Smart monitoring of gas/temperature changes within food packaging based on natural colorants

Deep learning-assisted flavonoid-based fluorescent sensor array for the nondestructive detection of meat freshness

Gas sensors containing indicators have been widely used in meat freshness testing. However, concerns about the toxicity of indicators have prevented their commercialization. Here, we prepared three fluorescent sensors by complexing each flavonoid (fisetin, puerarin, daidzein) with a flexible film, forming a fluorescent sensor array. The fluorescent sensor array was used as a freshness indication label for packaged meat. Then, the images of the indication labels on the packaged meat under different freshness levels were collected by smartphones. A deep convolutional neural network (DCNN) model was built using the collected indicator label images and freshness labels as the dataset. Finally, the model was used to detect the freshness of meat samples, and the overall accuracy of the prediction model was as high as 97.1%. Unlike the TVB-N measurement, this method provides a nondestructive, real-time measurement of meat freshness.

Critical review and recent advances of emerging real-time and non-destructive strategies for meat spoilage monitoring

Monitoring and evaluating food quality, especially meat quality, has received a growing interest to ensure human health and decrease waste of raw materials. Standard analytical approaches used for meat spoilage assessment suffer from time consumption, being labor-intensive, operation complexity, and destructiveness. To overcome shortfalls of these traditional methods and monitor spoilage microorganisms or related metabolites of meat products across the supply chain, emerging analysis devices/systems with higher sensitivity, better portability, on-line/in-line, non-destructive and cost-effective property are urgently needed. Herein, we first overview the basic concepts, causes, and critical monitoring indicators associated with meat spoilage. Then, the conventional detection methods for meat spoilage are outlined objectively in their strengths and weaknesses. In addition, we place the focus on the recent research advances of emerging non-destructive devices and systems for assessing meat spoilage. These novel strategies demonstrate their powerful potential in the real-time evaluation of meat spoilage.

Screening and Characterization of Antioxidant Film Applicable to Walnut Kernels from Juglans sigillata

Walnuts play a positive role in human health due to their large amounts of unsaturated fatty acids, whereas lipid oxidation can easily occur during storage. Herein, three natural antioxidants (epicatechin, sesamol, and myricetin) were added to the composite film cross-linked with chitosan and soy protein peptide, and the antioxidant film appropriate for the preservation of walnut kernels from Juglans sigillata was screened to improve the storage quality of walnuts. The results showed that three antioxidant films could all enhance the storage performance of walnut kernels, with sesamol being the best. The characterization of antioxidant film cross-linked with chitosan and soy protein peptide containing sesamol (C/S-ses film) revealed that the composite film improved the slow release and stability of sesamol; in addition, the presence of sesamol could effectively reduce the light transmittance and water vapor permeability of the composite film, together with significantly enhancing the antioxidant and antimicrobial activities, resulting in an effective prolongation of the storage period of walnut kernels. These findings indicated that C/S-ses possess excellent potential for retarding the oxidative rancidity of unsaturated fatty acids and will provide an effective strategy for the preservation of walnut kernels.

A comprehensive report on valorization of waste to single cell protein: strategies, challenges, and future prospects

The food insecurity due to a vertical increase in the global population urgently demands substantial advancements in the agricultural sector and to identify sustainable affordable sources of nutrition, particularly proteins. Single-cell protein (SCP) has been revealed as the dried biomass of microorganisms such as algae, yeast, and bacteria cultivated in a controlled environment. Production of SCP is a promising alternative to conventional protein sources like soy and meat, due to quicker production, minimal land requirement, and flexibility to various climatic conditions. In addition to protein production, it also contributes to waste management by converting it into food and feed for both human and animal consumption. This article provides an overview of SCP production, including its benefits, safety, acceptability, and cost, as well as limitations that constrains its maximum use. Furthermore, this review criticizes the downstream processing of SCP, encompassing cell wall disruption, removal of nucleic acid, harvesting of biomass, drying, packaging, storage, and transportation. The potential applications of SCP, such as in food and feed as well as in the production of bioplastics, emulsifiers, and as flavoring agents for baked food, soup, and salad, are also discussed.

Fabrication and characterization of chitosan/anthocyanin intelligent packaging film fortified by cellulose nanocrystal for shrimp preservation and visual freshness monitoring

In this study, a multi-functional packaging film was fabricated, utilizing the natural polysaccharide chitosan (CS) as the base material, integrating natural blueberry anthocyanin (AN) as pH-responsive indicator, and reinforced with cellulose nanocrystals (CNCs). The implications of addition levels of CNCs on the characteristics of the films were systematically investigated, resulting in that CS-AN-CNCs 9 % film exhibited optimal performance. Specifically, the film showed a substantial enhancement in maximum tensile strength from 15 MPa to 35 MPa; On the other hand, the swelling degree properties, the oxygen permeability and water vapor permeability decreased from 159.2 % to 92.0 %, from 51.7 g/(m2d) to 12.2 g/(m2d), from 31.6 × 10-12 g/(m·s·Pa) to 1.6 × 10-12 g/(m·s·Pa), respectively. Moreover, the CS-AN-CNCs 9 % film exhibited antioxidant, antibacterial, coupled with a color metrically responsive to pH variations, displaying great potential in indicating the shrimp freshness and delaying spoilage. Another notable advantage of the-prepared packaging material lies in its completely biodegradability, therefore meeting the requirement of environmental protection. Therefore, the prepared CS-AN-CNCs film as an intelligent packaging solution with potential applications in food preservation and freshness monitoring applications.

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.

Irreversible colorimetric bio-based curcumin bilayer membranes for smart food packaging temperature control applications

Research into innovative food safety technologies has led to the development of smart packaging with embedded chemical sensors that can monitor food quality throughout the supply chain. Thermochromic materials (TM), which are able to dynamically change colour in response to temperature fluctuations, have proven to be reliable indicators of food quality in certain environments. Natural colourants such as curcumin are becoming increasingly popular for smart packaging due to their low toxicity, environmental friendliness and ability to change colour. The innovation in this research lies in the production of a bio-based bilayer membrane specifically designed for irreversible temperature monitoring. Membrane A was prepared by dissolving cellulose acetate and curcumin in acetone at room temperature, with glycerol serving as a plasticiser. At the same time, membrane B was carefully formulated by dissolving cellulose acetate and triethanolamine in acetone, with sorbitol as plasticiser. The preparation of these different membranes revealed a remarkable event: a gradual and irreversible colour transition from an initial yellow to a brick-red hue after 24 hours of storage at 25 °C. The chemical structure and morphological analyses of the membranes were performed using several techniques, including FTIR, DSC and SEM. The membrane labels were adhered to aluminium cans and their colorimetric response was observed over a period of 10 days. Minimal colour variations were observed, confirming the reproducibility and stability of the curcumin-based membranes as temperature sensors.

Recent Advances in the Carotenoids Added to Food Packaging Films: A Review

Food spoilage is one of the key concerns in the food industry. One approach is the improvement of the shelf life of the food by introducing active packaging, and another is intelligent packaging. Detecting packed food spoilage in real-time is key to stopping outbreaks caused by food-borne diseases. Using active materials in packaging can improve shelf life, while the nonharmful color indicator can be useful to trace the quality of the food through simple color detection. Recently, bio-derived active and intelligent packaging has gained a lot of interest from researchers and consumers. For this, the biopolymers and the bioactive natural ingredient are used as indicators to fabricate active packaging material and color-changing sensors that can improve the shelf life and detect the freshness of food in real-time, respectively. Among natural bioactive components, carotenoids are known for their good antimicrobial, antioxidant, and pH-responsive color-indicating properties. Carotenoids are rich in fruits and vegetables and fat-soluble pigments. Including carotenoids in the packaging system improves the film's physical and functional performance. The recent progress on carotenoid pigment-based packaging (active and intelligent) is discussed in this review. The sources and biological activity of the carotenoids are briefly discussed, and then the fabrication and application of carotenoid-activated packaging film are reviewed. The carotenoids-based packaging film can enhance packaged food's shelf life and indicate the freshness of meat and vegetables in real-time. Therefore, incorporating carotenoid-based pigment into the polymer matrix could be promising for developing novel packaging materials.

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.

Betalains as promising natural colorants in smart/active food packaging

Betalains are water-soluble nitrogen pigments with beneficial effects, including antioxidant, antimicrobial, and pH-indicator properties. The development of packaging films incorporated with betalains has received increasing attention because of pH-responsive color-changing properties in the colorimetric indicators and smart packaging films. As such, intelligent and active packaging systems based on biodegradable polymers containing betalains have been recently developed as eco-friendly packaging to enhance the quality and safety of food products. Betalains could generally improve the functional properties of packaging films, such as higher water resistance, tensile strength, elongation at break, and antioxidant and antimicrobial activities. These effects are dependent on betalain composition (about its source and extraction), content, and the kind of biopolymer, film preparation method, food samples, and storage time. This review focused on betalains-rich films as pH- and ammonia-sensitive indicators and their applications as smart packaging to monitor the freshness of protein-rich foods such as shrimp, fish, chicken, and milk.

Recent advancements in natural colorants and their application as coloring in food and in intelligent food packaging

Colorants are widely employed in the food industry as an essential ingredient in many products since color is one of the most valued attributes by consumers. Furthermore, the utilization of colorants is currently being extended to the food packaging technologies. The objective of this review was to compile recent information about the main families of natural coloring compounds, and to describe their real implications in food coloring. In addition, their technological use in different food systems (namely, bakery products, beverages, meat and meat products, and dairy products) and their utilization in intelligent packaging to monitor the freshness of foodstuffs with the aim of extending food shelf life and improving food properties was discussed. The potential of using natural colorant in different food to improve their color has been demonstrated, although color stability is still a challenging task. More interestingly, the application of intelligent colorimetric indicators to exhibit color changes with variations in pH can enable real-time monitoring of food quality.

Sustainable and Bio-Based Food Packaging: A Review on Past and Current Design Innovations

Food loss and waste occur for many reasons, from crop processing to household leftovers. Even though some waste generation is unavoidable, a considerable amount is due to supply chain inefficiencies and damage during transport and handling. Packaging design and materials innovations represent real opportunities to reduce food waste within the supply chain. Besides, changes in people's lifestyles have increased the demand for high-quality, fresh, minimally processed, and ready-to-eat food products with extended shelf-life, that need to meet strict and constantly renewed food safety regulations. In this regard, accurate monitoring of food quality and spoilage is necessary to diminish both health hazards and food waste. Thus, this work provides an overview of the most recent advances in the investigation and development of food packaging materials and design with the aim to improve food chain sustainability. Enhanced barrier and surface properties as well as active materials for food conservation are reviewed. Likewise, the function, importance, current availability, and future trends of intelligent and smart packaging systems are presented, especially considering biobased sensor development by 3D printing technology. In addition, driving factors affecting fully biobased packaging design and materials development and production are discussed, considering byproducts and waste minimization and revalorization, recyclability, biodegradability, and other possible ends-of-life and their impact on product/package system sustainability.

Alizarin: Prospects and sustainability for food safety and quality monitoring applications

Active and intelligent food packaging has emerged to ensure food safety, quality, or spoilage monitoring and extend the shelf life of food. The development of intelligent packaging has accelerated significantly in recent years with a focus on monitoring changes in the quality of packaged products in real-time throughout the food supply chain. As one of the popular natural colorants, alizarin has attracted much consideration due to its excellent functional properties and quality to color change under varying pH. Alizarin is an efficient and cost-effective biomaterial with numerous biological features such as antioxidant, antibacterial, non-cytotoxic, and antitumor. This review focuses on an in-depth summary and prospects for alizarin as a natural and safe colorant that has the potential to be incorporated into intelligent packaging to track the freshness of packaged foodstuffs. The use of alizarin as an intelligent packaging agent shows huge potential for the application of food packaging and brings it one step closer to real-time monitoring of food quality throughout the supply chain. Finally, various limitations and future requirements are discussed to underscore the importance of developing alizarin-based intelligent functional food packaging systems.

Application of smart packaging for seafood: A comprehensive review

Nowadays, due to the changes in lifestyle and great interest of consumers in a healthy life, people have started increasing their seafood consumption. But due to their short shelf life, experts are looking for a new packaging called smart packaging (SMP) for seafood. There are different indicators/sensors in SMP; one of the effective indices is time-temperature, which can show consumers the best time of using seafood based on their shelf life and experienced temperature. Another one is radio-frequency identification (RFID) that is a transmission device that represents a separate form of the electronic information-based SMP systems. RFID does not belong to any of the categories of markers or sensors; it is an auto recognition system that applies cordless sensors to indicate segments and collect real-time information without manual interposition. This review covers the use of SMP in all marine foods, including fish, due to its high consumption and high content of polyunsaturated fatty acids, eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3), which are the considerable factors of n-3 polyunsaturated fatty acids for human.

A data-driven decision support system with smart packaging in grocery store supply chains during outbreaks

The unexpected emergence of the COVID-19 pandemic has changed how grocery shopping is done. The grocery retail stores need to ensure hygiene, quality, and safety concerns in-store shopping by providing "no-touch" smart packaging solutions for agri-food products. The benefit of smart packaging is to inform consumers about the freshness level of a packaged product without having direct contact. This paper proposes a data-driven decision support system that uses smart packaging as a smart product-service system to manage the sustainable grocery store supply chain during outbreaks to prevent food waste. The proposed model dynamically updates the price of a packaged perishable product depending on freshness level while reducing food waste and the number of rejected customers and maximising profit by increasing the inventory turnover rate of grocery stores. The model was tested on a hypothetical but realistic case study of a single product. The results of this study showed that stock capacities, freshness discount rate, freshness period, and quantity discounts significantly affect the performance of a grocery store supply chain during outbreaks.

On-package indicator films based on natural pigments and polysaccharides for monitoring food quality: a review

Deterioration of food quality and freshness is mainly due to microbial growth and enzyme activity. Chilled fresh food, especially meat and seafood, as well as pasteurized products, rapidly lose quality and freshness during packing, distribution and storage. Real-time food quality monitoring using on-package indicator films can help consumers make informed purchasing decisions. Interest in the use of intelligent packaging systems for monitoring safety and food quality has increased in recent years. Polysaccharide-based films can be developed into on-package indicator films due to their excellent film-forming properties and biodegradability. Another important component is the use of colorants with visible color changes at various pH levels. Currently, natural pigments are receiving increased attention because of their safety and environmental friendliness. This review highlights the recent findings regarding the role of natural pigments, the effects of incorporating natural pigments and polysaccharides on properties of indicator film, current application and limitations of on-package indicator films based on polysaccharides in some foods, problems and improvement of physical properties and color conversion of indicator film containing natural pigments, and development of polysaccharide-based pH-responsive films. © 2022 Society of Chemical Industry.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.

Impact of ultrasonication applications on color profile of foods

Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red-purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.

Fabrication of intelligent/active films based on chitosan/polyvinyl alcohol matrices containing Jacaranda cuspidifolia anthocyanin for real-time monitoring of fish freshness

The present work describes the natural anthocyanin from Jacaranda cuspidifolia (JC) flower immobilized within a biopolymer matrix composed of chitosan (CS) and polyvinyl alcohol (PVA) gave novel intelligent/active packaging films (CPC). We introduced microwave irradiation to prepare polymeric composite films noticed faster mixing of the polymers and extract take place than the conventional method. The prepared composite films are characterized by various analytical and spectroscopic techniques. The smooth SEM images demonstrated CS/PVA matrix miscibility and compatibility with anthocyanin for the film formation. The addition of anthocyanin to the CS/PVA films significantly reduced UV-Vis light transmission, while causing a slight decrease in the films transparency. An increased anthocyanin concentration on polymer films showed improved oxygen permeability (77.09 %), moisture retention capacity (11.64 %), and water vapor transmission rate (43.10 %) substantially. Additionally, the prepared CPC smart films exhibited strong antioxidant (97.92 %) as well as antibacterial activities against common foodborne pathogens such as S. aureus, and E. coli. Furthermore, the prepared smart films demonstrated pink color in acidic, while grey to yellowish in basic solvent. Further, the color response of the freshness label was consistent with the spoilage Total Volatile Basic-Nitrogen (TVB-N) content determined in the fish samples with varied time period. The CPC smart films also showed promising application in terms of monitoring freshness of the fish fillets at room temperature. The obtained results suggested that, the prepared CPC smart films have potential to be used as quality indicator in the marine food packaging system.

Active edible films with plant extracts: a updated review of their types, preparations, reinforcing properties, and applications in muscle foods packaging and preservation

Currently, edible films have been increasingly explored to solve muscle food spoilage during storage, especially through the incorporation of plant extracts to develop edible packaging materials. Natural polymers matrices with plant extracts are befitting for fabricating edible films by casting methods. In the films system, the structure and physicochemical properties were strengthened via chemical interactions between active molecules in plant extracts and the reactive groups in the polymer chain. The antibacterial and antioxidant properties were dramatically reinforced through both physical and chemical actions of the plant extracts. Additionally, edible films imbedded with color-rich plant extracts could be considered as potential sensitive indicators to monitor the spoilage degree of muscle foods in response to change in gas or temperature. Furthermore, these films could increase sensory acceptability, improve quality and prolong the shelf life of muscle foods. In this article, the types, preparation methods and reinforcing properties of the edible films with plant extracts were discussed. Also, the applications of these films were summarized on quality maintenance and shelf-life extension and intelligent monitoring in muscle foods. Finally, a novel technology for film preparation achieving high-stability and sustained release of active compounds will become an underlying trend for application in muscle food packaging.

Smart Biopolymer-Based Nanocomposite Materials Containing pH-Sensing Colorimetric Indicators for Food Freshness Monitoring

Nanocomposite biopolymer materials containing colorimetric pH-responsive indicators were prepared from gelatin and chitosan nanofibers. Plant-based extracts from barberry and saffron, which both contained anthocyanins, were used as pH indicators. Incorporation of the anthocyanins into the biopolymer films increased their mechanical, water-barrier, and light-screening properties. Infrared spectroscopy and scanning electron microscopy analysis indicated that a uniform biopolymer matrix was formed, with the anthocyanins distributed evenly throughout them. The anthocyanins in the composite films changed color in response to alterations in pH or ammonia gas levels, which was used to monitor changes in the freshness of packaged fish during storage. The anthocyanins also exhibited antioxidant and antimicrobial activity, which meant that they could also be used to slow down the degradation of the fish. Thus, natural anthocyanins could be used as both freshness indicators and preservatives in biopolymer-based nanocomposite packaging materials. These novel materials may therefore be useful alternatives to synthetic plastics for some food packaging applications, thereby improving the environmental friendliness and sustainability of the food supply.

Titanium dioxide nanoparticles as multifunctional surface-active materials for smart/active nanocomposite packaging films

Environmental issues such as plastic packaging and high demand for fresh and safe food has increased the interest for developing smart/active food packaging films with colloidal nanoparticles (NPs). Titanium dioxide nanoparticles (TNPs) are cost effective and stable metal oxide NPs which could be used as a functional nano-filler for biodegradable food packaging due to their excellent biocompatibility, photo catalyzing, and antimicrobial properties. This article has comprehensively reviewed the functional properties and advantages of TNPs-containing smart/active films. The advantage of adding TNPs for ameliorating food packaging materials such as their physical, mechanical, moisture/light barrier, optical, thermal resistance, microstructure and chemical properties as well as, antibacterial, and photocatalytic properties are discussed. Also, the practical and migration properties of administrating TNPs in food packaging material are investigated. The ethylene decomposition activity of TNPs containing active films, could be used for increasing the shelf life of fruits/vegetables after harvesting. TNPs are safe with negligible migration rates which could be used for fabrication of multifunctional smart/active packaging films due to their antimicrobial properties and ethylene gas scavenging activities.

Alginate-based hydrogels embedded with ZnO nanoparticles as highly responsive colorimetric oxygen indicators

Simple fabrication of hydrogel-based colorimetric oxygen indicators as alternative smart materials for oxygen sensitive products and systems.

Application of Nanotechnology to Improve the Performance of Biodegradable Biopolymer-Based Packaging Materials

There is great interest in developing biodegradable biopolymer-based packaging materials whose functional performance is enhanced by incorporating active compounds into them, such as light blockers, plasticizers, crosslinkers, diffusion blockers, antimicrobials, antioxidants, and sensors. However, many of these compounds are volatile, chemically unstable, water-insoluble, matrix incompatible, or have adverse effects on film properties, which makes them difficult to directly incorporate into the packaging materials. These challenges can often be overcome by encapsulating the active compounds within food-grade nanoparticles, which are then introduced into the packaging materials. The presence of these nanoencapsulated active compounds in biopolymer-based coatings or films can greatly improve their functional performance. For example, anthocyanins can be used as light-blockers to retard oxidation reactions, or they can be used as pH/gas/temperature sensors to produce smart indicators to monitor the freshness of packaged foods. Encapsulated botanical extracts (like essential oils) can be used to increase the shelf life of foods due to their antimicrobial and antioxidant activities. The resistance of packaging materials to external factors can be improved by incorporating plasticizers (glycerol, sorbitol), crosslinkers (glutaraldehyde, tannic acid), and fillers (nanoparticles or nanofibers). Nanoenabled delivery systems can also be designed to control the release of active ingredients (such as antimicrobials or antioxidants) into the packaged food over time, which may extend their efficacy. This article reviews the different kinds of nanocarriers available for loading active compounds into these types of packaging materials and then discusses their impact on the optical, mechanical, thermal, barrier, antioxidant, and antimicrobial properties of the packaging materials. Furthermore, it highlights the different kinds of bioactive compounds that can be incorporated into biopolymer-based packaging.

Emerging chitosan-essential oil films and coatings for food preservation - A review of advances and applications

With the rising demand for fresh and ready-to-eat foods, antimicrobial packaging has been developed to control or prevent microbial growth as well as maintain food quality and safety. Chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus, chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. This review summarized the effect of essential oils on modifying the physicochemical characteristics of chitosan-based films. Notably, the antimicrobial efficacy of the developed composite films or coatings was highlighted. The advances in the preparation methods and application of chitosan films were also discussed. Broadly, this review will promote the potential applications of chitosan-essential oils composite films or coatings in antimicrobial packaging for food preservation.

Preparation, characterization and application of smart packaging films based on locust bean gum/polyvinyl alcohol blend and betacyanins from cockscomb (Celosia cristata L.) flower

Cockscomb (Celosia cristata L.) is an edible and ornamental plant rich in natural pigments of betacyanins. In this study, smart packaging films were developed based on locust bean gum (LBG), polyvinyl alcohol (PVA) and betacyanins from cockscomb flower. Effect of cockscomb flower extract content (4 wt%, 8 wt% and 12 wt%) on the structural, physical and functional properties of LBG/PVA blend films was investigated. The addition of cockscomb flower extract elevated the immiscibility between LBG and PVA. Cockscomb flower extract interacted with LBG and PVA through hydrogen bonds, resulting in reduced film crystallinity. The film containing 8 wt% of cockscomb flower extract showed the lowest water vapor permeability (10.34 × 10^-11 g m^-1 s^-1 Pa^-1) and the highest tensile strength (23.63 MPa). The film containing 12 wt% cockscomb flower extract exhibited the lowest light transmittance and the highest elongation at break (41.12%) and antioxidant activity. Cockscomb flower extract made the films become reddish-purple and endowed the films with pH-sensitivity and ammonia-sensitivity. The films containing cockscomb flower extract showed obvious color changes from reddish-purple to brown/yellow when shrimp spoiled. Our results suggested LBG/PVA blend films with cockscomb flower extract were suitable smart packaging films for indicating shrimp freshness.

Informative and corrective responsive packaging: Advances in farm-to-fork monitoring and remediation of food quality and safety

Microbial growth and fluctuations in environmental conditions have been shown to cause microbial contamination and deterioration of food. Thus, it is paramount to develop reliable strategies to effectively prevent the sale and consumption of contaminated or spoiled food. Responsive packaging systems are designed to react to specific stimuli in the food or environment, such as microorganisms or temperature, then implement an informational or corrective response. Informative responsive packaging is aimed at continuously monitoring the changes in food or environmental conditions and conveys this information to the users in real time. Meanwhile, packaging systems with the capacity to control contamination or deterioration are also of great interest. Encouragingly, corrective responsive packaging attempting to mitigate the adverse effects of condition fluctuations on food has been investigated. This packaging exerts its effects through the triggered release of active agents by environmental stimuli. In this review, informative and corrective responsive packaging is conceptualized clearly and concisely. The mechanism and characteristics of each type of packaging are discussed in depth. This review also summarized the latest research progress of responsive packaging and objectively appraised their advantages. Evidently, the mechanism through which packaging systems respond to microbial contamination and associated environmental factors was also highlighted. Moreover, risk concerns, related legislation, and consumer perspective in the application of responsive packaging are discussed as well. Broadly, this comprehensive review covering the latest information on responsive packaging aims to provide a timely reference for scientific research and offer guidance for presenting their applications in food industry.

Development and characterization of electrospun nanofibers based on pullulan/chitin nanofibers containing curcumin and anthocyanins for active-intelligent food packaging

An electrospun nanofiber based on pullulan/chitin nanofibers (PCN) containing curcumin (CR) and anthocyanins (ATH) was developed using an electrospinning technique for active-intelligent food packaging. The results of scanning electron microscopy and attenuated total reflection Fourier transform infrared spectroscopy indicated that CR and ATH were successfully immobilized on the film-forming substrate based on PCN. The physical and chemical properties of nanofibers with no colorant, a single colorant, and double colorants were compared. The nanofiber containing ATH and CR (PCN/CR/ATH) had stronger antioxidant and antimicrobial activities than those of nanofibers containing CR (PCN/CR) or ATH (PCN/ATH). With respect to pH sensitivity, the color of the PCN/CR nanofibers did not change obviously, but the color of the PCN/ATH and PCN/CR/ATH nanofibers changed significantly with the change in pH. Furthermore, the PCN/CR/ATH nanofibers clearly changed color with the progressive spoilage of Plectorhynchus cinctus at room temperature. Therefore, the electrospun PCN/CR/ATH nanofiber have great application potential in active-intelligent food packaging.

Smart and Active Food Packaging: Insights in Novel Food Packaging

The demand for more healthy foods with longer shelf life has been growing. Food packaging as one of the main aspects of food industries plays a vital role in meeting this demand. Integration of nanotechnology with food packaging systems (FPSs) revealed promising promotion in foods’ shelf life by introducing novel FPSs. In this paper, common classification, functionalities, employed nanotechnologies, and the used biomaterials are discussed. According to our survey, FPSs are classified as active food packaging (AFP) and smart food packaging (SFP) systems. The functionality of both systems was manipulated by employing nanotechnologies, such as metal nanoparticles and nanoemulsions, and appropriate biomaterials like synthetic polymers and biomass-derived biomaterials. “Degradability and antibacterial” and “Indicating and scavenging” are the well-known functions for AFP and SFP, respectively. The main purpose is to make a multifunctional FPS to increase foods’ shelf life and produce environmentally friendly and smart packaging without any hazard to human life.

Recent Advances in the Development of Smart and Active Biodegradable Packaging Materials

Interest in the development of smart and active biodegradable packaging materials is increasing as food manufacturers try to improve the sustainability and environmental impact of their products, while still maintaining their quality and safety. Active packaging materials contain components that enhance their functionality, such as antimicrobials, antioxidants, light blockers, or oxygen barriers. Smart packaging materials contain sensing components that provide an indication of changes in food attributes, such as alterations in their quality, maturity, or safety. For instance, a smart sensor may give a measurable color change in response to a deterioration in food quality. This article reviews recent advances in the development of active and smart biodegradable packaging materials in the food industry. Moreover, studies on the application of these packaging materials to monitor the freshness and safety of food products are reviewed, including dairy, meat, fish, fruit and vegetable products. Finally, the potential challenges associated with the application of these eco-friendly packaging materials in the food industry are discussed, as well as potential future directions.

Valorization of natural colors as health-promoting bioactive compounds: Phytochemical profile, extraction techniques, and pharmacological perspectives

Color is the prime attribute with a large impact on consumers' perception, selection, and acceptance of foods. However, the belief in bio-safety protocols, health benefits, and the nutritional importance of food colors had focused the attention of the scientific community across the globe towards natural colorants that serve to replace their synthetic toxic counterparts. Moreover, multi-disciplinary applications of greener extraction techniques and their hyphenated counterparts for selective extraction of bioactive compounds is a hot topic focusing on process intensification, waste valorization, and retention of highly stable bioactive pigments from natural sources. In this article, we have reviewed available literature to provide all possible information on various aspects of natural colorants, including their sources, photochemistry and associated biological activities explored under in-vitro and in-vivo animal and human studies. However a particular focus is given on innovative technological approaches for the effective extraction of natural colors for nutraceutical and pharmaceutical applications.

Bio-Based Sensors for Smart Food Packaging-Current Applications and Future Trends

Intelligent food packaging is emerging as a novel technology, capable of monitoring the quality and safety of food during its shelf-life time. This technology makes use of indicators and sensors that are applied in the packaging and that detect changes in physiological variations of the foodstuffs (due to microbial and chemical degradation). These indicators usually provide information, e.g., on the degree of freshness of the product packed, through a color change, which is easily identified, either by the food distributor and the consumer. However, most of the indicators that are currently used are non-renewable and non-biodegradable synthetic materials. Because there is an imperative need to improve food packaging sustainability, choice of sensors should also reflect this requirement. Therefore, this work aims to revise the latest information on bio-based sensors, based on compounds obtained from natural extracts, that can, in association with biopolymers, act as intelligent or smart food packaging. Its application into several perishable foods is summarized. It is clear that bioactive extracts, e.g., anthocyanins, obtained from a variety of sources, including by-products of the food industry, present a substantial potential to act as bio-sensors. Yet, there are still some limitations that need to be surpassed before this technology reaches a mature commercial stage.