Water Vapor Permeability Research Articles

Cassava starch‐based film infused with biogenic selenium nanoparticles (bio‐SeNPs) to reduce foodborne pathogens

SummaryThe urgent investigation of antimicrobial films is imperative to mitigate the proliferation of pathogens in food, extending product shelf life and ensuring food safety, crucial aspects for public health and the sustainability of the global food system. We developed cassava starch‐based films containing 1% and 2% biogenic selenium nanoparticles (Bio‐SeNPs) produced by enterocin MF5 to assess antimicrobial activity. The addition of Bio‐SeNPs altered the luminosity and gave a reddish hue to the films. UV–visible, FTIR, and thermogram analyses revealed intermolecular interactions between the starch and Bio‐SeNPs. Scanning electron microscopy showed a smooth and homogeneous surface of the nanocomposite films. Water vapour permeability ranged from 9.4 to 0.68 g mm h−1 m−2 kPa−1, lower than control values. Swelling values were higher in the film containing 1% Bio‐SeNPs, and water vapour transmission was lower. The films exhibited MICs of 5.5 μL mL−1 for Listeria spp., 10.9 μL mL−1 for Salmonella spp., and 250 μL mL−1 for Escherichia coli. Antimicrobial activity ranged from 1.5–1.9 log and 1.6–2.0 log in liquid medium and dry film, respectively, after 24 h. The films were also applied to cherry tomatoes without altering their characteristics compared to the positive control. Our study demonstrated the high potential of using Bio‐SeNPs in biodegradable films to prevent food contamination.

Evaluation of phenolic compounds as cross-linkers to improve the qualities of halal gelatin from milkfish scales (Chanos chanos)

Gelatin is a versatile substance extensively used in medical and pharmaceutical industries for many applications, including capsule shells, X-ray film, infusion for plasma substitute, and the fabricating of artificial tissue. Fish scale gelatin is a profitable alternative source as a halal material despite its inferior quality. An addition of phenolic cross-linker may enhance the qualities of fish scale gelatin. The aim of this study was to determine the ability of phenolics to act as cross-linkers for fish scale gelatin and to identify the factors affecting this process. Gelatin production from fish scales (Chanos chanos) was carried out through basic pre-extraction and acidic pre-extraction. Thereafter, the gelatin was reacted with 10 different phenolics (phenol, pyrocatechol, resorcinol, α-naphthol, vanillin, L-tyrosine, curcumin, gallic acid, quercetin, and tannic acid). The resultant gelatins were characterized by infrared spectrum, X-ray diffraction pattern, swelling index, degree of cross-linking, viscosity, gel strength, mechanical profile, thermal profile, and water vapor permeability. Gelatin with the most favorable characteristics was further investigated for the effects of acidity (pH 4, 7, and 10) and cross-linker concentrations (2.5–10%). The findings revealed the formation of cross-linkage through shifted vibrational peaks of amide A, amide B, and amide II in the infrared spectrum. Shifted X-ray diffraction peaks in the gelatin with phenol addition also indicated the formation of cross-linkage. Significant improvement in the gelatin characteristics, such as swelling index, degree of cross-linking, viscosity, gel strength, mechanical profile, thermal profile, and water vapor permeability, could be attributed to the addition of phenolics cross-linkers. The highest improvement was observed in gelatin added with basic tannic acid 10%. Gelatin cross-linked with basic tannic acid 10% had a moisture content of 9.24±0.14%, swelling index of 323±17%, degree of cross-linking of 69.99±0.84%, viscosity of 8.48±0.23 cP, gel strength of 151.5±6.9 Bloom, melting temperature of 213.5°C, tensile strength of 7.00±0.54 N.cm-2, elongation at the break of 114.08±14.63%, elastic modulus of 58.45±8.20 N.cm-2 and water vapor permeability of 0.57±0.07 g.mm.m-2.h-1. kPa-1. The qualities of tannic acid-cross-linked gelatin films and film-forming gel increased when manufactured under basic conditions in comparison to acidic or neutral conditions. Furthermore, increasing the quantity of tannic acid to 10% improved the overall characteristics as compared to non-cross-linked gelatin. In conclusion, tannic acid has the ability to cross-link the fish gelatin, thereby enhancing its qualities.

Sustainable gelatin-kappa carrageenan active packaging with Mekwiya date seeds to enhance goat meat quality and shelf life

This research aimed to elaborate a gelatin-Kappa carrageenan-based packaging with 0.22 %, 0.44 %, and 0.88 % w/v of Mekwiya date palm seeds extract (DSEMK). This extract improved the mechanical, physical, and thermal properties of the films. Moisture content, water solubility, and water vapor permeability were reduced from 17.54 ± 0.02 to 12.18 ± 0.02, from 77.61 ± 0.02 to 25.35 ± 0.29 %, and from 5.28 ± 0.29 to 1.69 ± 0.03 g s−1 m−1 Pa−1 × 10−10, respectively. During thermal degradation, DSEMK4 film had a residual weight of 27.99 %, compared to 20.67 % for the control. Despite a decline in the film's tensile strength from 24.19 to 8.94 MPa with the incorporation of DSEMK, elongation at the breaking point increased from 37.66 ± 0.16 to 46.17 ± 0.25 %. The film containing DSEMK4 displayed the highest phenolic contents and illustrated the best antioxidant effects in DPPH and FRAP assays, with IC50s of 756 and 1445 μg/mL, respectively and inhibited pathogen growth on the meat surface. Over storage at 4 °C, monitoring of pH, lipid and protein oxidation parameters, microbial spoilage, optical properties, and sensory attributes disclosed that the DSEMK-films successfully enhanced the meat quality and safety. These findings were supported by principal component analysis and heat maps.

Recovery and characterization of cellulose microfibers from fallen leaves and evaluation of their potential as reinforcement agents for production of new biodegradable packaging materials.

In the present work, cellulose microfibers (CMFs) isolated from fallen autumn leaves of cherry plum (Prunus cerasifera pissardii nigra), white mulberry (Morus alba) and plane (Platanus orientalis) trees were characterized and used as reinforcement agents in sodium alginate-based biodegradable films. Fourier transform infrared spectroscopy (FT-IR) characterization showed that the CMFs were successfully isolated from the leaves with high purity. The extracted CMFs had a particle size ranging from 321.20 nm to 632.26 nm and negative zeta potential values (-27.33 to -21.40). The extraction yield of CMFs ranged from 19.53% to 26.00%. Incorporation of the leaf-derived CMFs into sodium alginate based films (1%, w:w) increased their tensile strength (from 153.73 to 187.78 MPa) and elongation at break values (from 105.97% to 89.90%) and significantly decreased oxygen (from 121.46 to 75.56 meq kg-1) and water vapor permeabilities (from 2.36 to 1.60 g mm h-1 m-2 kPa-1)(p < 0.05). Furthermore, the supplementation of CMFs into the biopolymer matrix had no significant effect on the color (L*: 85.35-85.67; a*: -0.75-0.71; b*: 4.23-4.94) and moisture content (44.64-48.42%) of the film samples, although the thickness increased (40.33-94.66 μm). Scanning electron microscopy (SEM) images showed that CMFs were homogeneously dispersed in the film matrix. Overall, this study confirms that fallen cherry plum, white mulberry, and plane leaves are valuable sources of CMFs which could be used in the manufacturing of biodegradable nanocomposite films as reinforcement agents.

Impact of Calcium Chloride Addition on the Microstructural and Physicochemical Properties of Pea Protein Isolate-Based Films Plasticized with Glycerol and Sorbitol

Ca2+ can boost protein-protein interactions and, if present at an appropriate level, can potentially improve some physicochemical properties of protein-based gels and films. This study aimed to determine the effects of CaCl2 (0%–0.05% w/w) on the microstructural, optical, water affinity, and mechanical characteristics of glycerol (Gly)- and sorbitol (Sor)-plasticized pea protein isolate (PPI)-based films. CaCl2 caused darkening and a color shift of the films from yellow to yellow-green. Additionally, decreased light transmission, particularly in the UV range, acidification, and reduced moisture content were observed. CaCl2 decreased the water vapor permeability of the Gly plasticized film by an average of 20% with no effect on the Sor-plasticized film. All films were completely soluble in water. CaCl2 negatively impacted the mechanical integrity of the films, reducing the tensile strength of the Gly- and Sor-plasticized films by ~16% and 14%–37%, respectively. Further increases in CaCl2 content (0.1% and 0.2% w/w) led to concentration-dependent microvoids resulting from protein over-crosslinking and/or coagulation. In summary, the incorporation of CaCl2 into PPI-based films did not provide significant benefits and actually worsened key properties, such as transparency and mechanical strength. The type of plasticizer influenced how CaCl2 affected some properties of the PPI-based film.

Pomegranate peel extract incorporated soy protein isolate/Artemisia sphaerocephala Krasch. gum composite films for fresh-cut apples preservation

The objective of this study was to prepare an active packaging film using phosphorylated soy protein isolate (PPS) and Artemisia sphaerocephala Krasch. gum (ASKG) as film matrices, with the incorporation of pomegranate peel extract (PPE) to preserve fresh-cut apples. The results showed that PA-PPE (PPS/ASKG-PPE) films significantly increased thickness by 24.47 %, tensile strength by 58.76 %, and elongation at break by 30.48 %. Additionally, water vapor permeability and oxygen permeability decreased significantly to 6.17 × 10−13 and 0.62 × 10−13 Kg•m•m−2•s−1•Pa−1, respectively. FTIR, XRD, and SEM analyses confirmed the formation of intermolecular hydrogen bonds between PPS, ASKG, and polyphenols extracted from pomegranate peel, indicating excellent compatibility. Furthermore, radical scavenging activity experiments demonstrated that these films exhibited a remarkable ability to scavenge DPPH and ABTS+ radicals up to 70.44 % and 74.28 %, respectively, when the PPE content was at 3 wt%. Moreover, PPS could achieve a sustained release effect on polyphenols with a relatively low release rate (63.83 %) even after seven days' time elapsed. Finally, the PA-PPE film displayed superior performance in reducing the weight loss and browning index of fresh-cut apples within 24 h of storage. The development of PA-PPE film could promote sustainable resource protection and demonstrate promising prospects in the field of fresh-cut fruit packaging.

Intelligent locust bean gum-k-carrageenan nanofibrous mats with Rosa canina petal anthocyanins and chitosan nanoparticles: Preparation, characterization, and application for monitoring of beef meat freshness

The objectives of the present experiment were to add Rosa canina petal extract (RCE, 3.5%) and chitosan nanoparticles (CNP, 1.5%) into the locust bean gum-kappa-carrageenan (LBG-KC) nanofiber mats and to examine their utilization for the freshness tracking of beef meat during the 6-day storage period. The surface morphology analysis of nanofibers using the scanning electron microscope showed that all developed nanofibers were cylindrical, uniformly disordered network structures with smooth surfaces. The tensile strength, elongation at break, water vapor permeability, water solubility, and moisture content of RCE/CNP-loaded nanofiber mats were recorded to be 10.00–31.77 MPa, 16.55%–22.98%, 5.04–9.18 × 10‾5 g mm/m2 h Pa, 3.80%–10.08%, and 2.10%–4.89%, respectively. The LBG-KC + RCE 3.5% and LBG-KC + RCE 3.5% + CNP 1.5% nanofibers were red, dark blue, green, and brown at pH values 1–6, 7–8, 9, and 10–12, respectively. After 4 days of beef meat storage at refrigerated conditions, the total viable count, pH, and total volatile basic nitrogen were 7.24 log CFU/g, 7.11, and 28.89 mg N/100 g, respectively. Moreover, on the 0th day, the pH-sensitive indicators presented a white color and after 4 days of meat storage, the indicator color changed to dark blue, which could indicate beef meat spoilage.

Functional pH-sensitive film based on pectin and whey protein for grape preservation and shrimp freshness monitoring

A pH-sensitive film was prepared from pectin (P) and whey protein (W), incorporating anthocyanin-rich purple sweet potato extract (PPE) as the pH indicator. The effect of PPE content on the structure and properties of the films and the pH indicating function were determined and evaluated for shrimp freshness and grape preservation. The solubility (60.23 ± 7.36 %) and water vapor permeability (0.15 ± 0.04 × 10−11 g·cm/(cm2·s·Pa)) of the pectin/whey protein/PPE (PW-PPE) film with 500 mg/100 mL PPE were the lowest of the films tested and much lower than PW films without PPE. PW-PPE films were non-cytotoxic and had excellent biodegradability in soil. Grapes coated with PW-PPE film had reduced weight loss from water evaporation, and decay during storage was inhibited. The total color change (ΔE) of the PW-PPE films had a strong linear correlation with the pH of shrimps during storage. PW-PPE films have application potential to monitor the real-time freshness of meat and extend the shelf life of fruit.

Multifunctional Sericin-Chitosan-Aloe Vera Composite Film for Food Packaging

Abstract In recent years, the demand for innovative, sustainable, and efficient food packaging solutions has surged in response to growing concerns about environmental impact, food safety, and quality preservation. A sericin-based polymer composite film with multifunctional properties shows promise as an alternative for enhancing food packaging. In this study, sericin-based composite films were prepared by incorporating Aloe vera gel, chitosan, and glycerol into a sericin solution (1.5 % w/v) through facile homogenisation at 70 °C, followed by casting and subsequent drying on a glass platform. The resulting dried film exhibited uniformity, a smooth texture, and successful integration of the composite components. The film demonstrated a moisture content of 21.02 % and a porosity of 3.56 %, with a thickness of (62.1 ± 2.3) µm. It exhibited moderate transparency with reasonable water vapour permeability. Notably, the DPPH scavenging results indicated that the film has a potent antioxidant capacity with an efficacy rate of 99.1 %, supported further by a phenolic content of 11.5 mg GAE per gram of film. Controlled solute migration of components from the composite films was observed, particularly under acidic conditions. Importantly, toxicity evaluation on A549 cells revealed no adverse effects, even at higher concentrations. Due to its consistent film-forming ability, antioxidant potency, controlled migration, and safe nature, the developed sericin polymer-based film could be an effective alternative for food packaging sensitive foods, maintaining oxidative stability, reducing moisture loss, improving quality, and extending shelf life.

Effect of Lipid-soluble rosemary (Rosmarinus Officinalis L.) extract (carnosic acid) on properties of microcrystalline cellulose/corn starch composite films

The development of biodegradable bioactive films is crucial due to the environmental pollution caused by petroleum-based materials and the food spoilage. Microcrystalline cellulose (MCC)/corn starch (CS) composite films containing lipid-soluble rosemary extract (carnosic acid) (RE) (1 %∼7 %, w/w) were prepared and the effect of RE on the structural, physicochemical, antimicrobial and antioxidant properties of MCC/CS composite films was investigated. The incorporation of lower RE content (1 %) promoted the interactions between film components, thus forming a compact and smooth surface and cross structures. The incorporation of RE changed the long-range order structure of MCC/CS composite film, strengthened the intermolecular interaction between film components, and improved thermal stability. The tensile strength increased from 8.35 MPa to 10.53 MPa and the water vapor permeability decreased from 0.63 to 0.58 g.mm.h-1.m-2.KPa-1. Moreover. Antibacterial (Escherichia coli and Staphylococcus aureus) and antioxidant activity were upsurged as RE contents increased. TOPSIS method indicated the MCC/CS-3 % film and MCC/CS-5 % film were the best films. The above results indicated that an effective use of RE as an enhancer and bacteriostatic agent showed a promising application in food packaging.

Exploring the potential of chlorogenic acid/chitosan nanoparticle-loaded edible films with photodynamic technology for Mongolian cheese application

This study aimed to evaluate the efficiency of edible films made from chlorogenic acid/chitosan (CGA/CS) nanoparticles combined with photodynamic technology (PDT). Hydroxypropyl starch (HS) and κ-carrageenan (KC) were used as the main ingredients in the preservation of Mongolian cheese under the PDT condition. The mechanical characteristics, water vapor adsorption, solubility, permeability, and release of chlorogenic acid in aqueous media were evaluated. The incorporation of CGA/CS significantly enhanced the tensile strength and barrier characteristics of the edible films. The antimicrobial efficacy of the edible film was assessed over a period of 7 days while the cheese was being stored, followed by PDT application. The use of antimicrobial PDT did not cause lipid oxidation in cheese samples. Additionally, the combination of CGA/CS@HS/KC helped to reduce fat oxidation in Mongolian cheese. Utilizing an edible film in conjunction with PDT presents a viable solution for prolonging the shelf life of Mongolian cheese while maintaining its sensory attributes and nutritional qualities.

Ethyl cellulose matrixed poly(sulfur-co-sorbic acid) composite films: Regulation of properties and application for food preservation

Developing non-toxic and sustainable materials with versatile and diverse functions has always been a crucial issue in food preservation packaging. Recently, inverse vulcanization has emerged as a precise and eco-friendly solution, attributed to the versatility of resulting polysulfides. In this study, a polysulfide crosslinked with sorbic acid was prepared by inverse vulcanization, and further combined with bio-macromolecular ethyl cellulose to form composite films via a casting method. Thanks to the ethanol-solubility and good compatibility of ethyl cellulose towards the polysulfide, morphology of the films can be tailored by adjusting the component ratio, thereby achieving favorable water vapor permeability (2.20 × 10−12 gs−1m−1Pa−1), oxygen permeability (4.01 × 10−4 gs−1 m−2), elasticity modulus (~400 MPa), elongation at break (~16 %), etc. Some films demonstrate remarkable antibacterial activity against a broad spectrum of bacteria and fungi, demonstrating their effectiveness in food preservation. The browning and spoilage of preserved Agaricus bisporus were inhibited, with 79.2 % of the initial firmness retained and a 5.6 % weight loss recorded on the 6th day. For the 15-day preservation of grapes, minimal changes in appearance, firmness, or TSS were observed, underscoring the promising potential of this composite for food preservation applications.

Effects of ethyl maltol on properties of starch-based active packaging: Morphology, volatile release and mold inhibition

Ethyl maltol, known for its caramel-like flavor and antimicrobial properties, blends compatibly with baked goods. In this study, ethyl maltol-incorporated starch films were developed as potential active food packaging materials. Films containing 0–10% ethyl maltol were prepared and characterized for their physicochemical, antimicrobial, and barrier properties. Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed interactions between ethyl maltol and starch, leading to modified thermal properties and enhanced film smoothness. Dynamic mechanical analysis revealed a shift in the relaxation temperature with increasing ethyl maltol content, indicating changes in polymer chain mobility. Water vapor permeability decreased with ethyl maltol incorporation, likely due to reduced hydrophilicity, while oxygen permeability increased, suggesting increased hydrophobicity. Ethyl maltol exhibited antifungal activity against Aspergillus niger, with a maximum inhibition zone of 1.53 mm at 10% loading. When incorporated into starch films, ethyl maltol effectively inhibited fungal growth in butter cake, extending its shelf life by up to three-fold. The controlled release kinetics of ethyl maltol from the films was analyzed using gas chromatography-mass spectrometry (GC-MS), revealing a linear release profile. These results demonstrate the potential of ethyl maltol-incorporated starch films as active, biodegradable food packaging materials with antimicrobial properties and significant shelf-life extension benefits.

Simple fabrication of green nanocellulose-reinforced sugarcane (S. officinarum) bagasse film with improved water barrier properties

This study reports a simple fabrication of green sugarcane (Saccharum officinarum) bagasse nanocomposite-based films with improved water barrier properties. In this work, cellulose nanofibers derived from sugarcane bagasse (SB-CNF) were employed as reinforcing agents. The reinforcing effects of varying SB-CNF concentrations, ranging from 10 to 40 wt%, on the characteristics and functionalities of nanocomposite films were measured. Our results demonstrated that the film incorporating 30 % SB-CNF into the SB matrix exhibited optimal characteristics and was chosen for further evaluation of its water barrier properties. To enhance the water barrier properties of the resulting films, different concentrations of lysozyme (0, 3.5, 7, 10.5, and 14 wt%) were incorporated into the film matrix. With the addition of 3.5 % LZ, the film exhibited enhanced water barrier properties, yielding a water contact angle of 97.60 ± 0.79°, a water solubility of 18.64 ± 0.79 %, and a water vapour permeability of 0.65 ± 0.04 g mm/m2 d kPa. The film also showcased its ability to retain water over the course of 120 minutes, with a swelling ratio of 430 %. An increase in mechanical strength (67.28 ± 0.58 MPa) and transparency (88.70 ± 0.39 %) of the film was also noted. The observed findings were attributed to the good dispersion and excellent intermolecular interactions between the lysozyme and the SB/30 %SB-CNF. These results offer a promising prospect for utilization in food packaging applications, with an emphasis on food preservation.

Films of polylactic acid with graphene oxide-zinc oxide hybrid and Mentha longifolia essential oil: Effects on quality of refrigerated chicken fillet

This study was conducted to investigate the morphological, thermal, mechanical, FTIR, physicochemical (thickness, humidity, solubility in water and water vapor permeability) and antimicrobial properties of polylactic acid film (PLA) containing hybrid graphene oxide‑zinc oxide (GO-ZnO: 1.5 % w/v) and Mentha longifolia essential oil (ML:1 % v/v) on chicken fillet kept in the refrigerator. The studied groups were microbially (total count of mesophilic aerobic bacteria, psychrotrophic bacteria, Enterobacteriaceae, Staphylococcus aureus, and lactic acid bacteria), chemically (pH, TVB-N) and sensory (color, odor, and taste) evaluated at 8-day interval (0, 2, 5 and 8). In the examination of the morphological characteristics, the PLA film had a smooth and uniform surface and the addition of ML essential oil created a discontinuous structure and the addition of GO-ZnO led to the production of a denser and more homogeneous film. The presence of GO-ZnO increased the thickness, decreased moisture content and solubility in water, and added ML essential oil increased moisture content and decreased solubility in water (p˂0.05). The results of the mechanical evaluation showed that the addition of ML essential oil and GO-ZnO reduced elongation at break and tensile strength (p˂0.05). The addition of ML essential oil increased the thermal resistance and the addition of GO-ZnO decreased the thermal resistance compared to the film containing ML essential oil. The antimicrobial effect of films containing ML essential oil was confirmed in this study (p˂0.05). The addition of GO-ZnO did not change the count of any of the microbial groups. TVB-N showed that groups containing ML essential oil had lower levels of volatile nitrogenous bases than the control group (p˂0.05). Sensory evaluation of the studied groups showed that chicken fillets packed with films containing ML essential oil had the highest score in terms of color, smell and taste. The results of the present study showed that PLA film containing GO-ZnO and ML essential oil can be used to increase the shelf life and maintain the sensory characteristics of chicken fillets, and it can be used as a suitable packaging to increase the shelf life of food products.

Self-powered sensors utilizing single-pillar thermocells with pyrolytic graphite sheet electrodes: harvesting body heat and solar thermal energy

This study investigates the development of self-powered sensors employing single-pillar thermocells to harness body heat and solar thermal energy. A pyrolytic graphite sheet was selected for its low water vapor permeability, and its surface was modified to be hydrophilic to minimize interfacial resistance. Two types of DC–DC converters, Asahi Kasei Microdevices AP4473 and matrix mercury, underwent evaluation for compatibility with these thermocells. The compact 1.5 cm3 (1 cm × 1 cm × 1.5 cm) device effectively powered the AP4473 converter, illuminating a light-emitting diode. A larger device (2.5 cm × 2.5 cm × 1.5 cm) efficiently drove the matrix mercury converter, enabling the operation of bluetooth low-power sensors. These self-powered sensors wirelessly provided humidity and temperature data using solar thermal energy for approximately 4 h per day during peak temperature differences in January. This study showcases the potential of thermocells for sustainable energy harvesting and suggests avenues for future research, such as exploring alternative heat sources like geothermal energy to power these sensors.

Design and Development of Film Forming Gel of Tavaborole by using Factorial Design

Film forming gel (FFG) could be a novel approach in film forming drug delivery system which has pulled in the intrigued of pharmaceutical researcher in improvement and characterization of skin drug delivery system. FFG were developed by varying concentration of the polymers and plasticizer. The formulations were prepared using 32 full factorial design. FFG were evaluated for important parameters like drying time, drug release, antifungal activity, skin irritation and stability studies. The FFG was characterized for pH, viscosity, drug content, effective dosage volume and mechanical properties of the film formed after application; bioadhesion and water vapour permeability were also tested. All the formulations showed results within acceptable range for various tests. The optimized formulation showed drug release of 98.76% and antifungal activity in terms of efficacy as 95.83%. It is stated that the created formulation will shorten therapy duration, increase patient acceptance, and represent a breakthrough in the treatment of skin infections.

Optimized hybrid edible surface coating prepared with gelatin and cellulose nanofiber for cherry tomato preservation

The use of renewable bioresources and their nanoforms in developing edible coating materials is considered a promising approach for preserving food freshness. Herein, cellulose nanofibers (CNF) with different morphologies were combined with gelatin to prepare composite preservation film following by brushing over the surface of cherry tomatoes as an edible coating. The gelatin-based composite film containing 0.3 % CNF20 (GC2–0.3) exhibited the lowest water vapor permeability (WVP, 1.97 × 10−4 barrer), lower oxygen permeability (OP, 2.54 × 10−2 barrer), higher transparency (Tr = 85.28 %) and excellent mechanical properties (σ = 47.45 MPa, E = 1.84 GPa). When coated on cherry tomatoes, it maintained good luster and freshness, significantly reducing the water loss of cherry tomatoes. The weight loss was only 16 % after 14 days of storage at 25 °C and 30 % humidity, compared to >30 % for the uncoated cherry tomatoes. This work provides a viable strategy for developing sustainable, green fresh-keeping materials that can prolong the storage time of the putrescible food.

Anthocyanin modified by chondroitin sulphate and tannic acid improved the quality-indicating properties of gelatin-based intelligent film

A highly pH-responsive gelatin film incorporating purple cabbage anthocyanin (PCA) and chondroitin sulphate (CS)/tannic acid (TA) was developed. Co-pigmentation of PCA via CS/TA improved its photothermal stability and visibility of color change in gelatin film. The morphological and structural properties of CS-PCA and TA-PCA films revealed that a more stable network was formed as new hydrogen bonds were generated by the co-pigmentation. Meanwhile, the co-pigmentation improved film's mechanical and hydrophobic properties, expressed as higher tensile strength (16.65 and 17.97 Mpa) and lower water vapor permeability (1.45 and 1.41) in CS-PCA and TA-PCA films, compared to PCA film. CS-PCA and TA-PCA films showed distinct color transitions for chilled fish fillets during storage. Total color difference (ΔE) of CS-PCA and TA-PCA films correlated well with the deterioration indexes of total volatile base nitrogen (TVB-N). All the results provided a novel pH-sensitive intelligent packaging strategy by co-pigmenting CS/TA with PCA for freshness monitoring.

Microencapsulation of Betalains Extracted from Garambullo (Myrtillocactus geometrizans) to Produce Active Chitosan-Polyvinyl Alcohol Films with Delayed Release of Bioactive Compounds.

Garambullo is a plant with little industrial application. However, garambullo contains betalains, photosensitive phytochemical compounds, which through microencapsulation can be used in chitosan-polyvinyl alcohol (PVOH) films for application in tomato coatings. These biopackages were characterized by physical tests, water vapor permeability, puncture tests, extension, color, differential scanning calorimetry (DCS), Fourier transform infrared (FTIR) spectroscopy, and antioxidant and antimicrobial activity analyses. The influence of the biopackages on the tomato coatings was measured using parameters such as minimum weight loss close to 2% at day 9, pH of 4.6, Brix of 5.5, titratable acidity of 1 g acid/100 mL sample, and shelf life of up to 18 days. The biopackages containing betalain microcapsules had a water vapor permeability of 2 × 10-14 g/h·m·Pa and an elongation of 5 ± 0.5%, indicating that the package did not stretch. The deformation at the breaking point for the package without and with microcapsules was 0.569 and 1.620, respectively. With respect to color, adding white microcapsules and betalains can cause the material to darken, resulting in a yellowish color. Furthermore, the phenolic content was greater for the biopackages with betalains, while there was no significant difference in the antioxidant activity since the active compounds were not released. According to the in vitro results, the inhibition of B. cinerea was achieved on the eighth day when the active compounds were released from the microcapsules. The tomato with betalains lost 2% of its weight, and B. cinerea was inhibited, extending its shelf life to 18 days. The proposed biopackages have good properties as biopolymers and inhibit the presence of B. cinerea.