Intelligent Packaging Applications Research Articles

Blueberry extract loaded into rice milk/alginate-based hydrogels as pH-sensitive systems to monitor the freshness of minced chicken

Hydrogel beads from rice milk and blueberry (BB) skins were fabricated as novel bio-based pH-sensitive devices. The encapsulation of BB into rice milk/alginate beads was achieved through a simple methodology. The colourimetric response of beads in different pH media was evaluated along with the proof of reusability, showing appropriate reversibility. The evaluation of the stability of BB-loaded beads in accelerated ageing conditions (4, 25 and 40 °C and under visible/UV light) showed high stability of beads (up to 28 days) even in the presence of harsh conditions. The half-time of cyanidin-3-glucoside decreases at high temperatures and under UV light exposure. The sensitivity to ammonia (NH3) and trimethylamine (TMA), as main spoilage volatiles of protein food products, was evaluated. The detection limits (LOD) for NH3 and TMA were 22.4 ppm and 72.1 ppm, respectively. Finally, the hydrogel beads were applied to monitor the spoilage of minced chicken breast. The colour of the beads, changing from dark reddish to green/yellowish and indicative of a high level of amine, could be detected by the naked eye after 3–5 days. This research proposes a sustainable, low-cost, and simple method to fabricate BB-loaded hydrogel beads as a promising tool for intelligent packaging applications.

Unlocking the potential of 2D nanomaterials for sustainable intelligent packaging

The demand for high food safety standards, spoilage prevention, and the minimization of food waste has spurred extensive investigation into intelligent food packaging. Within this field, considerable attention has been directed towards two-dimensional (2D) nanomaterials owing to their exceptionally thin layered configuration and diverse physicochemical, electrical, optical, and thermal properties. These attributes render 2D nanomaterials highly suitable for enhancing sensing capabilities in intelligent packaging systems. This review delves into the forefront of research concerning the utilization of 2D nanomaterials in intelligent packaging applications. It provides a comprehensive survey of intelligent food packaging concepts and explores various 2D materials, including graphene-based materials, MXene, and silicate clay, investigated for their potential in intelligent packaging systems. Additionally, the review interprets the structure, properties, and utilization of 2D materials in diverse biosensing systems encompassing gas, moisture, pH, and bacteria sensors, indicators, or wireless tags. Moreover, it examines the influence of 2D materials on the mechanical, optical, thermal, barrier, and bioactive properties of smart packaging, while also deliberating on their respective advantages and limitations. By combining these foundational elements, this study offers a distinctive and thorough contribution to the domain of food packaging, laying the groundwork for the future development of sustainable and high-performance packaging materials.

Recent Progress in Intelligent Packaging for Seafood and Meat Quality Monitoring

AbstractFood waste plays a crucial role in environmental and human health issues. To address these issues, intelligent packaging systems are proposed for the accurate assessment of the quality of food products. Intelligent packaging is a technology that integrates sensing systems with conventional packaging to provide smart sensing communication functions for real‐time food quality monitoring. The most important parts of this technology are generally classified as quantitative sensors (sensors) and qualitative sensors (indicators). Since seafood and meat products can spoil easily if not stored properly, applying intelligent packaging for real‐time monitoring of the safety of these products is beneficial. In this review, the spoiling process and essential performance characteristics are indicators of the quality of these food products are first discussed. Then, The characteristics and importance of various sensors and indicators that can be used for seafood and meat quality monitoring are presented. While discussing these topics, an updated review of recent scientific studies, preconditions, materials, advantages, and limitations are provided. Furthermore, the future need for improvements in intelligent packaging systems for real‐time quality and safety monitoring of food products is discussed. Finally, several important research examples of the challenges and perspectives of intelligent packaging applications for meat and seafood quality monitoring are presented.

Flexible Sensing Antenna for Overbending Detection in Intelligent Packaging Applications

Flexible Sensing Antenna for Overbending Detection in Intelligent Packaging Applications

Dual-function β-cyclodextrin/starch-based intelligent film with reversible responsiveness and sustained bacteriostat-releasing for food preservation and monitoring

The full combination of high sensitivity indication and long-lasting bacteriostatic function is an innovative need to meet the practicality of intelligent film packaging systems for food products. Hence, Blueberry anthocyanins (BA) copigmentated by ferulic acid (FA) was used as an indicator, and cinnamon essential oil (CO) encapsulated by β-cyclodextrin (β-CD) as a bacteriostat, potato starch (PS) as a film-forming substrate to prepared a dual-function starch-based intelligent active packaging film with pH indicator and antibacterial function. FA had the best copigmentation effect with a threefold increase in a value compared to other phenolic acids. The ΔE value increased from 3.24 to 5.13 at pH 2–8, and the change was still prominent in acid-base alternating test, indicating a high response sensitivity. Notably, the yellow gamut of indicating terminus increased its visibility to the naked eye. The release behavior of CO from film was in line with Fick's diffusion. Meanwhile, the release of CO delayed to about 90 h through β-cyclodextrin encapsulation, showing a high growth-inhibition rate in E. coli and S. aureus of almost 100 %. In this study, a dual-function film with indication and bacteriostasis was prepared and enhanced with both, expanding its wide application in intelligent packaging of fresh food.

Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness

The present study was conducted with the aim of fabricating smart bilayer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata extract nanofibers (CMC-CNC and PLA-VOE) for freshness monitoring of Pacific white shrimps, minced lamb meat, chicken fillets, and rainbow trout fillets, during refrigerated storage conditions. The fabricated indicators based on CMC-PLA-VOE 5%, CMC-CNC 1%-PLA-VOE 5%, and CMC-CNC 3%-PLA-VOE 5% presented remarkable color changes in pH 1–12 buffer solutions, including red at pH 1–6, violet at pH 7–8, green at pH 9–10, and brown at pH 11–12. Significantly lower water vapor permeability and oxygen transmission rate of prepared polymers were found in comparison with the control groups (P < 0.05). Regarding the monitoring of food samples in real-time, the samples spoiled after 3 days, evidenced by total viable count, psychrotrophic bacterial count, total volatile basic nitrogen, and pH values of 7.17–7.54 log CFU/g, 5.68–6.23 log CFU/g, 25.14–28.12 mg N/100 g, and 7.10–7.66, respectively. Meanwhile, the noticeable color change of prepared indicators from white to violet (day 3) and finally dark violet (day 7) was observed, indicating a potential application in intelligent packaging for real-time control of the freshness of perishable food samples.

Resazurin-impregnated gelatin-based indicator for intelligent packaging applications

Modified resazurin (Res) incorporating gelatin (Gel) based indicator films were prepared to monitor the quality of packed shrimp in real time. FE-SEM micrographs show uniform dispersion of Res with minimal irregularities in the indicator film. The integration of Res increased the film's load-bearing ability and tensile strength without affecting the film's transparency and water vapor permeability. FT-IR and XPS profiles showed high compatibility and intermolecular H-bonds between the Res and Gel polymer matrices. The release rate of Res from the Gel-Res indicator film depended on the food simulant showing higher release rates in aqueous solutions (water and 10% ethanol) than in alcohol solutions (50% and 95% ethanol solutions). The Gel-Res indicator film exhibited excellent color stability even after storage for 60 days at room temperature. It was sensitive to ammonia vapor and alkaline pH solutions with a color change from yellow to pink with a total color difference (ΔE) of 15.4. In shrimp packaging tests, Gel-Res films exhibited noticeable color changes, which corresponded well with TVB-N levels and pH changes. These results suggest that the Gel-Res indicator films have acquired ideal prerequisites for potential intelligent seafood packaging.

Alginate microbeads incorporated with anthocyanins from purple corn (Zea mays L.) using electrostatic extrusion: Microencapsulation optimization, characterization, and stability studies

Microencapsulation of purple corn anthocyanins was carried out via an electrostatic extruder using alginate as a wall material. The influence of alginate concentration (1–2 %), extract concentration (20–30 %), and extrusion voltage (3–5 kV) on encapsulation efficiency and mean particle size was evaluated using response surface methodology. Optimal conditions were obtained to produce two different extract-loaded microbeads. Microbeads with the highest encapsulation efficiency (EE) and minimum particle size were achieved at 1 % alginate, 20 % extract, and 5 kV extrusion voltage (EEC3G = 70.26 %, EETPC = 91.59 %, particle size = 1.29 mm). In comparison, the microbeads with the efficient entrapment and maximum particle size were obtained at 1 % alginate, 26 % extract, and 3 kV (EEC3G = 81.15 %, EETPC = 91.01 %, particle size = 1.87 mm). Brunauer-Emmett-Teller (BET) surface area, pore size, and pore volume decreased after the inclusion of extract, with the lowest values reported for the smallest microbeads containing the extract. Scanning electron microscopy confirmed the results obtained by BET method and demonstrated fewer cracks and lower shrinkage of encapsulated samples. Fourier-transform infrared results proved the presence of anthocyanins and further possible interactions between phenolics and alginate. Stability studies revealed the color maintenance of anthocyanins-loaded microbeads during 4 weeks of storage at 4 °C and 8 °C. Moreover, the small and large particles showed a 7.6 and 3.4-fold reduction in degradation rate at 4 °C compared to their unencapsulated counterparts. Anthocyanins-loaded alginate microbeads retained over 80 % of cyanidin-3-glucoside at 4 °C and 8 °C, suggesting a promising potential of optimized microbeads for intelligent packaging applications.

Betanin and Nano-Calcium Carbonate Incorporated Polyvinyl alcohol/Starch Films for Active and Intelligent Packaging Applications

Betanin and Nano-Calcium Carbonate Incorporated Polyvinyl alcohol/Starch Films for Active and Intelligent Packaging Applications

The potential of anthocyanin-loaded alginate hydrogel beads for intelligent packaging applications: Stability and sensitivity to volatile amines

pH indicators have emerged as promising tools for real-time monitoring of product freshness and quality in intelligent food packaging applications. However, ensuring the stability of these indicators is critical for practical use. This study aims to evaluate the stability of anthocyanins-loaded alginate hydrogel beads of varying sizes at different temperatures under accelerated light conditions and relative humidity (RH) levels of 53% and 97% during 21 days of storage. Moreover, their sensitivity to the principal spoilage volatiles of muscle food products such as ammonia (NH3), dimethylamine (DMA) and trimethylamine (TMA) was investigated. The half-life of cyanidin-3-glucoside in small hydrogel beads was roughly twice as long as that of the larger beads under accelerated light exposure at 4 °C and they were less likely to undergo noticeable color changes over time. Both sizes of hydrogel beads stored at 97% RH and 4 °C showed color stability over the 21-day period with minimal color variation (|ΔE| ≤ 3). The UV–vis spectra of the purple corn extract exhibited changes across pH 2 to 12, as evidenced by the visible color variations, ranging from pink to green. The limit of detection (LOD) for NH3 was 25 ppm for small beads and 15 ppm for large ones. Both types of beads exhibited similar LOD for DMA and TMA, around 48 ppm. This research showed that alginate hydrogel beads containing anthocyanins from purple corn are a viable option for developing intelligent packaging of muscle foods. Furthermore, the use of hydrogel beads of different sizes can be customized to specific muscle foods based on the primary spoilage compound generated during spoilage.

Shikonin: Extraction, properties and applications in active and intelligent packaging

AbstractShikonin is a naphthoquinone compound, generally extracted from the roots of the Oriental medicinal herb Lithospermum erythrorhizon or the Indian medicinal herb Arnebia euchroma. It has a rich history of being utilized as a pharmacological compound to treat various diseases such as inflammation, wounds and microbial infections. Besides, it also possesses anticancer, antiviral and antioxidant properties, which interest current medical researchers. Food packaging researchers have recently utilized shikonin's antimicrobial and antioxidant properties for active food packaging. Its halochromic properties and ability to change colour with pH variation have attracted tremendous attention for intelligent packaging applications. This review article covers the important extraction processes for shikonin. Further, the important properties of these functional compounds have been discussed. Finally, the advancements in applying shikonin as a multifunctional material in biopolymer‐based films for smart packaging applications have been reviewed for the first time.

Colorimetric indicator based on chitosan/gelatin with nano-ZnO and black peanut seed coat anthocyanins for application in intelligent packaging

Chitosan/gelatin (CG) based intelligent pH-sensing indicator films were fabricated by incorporating zinc oxide nanoparticles (nano-ZnO) (CGZ) and different amounts of black peanut seed coat anthocyanins (BPCSA) (CGZ-h). Chitosan/gelatin showed good compatibility with anthocyanins and nano-ZnO, and the addition of nano-ZnO and BPSCA did not affect the original crystal structure of films. Addition with BPSCA simultaneously increased the tensile strength and elongation at break of CGZ-h films. BPSCA decreased the water vapor permeability, whereas they increased the UV barrier property of the CGZ-h films. CGZ-h films exerted strong antioxidant and antibacterial activities, which mainly attributed to the BPSCA and nano-ZnO, respectively. CGZ-h films presented good pH-sensing color-change properties in different buffer solutions. The CGZ-h2 film was used to monitor the freshness of shrimp at 4 °C. The result showed that distinctive color change of the CGZ-h2 film was highly correlated with the change of the total volatile basic nitrogen, pH and total viable count of shrimp. These results revealed the potential application of CGZ-h for real-time monitoring the freshness of food.

A starch-based pH-sensing and ammonia detector film containing betacyanin of paperflower for application in intelligent packaging of fish

An easy-to-use food packaging label with pH and ammonia sensitivity was developed by adding betacyanin (5, 10 and 15 mg per g of starch) from flowers of paperflower (Bougainvillea glabra) to potato starch film made using the solvent casting method. The betacyanin was well dispersed into the starch matrix and formed new interactions with it as revealed by FTIR. The film containing 15 mg/g of betacyanin showed a color change from light pink to yellow as a response to pH adjustment of between 2 to 13. It was also able to detect the presence of ammonia in a range of 0.1 and 0.01 mg of ammonia per ml of water. Surface hydrophobicity and water vapor barrier capacity of the starch film increased by addition of the betacyanin, yet their mechanical strength decreased in the presence of the betacyanin. The ability of the film in the real-time indication of fish quality as a label was also evaluated during the storage of Caspian sprat at 4 °C. A visual change in the color of the packaging label from pink to yellow in parallel with the increase in the total volatile basic nitrogen (TVB-N), microbial count of the fish samples was detected. The starch/betacyanin film could be a novel intelligent label for application in food packaging.

Corn starch/polyvinyl alcohol based films incorporated with curcumin-loaded Pickering emulsion for application in intelligent packaging

The intelligent pH indicator films were prepared by incorporating curcumin-loaded Pickering emulsion with corn starch (CS) and polyvinyl alcohol (PVA) matrix. The mechanical properties, barrier properties and functional characteristics of the films were studied and the films were applied to monitor fish freshness. Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) showed that Pickering emulsion can form hydrogen bonds with CS and PVA. The antioxidant activity of the films was detected, which showed that Pickering emulsion could reduce the decomposition of curcumin during the process of preparation and storage. Bactericidal tests showed that the films can inhibit the growth of S. aureus, B. subtilis, and E. coli, and the effect of the films on Gram-positive (G+) bacteria is stronger than Gram-negative (G−) bacteria. Application of the films presented here is supported by an activation test of Pangasius bocouti. With time changed, the color of films changed from yellow to red, and the color change of films prepared with curcumin-loaded Pickering emulsion was more evident than the films prepared with curcumin solution. Therefore, the films prepared with curcumin-loaded Pickering emulsion had better performance and can be used to indicate the quality of food.

PH-sensitive soluble soybean polysaccharide/SiO2 incorporated with curcumin for intelligent packaging applications.

In the present work, the effect of various concentrations of SiO2 nanoparticles (5, 10, and 15%) on physicochemical and antimicrobial properties of soluble soybean polysaccharide (SSPS)‐based film was investigated. Then, the migration of SiO2 nanoparticles to ethanol as a food simulant was evaluated. Subsequently, curcumin was added to the nanocomposite formulation to sense the pH changes. Finally, the cytotoxicity of the developed packaging system was investigated. With increasing nanoparticle concentration, the film thickness, water solubility, and water vapor permeability decreased and mechanical performance of the films improved. SSPS/SiO2 nanocomposite did not show antibacterial activity. SEM analysis showed that SiO2 nanoparticles are uniformly distributed in the SSPS matrix; however, some outstanding spots can be observed in the matrix. A very homogeneous surface was observed for neat SSPS film with R a and R q values of 3.48 and 4.26, respectively. With the incorporation of SiO2 (15%) into SSPS film, R a and R q values increased to 5.67 and 5.98, respectively. Small amount of SiO2 nanoparticles was released in food simulant. The nanocomposite incorporated with curcumin showed good physical properties and antibacterial activity. A strong positive correlation was observed between TVBN content of shrimp and a* values of the films during storage time (Pearson's correlation = 0.985).

Colorimetric indicator based on purple tomato anthocyanins and chitosan for application in intelligent packaging

Intelligent colorimetric indicator films were prepared to monitor freshness/spoilage of milk and fish by incorporating purple tomato anthocyanin (PTA) into chitosan (CS) matrix via solution casting method with PTA concentration (w/w, based on CS) of 10%, 30%, and 50%, respectively. The pH-response, UV absorption, Swelling Index, and the mechanical properties of CS/PTA films were determined. It was found that the color of the original CS/PTA films became darker with an improvement of PTA content and expressed well pH-sensitivity. With increasing of pH, the color of the CS/PTA films exposed to pH = 3–11 solutions became darker and the change in color of the CS/10% PTA film was the most discernable. The tensile strength and Young's modulus of the CS/PTA film was much lower than that of CS film, however, the elongation at breaking and Swelling Index were both improved by adding PTA. The intelligent films with 10% PTA changed their color during progressive spoilage of milk or fish, revealing their potential application for monitoring food freshness/spoilage.

PH-responsive chitosan-based film incorporated with alizarin for intelligent packaging applications

A chitosan-based pH-responsive functional film was prepared by the incorporation of alizarin and its properties were tested for active and intelligent food packaging applications. SEM and FTIR results showed that alizarin was uniformly distributed in the chitosan matrix to form a homogeneous film. The alizarin-added chitosan film showed high UV-blocking property with increased elongation at break, surface hydrophobicity, and thermal stability of the film. The release rate of alizarin from the film was dependent on the solution showing a higher release rate in a 50% ethanol solution than that in water, 10% and 95% ethanol solutions. The synergistic effect of antibacterial activity by the addition of alizarin was negligible against E. coli but slightly increased against L. monocytogenes. However, the antioxidant activity of the chitosan film was significantly increased by the addition of alizarin. The color of the composite film changed vividly from slightly yellow to purple in response to a pH change in the range of 4–10, and the composite film was very sensitive to ammonia vapor. The composite coating could indicate the onset of fish spoilage by showing color change from khaki to light brown as the pH of the packaged fish changed.

Cinnamil- and Quinoxaline-Derivative Indicator Dyes for Detecting Volatile Amines in Fish Spoilage.

Colorimetric indicators are versatile for applications such as intelligent packaging. By interacting with food, package headspace, and/or the ambient environment, color change in these indicators can be useful for reflecting the actual quality and/or monitoring distribution history (e.g., time and temperature) of food products. In this study, indicator dyes based on cinnamil and quinoxaline derivatives were synthesized using aroma compounds commonly present in food: diacetyl, benzaldehyde, p-tolualdehyde and p-anisaldehyde. The identities of cinnamil and quinoxaline derivatives were confirmed by Fourier transform infrared (FT–IR) spectroscopy, mass spectrometry (MS), 1H nuclear magnetic resonance (NMR) and 13C NMR analyses. Photophysical evaluation showed that the orange-colored cinnamil derivatives in dimethylsulfoxide (DMSO) turned to dark brownish coloration when exposed to strong alkalis. The cinnamil and acid-doped quinoxaline derivatives were sensitive to volatile amines commonly present during the spoilage in seafood. Quinoxaline derivatives doped by strong organic acid were effective as pH indicators for volatile amine detection, with lower detection limits than cinnamil. However, cinnamil exhibited more diverse color profiles than the quinoxaline indicators when exposed to ammonia, trimethylamine, triethylamine, dimethylamine, piperidine and hydrazine. Preliminary tests of acid-doped quinoxaline derivatives on fresh fish demonstrated their potential as freshness indicators in intelligent packaging applications.

PEDOT: PSS Thermoelectric Generators Printed on Paper Substrates

Flexible electronics is a field gathering a growing interest among researchers and companies with widely varying applications, such as organic light emitting diodes, transistors as well as many different sensors. If the circuit should be portable or off-grid, the power sources available are batteries, supercapacitors or some type of power generator. Thermoelectric generators produce electrical energy by the diffusion of charge carriers in response to heat flux caused by a temperature gradient between junctions of dissimilar materials. As wearables, flexible electronics and intelligent packaging applications increase, there is a need for low-cost, recyclable and printable power sources. For such applications, printed thermoelectric generators (TEGs) are an interesting power source, which can also be combined with printable energy storage, such as supercapacitors. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), or PEDOT:PSS, is a conductive polymer that has gathered interest as a thermoelectric material. Plastic substrates are commonly used for printed electronics, but an interesting and emerging alternative is to use paper. In this article, a printed thermoelectric generator consisting of PEDOT:PSS and silver inks was printed on two common types of paper substrates, which could be used to power electronic circuits on paper.

VO₂(B)/Graphene Composite-Based Symmetrical Supercapacitor Electrode via Screen Printing for Intelligent Packaging.

More multipurpose and convenient demand driven by Radio Frequency Identification (RFID) and intelligent packaging require flexible power sources. A VO2(B)/graphene (VO2(B)/GN) core-shell composite was successfully synthesized by the hydrothermal treatment with V2O5 and graphite. The as-obtained sample was characterized by XRD, FT-IR, SEM, TEM, and XPS measurements. In addition, the electrochemical properties of VO2(B)/GN were tested. Due to its great electrochemical performance and mechanical properties, graphene could increase the electrochemical performance and strengthen the structural stability of the material at the same time. With increasing loading amount of GN, the specific capacitance of VO2(B)/GN increased correspondingly. With 20% GN loading, the initial discharge specific capacity could reach 197 F g−1 at 0.5 A g−1, and 160 F g−1 at 1 A g−1 in 0.5 M Na2SO4 electrolyte, which is better than that of pure rod-like VO2(B). The capacitance of the VO2(B)/GN (20%) composite electrode retains 95.49% after 1000 cycles, which is higher than that of a pure VO2(B) electrode (85.43%), indicating that the VO2(B)/GN composite possesses better cycling stability. Moreover, a symmetrical solid-state supercapacitor (SCs) using VO2(B)/GN(20%) as the anode was assembled. Four printed SCs were connected in series to light up a 1.5 V red LED. This demonstrates its potential application in intelligent packaging to trace food safety.