Preparation of bioactive gelatin film using semi-refined pectin reclaimed from blueberry juice pomace: Creating an oxidation and light barrier for food packaging

Development of apple pectin/soy protein isolate-based edible films containing punicalagin for strawberry preservation

In this study, we developed punicalagin-loaded antimicrobial films based on soy protein isolate (SPI) and apple pectin (AP). The AP was derived from apple pomace waste while the punicalagin was obtained from pomegranate peel. Punicalagin was identified to exist in both α- and β-isomers, with the β-type being predominant. The composite films were characterized using scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Our results demonstrated that the incorporation of AP significantly enhanced the mechanical strength, heat resistance, and barrier properties of the films. Moreover, the composite films integrated with punicalagin exhibited excellent antimicrobial activities against Staphylococcus aureus (with a minimum bactericidal concentration value of 0.25 %), Escherichia coli (with a minimum bactericidal concentration value of 0.50 %), and Aspergillus niger. Finally, these antimicrobial film solutions were tested as coatings on strawberries and found to have significantly better effects on reducing weight loss, improving shelf-life, and maintaining the freshness of strawberries compared to coatings without punicalagin. The results indicate that antimicrobial coatings loaded with punicalagin hold great promise as multifunctional active packaging materials for fruit preservation.

Polysaccharide- and protein-based edible films combined with microwave technology for meat preservation

To reduce food-borne bacterial infection caused by food spoilage, developing highly efficient food packing film is still an urgent need for food preservation. Herein, microwave-assisted antibacterial nanocomposite films CaO2@PVP/EA/CMC-Na (CP/EC) were synthesized using waste eggshell as precursor, egg albumen (EA) and sodium carboxymethylcellulose (CMCNa) as matrix by casting method. The size of CaO2@PVP (CP) nanoparticles with monodisperse spherical structures was 100-240 nm. When microwave and CP nanoparticles (0.05 mg/mL) were treated for 5 min, the mortality of E. coli and S. aureus could reach >97 %. Under microwave irradiation (6 min), the bactericidal rate of 2.5 % CP/EC film against E. coli and S. aureus reached 98.6 % and 97.2 %, respectively. After adding CP nanoparticles, the highest tensile strength (TS) and elongation at break (EB) of CP/EC film reached 19.59 MPa and 583.43 %, respectively. At 18 °C, the proliferation of bacterial colonies on meat can be significantly inhibited by 2.5 % CP/EC film. Detailed characterization showed that the excellent meat preservation activity was due to the synergistic effect of dynamic effect generated by ROS and thermal effect of microwave. This study provides a promising approach for the packaging application of polysaccharide- and protein-based biomass nanocomposite antibacterial edible films.

Curcumin and silver nanoparticles loaded antibacterial multifunctional pectin/gelatin films for food packaging applications

Renewable biomass-based materials have a huge potential to replace petroleum-based products in food packaging. Herein, pectin/gelatin films loaded with curcumin and silver nanoparticles (AgNPs) are prepared by solution-pouring technology to serve as antimicrobial multifunctional food packaging films. AgNPs and curcumin are found to equally distribute in the films. Fourier transform infrared spectroscopy (FT-IR) reveal the hydrogen bonding and electrostatic interaction among curcumin, AgNPs, pectin and gelatin. The composite films show good antioxidant activity, mechanical performance, hydrophobicity and antibacterial ability. The films of P-GCA 0.5 showed 99.57 ± 0.16 % and 100 % inhibition against E. coli and S. aureus, respectively. The films also demonstrate excellent water vapor barrier qualities. In addition, the composite films possess pH-responsive color change behaviors from yellow (pH 3-8) to light red (pH 8-9) to dark red (pH 11-12), which is suitable for monitoring the freshness of shrimp packaging based on pH changes during deterioration process. As sustainable biomass-based materials, the multifunctional composite films are promising in intelligent food packaging applications.

Gelatin-based multifunctional composite films integrated with dialdehyde carboxymethyl cellulose and coffee leaf extract for active food packaging

In this study, dialdehyde carboxymethyl cellulose (DCMC, 10 wt% based on gelatin) and varying contents of coffee leaf extract (CLE, 1, 3, 5 and 7 wt% based on gelatin) were incorporated into gelatin (GEL) matrix to develop multifunctional food packaging films. DCMC acted as a physical reinforcing filler through crosslinking with GEL matrix by Schiff-base reaction, CLE served as an active filler to confer film functional properties. The micro-morphology, micro-structure, physicochemical and functional properties of the GEL/DCMC/CLE composite film were investigated. The results demonstrated that mechanical, barrier properties and thermal stability of films were significantly improved by incorporation of CLE. Compared with pure GEL film, the GEL/DCMC/5%CLE film exhibited excellent UV light blocking while kept enough transparency, the best mechanical property, water resistance, water vapor and oxygen barrier, as well as thermal stability. GEL/DCMC/5%CLE film also possessed strong antioxidant activity and some antibacterial activity against E. coli and S. aureus. Packaging application testing demonstrated that the resultant GEL/DCMC/5%CLE film effectively delayed the lipid oxidation of walnut oil and preserved the postharvest freshness of fresh walnut kernels under ambient conditions.

Monitor the freshness of shrimp by smart halochromic films based on gelatin/pectin loaded with pistachio peel anthocyanin nanoemulsion

This paper focuses on the combination of gelatin (Gel), pectin (Pec), and Pistachio peel anthocyanins (PSAs) to develop a halochromic film for food applications (shrimp). The results of spectroscopic properties showed that the film components had proper interaction and compatibility. Furthermore, the addition of PSAs and Pec improved the thermal stability of films. The addition of Pec and PSAs significantly improved the physical properties and mechanical resistance of the films. So that, the permeability to water vapor and oxygen reduced from 2.81 to 2.74 (g‧s-1‧Pa-1‧m-1) and 5.25 to 4.70 (meq/kgO2), respectively. In addition, the strength and flexibility of halochromic film reached 0.7 MPa and 56 % compared to Gel film (0.62 MPa, and 46.96 %). Most importantly, the color changes of the smart film from cherry/pink to yellow/brown, which were proportional to the color changes of the anthocyanin solution at different pHs, were able to monitor the shrimp freshness and spoilage at room (20 °C) and refrigerated (4 °C) temperature for 14 days.

Structural characterization, antioxidant and antibacterial activity of three pectin polysaccharides from blueberry

In this study, three pectin polysaccharides BP1, BP2 and BP3, were purified from blueberries. The weight-average molecular weight (Mw) of BP1, BP2, and BP3 were detected to be 9.027 × 104, 9.313 × 104, and 1.223 × 106 Da, respectively. The structures of the three pectin polysaccharides were characterized and compared based on the results of molecular weight, monosaccharide composition, GC-MS and NMR analysis. Structural characterization revealed that BP1, BP2, and BP3 all contain homogalacturonan (HG) and rhamnogalacturonan I (RG-I) domains, and the rhamnose residues in RG-I domains are substituted at C-4 with side chains such as araban and galactosan. BP2 had the highest degree of esterification and HG domain ratio, followed by BP3 and BP1. In addition, BP1, BP2 and BP3 showed great antioxidant and antibacterial activities, and could destroy the cell membrane of Staphylococcus aureus and Escherichia coli. Moreover, the better DPPH and ABTS free radical scavenging and antibacterial activities of BP1 and BP2 than BP3 might be related to their lower molecular weight. The results of this study will provide essential information for the structure-activity relationship of pectin polysaccharides and research basis for development and application of blueberry pectin polysaccharides.

A High-Performance Food Package Material Prepared by the Synergistic Crosslinking of Gelatin with Polyphenol-Titanium Complexes

This study aims to enhance gelatin film performance in the food industry by incorporating polyphenol-titanium complexes (PTCs) as crosslinkers. PTCs introduce multiple linkages with gelatin, including coordination and hydrogen bonds, resulting in synergistic crosslinking effects. This leads to an increased hydrodynamic volume, particle size, and thermal stability of the gelatin films. Compared to films crosslinked solely by polyphenols or titanium, PTC-crosslinked gelatin films exhibit significant improvements. They show enhanced mechanical properties with a tensile strength that is 1.7 to 2.6 times higher than neat gelatin films. Moreover, these films effectively shield UV light (from 82% to 99%), providing better protection for light-sensitive food ingredients and preserving lutein content (from 74.2% to 78.1%) under light exposure. The incorporation of PTCs also improves film hydrophobicity, as indicated by water contact angles ranging from 115.3° to 131.9° and a water solubility ranging from 31.5% to 33.6%. Additionally, PTC-enhanced films demonstrate a superior antioxidant ability, with a prolonged polyphenol release (up to 18 days in immersed water) and a higher free radical scavenging ability (from 22% to 25.2%). Overall, the improved characteristics of gelatin films enabled by PTCs enhance their performance, making them suitable for various food packaging applications.

Furoic acid-mediated konjac glucomannan/flaxseed gum based green biodegradable antibacterial film for Shine-Muscat grape preservation

Considering the growing threats to the environment and human health, such as plastic pollution and food spoilage, the development of naturally antibacterial food packaging materials with biodegradable capabilities has recently attracted considerable attention. This work applies the concept of green environmental protection to packaging technology, and a new type of green edible antibacterial packaging film was developed. The basic idea is to incorporate furoic acid (FA), which possesses excellent antibacterial activity, into the flaxseed gum and konjac glucomannan matrix (FK) as a filler to obtain a series of FK-FA bioactive films. This incorporation simultaneously improves the hydrophobicity and UV-barrier ability by 12.28 % and 42.87 %, respectively. Meanwhile, the diameters of the antibacterial zone of the FK-FA0.4% films (composite FK films containing 0.4 % FA) against E. coli and S. aureus increased to 38.98 mm and 36.29 mm from 24.00 mm of pure FK film, respectively. As a consequence, the grape sample sealed with FK-FA0.4% film remained edible on the 18th day of storage, while those packaged with commercial PE film and pure FK were seriously rotted and lost edible value on the 12th day, further confirming the enhanced preservation capacity. Finally, the as-prepared films were established to be biodegradable and were almost completely degraded within 25 days under simulated environmental conditions. Overall, these promising results show the potential of FK-FA films for replacing plastic packaging materials as eco-friendly edible films with prolonged shelf life for active packaging.

Preparation and characterization of corn starch-based antimicrobial indicator films containing purple corncob anthocyanin and tangerine peel essential oil for monitoring pork freshness

A novel antibacterial indicator film was prepared by mixing corn starch with tangerine peel essential oil (TEO) Pickering emulsion emulsified by ultrasonic and esterified modified starch (UDSt), and then incorporated with purple corncob anthocyanin (PCA), which was used to monitor the freshness of pork. The results showed that the UDSt can effectively stabilize the TEO emulsion. PCA showed obvious color changes at different pH. With the increase of pH, the color of film changed from red to yellow, and its response to volatile ammonia changed from pink to cyan, showing better response ability. The loading of TEO conferred the film excellent bacteriostatic ability against E. coli and S. aureus. The film also had good ability of light blocking and free radical scavenging. In the process of pork deterioration, the antibacterial indicator film changed from pink to yellow, which was closely related to pork quality and had a good linear indicator correlation. The addition of TEO reduced the release of PCA in the antibacterial indicator film and helped to maintain the functional properties of the film. This type of antibacterial indicator film had considerable application potential in indicating food freshness.

Applications and safety aspects of bioactives obtained from by-products/wastes

Due to the negative impacts of food loss and food waste on the environment, economy, and social contexts, it is a necessity to take action in order to reduce these wastes from post-harvest to distribution. In addition to waste reduction, bioactives obtained from by-products or wastes can be utilized by new end-users by considering the safety aspects. It has been reported that physical, biological, and chemical safety features of raw materials, instruments, environment, and processing methods should be assessed before and during valorization. It has also been indicated that meat by-products/wastes including collagen, gelatin, polysaccharides, proteins, amino acids, lipids, enzymes and chitosan; dairy by-products/wastes including whey products, buttermilk and ghee residue; fruit and vegetable by-products/wastes such as pomace, leaves, skins, seeds, stems, seed oils, gums, fiber, polyphenols, starch, cellulose, galactomannan, pectin; cereal by-products/wastes like vitamins, dietary fibers, fats, proteins, starch, husk, and trub have been utilized as animal feed, food supplements, edible coating, bio-based active packaging systems, emulsifiers, water binders, gelling, stabilizing, foaming or whipping agents. This chapter will explain the safety aspects of bioactives obtained from various by-products/wastes. Additionally, applications of bioactives obtained from by-products/wastes have been included in detail by emphasizing the source, form of bioactive compound as well as the effect of said bioactive compound.

Fabrication, performance, and potential environmental impacts of polysaccharide-based food packaging materials incorporated with phytochemicals: A review

Although food packaging preserves food's quality, it unfortunately contributes to global climate change since the considerable carbon emissions associated with its entire life cycle. Polysaccharide-based packaging materials (PPMs) are promising options to preserve foods, potentially helping the food industry reduce its carbon footprint. PPMs incorporated with phytochemicals hold promise to address this critical issue, keep food fresh and prolong the shelf life. However, phytochemicals' health benefits are impacted by their distinct chemical structures thus the phytochemicals-incorporated PPMs generally exhibit differential performances. PPMs must be thoughtfully formulated to possess adequate physicochemical properties to meet commercial standards. Given this, this review first-time provides a comprehensive review of recent advances in the fabrication of phytochemicals incorporated PPMs. The application performances of phytochemicals-incorporated PPMs for preserving foods, as well as the intelligent monitoring of food quality, are thoroughly introduced. The possible associated environmental impacts and scalability challenges for the commercial application of these PPMs are also methodically assessed. This review seeks to provide comprehensive insights into exploring new avenues to achieve a greener and safer food industry via innovative food packaging materials. This is paramount to preserve not only food shelf life but also the environment, facilitating the eco-friendly development of the food industry.

Valorization of fruit and vegetable processing by-products/wastes

Fruit and vegetable processing by-products and wastes are of great importance due to their high production volumes and their composition containing different functional compounds. Particularly, apple, grape, citrus, and tomato pomaces, potato peel, olive mill wastewater, olive pomace and olive leaves are the main by-products that are produced during processing. Besides conventional techniques, ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction (sub-critical water extraction), supercritical fluid extraction, enzyme-assisted extraction, and fermentation are emerging tools for the recovery of target compounds. On the other hand, in the view of valorization, it is possible to use them in active packaging applications, as a source of bioactive compound (oil, phenolics, carotenoids), as functional ingredients and as biofertilizer and biogas sources. This chapter explains the production of fruit and vegetable processing by-products/wastes. Moreover, the valorization of functional compounds recovered from the fruit and vegetable by-products and wastes is evaluated in detail by emphasizing the type of the by-products/wastes, functional compounds obtained from these by-products/wastes, their extraction conditions and application areas.

Carbon dots, cellulose nanofiber, and essential oil from Torreya grandis aril added to fish scale gelatin film for tomato preservation

In this study, carbon dots (CDs), cellulose nanofibers (CNF) and essential oil nanoemulsion (EON) were extracted from the aril waste of Torreya grandis following nuts production. These three nanomaterials were formulated for the preparation of a composite film to be employed for postharvest tomato storage. Visual, microscopical and physicochemical properties of the prepared nanocomposite films were analyzed at different levels of CDs and CNF for optimization purposes. The UV absorption and antioxidant capacity of gelatin film with 10 % CDs (G/10CD) were enhanced compared with gelatin (G) film, concurrent with a reduction in water barrier capacity, water contact angle (WCA) and tensile strength (TS). Compared with G/10CD film, the WCA of gelatin film after incorporation of 10 % CDs and 3 % CNF (G/10CD/3CNF) was significantly increased by 14.5°at 55 s. In contrast, TS increased by 1.26 MPa, as well as the significant enhancement in water barrier capacity. The above composite film mixed with NEO (G/10CD/3CNF/EON) exerted further antimicrobial effects against Escherichia coli. G/10CD/3CNF/EON coating effectively extended tomato shift life compared with the control group. Therefore, this new eco-friendly film presents several advantages of biodegradability, sustainability as well as multifunctional properties posing it as potential packaging material for food applications.

Acylated pectin/gelatin-based films incorporated with alkylated starch crystals: Characterization, antioxidant and antibacterial activities, and coating preservation effects on golden pomfret

Pectin and starch crystals were modified by ethyl gallate and octadecyl-trimethoxysilane, respectively, followed by using acylated pectin (AP) and alkylated starch crystals (ASCs) as bioactive reagents and hydrophobic enhancers to improve the physiochemical properties of gelatin-based films and evaluate their coating preservation effects on golden pomfret. The properties of AP and ASC were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), proton-nuclear magnetic resonance (¹H NMR) and X-ray diffraction (XRD). The ethyl-gallate-modified pectin/gelatin (AP/G) containing 3 % ASC (AP/G/ASC-3 %) was shown to have the maximum tensile strength and Young's modulus of all the tested composite films. The AP/G containing 10 % ASC exhibited a water contact angle higher than 94°, coupled with a significant improvement in UV-shielding efficiency. FTIR and SEM analysis of the AP/G/ASC-3 % film indicated that the molecular interactions in the composite film components were noncovalent linkages, including hydrogen bonds, hydrophobic interactions, and electrostatic interactions, contributing to homogeneous and smooth microstructures. Additionally, the solutions of AP/G and AP/G/ASC composite films presented obvious antioxidant and antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the AP/G and AP/G/ASC active coatings could effectively inhibit lipid oxidation and improve the textural acceptability of golden pomfret (Trachinotus blochii) fillets during 4 °C storage.

Pectin from plantain peels: Green recovery for transformation into reinforced packaging films

Plantain peels as agro-waste are generated in the millions of tons per year with no profitable management strategies. On the other hand, the excessive use of plastic packaging threatens the environment and human health. This research aimed to address both problems via a green approach. High-quality pectin was recovered from plantain peels via an enzyme-assisted and ethanol-recycling process. The yield and galacturonic acid (GalA) content of the recovered low methoxy pectin was 12.43% and 25.0%, respectively, when cellulase was added at 50 U per 5 g peel powder, with a significantly higher recovery rate and purity than the pectin products extracted with no cellulase (P ≤ 0.05). The recovered pectin was further integrated and reinforced with beeswax solid-lipid nanoparticles (BSLNs) to fabricate films as a potential alternative packaging material to single-use plastics. The reinforced pectin films showed improved light barrier, water resistance, mechanical, conformational, and morphological properties. This study presents a sustainable strategy to transform plantain peels into pectin products and pectin-based packaging films with broad applications.

Biopolymers as green-based food packaging materials: A focus on modified and unmodified starch-based films

The ideal food packaging materials are recyclable, biodegradable, and compostable. Starch from plant sources, such as tubers, legumes, cereals, and agro-industrial plant residues, is considered one of the most suitable biopolymers for producing biodegradable films due to its natural abundance and low cost. The chemical modification of starch makes it possible to produce films with better technological properties by changing the functional groups into starch. Using biopolymers extracted from agro-industrial waste can add value to a raw material that would otherwise be discarded. The recent COVID-19 pandemic has driven a rise in demand for single-use plastics, intensifying pressure on this already out-of-control issue. This review provides an overview of biopolymers, with a particular focus on starch, to develop sustainable materials for food packaging. This study summarizes the methods and provides a potential approach to starch modification for improving the mechanical and barrier properties of starch-based films. This review also updates some trends pointed out by the food packaging sector in the last years, considering the impacts of the COVID-19 pandemic. Perspectives to achieve more sustainable food packaging toward a more circular economy are drawn.