and, consequently, reduce their waste. Chitosan, which presents a potential for chemical modifications and capacity to form films, can be an alternative for coating due to its biocompatibility, biodegradability, and antimicrobial properties. Chitosan film can be obtained through casting method presenting suitable mechanical properties, such as resistance to traction and elongation, ability to adhere to surfaces and selective permeability to gases, such as O₂ and CO₂. However, it is highly permeable to water vapor, which can limit its potential coating use. The properties of chitosan films can be improved through the formation of composites by inserting nanoclays as montmorillonite in the polymeric matrix. The objective of this study was to develop and characterize chitosan/montmorillonite nanocomposites for fruit coating aiming for future applications in the field of smart packaging. Nanocomposites were characterized by its microstructure, thermal, mechanical, and physicochemical properties. X-ray diffraction analysis indicated changes in crystallinity with the insertion of montmorillonite. Nanocomposites became more transparent and significantly reduced its water permeability rate with 0.5% w/w montmorillonite addition. Elastic rigidity and tensile strength of the films were improved. Chitosan/montmorillonite nanocomposites demonstrated the potential to improve the storage time of Williams pears.

Application of Potentially Probiotic Fruit-Derived Lactic Acid Bacteria Loaded into Sodium Alginate Coatings to Control Anthracnose Development in Guava and Mango During Storage

This study evaluated the efficacy of potentially probiotic fruit-derived lactic acid bacteria (LAB) strains loaded into sodium alginate (SA) coatings to control the anthracnose development in guava cv. Paluma and mango cv. Palmer caused by distinct pathogenic Colletotrichum species (C. asianum, C. fructicola, C. tropicale, C. siamense, C. karstii, and C. gloeosporioides) during 15 days of room temperature storage (25 ± 0.5 °C). The effects of the formulated coatings on physicochemical parameters indicative of overall postharvest quality of guava and mango were evaluated. The eight examined LAB strains caused strong inhibition on the mycelial growth of all target Colletotrichum species in vitro. LAB strains with the highest inhibitory effects (Levilactobacillus brevis 59, Lactiplantibacillus pentosus 129, and Limosilactobacillus fermentum 263) on the target Colletotrichum species were incorporated into SA coatings. These strains had viable counts of > 6 log CFU/mL in SA coatings during 15 days of room temperature storage. Application of coatings with SA + L. brevis 59, SA + L. pentosus 129, and SA + L. fermentum 263 delayed the development and decreased the severity of anthracnose lesions in guava and mango artificially contaminated with either of the tested Colletotrichum species. These coatings impacted positively on some physicochemical parameters indicative of postharvest quality and more prolonged storability of guava and mango. The formulated SA coatings loaded with tested fruit-derived potentially probiotic LAB strains could be innovative and effective strategies to control postharvest anthracnose and extend the storability of guava and mango.

Improvement of the Performance of Chitosan-Aloe vera Coatings by Adding Beeswax on Postharvest Quality of Mango Fruit

The effect of the application of chitosan–Aloe vera coatings emulsified with beeswax (0, 0.5, 1, 1.5 and 2%) during storage of Mangifera indica L. (cv Anwar Ratol) was investigated. Particle size of emulsions was reduced significantly with an increase in beeswax concentration. Water vapor permeability of the coatings was reduced by 43.7% with an increase in concentration of beeswax to 2%. The coated mangoes (at all concentrations of beeswax) exhibited reduced weight loss, delayed firmness loss, minimized pH change, maintained the total soluble solid contents, and retained free radical scavenging activity and total phenolic contents when stored at 18 °C and 75 ± 5% R.H. The best results were produced with a formulation containing 2.0% beeswax. Antimicrobial properties of chitosan and Aloe vera coatings were also improved with an increase in beeswax concentration and remarkably reduced the disease incidence in mangoes. In conclusion, beeswax-emulsified chitosan–Aloe vera coatings can be effectively used to increase the shelf life and marketable period of mangoes.

Optical and thermal properties of edible coatings for application in solar drying

Solar drying is a sustainable process that may impact the quality of dried food. This is because, pigments contained in food are sensitive to sunlight, and exposure to ultraviolet radiation can affect them. We applied biopolymer-based coatings on strawberry, from hydro-colloidal solutions of Opuntia ficus indica-mucilage, fenugreek, xanthan gum, gum Arabic, and guar gum to evaluate their potential use as UV filters for solar drying of food. Thermal properties and the optical transmittance, absorbance and reflectance of the coatings were measured to assess their influence on food-sunlight interaction. During the drying experiments, the moisture content, total anthocyanins (TA), and total phenolic compounds (TPC) were measured. Optical and thermal properties are influenced by the biopolymer-based coatings. Also, the optical properties are influenced by the coating thickness. The differences in optical and thermal properties influence the drying process. Differences exist in the drying rate for strawberry slices with coating, compared with those without the coatings. In general, the TA and TPC content in the product are better preserved under solar drying than in control experiments done in a drying oven. A partial transmittance of solar UV radiation is recommended to obtain increased TA and TPC contents in the dried product.