Effect of Chitosan Coatings with Cinnamon Essential Oil on Postharvest Quality of Mangoes

Pickering emulsion stabilized by hollow Zein/SSPS nanoparticles loaded with Thymol: Formation, characterization, and application in fruit preservation

Using Pickering emulsion (PE) as the carrier of active compounds in bio-based coatings constitutes a highly promising research domain. This study focused on creating a food-grade, biocompatible, and antibacterial PE to coat fresh fruits and vegetables, extending their shelf life. Hollow zein/soluble soybean polysaccharide nanoparticles loaded with thymol (H-ZSH/T) were produced using NaHCO3 as a sacrificial template to stabilize PE. The results revealed that the prepared hollow zein-based nanoparticles had superior dispersibility and structure compared to solid nanoparticles, with an average particle size of 92.24-95.18 nm and polydispersity index (PDI) of 0.151-0.179. Thymol was successfully encapsulated through hydrogen bonding, electrostatic attraction, and hydrophobic interactions. The zein-based nanoparticles loaded with thymol showed notable antibacterial properties against E. coli and S. aureus, with a more substantial effect on E. coli. H-ZHS/T demonstrated the highest antibacterial efficacy by disrupting bacterial cell membranes. The prepared PE was an oil-in-water type; increasing the oil fraction improved stability and droplet size while reducing the creaming index. Rheological assessments indicated elastic gel-like characteristics, ensuring both stability and uniformity. The PE coating significantly slowed the loss of fruit hardness, inhibited microbial growth, and extended the shelf life of blueberries and fresh-cut cantaloupe. These findings demonstrated that H-ZHS/T-stabilized PE is an effective and eco-friendly food coating.

Dual structure on-demand release chitosan-based coating film for peach preservation

After harvest, fruits and vegetables go through the stages of storage, transportation and sales, and how to regulate the role of preservative in different stages is an urgent problem to be solved. Herein, chitosan-stearic acid is synthesized, then interacting with trans-2-hexenal (E2H) to prepare nanoclusters. Subsequently, the temperature-sensitive liposomes were designed to encase E2H by using the special temperature-responsive open-chain phospholipids, and then combined with chitosan to obtain chitosan-based coating film for peach preservation. The thermosensitive liposomes were uniformly distributed, highly dispersed and spherical, which has excellent temperature response characteristics, and the release of active substances could be regulated in the temperature range of 10 °C-40 °C to achieve the effect of on-demand release. In addition, thermosensitive liposomes also have excellent antioxidant and antibacterial activities. Therefore, the obtained chitosan-based coating could maintain the freshness of peaches, improve the quality and extend the storage period of peaches. The edible chitosan coating and active preservative prepared in this study have potential application value in responsive intelligent active packaging.

Metal-organic frameworks-based moisture responsive essential oil hydrogel beads for fresh-cut pineapple preservation

The preservation of fresh-cut fruits and vegetables has attracted attention to the shelf-life reduction caused by high humidity. Herein, alginate/copper ions cross-linking, in-situ growth and self-assembly techniques of metal-organic frameworks (MOFs) were utilized to prepare a moisture responsive hydrogel bead (HKUST-1@ALG). As the multistage porous structure formation, tea tree essential oil (TTO) load capacity in hydrogel bead (TTO-HKUST-1@ALG) was increased from 6.1% to 21.6%. TTO-HKUST-1@ALG had excellent moisture response performance, and the release rates of TTO increased from 33.89% to 70.98% with moisture increasing from 45% to 95%. Besides, TTO-HKUST-1@ALG exhibited excellent antimicrobial, antioxidant capacity, and biocompatibility. During storage, TTO-HKUST-1@ALG effectively improved the cell membrane integrity by maintaining the balance of reactive oxygen species metabolism. The degradation of cell wall structure and tissue softening were delayed by inhibiting the cell wall-degrading enzymes activity. Briefly, TTO-HKUST-1@ALG improved the storage quality and extended shelf-life of fresh-cut pineapple, which was a promising preservative.

Effect of polyethoxylated flavonoids (PMFs)-loaded citral and chitosan composite coatings on citrus preservation: From the perspective of fruit resistance

Previous studies have shown that polymethoxylated flavonoids-loaded citral emulsion (PCT) can inhibit the growth and reproduction of Penicillium in citrus; however, PCT is difficult to apply to fruit preservation due to its high fluidity and volatility. Therefore, in this study, we combined PCT with chitosan (CS) to investigate the effect of a composite coating on citrus preservation. The results showed that compared to the control group, the CS-PCT group could effectively reduce the decay rate and maintain moisture availability, color difference, and hardness. Moreover, the contents of nonenzymatic antioxidants and volatile substances with antimicrobial activity were better preserved. In addition, the activities of related antioxidant enzymes were greater in the treatment group, and the expression of the corresponding enzyme-encoding genes was upregulated. Consequently, CS-PCT treatment could effectively maintain fruit quality and improve the resistance of citrus fruits during storage; moreover, it can be considered a nontoxic and efficient citrus preservative.

Citric acid crosslinked carboxymethyl cellulose edible films: A case study on preserving freshness in bananas

The study involves the preparation and characterization of crosslinked-carboxymethyl cellulose (CMC) films using varying amounts of citric acid (CA) within the range 5 %-20 %, w/w, relative to the dry weight of CMC. Through techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, carbonyl content analysis, and gel fraction measurements, the successful crosslinking between CMC and CA is confirmed. The investigation includes an analysis of chemical structure, physical and optical characteristics, swelling behavior, water vapor transmission rate, moisture content, and surface morphologies. The water resistance of the cross-linked CMC films exhibited a significant improvement when compared to the non-crosslinked CMC film. The findings indicated that films crosslinked with 10 % CA demonstrated favorable properties for application as edible coatings. These transparent films, ideal for packaging, prove effective in preserving the quality and sensory attributes of fresh bananas, including color retention, minimized weight loss, slowed ripening through inhibiting amyloplast degradation, and enhanced firmness during storage.

Effect of EVA film and chitosan coating on quality and physicochemical characteristics of mango fruit during postharvest storage

Mango (Mangifera indica L.) is a major tropical fruit, but a short postharvest life hampers marketing. The objective of this work is to assess the influence of a novel nanocomposite poly (ethylene-co-vinyl acetate) (EVA) film and Chitosan (CTS) affect on mango postharvest quality while stored at 20 °C. The results showed that the film coating treatment reduced the decay rate and weight loss of mangoes, maintaining good postharvest quality of mango fruit. The film coating treatment increased the antioxidant capacity of mangoes by inhibiting PPO activity and increasing the activity of antioxidant enzymes. ACS, ACO, and ethylene release were all suppressed, as well as the expression of the ethylene receptors genes ETR1, ETR2, and ERS2, thus delaying mango aging. After harvest, the EVA treatment was superior to the CTS treatment in mango preservation.

Nanoscale Pickering emulsion food preservative films/coatings: Compositions, preparations, influencing factors, and applications

Pickering emulsion (PE) technology effectively addresses the issues of poor compatibility and low retention of hydrophobic active ingredients in food packaging. Nonetheless, it is important to recognize that each stage of the preparation process for PE films/coatings (PEFCs) can significantly influence their functional properties. With the fundamental considerations of environmental friendliness and human safety, this review extensively explores the potential of raw materials for PEFC and introduces the preparation methods of nanoparticles, emulsification technology, and film-forming techniques. The critical factors that impact the performance of PEFC during the preparation process are analyzed to enhance food preservation effectiveness. Moreover, the latest advancements in PE packaging across diverse food applications are summarized, along with prospects for innovative food packaging materials. Finally, the preservation mechanism and application safety have been systematically elucidated. The study revealed that the PEFCs provide structural flexibility, where designable nanoparticles offer unique functional properties for intelligent control over active ingredient release. The selection of the dispersed and continuous phases, along with component proportions, can be customized for specific food characteristics and storage conditions. By employing suitable preparation and emulsification techniques, the stability of the emulsion can be improved, thereby enhancing the effectiveness of the films/coatings in preserving food. Including additional substances broadens the functionality of degradable materials. The PE packaging technology provides a safe and innovative solution for extending the shelf life and enhancing the quality of food products by protecting and releasing active components.

Formulation of a Stable Oil-in-Water Microemulsion of Torreya grandis cv. Merrillii Aril Essential Oil and Its Application in Loquat Fruit Preservation

Loquat is a nutrient-rich fruit with juicy and sweet pulp, but it is vulnerable to rot and deterioration without proper postharvest preservation measures. This study aimed to improve the postharvest quality of loquat by developing a microemulsion system based on an essential oil extracted from the Torreya grandis cv. Merrillii aril (TaEO), which has antimicrobial and antioxidant properties. An optimal TaEO microemulsion (TaEO-ME) was formulated, using a mixture of Tween-40 and Tween-80 as the surfactant, 1-butanol as the co-surfactant, and TaEO as the oil phase, with mass ratios of 9:1, 3:1, and 6:1, respectively. Two TaEO-ME formulations with 60% and 70% water contents were stable for 180 days at room temperature, with a mean droplet size below 12 nm and polydispersity index less than 0.24. They also exhibited higher stability and enhanced biological activities compared to free TaEO. Loquat fruit treated with TaEO-ME displayed a reduced decay index and lower membrane lipid peroxidation after 15 days of storage at 15 °C, as indicated by the lower malondialdehyde content and higher peroxidase activity. Moreover, the TaEO-ME treatment preserved the nutrient quality by maintaining the total phenolic compounds and ascorbic acid content. Our findings suggested that TaEO-ME can be used as a substitute for chemical preservatives to keep fruits fresh.

Application of a Chitosan-Cinnamon Essential Oil Composite Coating in Inhibiting Postharvest Apple Diseases

The purpose of this study was to explore the film-forming properties of cinnamon essential oil (CEO) and chitosan (CS) and the effect of their composite coating on postharvest apple diseases. The results demonstrated that the composite coating exhibits favorable film-forming properties at CEO concentrations below 4% (v/v). The effectiveness of the composite coating in disease control can be attributed to two factors: the direct inhibitory activity of CEO against pathogens in vitro and the induced resistance triggered by CS on the fruits. Importantly, the incorporation of CEO did not interfere with the induction of resistance by CS in harvested apples. However, it is noteworthy that the inhibitory effect of the CS-CEO composite coating on apple diseases diminished over time. Therefore, a key aspect of enhancing the preservation ability of fruits is improving the controlled release properties of CEO within CS coatings. This will enable a sustained and prolonged antimicrobial effect, thereby bolstering the fruit preservation capabilities of the composite coatings.

Cinnamon essential oil vapor alleviates the reduction of aroma-related volatiles in cold-stored "Feicheng" peach using HS-GC-IMS

"Feicheng" peach is popular for its unique aroma, but its defect of being highly sensitive to chilling injury (CI) often leads to aroma loss and internal browning. Essential oils (EOs) are often used to enhance the antioxidant capacity of plants and fruits, as well as to trigger their defense against biotic/abiotic stresses. This study aimed to examine the effect of cinnamon essential oil (CEO) vapor treatment on the aroma quality of peach fruit during cold storage using HS-GC-IMS. The results showed that 50 μL/L CEO vapor reduced the severity of internal browning (IB) in peaches at the stage of 7 ~ 21 d during refrigeration (Significantly, the L* value was higher and the IB index was lower than that of control, p < 0.05). Meanwhile, the evident reduction or loss of aroma content caused by CI was restored to a higher level than the control (p < 0.05). Furthermore, CEO treatment promoted the release of aroma-related volatiles as evidenced by more propyl acetate, and the dimer of amyl acetate, isoamyl acetate, butyl acetate detected than that on harvest day and no-treated group after 21 d of cold storage plus 2 d of shelf life. Genes of PpLOX1, PpLOX2, PpHPL1 and PpADH1 associated with aroma-related volatile biosynthesis revealed higher transcript abundance in peach fruits treated with CEO than the control (p < 0.05). Overall, our study demonstrated that CEO in vapor phase may be beneficial to alleviate the quality deterioration in aroma and flesh color of "Feicheng" peaches caused by CI, which lays a theoretical reference for maintaining postharvest quality of peach fruits.

The Effects of Combined 1-Methylcyclopropene and Melatonin Treatment on the Quality Characteristics and Active Oxygen Metabolism of Mango Fruit during Storage

In this study, mango fruit (Tainong No. 1) was treated with either 0.1 mg/L 1-methylcyclopropene (1-MCP) alone or with a combination of 0.1 mg/L 1-MCP and 0.2 mM melatonin (MT). The mango fruit was then stored for 10 days at 25 °C and 85-90% relative humidity. Quality characteristics and the active oxygen metabolism of postharvest mangoes were evaluated every 2 days. Compared to untreated mango fruit, those with the treatments of 1-MCP alone or 1-MCP + MT had a better appearance and higher levels of soluble sugar, ascorbic acid, and titratable acidity. Moreover, these treatments prevented the loss of fruit firmness, successfully delayed the escalation of a* and b* values, and reduced malondialdehyde content and superoxide anion generation rate. After 10 days of storage, mango fruit treated by 1-MCP alone or 1-MCP + MT exhibited increased activities of antioxidant enzymes such as ascorbate peroxidase, catalase, superoxide dismutase, and other peroxidases; nevertheless, the two treatment protocols maintained higher mango total phenolic content only at the later stage of storage. These findings suggest that mango fruit treated with 1-MCP alone or with 1-MCP + MT improves the quality characteristics and antioxidant activities. Moreover, compared to 1-MCP treatment alone, 1-MCP + MT-treated mangoes exhibited higher quality and a stronger regulation of active metabolism during storage.

Synergistic Effects of Tragacanth and Anti-ethylene Treatments on Postharvest Quality Maintenance of Mango (Mangifera indica L.)

Mango (Mangifera indica L.) is one of the most popular tropical fruits grown in Egypt and several other countries, making it a potential export commodity. Excessive deterioration after harvest requires various treatments to maintain fruit quality. We evaluated the treatments effects of melatonin (MT) as an anti-ethylene agent and tragacanth gum (TRG) as an edible coating individually and together (MT-TRG) before storing mangoes at 12 °C for 32 days under 85-90% relative humidity. Compared with control, all treatments were significantly effective in preserving fruit quality. Fruits treated with MT-TRG showed significantly lower decay values, respiration rates, ethylene production, and weight loss than untreated fruits. MT-TRG treatment significantly enhanced fruit quality, thereby maintaining fruit appearance, flesh color, firmness, total soluble solids and phenolic contents, and pectin methyl esterase, polyphenol oxidase, and peroxidase activities during the storage period. We propose 200 µM MT + 1% TRG as a safe postharvest treatment to reduce the deterioration of mangoes and maintain fruit quality.

Effect of sustained-release tea tree essential oil solid preservative on fresh-cut pineapple storage quality in modified atmospheres packaging

The quality and safety of fresh-cut pineapple deteriorate during handling and storage due to physicochemical and microbial changes, so its preservation has attracted extensive attention. This study prepared sustained-release tea tree essential oil (TTO) solid preservative (SP) with an encapsulation efficiency of 71.45% and applied it on fresh-cut pineapple in modified atmospheres packaging (MAP). Results showed that TTO adsorbed on nano silicon dioxide (SiO₂) was embedded in the starch-carboxymethyl cellulose network structure by extrusion. The hydrogen bond and hydrophobic interaction resulted in compact structure and good sustained-release performance of SP. The SP improved sensory quality and reduced nutrient loss and microbial spoilage of fresh-cut pineapple, which extended its shelf-life to four days. In addition, antioxidant capacity was enhanced with increasing antioxidant enzyme activity, antioxidant content, and 2,2-diphenyl-1-picrylhydrazine scavenging capacity and decreasing MDA accumulation. Therefore, sustained-release TTO solid preservative has potential for the preservation of fresh-cut pineapple.

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.

Antimicrobial and Antioxidant Effects of Kappa-Carrageenan Coatings Enriched with Cinnamon Essential Oil in Pork Meat

Fresh pork is susceptible to microbial contamination and lipid oxidation, which leads to food safety and quality issues. This study aimed to develop a kappa-carrageenan (KC) coating embedded with cinnamon essential oil (CEO) for antimicrobial and antioxidant purposes in pork meat. The uncoated controls and coated samples were subjected to microbial (total viable count, lactic acid bacteria, and H2S-producing bacteria), chemical (DPPH and pH), and physical (surface color) analyses during refrigerated storage at 4 °C for 7 days. It was observed that KC coatings exhibited a better preservation effect on pork meat after the addition of CEO. The KC−CEO coatings were effective in retarding the growth of total viable count, lactic acid bacteria, and H2S-producing bacteria. In a DPPH test, the level of lipid oxidation in pork meat was also significantly (p < 0.05) reduced by the KC−CEO coatings. Furthermore, these coatings displayed pronounced activity in inhibiting the adverse alterations of pH value and surface color. Practically, KC−CEO-coated samples still exhibited an attractive bright red color at the end of refrigerated storage. Taken together, the developed KC−CEO coatings exerted pronounced antimicrobial and antioxidant activities in pork, thus providing a potential approach to preserving perishable meat.

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.