Development and characterization of an edible chitosan/zein-cinnamaldehyde nano-cellulose composite film and its effects on mango quality during storage

Active whey protein/hydroxypropyl methylcellulose edible films incorporated with cinnamaldehyde: Characterization, release kinetics and application to Mongolian cheese preservation

Edible films with modulated release of antimicrobial agents are important for food preservation. Herein, antimicrobial edible films were prepared using whey protein (WP) and hydroxypropyl methylcellulose (HM) as polymer matrix materials and cinnamaldehyde (CIN) as antimicrobial agent. The mass ratios of WP and HM were 100/0, 75/25, 50/50, 25/75 and 0/100. The release kinetics of CIN through the film was studied, applying the Fickian model, power law and Weibull model. The films were also characterized by physical and structural characteristics, and antibacterial activity. In comparison to other films, the CIN-loaded film with a WP/HM ratio of 50/50 had better moisture resistance, water vapor barrier properties and mechanical properties. High correlation factors were obtained by fitting the CIN release data with the power law (R2 > 0.96) and Weibull model (R2 > 0.97). The diffusion mechanism of CIN was pseudo-Fickian. The diffusion coefficients (D1 and D2) had a positive linear relationship with the HM ratio, suggesting that a high HM ratio was beneficial to the CIN release. Finally, the WH50-C film was successfully used to preserve Mongolian cheese. This research provides a new perspective on the design of active packaging film with sustained-release characteristics.

Enhanced antioxidant and antibacterial activities of chitosan/zein nanoparticle Pickering emulsion-incorporated chitosan coatings in the presence of cinnamaldehyde and tea polyphenol

Pickering emulsions were prepared by using zein/chitosan nanoparticles as stabilizer and then incorporated into chitosan coatings. To improve the stability and performances, tea polyphenol and cinnamaldehyde (CA) were used to modulate the formation and functionalities of Pickering emulsions. The oil phase in Pickering emulsions were set at 5 % and 20 % to alter the hydrophobicity of chitosan coatings. Physical, structural, antioxidant and antibacterial activities of chitosan coatings with Pickering emulsions were characterized. Tea polyphenol significantly enhanced antioxidant capacity of chitosan coatings from 2.09 % to 57.61 % of DPPH value and from 2.63 % to 38.85 % of ABTS value. CA effectively increased the antibacterial activity of chitosan coatings against S. aureus and E. coli. Under 20 % oil content, the inhibition zones on S. aureus and E. coli increased from 3.03 ± 0.23 mm to 18.39 ± 1.22 mm and 7.66 ± 1.61 mm to 15.70 ± 1.75 mm, respectively. The preservative effect of chitosan coatings on fresh pork was further confirmed that the shelf-life of fresh pork could be extended by >4 days. These results suggested a great potential application of Pickering emulsion-incorporated chitosan coatings in the preservation of fresh pork.

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.

Effects of Litsea cubeba Essential Oil-Chitosan/Corn Starch Composite Films on the Quality and Shelf-Life of Strawberry (Fragaria × ananassa)

In this work, we have developed a composite chitosan film incorporating the Litsea cubeba essential oil (LCEO) and starch with good physical properties, and investigated the effect of coating strawberries with this composite film. The best formula of the LCEO/chitosan/corn starch/glycerol (LCEO/CH/CS/gly) composite films is 0.25% LCEO, 2.75% CH, 0.40% corn starch, and 0.75% glycerol. Coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly films resulted in significantly lower respiration intensity and a slower decay rate, much slower decreases in the firmness, and reductions in the sugar and ascorbic acid content of the fruit during storage (p < 0.05). The coatings also led to a much slower accumulation of malondialdehyde and anthocyanins (p < 0.05). The LCEO/CH/CS/gly film was generally more effective than the CH/CS/gly film; however, the effect was more obvious in the later stages of storage. Thus, coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly film can be a viable method for extending the shelf-life of the fruit.

Enhanced mechanical properties and antibacterial activities of chitosan films through incorporating zein-gallic acid conjugate stabilized cinnamon essential oil Pickering emulsion

In this study, zein-gallic acid covalent complex prepared by alkali treatment was utilized as an emulsifier to stabilize cinnamon essential oil (CEO) Pickering emulsion, and the chitosan-based (CZGE) films loaded with CEO Pickering emulsion were prepared by blending. The influences of different contents of CEO Pickering emulsion on the physical properties and biological activities of CZGE films were investigated. The results showed that Pickering emulsion had good compatibility with chitosan matrix and enhanced the interaction between film-forming matrix polymer. In addition, incorporating with CEO Pickering emulsion (15 %, v/v) significantly improved the mechanical and barrier properties of the films, and also enhanced the light transmittance and thermal stability of the films. Furthermore, the loading of emulsion also improved the antioxidant activities of the films and led to the formation of high antimicrobial property against food pathogens, and the slow-release behavior of CEO could effectively extend the biological activity of the films. These results suggested that Pickering emulsion has potential as a loading system and a plasticizer in active packaging, and the feasibility of CZGE film in food packaging.

Improving the performance of Ca-alginate films through incorporating zein-caseinate nanoparticles-loaded cinnamaldehyde

This study aimed to fabricate and characterize the Ca-alginate films functionalized by incorporating zein nanoparticles containing cinnamaldehyde (CA). The zein nanoparticles were coated with Na-caseinate (CN) to inhibit the precipitation of zein in the alginate solution. Afterward, the physical, mechanical, morphological, and barrier properties of the nanocomposite films were evaluated. The particle sizes of different zein nanoparticles (with/without CA and CN) ranged between 43.58 and 251.66 nm. The addition of free CA, zein, and CN nanoparticles significantly increased the thickness, opacity, thermal stability, and water contact angle and improved the mechanical properties of the films. The water vapor permeability was not affected but the antimicrobial activity was improved on fresh-cut apples. The lightness of nanocomposite films decreased and the yellowness and greenness increased. According to SEM and AFM images, a dense and organized interlayer arrangement with a rougher surface was detected in the nanocomposite films. FTIR analysis showed that no new interactions were formed between the Ca-alginate and zein/CN nanoparticles. An excellent sustained CA release into the water was observed for the CA/zein nanoparticles-loaded alginate films. Overall, the results showed that Ca-alginate nanocomposite films of zein nanoparticles have good potential to carry hydrophobic bioactive compounds for specific pharmaceutical and food applications.

pH-responsive double-layer film based on chitosan/curcumin-β-cyclodextrin complex/cinnamaldehyde and zein/alizarin for pork freshness monitoring and maintaining

A pH-responsive double-layer film comprising chitosan (CS), zein (Z), curcumin-β-cyclodextrin complex (Cur- β-CD), alizarin (AL) and cinnamaldehyde (CIN) was developed to detect spoilage and prolong the shelf life of pork. The outer Z/AL is the colorimetric responsive and highly protective outer layer, while the CS/Cur- β-CD/CIN is the fluorescence responsive and functional layer. The CS/Cur- β-CD/CIN-Z/AL film demonstrated excellent barrier properties against oxygen (8.48 × 10-13 g (m s Pa)-1) and water (2.42 × 10-11 g (m s Pa)-1) primarily due to the polar interactions in the Z structure and its hydrophobic nature. The addition of AL and Cur provided the CS/Cur- β-CD/CIN-Z/AL film with pH colorimetric and fluorescence response capabilities, respectively. Furthermore, the inclusion of Cur- β-CD, CIN and AL significantly enhanced the film's antioxidant and antibacterial properties, with radical scavenging rates of 79.29 % (DPPH) and 89.84 % (ABTS), as well as antibacterial efficiencies of 96.2 % (S. aureus) and 85.78 % (E. coli). To test the effectiveness of the double-layer film, a freshness monitoring and maintenance experiment was conducted on pork stored at 4 °C for 8 days. Various parameters of pork, including surface color, pH value, total volatile bases nitrogen (TVB-N), total viable counts (TVC), thiobarbituric acid reactive substance (TBARS), hardness and springiness, were measured, along with the color and fluorescence intensity (FL) of the film. The shelf life of the pork was extended by at least 2 days compared to the control group, and the pork was considered inedible if ΔE ≥ 12 or FL intensity ≤ 2160. Overall, this food packaging film shows promise in simultaneously monitoring and maintaining the freshness of pork.

Preparation and Characterization of a Novel Artemisia Oil Packaging Film and Its Application in Mango Preservation

In this work, a new food packaging film was synthesized via blending Artemisia oil (AO) into soybean protein isolate (SPI) and gelatin (Gel) for the postharvest storage of mango. The morphological architecture and mechanical properties of the films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and other technologies. The results show that the prepared films had relatively flat surfaces with good mechanical properties. AO enhanced the light-blocking ability of the film, increased the hydrophobicity, and affected the moisture content and water solubility of the film to a certain extent. Furthermore, the antioxidant performance and antifungal (Colletotrichum gloeosporioides) capacity of the films increased with higher AO concentration due to the presence of the active components contained in AO. During mango storage applications, the films showed good freshness retention properties. The above results indicate that SPI-Gel films containing AO have excellent physicochemical and application properties and have great potential in the field of food packaging.

A review of food preservation based on zein: The perspective from application types of coating and film

The application of zein in food preservation was discussed from a unique perspective of application types, including coating and film. For the study of coating, edibility is considered because the coating adheres to the surface of food directly. For the study of film, plasticizers improve their mechanical properties, while barrier performance and antibacterial performance are achieved by nanoparticles; the incorporation of polyphenols is mainly due to their antibacterial and antioxidant properties; other biopolymers realize the complementarity between zein and biopolymers within films. In the future, the interaction between the edible coating and food matrix needs to be concerned. The mechanism of various exogenous additives and zein in the film should be noticed. Importantly, food safety and the possibility of large-scale application should be followed. Additionally, the intelligent response is one of the key development directions of zein-based film in the future.

Development and Characterization of an Edible Zein/Shellac Composite Film Loaded with Curcumin

The development of functional edible films is promising for the food industry, and improving the water barrier of edible films has been a research challenge in recent years. In this study, curcumin (Cur) was added to zein (Z) and shellac (S) to prepare an edible composite film with a strong water barrier and antioxidant properties. The addition of curcumin significantly reduced the water vapor permeability (WVP), water solubility (WS), and elongation at break (EB), and it clearly improved the tensile strength (TS), water contact angle (WCA), and optical properties of the composite film. The ZS-Cur films were characterized by SEM, FT-IR, XRD, DSC, and TGA; the results indicated that hydrogen bonds were formed among the curcumin, zein, and shellac, which changed the microstructure and improved the thermal stability of the film. A test of curcumin release behavior showed controlled release of curcumin from the film matrix. ZS-Cur films displayed remarkable pH responsiveness, strong antioxidant properties, and inhibitory effects on E. coli. Therefore, the insoluble active food packaging prepared in this study provides a new strategy for the development of functional edible films and also provides a possibility for the application of edible films to extend the shelf life of fresh food.

Preparation and characterization of functionalized chitosan/polyvinyl alcohol composite films incorporated with cinnamon essential oil as an active packaging material

In this study, amphiphilic chitosan (NPCS-CA) was synthesized by grafting quaternary phosphonium salt and cholic acid onto the chain of chitosan, aiming to develop an active edible film based on NPCS-CA and polyvinyl alcohol (PVA) incorporated with cinnamon essential oil (CEO) by the casting method. The chemical structure of the chitosan derivative was characterized by FT-IR, ¹H NMR and XRD. Through the characterization of FT-IR, TGA, mechanical and barrier properties of the composite films, the optimal proportion of NPCS-CA/PVA was determined as 5/5. And, the tensile strength and elongation at break of the NPCS-CA/PVA (5/5) film with 0.4 % CEO were 20.32 MPa and 65.73 %, respectively. The results revealed that the NPCS-CA/PVA-CEO composite films exhibited an excellent ultraviolet barrier property at 200-300 nm and significantly reduced oxygen permeability, carbon dioxide permeability and water vapor permeability. Furthermore, the antibacterial property of film-forming solutions against E. coli, S. aureus, and C. lagenarium was distinctly improved with the increase of NPCS-CA/PVA proportion. And, the multifunctional films effectively extended the shelf-life of mangoes at 25 °C based on the characterization of surface changes and quality indexes. The NPCS-CA/PVA-CEO films could be developed as biocomposite food packaging material.

Integrated transcriptomic-metabolomic analysis reveals that cinnamaldehyde exposure positively regulates the phenylpropanoid pathway in postharvest Satsuma mandarin (Citrus unshiu)

Previously, wax + cinnamaldehyde (WCA) was proven to be able to effectively alleviate fruit decay and induce resistance in harvested Satsuma mandarin (Citrus unshiu). However, the potential molecular mechanism is largely unknown. In the present study, transcriptomics, metabolomics and biochemical analyses were combined to clarify this process. Transcriptomic analysis revealed that the expression of genes involved in secondary metabolites and related to pathogenesis and the phenylpropanoid pathway were significantly influenced by WCA treatment. In addition, metabolite profiling revealed that metabolites in the phenylpropanoid pathway were also predominantly impacted after WCA treatment. Correspondingly, enzymatic activities and gene expression involved in the phenylpropanoid pathway were positively regulated, especially in the first 24 h, resulting in increased levels of total phenolics, flavonoids and other secondary metabolites. Fruit inoculation experiments showed that WCA treatment significantly reduced the development of citrus green mold and sour rot while having no adverse effects on the edible quality of the tested citrus fruit. Our study confirms the potential role of WCA exposure in citrus to induce resistance through the phenylpropanoid pathway.

Bilayer pH-sensitive colorimetric indicator films based on zein/gellan gum containing black rice (Oryza sativa L.) extracts for monitoring of largemouth bass (Micropterus salmoides) fillets freshness

Anthocyanins as natural pH-sensitive material can be used to determine the freshness of largemouth bass (Micropterus salmoides) fillets. However, it is easily degraded. Using zein as the protective layer to improve the light blocking ability of the film, gellan gum (GG) and black rice extracts (BRE) as the sensing layer, a bilayer colorimetric indicator film for monitoring fish spoilage was developed. The functionality and stability of bilayer film and GG single film were compared. As compared to GG single film, Zein/GG bilayer film had stronger intermolecular interactions, higher mechanical properties, and higher optical barrier properties. Notably, Zein/GG-8 % BRE bilayer film exhibited higher stability than GG-8 % BRE film when the films were exposed to room temperature for 30 days. Zein/GG-8 % BRE bilayer film were further used to monitor freshness of largemouth bass fillets during storage. Zein/GG-8 % BRE bilayer film demonstrated a noticeable color change from red to brown when largemouth bass fillets spoiled. Moreover, the ∆E of films showed a good correlation with TVB-N of largemouth bass fillets (R² = 0.985). Our research results show that the Zein/GG-BRE bilayer indicator film has great potential application prospects in monitoring fish freshness.

Research Progress on Mango Post-Harvest Ripening Physiology and the Regulatory Technologies

Mango (Mangifera indica L.) is an important tropical fruit with a delicate taste, pleasant aroma, and high nutritional value. In recent years, with the promotion of the rural revitalization strategy and the development of the poverty alleviation industry, China has gradually become an important mango producer. However, the short shelf life of mango fruit, the difficulty in regulating the postharvest quality, and the lack of preservation technology are the main problems that need to be solved in China's mango industry. In this paper, the physiological changes and mechanisms of mango during postharvest ripening were summarized, including sugar and acid changes, pigment synthesis and accumulation, and aroma formation and accumulation. The physical, chemical, and biological technologies (such as endogenous phytohormones, temperature, light, chemical preservatives, and edible coatings) commonly used in the regulation of mango postharvest ripening and their action principles were emphatically expounded. The shortcomings of the existing mango postharvest ripening regulation technology and physiological mechanism research were analyzed in order to provide a reference for the industrial application and development of mango postharvest.

Effects of Hydroxypropyl Methylcellulose on Physicochemical Properties and Microstructure of κ-Carrageenan Film

We investigated the effects of different proportions of hydroxypropyl methylcellulose (HPMC) on the properties of κ-carrageenan film. Biodegradable κ-carrageenan/HPMC films (κCHM film) were prepared by the solution casting method and their physicochemical properties were evaluated. The results show that the addition of HPMC enhanced oxygen barrier capacity, mechanical properties (tensile strength and elongation at break) and thermal stability. Notably, when the addition of HPMC increased to 6% of κ-carrageenan (w:w), the κCHM-6 film not only effectively improved water resistance, including lower water solubility, water vapor permeability and higher water contact angle, but also made the structure of the κCHM-6 film more compact. Moreover, rheological measurement and atomic force microscopy characterization showed that κ-carrageenan had suitable compatibility with HPMC. Attenuated total reflection–Fourier transform infrared spectroscopy analysis further confirmed the enhancement of hydrogen bond interactions. This finding could contribute to promoting the potential application of κCHM film in food packaging.

Bio-based antibacterial food packaging films and coatings containing cinnamaldehyde: A review

As a typical bioactive compound from the bark and leaves of the trees of the genus Cinnamomum, cinnamaldehyde (CIN) is natural and safe. Its excellent antibacterial activity against various foodborne microorganisms is growingly regarded as a promising additive for improving and enhancing the properties of bio-based packaging films/coatings. This review systematically summarized the bio-based food packaging films/coatings containing CIN developed recently. The effects of CIN incorporation on physical and chemical properties of the antibacterial food packaging films/coatings, including thickness, color index, transparency, water content, water solubility, water contact angle, mechanical performances, water barrier performances, and antibacterial performances, were discussed. Simultaneously, this work also concluded that an explanation of the antibacterial mechanism of CIN and preparation methods of bio-based packaging films/coatings containing CIN/CIN carriers. Notably, the incorporation of CIN into the films/coatings could enhance their antibacterial performance extend the shelf-life of various foods, such as fish, meats, vegetables, fruits, and other perishable food, while improving their physical and chemical properties. Although incorporating CIN into food packaging films/coatings has been extensively studied, long-term follow-up research on the human safety of active food packaging films/coatings containing CIN needs to be carried out.

Chitosan-based antioxidant films incorporated with root extract of Aralia continentalis Kitagawa for active food packaging applications

Aralia continentalis Kitagawa and ginseng are both perennial herbs of Araliaceae. The study aimed to investigate the composite packaging films with better fresh-keeping ability. The different mass concentrations of Aralia continentalis Kitagawa root extract (ARE) 0.05%, 0.10%, and 0.15% (v/w) were compounded with chitosan (CH) to make composite packaging films. Food-based composite film, its thickness, density, water contact angle (WCA), oxygen barrier properties (OP), solubility, swelling, transparency, water vapor permeability (WVP), and other physical properties, as well as tensile strength (TS), elongation at break (EAB), Young’s modulus (YM), and the mechanical properties were measured, and the oxidation resistance, thermal properties, and biodegradability were also evaluated, and the structure was analyzed by infrared spectroscopy. The results showed that when the ARE content in the film was increased from 0.05 to 0.15 mg·mL−1, high antioxidant capacity of the CH/ARE film was exhibited (the DPPH and ABTS+ free radical scavenging rate was increased), and the thickness, density, swelling degree, solubility, TS, EAB, and YM of the CH/ARE composite film increased, while WCA, OP, WVP, transparency, and biodegradability were slightly reduced. We had noticed that with the increase in the ARE content, the surface microstructure in CH/ARE film changed significantly, indicating the good compatibility between CH and ARE. In summary, as a natural active substance, ARE can be combined with CH to form films, and the packaging film made can effectively improve the performance of the composite film.

Melatonin treatment improves postharvest quality and regulates reactive oxygen species metabolism in "Feizixiao" litchi based on principal component analysis

Postharvest quality of litchi reduces rapidly during storage at room temperature. This study aimed to investigate the effect of melatonin treatment on postharvest quality and oxidative stress markers of litchi fruit during cold storage. The "Feizixiao" litchi was treated with melatonin solution concentrations of 0.2 and 0.6 mmol·L^-1 and then stored at 4°C for 12 days. The results confirmed that the melatonin treatment effectively maintained the appearance and color of the litchi fruit, suppressed the peel browning, and improved the litchi quality. The treatment also significantly enhanced the levels of endogenous melatonin, antioxidant components (total phenolics, flavonoids, and anthocyanin), and antioxidant enzyme activities of the fruit. It also inhibited the other oxidative stress markers, such as O 2 - , H₂O₂, MDA, and protein carbonyl content, and upregulated the expressions of antioxidant and Msr-related genes. Correlation and principal component analyses further confirmed that the melatonin treatment effectively delayed the fruit senescence by enhancing the antioxidant enzyme activities and modulating peel browning and reactive oxygen species metabolism of the litchi fruit via regulating gene expression of the related enzymes (SOD and PPO). These findings suggested that the exogenous application of melatonin to litchi during the postharvest is an ideal way to preserve the fruit quality and delay fruit senescence.

Plant Protein-Based Delivery Systems: An Emerging Approach for Increasing the Efficacy of Lipophilic Bioactive Compounds

The development of plant protein-based delivery systems to protect and control lipophilic bioactive compound delivery (such as vitamins, polyphenols, carotenoids, polyunsaturated fatty acids) has increased interest in food, nutraceutical, and pharmaceutical fields. The quite significant ascension of plant proteins from legumes, oil/edible seeds, nuts, tuber, and cereals is motivated by their eco-friendly, sustainable, and healthy profile compared with other sources. However, many challenges need to be overcome before their widespread use as raw material for carriers. Thus, modification approaches have been used to improve their techno-functionality and address their limitations, aiming to produce a new generation of plant-based carriers (hydrogels, emulsions, self-assembled structures, films). This paper addresses the advantages and challenges of using plant proteins and the effects of modification methods on their nutritional quality, bioactivity, and techno-functionalities. Furthermore, we review the recent progress in designing plant protein-based delivery systems, their main applications as carriers for lipophilic bioactive compounds, and the contribution of protein-bioactive compound interactions to the dynamics and structure of delivery systems. Expressive advances have been made in the plant protein area; however, new extraction/purification technologies and protein sources need to be found Their functional properties must also be deeply studied for the rational development of effective delivery platforms.

Microfibrillated cellulose reinforced starch/polyvinyl alcohol antimicrobial active films with controlled release behavior of cinnamaldehyde

The starch/polyvinyl alcohol (ST/PVA) films incorporated with cinnamaldehyde (CIN) and microfibrillated cellulose (MFC) were developed. The effect of MFC content on the films' properties was studied. The SEM results showed that MFC promoted compatibility among starch, PVA and CIN. With increased content of MFC, the strength of the films was improved and their flexibility reduced, the films' crystallinity degree and hydrophobicity were improved. The oxygen and water vapor permeability of the films both reduced first and then increased as a whole. The release of CIN from films into the food stimulant (10% ethanol) could be controlled by MFC. When MFC content was between 1% and 7.5%, it decelerated the release of CIN but high MFC content exceeded 10% promoted the release of CIN. It revealed that films containing CIN could inhibit growth of S. putrefaciens. It showed a good prospect of using MFC to develop controlled release active ST/PVA films.

Effects of Edible Coating and Modified Atmosphere Technology on the Physiology and Quality of Mangoes after Low-Temperature Transportation at 13 °C in Vibration Mitigation Packaging

The mango is an important tropical fruit in the world, but it is easily perishable after harvest. In order to investigate the effect of the compound preservation technology on the physiology and quality of mangoes during transportation and storage, mangoes were treated with different packaging and preservation methods. All mangoes were subjected to simulated transportation by a vibration table for 24 h (180 r/min, 13 °C), and stored at 13 °C. The changes in the color, physicochemical characteristics, quality, and antioxidant-related enzymes of the mangoes were measured. The results show that the shelf life of inflatable bag packing (CK) was only 24 d, while the other treatments could be 30 d. The inflatable bag packing with modified atmosphere packaging (MAP) treatment (HPM) had the lowest yellowing degree (12.5%), disease index (34.4%), and mass loss (2.95%), at 30 d. Compared with the CK, the compound treatment containing MAP prolonged the peak respiration of the mangoes by 6 d and suppressed the increase in the total soluble solids and relative conductivity. Meanwhile, the HPM could effectively maintain moisture content, firmness, titratable acid, vitamin C, and the peroxidase and superoxide dismutase content, indicating that the treatment could maintain the better quality and antioxidation ability of mangoes. In summary, the MAP compound treatment better maintained the commercial characteristics of the mangoes, followed by the edible coating compound treatment. The results provide a theoretical reference for mango cushioning packaging and postharvest storage technology.

Tea polyphenols (TP): a promising natural additive for the manufacture of multifunctional active food packaging films

As a bioactive extract from tea leaves, tea polyphenols (TP) are safe and natural. Its excellent antioxidant and antibacterial properties are increasingly regarded as a good additive for improving degradable food packaging film properties. This article comprehensively reviewed the functional properties of active films containing TP developed recently. The effects of TP addition to enhancing active food packaging films' performance, including thickness, water sensitivity, barrier properties, color, mechanical properties, antioxidant, antibacterial, and intelligent discoloration properties, were discussed. Besides, the practical applications in food preservation of active films containing TP are also discussed. This work concluded that the addition of TP could impart antioxidant and antibacterial properties to active packaging films and act as a crosslinking agent to improve other physical and chemical properties of the film, such as mechanical and barrier properties. However, the effect of TP on specific properties of the active packaging film is complex, and the appropriate TP concentration needs to be selected according to the type of film matrix and the interaction between the components. Notably, the addition of TP improved the efficiency of the active packaging film in food preservation applications, which accelerates the process of replacing the traditional plastic-based food packaging with active packaging film.