Preparation and characterization of active and intelligent packaging films based on cassava starch and anthocyanins from Lycium ruthenicum Murr

Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin-sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

Immobilization of roselle anthocyanins into polyvinyl alcohol/hydroxypropyl methylcellulose film matrix: Study on the interaction behavior and mechanism for better shrimp freshness monitoring

The roselle anthocyanin extracts (RAE) were immobilized into polyvinyl alcohol (PVA)/hydroxypropyl methylcellulose (HPMC) film matrix, their interaction behavior and mechanism was fully understood for better shrimp freshness monitoring. Structural characterizations revealed RAE was firmly immobilized PVA/HPMC matrix by hydrogen bonds. With increasing RAE contents, dramatic increases of film thickness (from 15.90 ± 0.14 to 23.20 ± 3.35 μm), tensile strength (from 45.66 ± 1.07 to 56.98 ± 0.24 MPa), light barrier and active properties (increased by 83.18% for antioxidant and 146.91%, 59.18% for antibacterial activity against E. coli and S. aureus) were observed, while hydrophobic properties decreased significantly. Owing to great ammonia-sensitive ability, the PVA/HPMC/RAE (PHR) films were applied on shrimp freshness qualitative monitoring and greater visible color variations were identified with increasing RAE contents. Furthermore, mathematical models were established for quantitative monitoring. In conclusion, with the increasing RAE contents, the tighter interaction between RAE and PVA/HPMC matrix contributed to the better functional properties and freshness monitoring effects of PHR films.

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.

Hydrophobic Interface Starch Nanofibrous Film for Food Packaging: From Bioinspired Design to Self-Cleaning Action

Starch-derived edible food films have great potential as biodegradable food packaging materials because they reduce the overuse of traditional petroleum-based plastic. Herein, we demonstrate a direct method of mass producing a pure starch food packaging film that consisted of starch nanofibers by using a temperature-assisted electrospinning technique without addition of any nonstarch components. To overcome the major issue of ultralow hydrophobicity of starch nanofibrous film (SNF), we used a facile and low-cost solution immersion approach to create a fiber coating of stearic acid (STA) inspired by biological organisms with superhydrophobic properties, such as lotus leaves. Hierarchical flower-like micronanostructures were obtained on SNF by controlled assembly of STA onto the surface of starch nanofibers. Benefiting from the effective formation of STA self-assembled lamella, the multiscale microstructure surface features, low surface energy, and enhancing thermal stability of SNF were obtained and confirmed to result in the variety of its hydrophobicity, which can be also tailored by simple controlling of the solution concentration of STA. Importantly, the STA-self-assembled coated SNF enabled water to roll freely in all directions, which is a crucial factor for self-cleaning. Our novel strategy based on self-assembly can guide development of bioinspired hydrophobic interfaces for starch-based films for edible hydrophobic materials.

Nopal cladode as a novel reinforcing and antioxidant agent for starch-based films: A comparison with lignin and propolis extract

The potential use of nopal cladode flour (NC) as reinforcing/bioactive agent in cassava starch-based films was evaluated and compared with the use of propolis extract or lignin, which are commonly used for these purposes. Cassava starch-based films containing untreated NC (S-NC), NC treated at pH 12 (S-NC12), aqueous propolis extract at two different concentrations (SP1 or SP2), or lignin (S-L) were produced by the casting technique; glycerol was used as plasticizer. NC12 and NC affected the mechanical properties of the cassava starch-based film similarly as compared to propolis extract and lignin. Moreover, NC and NC12 had different performance as reinforcing and antioxidant agent in cassava starch-based film. Thus, S-NC12 film was more elongable (28.5 ± 6.5%), more hydrophobic (contact angle: 70.8° ± 0.1), less permeable to water vapor (0.8 ± 0.0 × 10^-10 g·m^-1·s^-1·Pa^-1) and had better antioxidant activity by ABTS^•+ (44.70 ± 0.3 μM Trolox·g^-1 of film) than the S-NC film. SEM and TGA analysis of films showed that NC12 was better incorporated into the cassava starch matrix than NC, lignin and propolis extract. Overall, nopal cladode flour has potential use in the production of active biodegradable packaging for the food preservation with high oxidation rate.

Recent Developments in Smart Food Packaging Focused on Biobased and Biodegradable Polymers

Food packaging has a crucial function in the modern food industry. New food packaging technologies seek to meet consumers and industrial's demands. Changes related to food production, sale practices and consumers' lifestyles, along with environmental awareness and the advance in new areas of knowledge (such as nanotechnology or biotechnology), act as driving forces to develop smart packages that can extend food shelf-life, keeping and supervising their innocuousness and quality and also taking care of the environment. This review describes the main concepts and types of active and intelligent food packaging, focusing on recent progress and new trends using biodegradable and biobased polymers. Numerous studies show the great possibilities of these materials. Future research needs to focus on some important aspects such as possibilities to scale-up, costs, regulatory aspects, and consumers' acceptance, to make these systems commercially viable.

Effect of greenly synthetized silver nanoparticles on the properties of active starch films obtained by extrusion and compression molding

Replacing packaging plastics with biodegradable active materials is an emerging concern. In this context, thermoplastic starch (TPS) films and nanocomposites containing different concentrations of silver nanoparticles synthetized with starch and yerba mate (TPS-AgNP₁: 0.006 wt.% and TPS-AgNP₂: 0.015 wt.%) were developed by extrusion and compression molding. Spherical AgNP of 20-130 nm were obtained after the green synthesis and excellent adhesion between AgNP and the matrix was observed. Consequently, both composites exhibited higher stiffness and tensile strength values than TPS, indicating a reinforcing effect of AgNP. TPS-AgNP₁ showed the highest strain at break and toughness values, and TPS-AgNP₂ presented the lowest moisture content and ability to delay E. coli growth. Additionally, all materials disintegrated after 4 weeks of burial and resulted thermally stable up to 240 °C. This investigation provides a convenient and inexpensive way to develop starch-based nanocomposites with improved properties which appear to be promising as active packaging materials.

Fabrication of halochromic smart films by immobilizing red cabbage anthocyanins into chitosan/oxidized-chitin nanocrystals composites for real-time hairtail and shrimp freshness monitoring

In this study, halochromic smart films were produced, characterized, and applied to monitor the freshness of hairtail and shrimp in real-time. Red cabbage anthocyanins (RCAs) solution illustrated significant color variations (red-pink-blue-green) in different pH environments. RCAs were successfully immobilized into chitosan (CS)/oxidized-chitin nanocrystals (OCN) composites through hydrogen bonding, and cohesive film structures were formed. When the proper concentration of RCAs was incorporated into the composites, improved water vapor permeability (WVP), oxygen permeability (OP), mechanical, UV-blocking, and antioxidant properties were observed. Moreover, the smart films exhibited distinguishable changes of color to ammonia vapor and acidic/alkaline environment within short time intervals, which were easy to discern by naked eyes. Finally, the smart films were applied to monitor the freshness of hairtail (Trichiurus lepturus) and shrimp (Penaeus vannamei). The film color changed significantly during storage time, and three stages of product freshness (fresh, medium fresh, and spoiled) were successfully differentiated. Strong correlations among three freshness indicators and two colorimetric parameters were also identified and analyzed. Overall, the smart system assembled from non-toxic and biodegradable components could contribute to monitoring the freshness of seafood, like hairtail and shrimp, in real-time.

Extraction and Characterization of Potential Biodegradable Materials Based on Dioscorea hispida Tubers

This study was driven by the stringent environmental legislation concerning the consumption and utilization of eco-friendly materials. Within this context, this paper aimed to examine the characteristics of starch and fibres from the Dioscorea hispida tuber plant to explore their potential as renewable materials. The extraction of the Dioscorea hispida starch and Dioscorea hispida fibres was carried out and the chemical composition, physical, thermal, morphological properties, and crystallinity were studied. The chemical composition investigations revealed that the Dioscorea hispida starch (DHS) has a low moisture t (9.45%) and starch content (37.62%) compared to cassava, corn, sugar palm, and arrowroot starches. Meanwhile, the Dioscorea hispida fibres (DHF) are significantly low in hemicellulose (4.36%), cellulose (5.63%), and lignin (2.79%) compared to cassava, corn hull and sugar palm. In this investigation the chemical, physical, morphological and thermal properties of the Dioscorea hispida fibre and Dioscorea hispida starch were examined by chemical composition investigation, scanning electron microscopy (SEM), particle size distribution, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR), respectively. It was found that Dioscorea hispida waste is promising alternative biomass and sustainable material with excellent potential as a renewable filler material for food packaging applications.

Application of a Natural Antioxidant from Grape Pomace Extract in the Development of Bioactive Jute Fibers for Food Packaging

There is an increasing demand for the use of new food packaging materials. In this study, natural jute fibers impregnated with a Petit Verdot Red Grape Pomace Extract (RGPE) was proposed as a new active food packaging material. Pressurized Liquid Extraction (PLE) and Enhanced Solvent Extraction (ESE) techniques were employed to obtain the bioactive RGPE. Afterward the supercritical solvent impregnation conditions to obtain RGPE-natural jute fibers were studied, by varying pressure, modifier percentage and dried RGPE mass. PLE technique offered the highest bioactive extract at 20 MPa, 55 °C, 1 h residence time using C₂H₅OH:H₂O (1:1 v/v), providing an EC50 of 3.35 ± 0.25 and antibacterial capacity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa (MIC of 12.0, 1.5 and 4.0 mg/mL RGPE respectively). The natural jute fibers impregnated with 3 mL of that RGPE (90 mg/mL) at 50 MPa and 55 °C generated the most efficient packing material with regards to its food preservation potential.

Preparation and Characterization of Biodegradable Composited Films Based on Potato Starch/Glycerol/Gelatin

The use of plastics is resisted worldwide. Therefore, finding alternatives to plastic packaging products is an urgent issue. This work was dedicated to the preparation of biodegradable composited films with potato starch, glycerol, and gelatin. The formulation of the biodegradable film was first optimized via response surface methodology combined with the multi-index comprehensive evaluation method that considered physical properties (thickness, water solution (WS), tensile strength (TS) and elongation at break (E%)) and barrier property (light transmittance (T%)). Results indicated that the optimal conditions were 2.5% starch, 2.0% glycerol, and 1.5% gelatin (based on water). The optimized film presented excellent properties with TS of 4.47 MPa, E% of 109.91%, WS of 43.64%, and T% of 41.21% at 500 nm, and the comprehensive evaluation score of the composite film was 28.68. Moreover, a model verification experiment was further conducted, which proved that the predicted value highly matched experimental values, indicting the credibility and accuracy of the model. The resulting films were further characterized on the basis of rheological measurements, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The rheological measurements proved that the film-forming solution exhibited low shear viscosity and non-Newtonian fluid behavior. FTIR and SEM revealed excellent compatibility among starch, glycerol, and gelatin. Hence, the resulting optimized film may be expected to provide theoretical basis and technical support for the food packing industry.

Insights into the structure and conformation of potato resistant starch (type 2) using asymmetrical flow field-flow fractionation coupled with multiple detectors

Insight into the structure and conformation characteristics of starch that influence its enzyme susceptibility is import for its potential application. In this study, the capacity of asymmetrical flow field-flow fractionation (AF4) coupled online with multi-angle light scatting (MALS) and differential refractive index (dRI) detectors (AF4-MALS-dRI) for monitoring of change in structure and conformation of potato starch during enzymatic hydrolysis was evaluated. The dissolution behavior of potato resistant starch (type 2) (PRS) was investigated. The effect of incubation time and amyloglucosidase concentration on the structure and conformation of potato starch was studied. The apparent density and the ratio of R_g (radius of gyration) to R_h (hydrodynamic radius) obtained from AF4-MALS-dRI were proven to be important parameters as they offer an insight into conformation of PRS at molecular level. Results suggested that gelatinization process made potato amylose molecules have a loose and random coil conformation which could contribute to an acceleration of enzymatic hydrolysis of potato starch. Furthermore, an intermediate with an elongated branched conformation was found between amylose and amylopectin populations, which may play a role in digestion property of potato starch. The results demonstrated that AF4-MALS-dRI is a powerful tool for better understanding of conformation of PRS.

Challenges and possible solutions to mitigate the problems of single-use plastics used for packaging food items: a review

Single-use plastic (SUP) being a versatile material, is adopted as an alternate to traditional materials specifically for the use in food packaging due to its inherent characteristics like high durability, inertness, and protecting ability but has become a curse for living being today due to its random usage and unplanned rejection to nature. Mostly plastics used in packaging of beverages, fresh meats, fruits and vegetables are under concern today. Single-use packages result in generation of several billion tons of garbage till date, which pollutes the environment. At the immediate past, it has come to light that micro plastics obtained due to slow degradation of SUP present in oceans, are also being consumed by marine organisms such as fishes and shellfish species which disturbs the marine life extensively. Hence, finding right strategy to mitigate the plastic waste related issues has becoming inevitable today. This review paper briefs various strategies undertaken worldwide to mitigate the pollution due to generation of plastic waste. Various notable impact of adopted strategies and recent innovations to replace the SUP products are also discussed and in view of this a roadmap is also suggested which can be used to achieve the milestone of Zero Plastic Waste.

Physicochemical properties and structure of modified potato starch granules and their complex with tea polyphenols

The physicochemical, rheological properties and structure of potato starch and starch-tea polyphenols (TPs) complex modified by enzyme and alcohol was investigated in this study. Cavities on the modified starch granules and morphology change could be investigated by SEM, while significant birefringence observed in complete granules by polarizing light microscope, but disappeared in crashed starch. TPs inhibited the aggregation of amylose and retrogradation of starch-TPs complex, resulting in the decrease of gel strength, and the increase of viscosity and gelatinization stability of starch granules. Fourier transform infrared (FT-IR) spectra showed that intramolecular hydrogen bond could be formed between TPs with modified starch, and the hydrogen bond force formed by starch and TPs was stronger than that between starch molecules. X-ray diffraction (XRD) analysis revealed that three modification methods did not change the crystalline structure of starch, but new diffraction peaks appeared in the four starch-TPs complex, suggesting that the hydrogen bond was incurred by interaction between TPs and amylose to form V-type crystalline. These results demonstrated that the complex formed by TPs and native/modified potato starch could be used in food industrial applications due to the inhibition of starch retrogradation.

Development of starch based intelligent films by incorporating anthocyanins of butterfly pea flower and TiO2 and their applicability as freshness sensors for prawns during storage

Intelligent pH sensitive starch films were developed by incorporation of anthocyanin pigment extracted from butterfly pea flower (BPE) and nanosized TiO2 using the method of solution casting. This research work evaluated the influence of BPE and TiO2 on the physical and structural properties of starch films. The physical properties of the starch films could be significantly altered by the addition of BPE and or TiO2. The starch films S/BPE and S/BPE/TiO2 exhibited higher barrier properties against water vapour as compared to the control films. Incorporation of BPE and TiO2 could decrease the thickness and moisture content of films. S, S/BPE starch films were transparent and, S/TiO2 and S/BPE/TiO2 films were opaque. Control starch films were colourless, whereas S/BPE films have purple colour. Owing to the inclusion of BPE and TiO2 particles, structural characterization by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) did not show any major changes in polymer structure. Thermogravimetric analysis revealed that the addition of TiO2 enhanced the thermal stability of starch films to a significant extent. The color of different starch-based films was determined using the CIE Lab scale under different pH conditions and compared with the control. The fabricated (S/BPE and S/BPE/TiO2) films exhibited visually perceptible colour changes in the pH range between 1 and 12. Consequently these films could be used as intelligent pH indicators for monitoring the freshness of prawn seafood samples. During the storage of prawn food samples for 6 days, the color of the film changed from light pink to green which is a clear indication of spoilage of food material.

Protective effect and mechanism of action of xanthan gum on the color stability of black rice anthocyanins in model beverage systems

We investigated the effect and mechanism of action of xanthan gum (XG) on the color stability of black rice anthocyanins (BRA) in model beverage systems (pH 3.0) containing l-ascorbic acid under different conditions. The color stability of BRA was significantly enhanced in the presence of XG under accelerated storage conditions (40 °C), particularly at 0.25% (w/v). The degradation of BRA followed a first-order reaction rate (R² > 0.89) during storage and thermal processing conditions. The addition of XG effectively improved the storage stability of BRA in the presence of l-ascorbic acid, particularly at 4 °C in the dark. Moreover, the thermal stability of BRA was enhanced by XG under thermal treatment (80 °C, 90 °C and 100 °C). The FTIR spectrum, X-ray diffraction and molecular simulation results showed that the interaction between XG and BRA was driven mainly by hydrogen bonds and hydrophobic interactions, leading to the increased stability of BRA. Our study demonstrated the benefits of using XG to improve the color stability of BRA in model beverage systems, further expanding the practical application of XG in anthocyanin-rich beverages.

Preparation of on-package halochromic freshness/spoilage nanocellulose label for the visual shelf life estimation of meat

In this work, grape anthocyanins (GA) were embedded in bacterial nanocellulose (BNC) by ex-situ method to fabricate an easy-to-use colorimetric label. The label revealed visible color responses to the pH buffers (2-11). According to the color parameter results [L*, a*, b*, and total color difference (TCD)], the label also presented appropriate color stability during the 60-day storage. During the application in minced beef, the label was bright red on the 1st day of storage at 4 °C. In accordance with the meat quality parameters [TVB-N, total mesophilic count, and sensory attributes], the label turned into purplish-red color on the 3rd and 5th days of storage (medium freshness meat) and turned into blue on the 7th day, representing the spoilage state. All the mentioned color changes could be distinguished by naked eyes. A strong Pearson's correlation coefficient was obtained between the TCD values and meat quality parameters, confirming the capability of the pH-sensing label to correctly distinguish the fresh meat from the spoiled meat.

Anthocyanin food colorant and its application in pH-responsive color change indicator films

Recently, interest in smart packaging, which can show the color change of the packaging film according to the state of the food and evaluate the quality or freshness of the packaged food in real-time, is increasing. As a color indicator, a natural colorant, anthocyanin, drew a lot of attention due to their various colors as well as useful functions properties such as antioxidant activity and anti-carcinogenic and anti-inflammatory effects, prevention of cardiovascular disease, obesity, and diabetes. In particular, the pH-responsive color-changing function of anthocyanins is useful for making color indicator smart packaging films. This review addressed the latest information on the use of natural pigment anthocyanins for intelligent and active food packaging applications. Recent studies on eco-friendly biodegradable polymer-based color indicator films incorporated with anthocyanins have been addressed. Also, studies on the use of smart packaging films to monitor the freshness of foods such as milk, meat, and fish were reviewed. This review highlights the potential and challenges for the use of anthocyanins as pH-responsive color-changing films for intelligent food packaging applications, which may be beneficial for further development of smart color indicator films for practical use.

Physical, Barrier, Mechanical, and Biodegradability Properties of Modified Starch Films with Nut By-Products Extracts

Starch-based films with phenolic extracts could replace the use of petroleum-based plastics. In this study, octenyl succinate starch (OSS) films with pecan nutshell extract (PSE) or hazelnut skin extract (HSE) were prepared. The water resistance, as well as the optical, physical, mechanical, and biodegradable properties of these films, were investigated. The PSE and HSE improved the water resistance (decreasing the solubility to 17% and increasing the contact angle to 96.80°) and UV-light barrier properties of the films. For PSE and HSE, as their concentrations increased, the film rigidity decreased since these extracts acted as plasticizers. Micrographs obtained by scanning electron microscopy (SEM) depicted a homogeneous surface as a result of extracts dispersion through the polymeric matrix and the interactions between the phenolic compounds (PC) of the extracts and the OSS. The phenolic extracts from nut by-products and octenyl succinic anhydride (OSA) starch could be used to develop films to replace the conventional plastics.

Prospect of Polysaccharide-Based Materials as Advanced Food Packaging

The use of polysaccharide-based materials presents an eco-friendly technological solution, by reducing dependence on fossil resources while reducing a product's carbon footprint, when compared to conventional plastic packaging materials. This review discusses the potential of polysaccharides as a raw material to produce multifunctional materials for food packaging applications. The covered areas include the recent innovations and properties of the polysaccharide-based materials. Emphasis is given to hemicelluloses, marine polysaccharides, and bacterial exopolysaccharides and their potential application in the latest trends of food packaging materials, including edible coatings, intelligent films, and thermo-insulated aerogel packaging.

Development of active and intelligent films based on cassava starch and Chinese bayberry (Myrica rubra Sieb. et Zucc.) anthocyanins

Chinese bayberry (Myrica rubra Sieb. et Zucc.) fruit is a functional food rich in anthocyanins. In this study, anthocyanin-rich bayberry extract (BBE) was added into cassava starch to develop food packaging films with antioxidant and pH-sensitive properties. Results showed the main anthocyanin in BBE was cyanidin-3-O-glucoside (95.6%). The addition of 1 wt% of BBE into the film matrix resulted in a dense and compact internal microstructure, which greatly improved the water vapor permeability and tensile strength of the film. However, the addition of 2, 3 and 4 wt% of BBE into film matrix produced heterogeneous inner microstructures due to the formation of agglomerated BBE. The intermolecular interactions between BBE and the starch film matrix were through hydrogen binding. As compared with the starch film, starch–BBE films exhibited higher thicknesses, tensile strength, UV-vis light barrier and antioxidant properties. Moreover, starch–BBE films presented significant color changes when exposed to hydrogen chloride and ammonia gases. The pH-sensitive starch–BBE films were able to monitor the freshness of pork. Our results suggested that starch–BBE films could be used as smart and active packaging materials in the food industry.

In this study, anthocyanin-rich Chinese bayberry extract (BBE) was added into cassava starch to develop food packaging films with antioxidant and pH-sensitive properties.