Active and intelligent biodegradable packaging films using food and food waste-derived bioactive compounds: A review

Intelligent films of marine polysaccharides and purple cauliflower extract for food packaging and spoilage monitoring

In this study, metalloanthocyanin-inspired, biodegradable packaging films were developed by incorporating purple cauliflower extracted (PCE) anthocyanins into alginate (AL)/carboxymethyl chitosan (CCS) hybrid polymer matrices based on complexation of metal ions with these marine polysaccharides and anthocyanins. PCE anthocyanins-incorporated AL/CCS films were further modified with fucoidan (FD) because this sulfated polysaccharide can form strong interactions with anthocyanins. Metals-involved complexation (Ca²⁺ and Zn²⁺-crosslinked films) improved the mechanical strength and water vapor permeability but reduced the swelling degree of the films. Zn²⁺-cross-linked films exhibited significantly higher antibacterial activity than did pristine (non-crosslinked) and Ca²⁺-cross-linked films. The metal ion/polysaccharide-involved complexation with anthocyanin reduced the release rate of anthocyanins, increased the storage stability and antioxidant capability, and improved the sensitivity of the colorimetric response of the indicator films for monitoring the freshness of shrimp. The anthocyanin-metal-polysaccharide complex film showed great potential as active and intelligent packaging of food products.

Kiwi Fruits Preservation Using Novel Edible Active Coatings Based on Rich Thymol Halloysite Nanostructures and Chitosan/Polyvinyl Alcohol Gels

The concept of this study is the replacement of previous fossil-based techniques for food packaging and food shelf-life extension, with novel more green processes and materials following the spirit of circular economy and the global trend for environmentally positive fingerprints. A novel adsorption process to produce thymol-halloysite nanohybrids is presented in this work. The high dispersion of this thymol-halloysite nanostructure in chitosan biopolymer is one of the goals of this study. The incorporation of this biodegradable matrix with poly-vinyl-alcohol produced a very promising food-packaging film. Mechanical, water-oxygen barrier, antimicrobial, and antioxidant properties were measured. Transparency levels were also tested using a UV-vis instrument. Moreover, the developed films were tested in-vivo for the preservation and the extension of the shelf-life of kiwi fruits. In all cases, results indicated that the increased fraction of thymol from thyme oil significantly enhances the antimicrobial and antioxidant activity of the prepared chitosan-poly-vinyl- alcohol gel. The use of the halloysite increases the mechanical and water-oxygen barrier properties and leads to a control release process of thymol which extends the preservation and the shelf-life of kiwi fruits. Finally, the results indicated that the halloysite improves the properties of the chitosan/poly-vinyl-alcohol films, and the thymol makes them further advantageous.

Gelatin-Based Film as a Color Indicator in Food-Spoilage Observation: A Review

The color indicator can monitor the quality and safety of food products due to its sensitive nature toward various pH levels. A color indicator helps consumers monitor the freshness of food products since it is difficult for them to depend solely on their appearance. Thus, this review could provide alternative suggestions to solve the food-spoilage determination, especially for perishable food. Usually, food spoilage happens due to protein and lipid oxidation, enzymatic reaction, and microbial activity that will cause an alteration of the pH level. Due to their broad-spectrum properties, natural sources such as anthocyanin, curcumin, and betacyanin are commonly used in developing color indicators. They can also improve the gelatin-based film's morphology and significant drawbacks. Incorporating natural colorants into the gelatin-based film can improve the film's strength, gas-barrier properties, and water-vapor permeability and provide antioxidant and antimicrobial properties. Hence, the color indicator can be utilized as an effective tool to monitor and control the shelf life of packaged foods. Nevertheless, future studies should consider the determination of food-spoilage observation using natural colorants from betacyanin, chlorophyll, and carotenoids, as well as the determination of gas levels in food spoilage, especially carbon dioxide gas.

Electrospun nanofibers fabricated by natural biopolymers for intelligent food packaging

An "intelligent" or smart packaging is able to continuously monitor physicochemical and/or biological variations of packaged food materials, providing real-time information concerning their quality, maturity, and safety. Electrospun nanofiber (ENF) structures, nowadays, reckon as versatile biomaterial platforms in designing intelligent packaging (IP) systems. Natural biopolymer-based ENF traits, for example, surface chemistry, rate of degradation, fiber diameter, and degree of alignment, facilitate the development of unique, tunable IP, enhancing food quality, and safety. In this review, after a brief overview of the electrospinning process, we review food IP systems, which can be utilized to detect variations in food features, for example, those based on alterations in temperature, O2 level, time, humidity, pH, or microbial contamination. Different intelligent approaches that are applicable in engineering IP materials are then highlighted, that is, indicators, data carriers, and sensors. The latest research on the application of ENFs made with natural biopolymers in food IP and their performance on different packaged food types (i.e. meat, fruits and vegetables, dairy products, etc.) are underlined. Finally, the challenges and outlook of these systems in the food industry are discussed.

Phenolic Compounds in Active Packaging and Edible Films/Coatings: Natural Bioactive Molecules and Novel Packaging Ingredients

In recent years, changing lifestyles and food consumption patterns have driven demands for high-quality, ready-to-eat food products that are fresh, clean, minimally processed, and have extended shelf lives. This demand sparked research into the creation of novel tools and ingredients for modern packaging systems. The use of phenolic-compound-based active-packaging and edible films/coatings with antimicrobial and antioxidant activities is an innovative approach that has gained widespread attention worldwide. As phenolic compounds are natural bioactive molecules that are present in a wide range of foods, such as fruits, vegetables, herbs, oils, spices, tea, chocolate, and wine, as well as agricultural waste and industrial byproducts, their utilization in the development of packaging materials can lead to improvements in the oxidative status and antimicrobial properties of food products. This paper reviews recent trends in the use of phenolic compounds as potential ingredients in food packaging, particularly for the development of phenolic compounds-based active packaging and edible films. Moreover, the applications and modes-of-action of phenolic compounds as well as their advantages, limitations, and challenges are discussed to highlight their novelty and efficacy in enhancing the quality and shelf life of food products.

Development of Shrimp Freshness Indicating Films by Embedding Anthocyanins-Rich Rhododendron simsii Flower Extract in Locust Bean Gum/Polyvinyl Alcohol Matrix

Freshness indicating films containing anthocyanins are one type of smart packaging technology. Anthocyanins in the films can show visual color changes when food spoilage occurs, thereby indicating the freshness degree of food in real-time. Rhododendron simsii is a landscape plant with attractive flowers that are abundant in anthocyanins. In this study, smart packaging films were prepared by embedding 2% and 4% R. simsii flower anthocyanins (RA) in locust bean gum- (LBG) and polyvinyl alcohol- (PVA) based matrices. The micro-structure, barrier, mechanical, thermal, antioxidant, and color-changeable properties of the films were determined. The potential application of the films in indicating the freshness of shrimp at 4 °C was also investigated. Results showed that the RA interacted with the LBG/PVA matrices through hydrogen bonds, which significantly improved the barrier, mechanical, thermal, antioxidant, pH-sensitive, and ammonia-sensitive properties of the films. Meanwhile, the performance of the films was remarkably influenced by the content of the RA. The film containing 4% RA had the highest light blocking ability, tensile strength (38.32 MPa), elongation at break (58.18%), and antioxidant activity, and also showed the lowest water vapor permeability (22.10 × 10^-11 g m^-1 s^-1 Pa^-1) and oxygen permeability (0.36 cm³ mm m^-2 day^-1 atm^-1). The films containing 2% and 4% RA could effectively change their colors when the level of total volatile basic nitrogen in the shrimp exceeded the safe value, which demonstrated the suitability of the films for indicating the freshness degree of shrimp.

Influence of Ulluco Starch Modified by Annealing on the Physicochemical Properties of Biodegradable Films

This work aimed to evaluate the use of annealing (ANN) ulluco starch in the preparation of biodegradable films and its impact on the physicochemical properties of the materials. Three film samples (FS1, FS2, and FS3) were prepared at a fixed starch concentration (2.6% w/v) using glycerol as a plasticizer and then compared to a control sample (FSC) prepared with native ulluco starch. The physical, mechanical, and thermal properties of the films were evaluated. The use of ANN starch decreased the solubility (from 21.8% to 19.5%) and the swelling power (from 299% to 153%) of the film samples. In addition, an increase in opacity and relative crystallinity (from 7.54% to 10.5%) were observed. Regarding the thermal properties, all the samples presented high stability to degradation, with degradation temperatures above 200 °C. However, the samples showed deficiencies in their morphology, which affected the barrier properties. The use of ANN starch has some advantages over native starch in preparing films. However, more analysis is needed to improve the barrier properties of the materials. This work reveals the potential of the ANN ulluco starch for biodegradable film preparation. In addition, the use of modified ulluco starch is an alternative to add value to the crop, as well as to replace non-biodegradable materials used in the preparation of packaging.

Active Packaging Films Made by Complex Coacervation of Tragacanth Gum and Gelatin Loaded with Curcumin; Characterization and Antioxidant Activity

The development of biopolymer-based green packaging films has gained remarkable attention in recent years. In this study, curcumin active films were prepared using different proportions of gelatin (GE) and a soluble fraction of tragacanth gum (SFTG) (1GE:1SFTG and 2GE:1SFTG) by complex coacervation. The various ratios of used biopolymers did not significantly impact the mechanical properties, thickness, and WVP of final films. However, biopolymers' ratio impacted the moisture content, water solubility, swelling ratio, and release rate. Blending curcumin with biopolymers caused a reduction in tensile strength (from 1.74 MPa to 0.62 MPa for film containing 1GE:1SFTG and from 1.77 MPa to 0.17 MPa for film containing 2GE:1SFTG) and proliferation in elongation at break (from 81.48% to 122.00% for film containing 1GE:1SFTG and from 98.87% to 109.58% MPa for film containing 2GE:1SFTG). Moisture content and water solubility of films experienced a decrease after the addition of curcumin. Antioxidant activity of curcumin-loaded films was almost five times higher than neat film samples. Furthermore, the interreaction between the carboxylic group of SFTG and amide I of GE formed an amide linkage and was proven by FTIR analysis. TGA showed a drop in the thermal stability of film samples compared to the main ingredients. In general, the complex coacervate of SFTG and GE has the advantage of developing eco-friendly and low-cost packaging film in the food industry, especially for the protection of fatty foods.

Plant-Based Innovations for the Transition to Sustainability: A Bibliometric and in-Depth Content Analysis

Plants maintain the ecological equilibrium of the earth and stabilize the ecosystem. Today, traditional commodities and new value-added markets can be served simultaneously. There is significant biosource and bioprocess innovation for biobased industrial products. Furthermore, plant-based innovation is associated with the transition to sustainability. This study performed a bibliometric and in-depth content analysis to review plant-based innovations in the research field between 1995 and 2022. A set of 313 articles was identified from the Scopus and Web of Science databases. Different analytical scientometric tools (topic mapping and overlay visualization networks) were used to analyze 124 articles; the most influential countries, institutions, authors, journals and articles were identified. Through in-depth studies, based on the grounded theory approach, five leading research areas related to plant-based innovation were determined: (1) agricultural/environmental innovation, (2) plant-based food or feed innovation, (3) innovation within the medical/pharmaceutical research area, (4) technology-related innovation and (5) economic/business aspects of plant-based innovations. Future research directions include exploring less examined and new topics, such as the sustainability implications of incorporating various plant-based foods and Industry 4.0 in plant-based innovation, and linking and developing findings from different research areas.

Extraction and Isolation of Natural Products

Bioactive compounds are substances that are generally found in small amounts in food and can have beneficial health effects [...]

Antioxidant packaging films developed by in-situ cross-linking chitosan with dialdehyde starch-catechin conjugates

In this study, four dialdehyde starch-catechin (DAS-catechin) conjugates were prepared by conjugating (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG) and (-)-epigallocatechin gallate (EGCG) with dialdehyde starch. Then, DAS-catechin conjugates were used as antioxidant and cross-linking agents to produce chitosan (CS) based antioxidant packaging films. The functionality of CS/DAS-catechin conjugate films was determined. Results showed four DAS-catechin conjugates formed Schiff-base linkages and hydrogen bond interactions with CS, resulting in improved film uniformity. Compared with plain CS film, CS/DAS-catechin conjugate films owned higher UV-vis light, water vapor and oxygen barrier ability, lower swelling degree, and stronger tensile strength, thermal stability and antioxidant activity. The cross-linking between CS and DAS-catechin conjugates delayed the biodegradable process of CS film. CS/DAS-catechin conjugate films showed good performance on inhibiting sunflower seed oil oxidation. Notably, CS/DAS-ECG conjugate film had the highest oxygen barrier, mechanical and antioxidant performances among four CS/DAS-catechin conjugate films. Therefore, CS/DAS-ECG conjugate film is an antioxidant packaging candidate for edible oil.

Recent Advances and Applications in Starch for Intelligent Active Food Packaging: A Review

At present, the research and innovation of packaging materials are in a period of rapid development. Starch, a sustainable, low-cost, and abundant polymer, can develop environmentally friendly packaging alternatives, and it possesses outstanding degradability and reproducibility in terms of improving environmental issues and reducing oil resources. However, performance limitations, such as less mechanical strength and lower barrier properties, limit the application of starch in the packaging industry. The properties of starch-based films can be improved by modifying starch, adding reinforcing groups, or blending with other polymers. It is of significance to study starch as an active and intelligent packaging option for prolonging shelf life and monitoring the extent of food deterioration. This paper reviews the development of starch-based films, the current methods to enhance the mechanical and barrier properties of starch-based films, and the latest progress in starch-based activity, intelligent packaging, and food applications. The potential challenges and future development directions of starch-based films in the food industry are also discussed.

Facile microfluidic fabrication and characterization of ethyl cellulose/PVP films with neatly arranged fibers

Much attention and endeavor have been paid to developing biocompatible food packaging films. Here, ethyl cellulose (EC) and polyvinylpyrrolidone (PVP) were fabricated into films through a facile method, microfluidic spinning. Morphology observations showed that the fibers were neatly arranged with an average diameter of 1-4 μm. FTIR and X-ray diffraction analysis suggested the existence of good compatibility and interaction between EC and PVP. Thermogravimetric analysis demonstrated that PVP ameliorates the thermal properties; moreover, the tensile properties were improved, with tensile strength (TS) and Young's modulus up to 11.10 ± 1.04 MPa and 350.16 ± 45.46 MPa, respectively. The optimal formula was EC/PVP (2:3), of which the film displayed an enhanced TS of 4.61 ± 1.15 MPa and a modified water contact angle of 61.8 ± 4.4°, showing fine tensile and hydrophilic performance. This study provides a facile and green film fabrication method promising to be used for food wrapping.

Recent advances in carrageenan-based films for food packaging applications

In order to solve the increasingly serious environmental problems caused by plastic-based packaging, carrageenan-based films are drawing much attentions in food packaging applications, due to low cost, biodegradability, compatibility, and film-forming property. The purpose of this article is to present a comprehensive review of recent developments in carrageenan-based films, including fabrication strategies, physical and chemical properties and novel food packaging applications. Carrageenan can be extracted from red algae mainly by hydrolysis, ultrasonic-assisted and microwave-assisted extraction, and the combination of multiple extraction methods will be future trends in carrageenan extraction methods. Carrageenan can form homogeneous film-forming solutions and fabricate films mainly by direct coating, solvent casting and electrospinning, and mechanism of film formation was discussed in detail. Due to the inherent limitations of the pure carrageenan film, physical and chemical properties of carrageenan films were enhanced by incorporation with other compounds. Therefore, carrageenan-based films can be widely used for extending the shelf life of food and monitoring the food freshness by inhibiting microbial growth, reducing moisture loss and the respiration, etc. This article will provide useful guidelines for further research on carrageenan-based films.

Polymeric Packaging Applications for Seafood Products: Packaging-Deterioration Relevance, Technology and Trends

Seafood is a highly economical product worldwide. Primary modes of deterioration include autolysis, oxidation of protein and lipids, formation of biogenic amines and melanosis, and microbial deterioration. These post-harvest losses can be properly handled if the appropriate packaging technology has been applied. Therefore, it is necessary for packaging deterioration relevance to be clearly understood. This review demonstrates recent polymeric packaging technology for seafood products. Relationship between packaging and quality deterioration, including microbial growth and chemical and biochemical reactions, are discussed. Recent technology and trends in the development of seafood packaging are demonstrated by recent research articles and patents. Development of functional polymers for active packaging is the largest area for seafood applications. Intelligent packaging, modified atmosphere packaging, thermal insulator cartons, as well as the method of removing a fishy aroma have been widely developed and patented to solve the specific and comprehensive quality issues in seafood products. Many active antioxidant and antimicrobial compounds have been found and successfully incorporated with polymers to preserve the quality and monitor the fish freshness. A thermal insulator has also been developed for seafood packaging to preserve its freshness and avoid deterioration by microbial growth and enzymatic activity. Moreover, the enhanced biodegradable tray is also innovative as a single or bulk fish container for marketing and distribution. Accordingly, this review shows emerging polymeric packaging technology for seafood products and the relevance between packaging and seafood qualities.

An intelligent colorimetric film based on complex anthocyanins and bacterial cellulose nanofibers for tilapia freshness detection in an actual cold chain

An intelligent colorimetric film was developed for the quality detection of tilapia fillets using bacterial cellulose (BC) as a substrate in combination with pelargonidin (Pg), cyanidin (Cy), and delphinium (Dp). The color of the BC-Pg-Cy-Dp film and Pg-Cy-Dp solution changed from rosy to blue-violet at pH 3-10. The mechanical and antioxidant properties of the film were improved after the addition of Pg-Cy-Dp. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) showed that a new hydrogen bond might be formed between the cellulose chain and the anthocyanin molecule, which increased the density of the film. The BC-Pg-Cy-Dp film displayed a large color difference from rosy to blue-violet when applied to tilapia fillet storage. The changes of K values indicated a good linear relationship with the change in ∆E at 4 °C and 25 °C. In the actual cold chain, the color of the film changed from rosy to purple, which could be identified by the naked eye and indicated that the fish were in the first fresh stage. Thus, the BC-Pg-Cy-Dp film can be used as an intelligent packaging film during storage to monitor the freshness of fish by the naked eye.

Bio-Based pH Indicator Films for Intelligent Food Packaging Applications

The widespread concerns about the environmental problems caused by conventional plastic food packaging and food waste led to a growing effort to develop active and intelligent systems produced from renewable biodegradable polymers for food packaging applications. Among intelligent systems, the most widely used are pH indicators, which are generally based on a pH-sensitive dye incorporated into a solid support. The objective of this study was to develop new intelligent systems based on renewable biodegradable polymers and a new bio-inspired pH-sensitive dye. The structure of the dye was elucidated through FT-IR and 1D and 2D NMR spectroscopic analyses. UV-VIS measurements of the dye solutions at various pH values proved their halochromic properties. Their toxicity was evaluated through theoretical calculations, and no toxicity risks were found. The new anthocyanidin was used for the development of biodegradable intelligent systems based on chitosan blends. The obtained polymeric films were characterized through UV-VIS and FT-IR spectroscopy. Their thermal properties were assessed through a thermogravimetric analysis, which showed a better stability of chitosan–PVA–dye and chitosan–starch–dye films compared to those of chitosan–cellulose–dye films and the dye itself. The films’ sensitivity to pH variations was evaluated through immersion in buffer solutions with pH values ranging from 2 to 12, and visible color changes were observed.

Ionic Liquid-Based Polymer Nanocomposites for Sensors, Energy, Biomedicine, and Environmental Applications: Roadmap to the Future

Current interest toward ionic liquids (ILs) stems from some of their novel characteristics, like low vapor pressure, thermal stability, and nonflammability, integrated through high ionic conductivity and broad range of electrochemical strength. Nowadays, ionic liquids represent a new category of chemical-based compounds for developing superior and multifunctional substances with potential in several fields. ILs can be used in solvents such as salt electrolyte and additional materials. By adding functional physiochemical characteristics, a variety of IL-based electrolytes can also be used for energy storage purposes. It is hoped that the present review will supply guidance for future research focused on IL-based polymer nanocomposites electrolytes for sensors, high performance, biomedicine, and environmental applications. Additionally, a comprehensive overview about the polymer-based composites' ILs components, including a classification of the types of polymer matrix available is provided in this review. More focus is placed upon ILs-based polymeric nanocomposites used in multiple applications such as electrochemical biosensors, energy-related materials, biomedicine, actuators, environmental, and the aviation and aerospace industries. At last, existing challenges and prospects in this field are discussed and concluding remarks are provided.

Poly-l-lactic acid (PLLA)/anthocyanin nanofiber color indicator film for headspace detection of low-level bacterial concentration

Since bacterial contamination is a significant threat to humans, early detection is essential to safeguard dietary safety and physical health. Here, a nanofiber color indicator film based on poly-l-lactic acid (PLLA) as the support and anthocyanin as the indicator material was prepared by electrostatic spinning. It was found that the PLLA/0.8CY nanofiber color indicator film was hydrophobic (the water contact angle of 102.4°) and contained uniform nanofibers with an average diameter of 750 nm. In addition, the film's humidity insensitivity, reusability, color stability, and ammonia sensitivity (the limits of detection 35.39 ppm) made the film environmentally friendly and more accurate and faster for bacterial detection. The film was able to sense 102 CFU/mL of gram-positive and negative bacteria after the model strain E. coli and L. monocytogene. Thus, the PLLA/0.8CY nanofiber color indicator film was able to perform headspace nondestructive detection of low-level bacterial contamination.

Preparation and Performance Characterization of a Composite Film Based on Corn Starch, κ-Carrageenan, and Ethanol Extract of Onion Skin

Using corn starch (CS) and κ-carrageenan(κC) as the raw material and active composite, respectively, films containing different concentrations of ethanol extract of onion skin were prepared. The effects of different concentrations of ethanol extract of onion skin (EEOS) on the physicochemical properties, as well as the antioxidant and antibacterial properties, of CS/κC films were also discussed. The addition of ethanol extract of onion skin inhibited the recrystallization of starch molecules in the composite films. It affected the microstructure of the composite films. The color of the composite films was deepened, the brightness was reduced, and the opacity was increased. Water vapor permeability increased, tensile strength decreased, and elongation at the break increased. The glass-transition temperature decreased. The clearance of DPPH radicals and ABTS cation radicals increased. Moreover, when the concentration of EEOS was 3%, the antioxidant effect of the films on oil was greatly improved and could effectively inhibit Staphylococcus aureus and Escherichia coli. The above results showed that adding ethanol extract of onion skin improved the physicochemical properties and biological activities of the CS/κC composite films, so CS/κC/EEOS composite films can be used as an active packaging material to extend food shelf-life. These results can provide a theoretical basis for the production and application of corn starch/κ-carrageenan/ethanol extract of onion skin composite films.

Facile fabrication of thermostable and colorimetric starch-based waterproof coating with edible organic materials

With the attention to pollution and human health, nontoxic food grade superhydrophobic coating as a strategy to reduce food waste has aroused wide interest. Herein, a food grade colorimetric starch-based waterproof coating was achieved using starch nanoparticle (SNP), stearic acid (STA) and anthocyanin. The as-prepared coating exhibited considerable thermostability and remarkable water repellency due to the low-surface-energy pomegranate pulp-like micro/nanostructure assembled by STA and SNP. The certain mechanical and chemical durability, prominent self-cleaning property and liquid food repellency in the coating had been thoroughly verified. Additionally, anthocyanin was creatively introduced to the coating via SNP loading, which endowed the coating with color response to different pH solutions. Thus, the coating is applicable to freshness monitoring without being disabled by water. This thermostable and colorimetric starch-based waterproof coating shows promising application prospects in advanced bio-based food-contact material field.

Monitoring dynamic changes in chicken freshness at 4 °C and 25 °C using pH-sensitive intelligent films based on sodium alginate and purple sweet potato peel extracts

A pH-sensitive intelligent indicator film was developed and used for monitoring dynamic changes in chicken freshness at 4 °C and 25 °C by immobilizing 0.2 %-1.0 % purple sweet potato peel extracts (PPE) with sodium alginate (SA). The films presented a wide range of colors from red-pink to green-yellow at 2-13, and the films with less PPE were more sensitive to ammonia. The color of films with 0.6 % PPE changed from pink to blue when used in monitoring chicken freshness at 4 °C (5 d) and 25 °C (60 h), which corresponded to changes in total volatile base nitrogen from 5.35 (5.35) mg/100 g to 16.2 (19.9) mg/100 g. Scanning electron microscopy and X-ray diffraction revealed that PPE improved the compactness and crystallinity of SA films, while Fourier transform infrared spectroscopy revealed hydrogen bonds between SA and PPE. Compared to SA films, the water vapor and light barrier abilities of films with 0.6 % were significantly improved (P < 0.05), there was no significant effect on tensile strength (P > 0.05), and the elongation of 0.6 % PPE films (P < 0.05) was decreased. Thus, PPE can serve as an excellent indicator of intelligent films for monitoring the freshness of meat products.

Development of Intelligent Gelatin Films Incorporated with Sappan (Caesalpinia sappan L.) Heartwood Extract

This study aimed to develop intelligent gelatin films incorporated with sappan (Caesalpinia sappan L.) heartwood extracts (SE) and characterize their properties. The intelligent gelatin film was prepared through a casting method from gelatin (3%, w/v), glycerol (25% w/w, based on gelatin weight), and SE at various concentrations (0, 0.25, 0.50, 0.75, and 1.00%, w/v). The thickness of the developed films ranged from 43 to 63 μm. The lightness and transparency of the films decreased with the increasing concentration of SE (p < 0.05). All concentrations of gelatin films incorporated with SE exhibited great pH sensitivity, as indicated by changes in film color at different pH levels (pH 1−12). Significant decreases in tensile strength were observed at 1.00% SE film (p < 0.05). The addition of SE reduced gelatin films’ solubility and water vapor permeability (p < 0.05). The chemical and physical interactions between gelatin and SE affected the absorption peaks in FTIR spectra. SE was affected by increased total phenolic content (TPC) and antioxidant activity of the gelatin film, and the 1.00% SE film showed the highest TPC (15.60 mg GAE/g db.) and antioxidant activity (DPPH: 782.71 μM Trolox/g db. and FRAP: 329.84 mM/g db.). The gelatin films combined with SE could inhibit S. aureus and E. coli, while the inhibition zone was not observed for E. coli; it only affected the film surface area. The result suggested that gelatin films incorporated with SE can be used as an intelligent film for pH indicators and prolong the shelf life of food due to their antioxidant and antimicrobial activities.

Promoting sustainable packaging applications in the circular economy by exploring and advancing molded pulp materials for food products: a review

Packaging ensures the safe handling and distribution of fresh and processed food products via diverse supply chains, and has become an indispensable component of the food industry. However, the rapidly expanding use of plastics, especially single-use plastics, as packaging material leads to inadequate waste management, littering, and consequently serious environmental damage, which predominantly affects marine and freshwater sources. Thus, the use of plastics for packaging purposes has become a major public concern and hence a concern among global policymakers. Notably, 26% of the total volume of global plastic production is primarily used for packaging, of which single-use plastics account for 50%, resulting in pollution that may last hundreds of years. This review provides an overview of the manner in which molded pulp products can be utilized to improve sustainability of food packaging applications, by highlighting the manufacturing processes, signifying characteristics features of recyclable molded pulp, and coupling circularity with eco-friendly and safe food product packaging. In this regard, current concepts advocate the implementation of a dynamic and sustainable approach using molded pulp products. This approach encompasses the design and production of eco-friendly packaging, distribution and consumption of packaged products, and collection and recycling of used packaging for subsequent reuse.

Exploration of multifunctional properties of garlic skin derived cellulose nanocrystals and extracts incorporated chitosan biocomposite films for active packaging application

For many years, garlic has been used as a condiment in food and traditional medicine. However, the garlic skin, which accounts for 25% of the garlic bulk, is considered agricultural waste. In this study, cellulose nanocrystals (CNCs) and garlic extract (GE) from garlic skin were isolated and used as fillers to manufacture biocomposite films. The films were characterized in terms of UV barrier, thermal, mechanical, biodegradability, and antimicrobial activity. The chitosan-containing films and CNCs have significantly improved the films' tensile strength, Young's modulus, and elongation but decreased the film transparency compared to chitosan films. The combination of the CNCs and GE, on the other hand, slightly reduced the mechanical properties. The addition of CNCs slightly decreased the film transparency, while the addition of GE significantly improved the UV barrier properties. Thermal studies revealed that the incorporation of CNC and GE had minimal effect on the thermal stability of the chitosan films. The degradability rate of the chitosan composite films was found to be higher than that of the neat chitosan films. The antimicrobial properties of films were studied against Escherichia coli, Streptomyces griseorubens, Streptomyces alboviridis, and Staphylococcus aureus, observing that their growth was considerably inhibited by the addition of GE in composite films. Films incorporating both CNCs and GE from garlic skin hold more promise for active food packaging applications due to a combination of enhanced physical characteristics and antibacterial activity.

Edible Bioactive Film with Curcumin: A Potential "Functional" Packaging?

Edible packaging has been developed as a biodegradable and non-toxic alternative to traditional petroleum-based food packaging. Biopolymeric edible films, in addition to their passive protective function, may also play a bioactive role as vehicles for bioactive compounds of importance to human health. In recent years, a new generation of edible food packaging has been developed to incorporate ingredients with functional potential that have beneficial effects on consumer health. Curcumin, a bioactive compound widely used as a natural dye obtained from turmeric rhizomes (Curcuma longa L.), has a broad spectrum of beneficial properties for human health, such as anti-inflammatory, anti-hypertensive, antioxidant, anti-cancer, and other activities. To demonstrate these properties, curcumin has been explored as a bioactive agent for the development of bioactive packaging, which can be referred to as functional packaging and used in food. The aim of this review was to describe the current and potential research on the development of functional-edible-films incorporating curcumin for applications such as food packaging.