Optimization of the formulation of chitosan edible coatings supplemented with carotenoproteins and their use for extending strawberries postharvest life

Carboxymethylcellulose hybrid nanodispersions for edible coatings with potential anti-cancer properties

Curcumin loaded lipid-polymer hybrid nanoparticles dispersions were fabricated from carboxymethylcellulose, stearic acid, polyethylene glycol and sesame oil using emulsion solvent evaporation method for their possible application as edible coatings for fresh vegetables and fruits. They were characterized by FTIR and TEM analysis. In addition, anti-bacterial, blood compatibility, cytotoxicity and anticancer studies were also carried out. The prepared nanodispersions showed excellent mixed nanostructured morphology with an average size of 94.96 nm. The hybrid nanodispersions showed excellent blood compatibility, non-toxicity and antitumor activity. The synthesized nanoparticle dispersion was employed as an edible coating solution for fresh apples and tomatoes. The hybrid system coated vegetables and fruits shows minimal weight loss after 15 days of storage. Hence, the formulated hybrid nanostructures of CMC are promising as edible coating solution, in addition to possessing the properties to fight cancer.

Development and Properties of Fish Gelatin/Oxidized Starch Double Network Film Catalyzed by Thermal Treatment and Schiff' Base Reaction

In order to improve the properties of fish gelatin (FG), oxidized starch (OS) was adopted to form hetero-covalent linkage with it based on thermal treatment and the Schiff’ base reaction. The effects of different ratios of FG/OS (ranging from 10:1 to 2:1) on the properties of films were investigated. OS improved the mechanical and barrier properties of films significantly, while the moisture content decreased as OS concentration increased. The optimum concentration was obtained at the loading amount of 1.5% (w/v) OS. FT-IR spectra revealed the covalent cross-linking between FG and OS induced by Schiff’ base reaction. Moreover, composite films had superior preservation effect on blueberry, according to the results of weight loss, total soluble solids, titratable acidity, and total anthocyanin content. Therefore, this study suggested that FG-OS double network films (FODF) has great potential in the packaging industry.

Humectability and physical properties of hydroxypropyl methylcellulose coatings with liposome-cellulose nanofibers: Food application

The objective of this study was to investigate the physical, rheological and humectability properties of edible coating forming suspensions (ECS) based on hydroxypropyl methylcellulose (HPMC) containing: liposomes that encapsulate rutin, glycerol and cellulose nanofibers on sliced surfaces of almonds and chocolate. On average, liposomes measured between 110.6 ± 10.0 nm and were characterized as stable and homogeneous suspensions. Adding these liposomes to the edible coatings produced significant changes (p< 0.05) in the density and surface tension, which favor the final appearance of the coating. The presence of liposomes increased the apparent viscosity of the ECS, showing a purely viscous and fluid behavior with a good fit (R² = 0.9996) with the Power Law model. The presence of liposomes and cellulose nanofibers decreased the value of the cohesive energy of the ECS. The studied ECS partially hydrate the surfaces of almond and chocolate as they showed contact angles under 90°.

Development of Starch-Based Antifungal Coatings by Incorporation of Natamycin/Methyl-β-Cyclodextrin Inclusion Complex for Postharvest Treatments on Cherry Tomato against Botrytis cinerea

The application of natamycin as a natural fungicide in edible coatings is challenging because of its low aqueous solubility. In this study, the natamycin/methyl-β-cyclodextrin (N/ME-β-CD) inclusion complex was fabricated and incorporated into waxy corn starch-based coatings for postharvest treatments. The phase solubility of natamycin in the presence of ME-β-CD at 293.2 K, 303.2 K, and 313.2 K is determined and used to calculate the process thermodynamic parameters. The N/ME-β-CD inclusion complex was confirmed and characterized by FTIR and 1H NMR spectroscopy. The results indicated that the inclusion complex was formed and the hydrophobic part (C16-C26) of natamycin might be partially inserted into the cavity of ME-β-CD form the wide rim. The effects of N/ME-β-CD incorporated starch-based coatings (N/ME-β-CD S coatings) on postharvest treatments of cherry tomatoes were evaluated in vivo. The N/ME-β-CD S coatings could reduce weight loss, delay fruit ripening, and inhibit fruit decay caused by Botrytis cinerea in tomato fruit during storage.

Aqueous ozone controls decay and maintains quality attributes of strawberry (Fragaria × ananassa Duch.)

Investigations were made on the changes in physical and biochemical attributes, fruit decay and storage life of 'Winter Dawn' strawberry fruits in response to aqueous ozone dip treatment for different exposure times. Fruits were subjected to 0.1 ppm aqueous ozone for different time intervals (1-4 min). The treated strawberries were air dried and stored under ambient (25 ± 2 °C and 45-50% RH) and low temperature (2 ± 1 °C and 90% RH) conditions. Results revealed that treatment of strawberry fruits with aqueous ozone @ 0.1 ppm for 2 min resulted in 21% lower weight loss, 16% higher firmness and 15% lesser change in fruit colour during 2 days in ambient storage. Under low temperature storage, 2 min ozone treated fruits exhibited ~ 21% lower PLW, 19% higher firmness and 46% lesser colour change as compared to control fruits during 14 days of storage. Fruit decay reduced significantly under both low and cold storage conditions. Thus, it can be concluded that application of aqueous ozone for 2 min was able to retain the strawberry fruit quality and extend its storage life till 14 days under low temperature storage and 2 days under ambient storage conditions.

Application of edible coatings on fresh and minimally processed fruits: a review

Purpose

This paper aims to update with information about edible coating on minimally processed and fresh fruits, focussing on the composition, active ingredients, antimicrobial concentration and their effect on ripening rate, phytonutrients retention and shelf-life of fruits. In future, the data will be helpful for the processors to select the best coating material and its effective concentration for different fresh and minimally processed fruits.

Design/methodology/approach

Major scientific information was collected from Scopus, Web of Science, Mendeley and Google Scholar. Several key words such as postharvest, edible coating, phytonutrients, shelf-life enhancement, bioactive compounds, minimally processed fruits and antimicrobial compounds were used to find the data. Relevant information was collected by using 90 recent research and review articles.

Findings

The main findings of this comprehensive review are to improve the quality of fruits, to meet the next-generation food security needs. However, in the process of achieving the goal of improving quality of food produce, embrace of synthetic, non-biodegradable packaging materials have increased, creating serious pollution problem. Amidst several alternatives for replacement of synthetic packaging, the option of biodegradable films and coatings showed promising results.

Originality/value

The paper represents recent information about the edible coating used for the enhancement of shelf-life of fresh and minimally processed fruits.

Effect of Sonication Duration in the Performance of Polyvinyl Alcohol/Chitosan Bilayer Films and Their Effect on Strawberry Preservation

In this study, we fabricated polyvinyl alcohol (PVA)/chitosan (CS) bilayer films by casting and investigated the effects of preparation conditions and CS content (2, 2.5, or 3 wt.%) on the ability of these films to preserve packaged strawberries. The best performance was achieved at a CS loading of 2.5 wt.% (ultrasound time, 25 min); the strain and stress values were 143.15 ± 6.43% and 70.67 ± 0.85 MPa, respectively, oxygen permeability was 0.16 ± 0.08 cm²·m²·day^-1·MPa^-1, water vapor permeability was 14.93 ± 4.09 g·cm^-1·s^-1·Pa^-1, and the shelf life of fresh strawberries packaged in the PVA/CS 2.5 wt.% bilayer film was determined to be 21 days at 5 ± 2 °C and a relative humidity of 60 ± 5%. Treatment with PVA/CS bilayer films prevented the decrease in the firmness of strawberries during storage (21 days). The evaluated physicochemical parameters (weight loss, decay, firmness, titratable acidity, soluble solid content, ascorbic acid content, and color) indicated that treatment with PVA/CS bilayer films led to better maintenance of the fruit quality. We believe that our study makes a significant contribution to literature because it paves the way to the fabrication of smart packaging materials and facilitates the commercialization of fresh strawberries as an important health food.

From Nature to Energy Storage: A Novel Sustainable 3D Cross-Linked Chitosan-PEGGE-Based Gel Polymer Electrolyte with Excellent Lithium-Ion Transport Properties for Lithium Batteries

Developing a gel polymer electrolyte with a cross-linked structure is one of the best choices to improve the mechanical strength of the gel polymer electrolyte without sacrificing its lithium-ion transportation properties. However, the cost is always too high. Herein, a novel gel polymer electrolyte based on three-dimensional cross-linked chitosan-poly(ethylene glycol) diglycidyl ether macromolecule network was designed and synthesized through a simple and environmental harmless method, with sustainable and cheap chitosan as major material. The obtained gel polymer electrolyte shows improved mechanical strength of 5.5 MPa, which is higher than that of other gel polymer electrolytes without inert frameworks. The optimized gel polymer electrolyte exhibits a good lithium ionic conductivity of 2.74 × 10^-4 S cm^-1 with a superior lithium-ion transfer number of 0.869 at 25 °C. Lithium battery assembled with this gel polymer electrolyte demonstrates an initial discharge capacity of 146.8 mA h g^-1, which retains 88.49% capacity after 360 cycles at 0.2C. Moreover, this gel polymer electrolyte possesses good interfacial compatibility with lithium anode. Therefore, the growth of lithium dendrite is greatly delayed. This research proves the great possibility of applying sustainable and cost-effective chitosan into gel polymer electrolyte and lithium batteries.

Effect of an Edible Coating Based on Chitosan and Oxidized Starch on Shelf Life of Carica papaya L., and Its Physicochemical and Antimicrobial Properties

Papaya production plays an important economic role in Mexico’s economy. After harvest, it continues to ripen, leading to softening, skin color changes, development of strong aroma, and microbial spoilage. The objective of this work was to apply an active coating of chitosan–starch to increase papaya shelf life and to evaluate physicochemical and antimicrobial properties of the coating. Papaya surfaces were coated with a chitosan-oxidized starch (1:3 w/w) solution and stored at room temperature (25 ± 1 °C) for 15 days. Variables measured were color, titratable acidity, vitamin C, pH, soluble solids, volatile compounds by gas chromatography, texture, homogeneity by image analysis, and coating antimicrobial activity. At the end of the storage time, there were no significant differences (p > 0.05) between coated and uncoated papayas for pH (4.3 ± 0.2), titratable acidity (0.12% ± 0.01% citric acid), and soluble solids (12 ± 0.2 °Bx). Papaya firmness decreased to 10 N for coated and 0.5 N for uncoated papayas. Volatile compounds identified in uncoated papaya (acetic acid, butyric acid, ethyl acetate, ethyl butanoate) are related to fermentation. Total microbial population of coated papaya decreased after 15 days, whereas population of uncoated papaya increased. This active coating permitted longer shelf life of papaya than that of the uncoated fruit.