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

Development and characterization of edible and active coating based on xanthan gum nanoemulsion incorporating betel leaf extract for fresh produce preservation

Developing an edible and active coating, incorporating environmentally-friendly antimicrobial agents into edible polymers, provides an eco-friendly alternative to conventional packaging and exhibits significant potential in preserving the quality of postharvest food. Herein, we aim to develop a novel edible and active coating based on xanthan gum (XG) nanoemulsion (NE) incorporating betel leaf extract (BLE) for the preservation of fresh produce. The total phenolic content, total flavonoid content, and antioxidant capacity of the methanol extract of BLE at various concentrations were characterized. Further development of the active coating at different formulations of Tween 80 (1 % and 3 % w/v), XG (0.1 % to 0.5 % w/v), and BLE (1 % to 5 % w/v) was characterized by physical stability, viscosity, and antimicrobial properties. Results showed that the active coating at 1 % BLE showed significant antimicrobial properties against diverse bacterial and fungal foodborne pathogens (e.g., B. cereus, S. aureus) and fungal cultures (e.g., C. albicans). The study also examined the shelf-life of tomatoes coated with the BLE-XG NE solution, stored at 4 °C for 27 days. Analyses of weight retention, soluble solids, pH, texture, sensory attributes, and microbial populations showed that the coating effectively preserved tomato quality, highlighting its potential to preserve fresh produce and enhance food security.

Chitosan/aloe vera gel coatings infused with orange peel essential oils for fruits preservation

Continuous fruit waste poses significant environmental and economic challenges, necessitating innovative fruit coating technologies. This research focuses on harnessing discarded orange peels to extract essential oil (OPEO), which is then integrated into a chitosan/aloe vera (CTS/AVG) matrix. The study comprehensively characterised the coating in terms of its physicochemical properties, antioxidant capacity, and antimicrobial efficacy. The investigation involved an analysis of particle size and distribution in the coating solutions, highlighting changes induced by the incorporation of orange peel essential oil (1 %, 2 % and 3 % v/w) into the chitosan/aloe vera (4:1 v/v) matrix, including particle size reduction and enhanced Brownian motion. The study quantifies a 33.21 % decrease in water vapour transmission rate and a reduction in diffusion coefficient from 9.26 × 10-11 m2/s to 6.20 × 10-11 m2/s following the addition of OPEO to CTS/AVG. Assessment of antioxidant potential employing DPPH radical scavenging assays, revealed that CTS/AVG/3 %OPEO exhibited notably superior radical scavenging activity compared to CTS/AVG, CTS/AVG/1 %OPEO, and CTS/AVG/2 %OPEO, demonstrated by its IC50 value of 17.01 ± 0.45 mg/mL. The study employs the well diffusion method, demonstrating a higher susceptibility of gram-negative bacteria to the coating solutions than gram-positive counterparts. Remarkably, CTS/AVG/3 %OPEO displayed the most pronounced inhibition against Escherichia coli, generating an inhibitory zone diameter of 14 ± 0.8 mm. The results collectively emphasised the potential of CTS/AVG/3 %OPEO as a viable natural alternative to synthetic preservatives within the fruit industry, attributed to its exceptional antioxidant and antimicrobial properties.

Composite coatings of beeswax + naphthalene acetic acid preserved fruit quality and antioxidants in stored lemon fruits

Lemon fruits are well recognized for their richness in antioxidants. The present study was conducted to maintain the antioxidant properties of lemon fruits under long term cold storage. Fruits were given different treatments of naphthalene acetic acid (NAA) @ 50, 100 and 150 ppm plus beeswax (BW) @ 2% and were stored at 6-8 °C and 90-95% RH for 60 days. At the end of storage, fruits coated with NAA (50 ppm) + BW (2%) retained 42.14 and 34.61% antioxidants, 62.72 and 56.54% phenolic content and 17.72 and 13.80% hydroxyl radical scavenging capacity in peel and pulp, respectively as compared to the control. This treatment also resulted in lesser weight loss (5.27%), higher ascorbic acid content (46.31 mg 100 ml-1 juice) and titratable acidity (5.23%). Hence, NAA + BW coatings were promising for the maintenance of the postharvest antioxidant quality of stored lemons.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01364-4.

Advancements in coating technologies: Unveiling the potential of chitosan for the preservation of fruits and vegetables

Post-harvest losses of fruits and vegetables pose a significant challenge to the agriculture industry worldwide. To address this issue, researchers have turned to natural and eco-friendly solutions such as chitosan coatings. Chitosan, a biopolymer derived from chitin, has gained considerable attention due to its unique properties such as non-toxicity, biodegradability, biocompatibility and potential applications in post-harvest preservation. This review article provides an in-depth analysis of the current state of research on chitosan coatings for the preservation of fruits and vegetables. Moreover, it highlights the advantages of using chitosan coatings, including its antimicrobial, antifungal, and antioxidant properties, as well as its ability to enhance shelf-life and maintain the quality attributes of fresh product. Furthermore, the review discusses the mechanisms by which chitosan interacts with fruits and vegetables, elucidating its antimicrobial activity, modified gas permeability, enhanced physical barrier and induction of host defense responses. It also examines the factors influencing the effectiveness of chitosan coatings, such as concentration, molecular weight, deacetylation degree, pH, temperature, and application methods.

Comparison of chitosan and gelatin-based films and application to antimicrobial coatings enriched with grapefruit seed extract for cherry tomato preservation

Bio-based single, composite, and bilayer edible films were developed based on chitosan and gelatin, including grapefruit seed extract (GSE) as an antimicrobial agent. The physicochemical and antimicrobial properties of films were analyzed, and it was found that compounding and laminating two polymers could enhance their physicochemical properties. The composite film was strong, endurable, and flexible compared with the single ones. In addition, the composite and bilayer films had lower water vapor permeability than the single ones. Edible films and coatings with GSE presented a greater bactericidal effect than the inactive ones. In addition, the hardness, weight, and color changes of the coated cherry tomatoes during 7-day storage did not differ, whereas a bacterial reduction against Salmonella Typhimurium was revealed. Taken together, composite and bilayer films with CH and GL and enriched with GSE were developed for food packaging applications, and it showed improved mechanical, water barrier, and antimicrobial properties.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01254-9.

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.

Effect of polyvinyl acetate (PVAc) based coating on quality characteristics of capsicum during storage

The effect of PVAc (Polyvinyl acetate) coating on various characteristics of capsicum was determined during postharvest storage at room temperature (30 ± 1 °C) and refrigeration temperature (10 ± 1 °C). Food grade PVAc was used to make different coating formulations (2.5, 5, 7.5, 10 and 12.5%) by dissolving alcohol-water mixtures. After coating, the samples were stored at room temperature (30 ± 1 °C) and refrigeration temperature (10 ± 1 °C) for a comparative study. Various physicochemical parameters viz. weight loss, TSS, acidity, chlorophyll, pH, ascorbic acid, and color were analyzed every three days of storage till spoilage. Results revealed that the physicochemical characteristics and the quality of the bell peppers were improved by coating treatments at both the storage conditions. PVAc concentrations of 10 and 12.5% performed better than other PVAc coatings in retaining the chlorophyll and water content, which ultimately increased the shelf life of capsicum without significantly affecting its green color. The coating reduced the weight loss and color change, maintained total soluble solids, titratable acidity, pH over the storage period. About 40-50% less weight loss was observed in case of higher PVAc coating concentrations (10 and 12%). Therefore, the present study results suggested that PVAc coating can maintain postharvest storage quality of capsicum at 30 ± 1 °C and 10 ± 1 °C storage conditions.

Graphical abstract

Pomegranate Husk Scald Browning during Storage: A Review on Factors Involved, Their Modes of Action, and Its Association to Postharvest Treatments

The pomegranate (Punica granatum L.), which contains high levels of health-promoting compounds, has received much attention in recent decades. Fruit storage potential ranges from 3 to 4 months in air and from 4 to 6 months in Controlled Atmospheres (CA) with 3-5% oxygen and 10-15% carbon dioxide. Storage life is limited by decay, chilling injury, weight loss (WL), and husk scald. In particular, husk scald (HS) limits pomegranate long-term storage at favorable temperatures. HS appears as skin browning which expands from stem end towards the blossom end during handling or long-term storage (10-12 weeks) at 6-10 °C. Even though HS symptoms are limited to external appearance, it may still significantly reduce pomegranate fruit marketability. A number of postharvest treatments have been proposed to prevent husk scald, including atmospheric modifications, intermittent warming, coatings, and exposure to 1-MCP. Long-term storage may induce phenolic compounds accumulation, affect organelles membranes, and activate browning enzymes such as polyphenol oxidases (PPO) and peroxidases (POD). Due to oxidation of tannins and phenolics, scalding becomes visible. There is no complete understanding of the etiology and biochemistry of HS. This review discusses the hypothesized mechanism of HS based on recent research, its association to postharvest treatments, and their possible targets.

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.

The Combined Effect of Hot Water Treatment and Chitosan Coating on Mango (Mangifera indica L. cv. Kent) Fruits to Control Postharvest Deterioration and Increase Fruit Quality

The synergistic effect of dipping in 55 °C for 5 min of hot water (HW) and 1% chitosan coating during the storage of mango at 13 ± 0.5 °C and 85%–90% relative humidity for 28 days was investigated. The combined treatment significantly suppressed the fruit decay percentage compared with both the single treatment and the control. In addition, the specific activities of key plant defense-related enzymes, including peroxidase (POD) and catalase (CAT), markedly increased. The increase occurred in the pulp of the fruits treated with the combined treatment compared to those treated with HW or chitosan alone. While the control fruits showed the lowest values, the combination of pre-storage HW treatment and chitosan coating maintained higher values of flesh hue angle (h°), vitamin C content, membrane stability index (MSI) percentage, as well as lower weight loss compared with the untreated mango fruits. The combined treatment and chitosan treatment alone delayed fruit ripening by keeping fruit firmness, lessening the continuous increase of total soluble solids (TSS), and slowing the decrease in titratable acidity (TA). The results showed that the combined application of HW treatment and chitosan coating can be used as an effective strategy to suppress postharvest decay and improve the quality of mango fruits.