Effect of an Edible Nanomultilayer Coating by Electrostatic Self-Assembly on the Shelf Life of Fresh-Cut Mangoes

Formulations based on pullulan and a derivative as coating material for the food sector

Carboxymethylated derivatives of pullulan (PU) were synthesized and evaluated as coating for the postharvest preservation of blueberries. Carboxymethylpullulan was obtained by etherification reaction with the substitution degrees of 0.52, 0.34, and 0.26 for CMP1, CMP2, and CMP3 respectively. Infrared spectroscopy and nuclear magnetic resonance results showed characteristic signals of the carbonyl group belonging to the carboxymethyl group. Thermal analysis showed that CMP1, CMP2, and CMP3 derivatives presented thermal stability values of 209.91 C, 214.73 C, and 225.52 °C, respectively, and were lower with respect to PU with Td of 238.84 °C. Furthermore, an increase in the glass transition temperature due to carboxymethylation was determined. The chemical modification decreased the contact angle with respect to PU (71.34°) with values for CMP1, CMP2, and CMP3 of 39.89°, 53.72° and 60.61°, respectively. The carboxymethylation also increased the water vapor permeability and mechanical properties of the films. In addition, it was found that the CMP molecules affected the optical properties. The application of CMP-based coatings reduced the mass loss and ripening rate of blueberries compared to native pullulan, therefore, packaging from CMP molecules could be used as a coating capable of delaying ripening and extending the shelf life of fruits.

Effect of nanocomposite alginate-based edible coatings containing thymol-nanoemulsion and/or thymol-loaded nanostructured lipid carriers on the microbial and physicochemical properties of carrot

In this study, the effect of thymol-nanoemulsion (NE) and thymol-loaded nanostructured lipid carriers (NLC) on the physiological and microbial quality of carrot was investigated. The NE and NLC droplet sizes were 86 and 140 nm with encapsulation efficiency of 97 and 94 %, respectively. The minimum inhibitory concentration and minimum bactericidal concentration of thymol decreased in NE and increased in NLC against E. coli and S. aureus. Moreover, thymol-containing coatings exhibited a higher peroxidase activity, total phenolic content, flavonoid content, DPPH radical scavenging activity, pH, and lower respiration rate, TSS, weight loss, and decay with the preference for samples coated with NLC and NE (particularly NLC). The NE and NLC treatments significantly reduced the total viable, mold and yeast, lactic acid bacteria, and Enterobacteriaceae counts compared to the free thymol-containing coating. Results showed that the application of NE and NLC containing alginate-based coating (with the preference for NLC) improved the postharvest quality of carrot and extended its shelf life. Meanwhile, the separate application of these systems gave better results than the simultaneous application of both systems in one sample.

Control of Browning, Enzyme Activity, and Quality in Stored Fresh-cut Fruit Salads through Chitosan Coating Enriched with Bergamot Juice Powder

In this study, fresh-cut fruit salads composed of apples, pears, kiwis, and pineapples were stored at +4 °C for 18 days under distinct conditions: non-coated (NC), chitosan-coated (CH), and bergamot juice powder extract-enriched chitosan-coated (CHBE). Storage endpoint decay percentages were as follows: NC group: 100%, CH group: 26.67-53.3%, CHBE group: 13.33-26.67%. CHBE had the highest moisture content (87.05-89.64%), soluble solids (12.40-13.26%), and chroma values (2.35-6.60). CHBE and NC groups had 2.10% and 6.61% weight loss, respectively. The NC group had the highest polyphenol oxidase activity (19.48 U mL-1) and browning index (0.70 A420/g); CH group: 0.85 U mL-1, 0.35 A420/g; CHBE group: 0.57 U mL-1, 0.27 A420/g. CHBE showed a titratable acidity of 1.33% and pH 3.73 post-storage, impeding microbial proliferation with the lowest counts (2.30-3.24 log CFU g-1). The microbial suitability of the NC group diminished after day 6, with an overall preference score of 1.00. Conversely, the CH and CHBE groups scored 3.15 and 4.56, highlighting the coatings' effectiveness. Bergamot juice powder extract further enhanced this, mitigating browning and enhancing quality. Results reveal tailored coatings' potential to extend shelf life, improve quality, and enhance fruit salads' acceptability. This study underscores the importance of edible coatings in addressing preservation challenges, emphasizing their role in enhancing food quality and consumer acceptability. Incorporating edible coatings is pivotal in mitigating deterioration issues and ensuring the overall success of fresh-cut fruit products in the market.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Development and Evaluation of Chitosan-Based Food Coatings for Exotic Fruit Preservation

Chitosan has gained agro-industrial interest due to its potential applications in food preservation. In this work, chitosan applications for exotic fruit coating, using feijoa as a case of study, were evaluated. For this, we synthetized and characterized chitosan from shrimp shells and tested its performance. Chemical formulations for coating preparation using chitosan were proposed and tested. Mechanical properties, porosity, permeability, and fungal and bactericidal characteristics were used to verify the potential application of the film in the protection of fruits. The results indicated that synthetized chitosan has comparable properties to commercial chitosan (deacetylation degree > 82%), and, for the case of feijoa, the chitosan coating achieved significant reduction of microorganisms and fungal growth (0 UFC/mL for sample 3). Further, membrane permeability allowed oxygen exchange suitable for fruit freshness and natural physiological weight loss, thus delaying oxidative degradation and prolonging shelf-life. Chitosan's characteristic of a permeable film proved to be a promising alternative for the protection and extension of the freshness of post-harvest exotic fruits.

Chitin and Chitosan as Polymers of the Future-Obtaining, Modification, Life Cycle Assessment and Main Directions of Application

Natural polymers are very widespread in the world, which is why it is so important to know about the possibilities of their use. Chitin is the second most abundant reproducible natural polymer in nature; however, it is insoluble in water and basic solvents. Chitin is an unused waste of the food industry, for which there are possibilities of secondary management. The research led to obtaining a soluble, environmentally friendly form of chitin, which has found potential applications in the many fields, e.g., medicine, cosmetics, food and textile industries, agriculture, etc. The deacetylated form of chitin, which is chitosan, has a number of beneficial properties and wide possibilities of modification. Modification possibilities mean that we can obtain chitosan with the desired functional properties, facilitating, for example, the processing of this polymer and expanding the possibilities of its application, also as biomimetic materials. The review contains a rich description of the possibilities of modifying chitin and chitosan and the main directions of their application, and life cycle assessment (LCA)-from the source of the polymer through production materials to various applications with the reduction of waste.

Effect of Composite Chitosan/Sodium Alginate Gel Coatings on the Quality of Fresh-Cut Purple-Flesh Sweet Potato

In this study, single-layer coating using chitosan (Ch) and sodium alginate (SA) solutions and their gel coating (ChCSA) formed by layer-by-layer (LbL) electrostatic deposition using calcium chloride (C) as a cross linking agent were prepared to improve storage qualities and shelf-life of fresh-cut purple-flesh sweet potatoes (PFSP). The preservative effects of single-layer coating in comparison with LbL on the quality parameters of fresh-cut PFSP, including color change, weight loss, firmness, microbial analysis, CO2 production, pH, solid content, total anthocyanin content (TAC), and total phenolic content (TPC) were evaluated during 16 days of storage at 5 °C. Uncoated samples were applicable as a control. The result established the effectiveness of coating in reducing microbial proliferation (~2 times), color changes (~3 times), and weight loss (~4 times) with negligible firmness losses after the storage period. In addition, TAC and TPC were better retained in the coated samples than in the uncoated samples. In contrast, quality deterioration was observed in the uncoated fresh cuts, which progressed with storage time. Relatively, gel-coating ChCSA showed superior effects in preserving the quality of fresh-cut PFSP and could be suggested as a commercial method for preserving fresh-cut purple-flesh sweet potato and other similar roots.

Application of Gelatin Composite Coating in Pork Quality Preservation during Storage and Mechanism of Gelatin Composite Coating on Pork Flavor

Gelatin coating is an effective way to prolong the shelf life of meat products. Aiming at solving the problem of flavor deterioration during the storage of pork at room temperature, pork coating technology was developed to preserve the pork at 25 °C, and the comprehensive sensory analysis of vision, touch, smell, and taste was used to study the effect of coating on preservation of pork flavor. Herein, uncoated (control) and coated pork samples (including gelatin coating and gelatin coating incorporated with ginger essential oil) were analyzed to investigate the integrity of pork periodically during storage at 25 °C for weight loss, color, texture (springiness, chewiness, cohesiveness, gumminess, and hardness), microstructure, odor (electronic nose), taste (electronic tongue), volatile flavor substance, and taste ingredients. The results suggested that ginger essential oil (GEO) gelatin coating and gelatin coating can effectively inhibit the loss of water dispersion and slow down the oxidation reaction, coating treatments could significantly (p < 0.05) retarded the weight loss of pork slices, with values of 20.19%, 15.95%, 13.12% for uncoated, gelatin coated, and GEO-gelatin coated samples during 24 h of storage, respectively. Compared with control group, the color, texture, smell, and taste evaluations demonstrated that coating treatments had improved sensory and texture attributes during the storage period. Furthermore, the comprehensive results from the physical property assays (especially the texture), morphological assay and volatile odor assays showed that the GEO-fish gelatin composite coating had better preservation effect on pork flavor than the fish gelatin coating. The study suggests that the gelatin composite coating could be developed as a prospective active packaging to preserve pork meat at room temperature.

Multifunctional Role of Chitosan Edible Coatings on Antioxidant Systems in Fruit Crops: A Review

Chitosan-based edible coatings represent an eco-friendly and biologically safe preservative tool to reduce qualitative decay of fresh and ready-to-eat fruits during post-harvest life due to their lack of toxicity, biodegradability, film-forming properties, and antimicrobial actions. Chitosan-based coatings modulate or control oxidative stress maintaining in different manner the appropriate balance of reactive oxygen species (ROS) in fruit cells, by the interplay of pathways and enzymes involved in ROS production and the scavenging mechanisms which essentially constitute the basic ROS cycle. This review is carried out with the aim to provide comprehensive and updated over-view of the state of the art related to the effects of chitosan-based edible coatings on anti-oxidant systems, enzymatic and non-enzymatic, evaluating the induced oxidative damages during storage in whole and ready-to-eat fruits. All these aspects are broadly reviewed in this review, with particular emphasis on the literature published during the last five years.

Advances in the application of chitosan as a sustainable bioactive material in food preservation

Chitosan is obtained from chitin and considered to be one of the most abundant natural polysaccharides. Due to its functional activity, chitosan has received intense and growing interest in terms of applications for food preservation over the last half-century. Compared with earlier studies, recent research has increasingly focused on the exploration of preservation mechanism as well as the targeted inhibition with higher efficiency, which is fueled by availability of more active composite ingredients and integration of more technologies, and gradually perceived as "chitosan-based biofilm preservation." In this Review, we comprehensively summarize the potential antimicrobial mechanisms or hypotheses of chitosan and its widely compounded ingredients, as well as their impacts on endogenous enzymes, oxidation and/or gas barriers. The strategies used for enhancing active function of the film-forming system and subsequent film fabrication processes including direct coating, bioactive packaging film and layer-by-layer assembly are introduced. Finally, future development of chitosan-based bioactive film is also proposed to broaden its application boundaries. Generally, our goal is that this Review is easily accessible and instructive for whose new to the field, as well as hope to advance to the filed forward.

Edible films and coatings for shelf life extension of mango: a review

Edible films and coatings are eco-friendly promising materials for preserving the quality and extending the shelf life of fresh and minimally-processed fruits. They can form protective layers around fruits, regulate their respiration rates, and protect them from loss of water, tissue softening, browning, and microbial contamination. Edible films and coatings have many advantages over other post-harvest treatments. They can add commercial value to fruits by enhancing their appearance, and act as carriers of functional ingredients, such as antioxidants, antimicrobial agents and nutraceuticals. Mango, a highly perishable tropical fruit, has a short post-harvest life, which limits transport to distant markets. Application of edible films and coatings on mango fruits is an effective method to preserve their quality and safety. This paper provides an overview of desirable properties for films and coatings, and recent development in different edible coatings for both fresh and minimally-processed mango. The most popular edible coating materials, such as chitosan, waxes, starch, gums, and cellulose used for mango are reviewed. The commercialization of coating formulations and equipment used for application of coatings are discussed. The environmental impacts, safety aspects, and the challenges encountered are outlined. The opportunities to use other coating materials, such as aloe-vera gel, microbial polysaccharides, and photosynthetic microorganisms are also examined.

Spray technology applications of xanthan gum-based edible coatings for fresh-cut lotus root (Nelumbo nucifera)

In this study, the effect of spraying method as an application technique for xanthan gum-based edible coatings was investigated, based on its barrier and microbial properties on fresh-cut lotus root. Xanthan gum solutions (0.1%, 0.3%, and 0.5%) were prepared and incorporated with 2% (w/w) citric acid as an anti-browning agent and 1% (w/w) glycerol as plasticizer. The coatings were then sprayed using a pilot spray system to 5 mm-thick slices of fresh-cut lotus root for 20 s, packed in polyethylene bags, stored for 16 d at 5 °C and analyzed for color, pH, morphology and microbial counts. It was found that spray-coated fresh-cut lotus root samples had significant reduction in the total color changes as compared to non-coated samples. The experimental results suggested that the spray coating treatments were effective in decreasing the enzymatic browning of fresh-cut lotus root during storage which could potentially increase its shelf-life in the market. In addition, we have also found that the xanthan gum-based spray coated treatments were also effective against inhibiting the growth of Bacillus subtilis during 24 h of incubation which were indicated by the lower microbial counts recorded as compared to non-coated fresh-cut lotus root samples. In this part of the work, the author highlighted the spray coating technique of xanthan gum-based edible coatings as a promising strategy in improving the storage stability of fresh-cut lotus root during post-harvest storage. Overall, the application of edible coatings is a promising strategy in extending the shelf life of fresh-cut lotus root. In the future, the author aims to widen the scope of the application of these coatings to other agricultural products which are prone to degradation during storage in the market.

Edible Coating Based on Roselle (Hibiscus sabdariffa L.) Mucilage Applied to Soursop Fruits in Postharvest Storage

The soursop fruit (Annona muricata L.) is a crop of significant economic value for Nayarit, which is characterized by having a bittersweet taste, making it attractive to the consumer. However, the soursop has rapid maturation which causes a short shelf life. Several postharvest management techniques have been applied to reduce its metabolic processes, such as refrigeration, use of 1-methylcyclopropene (1-MCP), and controlled and modified atmospheres. In recent years, polysaccharide-based coatings have been applied to fruits. Therefore, the objective of this investigation was to evaluate the physicochemical and biochemical changes, as well as the antioxidant activity of soursop fruits with a mucilage-based coating (2%), stored at 22°C and 15°C with a 90% RH. Weight loss, firmness, color, soluble solids, acidity, pH, phenols, flavonoids, vitamin C, and antioxidant activity were evaluated. The results obtained in the coated fruits stored at 15°C showed lower weight loss (6.4%), lower firmness (29.7 N), higher TSS concentration (10.4°Bx), and lower acidity (0.38%) compared with the uncoated fruits. The total phenolic content decreased in coated fruits stored at 22°C (54.3 mg EGA/100 g FW). The highest antioxidant activity (DPPH method) was recorded in fruits coated and stored at 15°C with an average value of 257.9 mg EAA/100 g FW. Moreover, a high concentration of vitamin C was observed in fruits coated and stored at 15°C and 22°C (20.5 and 17.5 mg EAA/100 g FW), concluding that the coating based on roselle mucilage (2%) in combination with a temperature of 15°C prevents weight loss, decreases titratable acidity, and increases the content of phenols and vitamin C. Furthermore, an increase in the shelf life up to eight days and in the antioxidant activity at the maturity of consumption was observed in the fruits coated with 2% roselle mucilage stored at 15°C.

Mango Fruit Yield and Critical Quality Parameters Respond to Foliar and Soil Applications of Zinc and Boron

Mango (Mangifera indica L.), the sixth most important fruit crop worldwide, is likely at risk under a climate change scenario of accelerated soil organic matter mineralization and constrained plant nutrient supplies such as zinc (Zn) and boron (B). We identified the optimum nutrient formulation and application method to possibly rectify nutrient deficits in mango plants grown in one of the warmest and driest regions—Multan, Pakistan. We evaluated the yield and physiological (quality) responses of 20-year-old mango trees to seven treatments of foliar and soil applications of Zn and B. Combined soil application of B and Zn resulted in optimum increases in leaf mineral B and Zn and fruit-set, retention, yield, pulp recovery and total soluble solids at ripening (p = 0.021), while reducing titratable acidity and early fruit shedding (p = 0.034). Additionally, this treatment improved fruit quality (taste, flavour, texture, aroma, acceptability; p ≤ 0.05). Yield was found to be correlated with retention percentage (P ≤ 0.001; R² = 0.91), which was in turn related to fruit-set number panicle⁻¹ (P = 0.039; R² = 0.61). Therefore, we suggest that combined soil application of B and Zn mitigates leaf mineral deficiencies and improves the yield and quality of mango more efficiently than other individual or combined foliar or soil treatments used in this study.

Emerging Chitosan-Based Films for Food Packaging Applications

Recent years have witnessed great developments in biobased polymer packaging films for the serious environmental problems caused by the petroleum-based nonbiodegradable packaging materials. Chitosan is one of the most abundant biopolymers after cellulose. Chitosan-based materials have been widely applied in various fields for their biological and physical properties of biocompatibility, biodegradability, antimicrobial ability, and easy film forming ability. Different chitosan-based films have been fabricated and applied in the field of food packaging. Most of the review papers related to chitosan-based films are focusing on antibacterial food packaging films. Along with the advances in the nanotechnology and polymer science, numerous strategies, for instance direct casting, coating, dipping, layer-by-layer assembly, and extrusion, have been employed to prepare chitosan-based films with multiple functionalities. The emerging food packaging applications of chitosan-based films as antibacterial films, barrier films, and sensing films have achieved great developments. This article comprehensively reviews recent advances in the preparation and application of engineered chitosan-based films in food packaging fields.

Chitosan-Based Coating with Antimicrobial Agents: Preparation, Property, Mechanism, and Application Effectiveness on Fruits and Vegetables

Chitosan coating is beneficial to maintaining the storage quality and prolonging the shelf life of postharvest fruits and vegetables, which is always used as the carrier film for the antimicrobial agents. This review focuses on the preparation, property, mechanism, and application effectiveness on the fruits and vegetables of chitosan-based coating with antimicrobial agents. Chitosan, derived by deacetylation of chitin, is a modified and natural biopolymer as the coating material. In this article, the safety and biocompatible and antimicrobial properties of chitosan were introduced because these attributes are very important for its application. The methods to prepare the chitosan-based coating with antimicrobial agents, such as essential oils, acid, and nanoparticles, were developed by other researchers. Meanwhile, the application of chitosan-based coating is mainly due to its antimicrobial activity and other functional properties, which were investigated, introduced, and analyzed in this review. Furthermore, the surface and mechanical properties were also investigated by researchers and concluded in this article. Finally, the effects of chitosan-based coating on the storage quality, microbial safety, and shelf life of fruits and vegetables were introduced. Their results indicated that chitosan-based coating with different antimicrobial agents would probably have wide prospect in the preservation of fruits and vegetables in the future.