Formation of high amylose corn starch/konjac glucomannan composite film with improved mechanical and barrier properties

Incorporating maltitol regulates the gel properties and structural features of κ-carrageenan-corn starch-soy protein isolate based quaternary system and its application of low glycemic index gummies

This study investigated the structure and gel features of maltitol-κ-carrageenan-corn starch-soy protein isolate quaternary system under the different maltitol addition (5 %-25 %), and evaluated the glycemic index (GI), digestibility, sensory and texture properties of gummies prepared based on this system. As maltitol incorporation increased, gelatinization temperature raised from 69.87 °C to 97.77 °C but the enthalpy value decreased from 8.40 J/g to 2.39 J/g. The quaternary complexes also showed structural changes, and there was the highest uniform of the dense gel network structure, the highest content of the short-range ordering structure, and the lowest crystallinity degree after the 20 % incorporation of maltitol. However, the textural properties (e.g., hardness, chewiness, gumminess and cohesiveness) and gel strength of the quaternary gels decreased, resulting from the formation of the weaker gel. Additionally, gummies at 20 % maltitol incorporation exhibited a low GI (33.38) value, digestibility and the desired sensory and texture characteristics.

Konjac glucomannan-based films and coatings for food packaging: Advances, applications, and future perspectives

BACKGROUND

Conventional petroleum-derived plastic food packaging poses risks to human health and environmental sustainability, while underperforming in preserving freshness and extending shelf life. This has spurred interest in biopolymers as sustainable alternatives. Konjac glucomannan (KGM), a natural biopolymer, stands out for its non-toxicity, film-forming ability, biodegradability, and biocompatibility, offering a sustainable solution to overcome conventional plastics' limitations.

SCOPE AND APPROACH

This review explores KGM's sources, production technologies, properties, and applications in food packaging. A literature search (2020-2025) using PubMed, Web of Science, and Scopus focused on peer-reviewed studies relevant to KGM-based films. Results show that KGM films enhance shelf life of perishable foods (e.g., fruits, vegetables, meats) by improving moisture retention, gas barriers, and antimicrobial activity.

CONCLUSION

Despite advantages, KGM films face challenges like mechanical strength limitations and humidity sensitivity. Strategies such as blending with biopolymers and incorporating nanoparticles improve performance. KGM-based packaging is emerging as an eco-friendly alternative to petroleum plastics, aligning with sustainability goals. Future research should optimize production processes and commercial scalability.

Improvement of soybean protein isolate/konjac glucomannan-seaweed polysaccharide-based connective tissue simulants: effects of pH and water mobility on gel structure and gelling mechanism

Hydrogels are considered to have good potential to mimic connective tissue. In this study, the mechanical properties and thermal stability of protein-polysaccharide composite hydrogels were enhanced by moisture and acid-base modulation in an attempt to overcome the application limitations. The results of texture profile analysis (TPA) and compression experiments showed that the appropriate outward migration of moisture significantly improved the gel's mechanical properties. Rheological analysis showed that the gel exhibited optimal mechanical properties under an alkaline environment and, combined with the differential scanning calorimetry (DSC) results, excellent thermal stability was observed in the pH 10.5 sample group. Furthermore, magnetic resonance imaging (MRI) and scanning electron microscopy (SEM) results showed that the alkaline environment was also conducive to the formation of a denser gel network structure, and the outward migration of water led to a more orderly and uniform structure. Fourier transform infrared spectroscopy (FTIR) results showed that hydrogen bonding also played a major role in the formation of the cellular network structure of the gel. These findings demonstrate the positive contribution of moisture and pH modulation to the processing and edible property enhancement of animal connective tissue-mimicking structure and provide a theoretical basis for the regulation of hydrogel properties.

Polymers Derived from Agro-Industrial Waste in the Development of Bioactive Films in Food

This review explores the potential of biopolymers as sustainable alternatives to conventional plastics in food packaging. Biopolymers derived from plant or animal sources are crucial in extending food shelf life, minimizing degradation, and protecting against oxidative and microbial agents. Their physical and chemical properties, influenced by the raw materials used, determine their suitability for specific applications. Biopolymers have been successfully used in fruits, vegetables, meats, and dairy products, offering antimicrobial and antioxidant benefits. Consequently, they represent a functional and eco-friendly solution for the packaging industry, contributing to sustainability while maintaining product quality.

Tapioca starch/konjac gum-based composite film incorporated with nanoliposomes encapsulated grape seed oil: Structure, functionality, controlled release and its preservation role for chilled mutton

In this study, grape seed oil nanoliposomes (GSO-NLs) were constructed and doped into tapioca starch/konjac gum composite films (TK-GSO-NLs) to evaluate the preservation of chilled mutton. The results showed that the GSO-NLs have a good spherical or rounded state and good stability. The doping of GSO-NLs resulted in a smooth, flat, and dense structure on the surface and cross-section of the TK films. The TK-GSO-NLs showed the best compatibility among the components, with excellent mechanical and barrier properties. FTIR and XRD confirmed the presence of ionic bonds between the components, further improving the copolymer crystal structure. Notably, the packaging material provided ideal antioxidant and bacteriostatic stability as well as delayed GSO release. This packaging could effectively maintain the quality of chilled mutton and prolong the shelf-life to 15 days. The study provides ideas for the design of green and active food packaging and for extending the shelf life of meat.

Food packaging films from natural polysaccharides and protein hydrogels: A comprehensive review

The development of innovative, biodegradable food packaging materials to combat plastic pollution has garnered significant attention from scholars and government agencies worldwide. Natural polysaccharides and proteins exhibit excellent modifiability, biodegradability, high ductility, and compatibility with food products, making them ideal candidates for constructing hydrogels. Hydrogel films based on these biopolymers have opened new research horizons in food packaging applications. This review examines natural polysaccharides and proteins commonly used in hydrogel film preparation and explores strategies to improve their packaging performance, including the use of binary mixtures and exogenous additives. To optimize functionality, the cross-linking mechanisms between materials and film-forming methods are summarized. Additionally, recent applications of hydrogel films in food packaging in are discussed, showcasing their ability to extend or monitor food freshness. Despite existing challenges, the current advancements present a promising and sustainable alternative to conventional plastic materials paving the way for innovative packaging solutions.

The amyloid fibril-stabilized Pickering emulsion significantly enhances the mechanical and barrier properties of Konjac Glucomannan active films for cherry preservation

Konjac glucomannan (KGM), a natural polymer, is an excellent candidate for use in food packaging due to its desirable film-forming characteristics. However, the limited barrier, antioxidant, and antimicrobial properties of pure KGM films restrict their practical applications. To reinforce the barrier and functional properties of KGM-based films, tea tree oil (TTO) Pickering emulsions stabilized by chitosan-modified soy protein derivative-amyloid fibril (AFS) were prepared and incorporated into KGM matrices. The effects of these Pickering emulsions on the structural and functional properties of KGM films were systematically investigated. The results indicated a favorable compatibility between Pickering emulsions and KGM. The strong interactions among KGM, AFS, and TTO lead to a denser and more compact film structure, improving barrier properties. Specifically, the water vapor and oxygen permeability values of the Pickering emulsion films (group E4C1) were reduced to 0.326 g·mm/(m2·day·KPa) and 4.63 g/m·s·Kpa, respectively. The tensile strength and elongation at the break of the film were increased respectively to 35.02 MPa and 71.8 %. The incorporation of TTO markedly enhanced water resistance, with the total antioxidant capacity of group E5C1 being 9.92 times greater than that of pure KGM films, as well as improving the antimicrobial activity of the KGM-based films. Furthermore, the emulsion film demonstrated effective preservation of cherries, extending their shelf life by approximately 10 days. In conclusion, this study successfully developed a film with enhanced barrier properties and antimicrobial activity, presenting promising applications in food preservation and packaging.

Evaluation of amylose content: Structural and functional properties, analytical techniques, and future prospects

Amylose content (AC) is critical in evaluating starch properties, significantly influencing the food industry and human nutrition. Although amylose is not completely linear, its unique structure makes it a key research focus across various scientific fields. Understanding amylose's structural and functional properties is essential for its applications in medical, nutritional, and industrial sectors. Accurate determination of AC, from simple qualitative assessments to precise quantitative measurements, is vital for effectively processing and using starch-rich products. The choice of AC determination method depends on the specific application and the required accuracy and detail. This review summarizes amylose's structural and functional characteristics and recent advancements in qualitative and quantitative AC determination techniques. It also provides insights into future trends and prospects for these technologies, emphasizing the need for more rapid, convenient, accurate, and customizable methods. In conclusion, advancements in amylose determination should enhance accuracy, speed, and ease of use to improve quality control and applications across various sectors while expanding our understanding of amylose and its functionalities.

Polysaccharide-Based Composite Films: Promising Biodegradable Food Packaging Materials

With growing concerns about environmental protection and sustainable development, the development of new biodegradable food packaging materials has become a significant focus for the future of food packaging. Polysaccharides, such as cellulose, chitosan, and starch, are considered ideal biodegradable packaging materials due to their wide availability, good biocompatibility, and biodegradability. These materials have garnered extensive attention from researchers in food packaging, leading to considerable advancements in the application of polysaccharide-based food packaging films, coatings, aerogels, and other forms. Therefore, this review focuses on the application of polysaccharide-based packaging films in food storage and preservation and discusses their preparation methods, application progress, challenges, and future development directions. Through an in-depth analysis of the existing literature, this review aims to provide sustainable and environmentally friendly solutions for the food packaging industry.

Konjac glucomannan-based composite materials: Construction, biomedical applications, and prospects

Konjac glucomannan (KGM) as an emerging natural polymer has attracted increasing interests owing to its film-forming properties, excellent gelation, non-toxic characteristics, strong adhesion, good biocompatibility, and easy biodegradability. Benefiting from these superior performances, KGM has been widely applied in the construction of multiple composite materials to further improve their intrinsic performances (e.g., mechanical strength and properties). Up to now, KGM-based composite materials have obtained widespread applications in diverse fields, especially in the field of biomedical. Therefore, a timely review of relevant research progresses is important for promoting the development of KGM-based composite materials. Innovatively, firstly, this review briefly introduced the structure properties and functions of KGMs based on the unique perspective of the biomedical field. Then, the latest advances on the preparation and properties of KGM-based composite materials (i.e., gels, microspheres, films, nanofibers, nanoparticles, etc.) were comprehensively summarized. Finally, the promising applications of KGM-based composite materials in the field of biomedical are comprehensively summarized and discussed, involving drug delivery, wound healing, tissue engineering, antibacterial, tumor treatment, etc. Impressively, the remaining challenges and opportunities in this promising field were put forward. This review can provide a reference for guiding and promoting the design and biomedical applications of KGM-based composites.

The Properties of Thin Films Based on Chitosan/Konjac Glucomannan Blends

In this work, blend films were prepared by blending 2% chitosan (CS) and 0.5% konjac glucomannan (KGM) solutions. Five ratios of the blend mixture were implemented (95:5, 80:20, 50:50, 20:80, and 5:95), and a pure CS film and a pure KGM film were also obtained. All the polymeric films were evaluated using FTIR spectroscopy, mechanical testing, SEM and AFM imaging, thermogravimetric analyses, swelling and degradation analyses, and contact angle measurements. The CS/KGM blends were assessed for their miscibility. Additionally, the blend films' properties were evaluated after six months of storage. The proposed blends had good miscibility in a full range of composition proportions. The blend samples, compared to the pure CS film, indicated better structural integrity. The surface structure of the blend films was rather uniform and smooth. The sample CS/KGM 20:80 had the highest roughness value (Rq = 12.60 nm). The KGM addition increased the thermal stability of films. The blend sample CS/KGM 5:95 exhibited the greatest swelling ability, reaching a swelling degree of 946% in the first fifteen minutes of the analysis. Furthermore, the addition of KGM to CS improved the wettability of the film samples. As a result of their good mechanical properties, surface characteristics, and miscibility, the proposed CS/KGM blends are promising materials for topical biomedical and cosmetic applications.

Development of starch-cellulose composite films with antimicrobial potential

This study explored the structure and performance of starch-based antibacterial films reinforced with black tea cellulose nanocrystals (BT-CNCs). The optimal addition amount of BT-CNCs is 5 % (w/w Starch). This nanocrystal-infused film, incorporating chitosan (CS), ε-polylysine (ε-PL), and zinc oxide nanoparticles (ZnONP) as antibacterial agents, exhibited a smooth, continuous surface. The addition of BT-CNCs and antibacterial agents did not change the group characteristic peaks of the film, but changed the crystallinity slightly. The films, namely St, St/CNCs, St/CNCs/CS, and St/CNCs/ε-P, maintained high light transmittance (above 80 %), except for the St/CNCs/ZnONP film, which effectively shielded UV radiation. The combined use of antibacterial agents and BT-CNCs enhanced the water and oxygen barrier properties of the film. Notably, the St/CNCs/CS film exhibited the lowest solubility (17.74 % ± 0.36) and the highest tensile strength (14.23 ± 0.16 MPa). The antibacterial efficacy of the films decreased in the order of St/CNCs/ZnONP, St/CNCs/ε-PL, and St/CNCs/CS, with a more pronounced inhibitory effect on E. coli compared to S. aureus. This study marries natural waste recycling with cutting-edge food packaging technology, setting a new benchmark for the development of sustainable packaging materials.

The effect of agar from the seaweed Gracilaria fisheri on properties of biodegradable starch foam

This work focuses on the potential of agar from the seaweed Gracilaria fisheri to modify the properties of starch foam. The effects of different ratios of glycerol and agar on the properties of starch foams were investigated. All formulations used in this study produced easy-to-handle, smooth, single-use foam trays with no visible cracks. The addition of agar slightly affected the off-white color of the foam but red and yellow color values significantly decreased with increments of agar content. As the agar content was increased, the foam became less dense. A foam produced at a glycerol:agar ratio of 3:7 exhibited the highest values of flexural stress at maximum load (3.23 MPa), modulus (194.46 MPa) and hardness (97.50), and the highest temperature at maximum weight loss (Tmax) (337 °C). Therefore, starch foam modified with agar from Gracilaria fisheri showed suitable physical, mechanical and thermal properties for food packaging, and could possibly be used in the place of expanded polystyrene (EPS) foam.

Investigation into the fabrication of plant-based simulant connective tissue utilizing algae polysaccharide-derived hydrogel

Connective tissue is an important component of meat products that provides support to animal muscles. Hydrogels are considered a promising alternative to connective tissues and simulate actual products by adjusting the gel texture and mouthfeel. This study used soybean protein isolate (SPI), corn starch (CS), konjac glucomannan (KGM), and seaweed powder (SP) as raw materials to examine the effect of different added SP and KGM concentrations on the gel texture. The G' of the gel increased five-fold when the SP and KGM concentration was increased from 1 % to 3 %. The results of mechanical property tests showed that with the addition of SP, the gel hardness increased from 316.00 g to 1827.23 g and the tensile strength increased from 0.027 MPa to 0.089 MPa. Sensory evaluation showed that the samples with 2 % SP and KGM presented the highest overall acceptability score and the most significant similarity to real connective tissue. The connective tissue simulants exhibited excellent water-holding capacity (>90 %), significantly increasing their juiciness. SEM indicated that 2 % KGM addition improved gel network structure stability. The results demonstrate the potential of seaweed polysaccharide-derived hydrogels as connective tissue mimics. This provides a new strategy for the preparation of high mechanical strength hydrogels and lays the foundation for structural diversification of plant-based meat.

Plant polysaccharide-derived edible film packaging for instant food: Rapid dissolution in hot water coupled with exceptional mechanical and barrier characteristics

A comprehensive multiscale analysis was conducted to explore the effects of different ratios of these materials on its properties. The results show that KC played a crucial role in controlling solution viscosity and gel and sol temperatures. The dissolution time at high water temperatures primarily decreased with an increase in SA content. Higher KC and CS content increased tensile strength (TS) and elongation at break (ε), while also exhibiting better thermal stability. Water vapor transmission (WVT) and permeability (PV) initially decreased, then increased with the increase of SA and CS contents. Finally, an SA:KC:CS ratio of 1:3:2 showed optimal comprehensive properties, with a dissolution time of about 60.0 ± 3.8 s, TS of 23.80 ± 0.29 MPa, ε of 18.61 ± 0.34 %, WVT of 21.74 ± 0.62 g/m2·24h, and PV of 5.39 ± 0.17 meq/kg. Meanwhile, the SA:KC:CS edible food packaging only introduced minimal effects on food after dissolution, and the total bacterial count met regulatory standards.

The present state and future outlook of pectin-based nanoparticles in the stabilization of Pickering emulsions

The stabilization of Pickering emulsions using micro/nanoparticles has gained significant attention due to their wide range of potential applications in industries such as cosmetics, food, catalysis, tissue engineering, and drug delivery. There is a growing demand for the development of environmentally friendly micro/nanoparticles to create stable Pickering emulsions. Naturally occurring polysaccharides like pectin offer promising options as they can assemble at oil/water interfaces. This polysaccharide is considered a green candidate because of its biodegradability and renewable nature. The physicochemical properties of micro/nanoparticles, influenced by fabrication methods and post-modification techniques, greatly impact the characteristics and applications of the resulting Pickering emulsions. This review focuses on recent advancements in Pickering emulsions stabilized by pectin-based micro/nanoparticles, as well as the application of functional materials in delivery systems, bio-based films and 3D printing using these emulsions as templates. The effects of micro/nanoparticle properties on the characteristics of Pickering emulsions and their applications are discussed. Additionally, the obstacles that currently hinder the practical implementation of pectin-based micro/nanoparticles and Pickering emulsions, along with future prospects for their development, are addressed.

Recent advances in modified starch based biodegradable food packaging: A review

This study reviews the importance of resistant starch (RS) as the polymer of choice for biodegradable food packaging and highlights the RS types and modification methods for developing RS from native starch (NS). NS is used in packaging because of its vast availability, low cost and film forming capacity. However, application of starch is restricted due to its high moisture sensitivity and hydrophilic nature. The modification of NS into RS improves the film forming characteristics and extends the applications of starch into the formulation of packaging. The starch is blended with other bio-based polymers such as guar, konjac glucomannan, carrageenan, chitosan, xanthan gum and gelatin as well as active ingredients such as nanoparticles (NPs), plant extracts and essential oils to develop hybrid biodegradable packaging with reduced water vapor permeability (WVP), low gas transmission, enhanced antimicrobial activity and mechanical properties. Hybrid RS based active packaging is well known for its better film forming properties, crystalline structures, enhanced tensile strength, water resistance and thermal properties. This review concludes that RS, due to its better film forming ability and stability, can be utilized as polymer of choice in the formulation of biodegradable packaging.

Development and evaluation of Bauhinia Kockiana extract-incorporated sago starch intelligent film strips for real-time freshness monitoring of coconut milk

The aim of this work was to fabricate an intelligent film using sago starch incorporated with the natural source of anthocyanins from the Bauhinia Kockiana flower and use it to monitor the freshness of coconut milk. The films were developed using the casting method that included the addition of the different concentrations (0, 5, 10, 15 mg) of Bauhinia Kockiana extract (BKE) obtained using a solvent. The anthocyanin content of Bauhinia Kockiana was 262.17 ± 9.28 mg/100 g of fresh flowers. The spectral characteristics of BKE solutions, cross-section morphology, physiochemical, barrier, and mechanical properties, and the colour variations of films in different pH buffers were investigated. Films having the highest BKE concentration demonstrated the roughest structure and highest thickness (0.16 mm), moisture content (9.72 %), swelling index (435.83 %), water solubility (31.20 %), and elongation at break (262.32 %) compared to the other films. While monitoring the freshness of coconut milk for 16 h, BKE15 showed remarkable visible colour changes (from beige to dark brown), and the pH of coconut milk dropped from 6.21 to 4.56. Therefore, sago starch film incorporated with BKE has excellent potential to act as an intelligent pH film in monitoring the freshness of coconut milk.

Chitosan/konjac glucomannan bilayer films: Physical, structural, and thermal properties

To overcome the limitations of chitosan (CS) and konjac glucomannan (KGM), the bilayer films of CS and KGM were prepared by layer-by-layer (LBL) casting method, and the effects of different mass ratios (i.e., C5: K0, C4:K1, C3:K2, C1:K1, C2:K3, C1:K4, and C0:K5) on the microstructures and physicochemical properties of bilayer films were examined to evaluate their applicability in food packaging. The results revealed that the bilayer films had uniform microstructures. When compared with pure films, the bilayer films displayed lower swelling degrees and water vapor permeability. However, the tensile tests revealed a reduction in the mechanical properties of the bilayer films, which was nonetheless superior to that of the pure KGM film. In addition, the intermolecular interactions between the CS and KGM layers were observed through FTIR and XRD analyses. Finally, TGA and DSC analyses demonstrated a decrease in the thermal stability of the bilayer films. Our cumulative results verified that CS-KGM bilayer films may be a promising material for use in food packaging and further properties of the bilayer films can be supplemented in the future through layer-by-layer modification and the addition of active ingredients.

Passerini three-component reaction for the synthesis of saccharide branched cellulose

In this work, we investigate a multicomponent synthetic method for combining saccharides with cellulose to produce saccharide branched cellulose (b-Cel). First, cellulose is modified conventionally using carboxymethyl to create carboxyl functional groups for multicomponent reactions. The Passerini three-component reaction (Passerini-3CR) is then used to synthesize the saccharide b-Cel, with particular attention paid to the scope of the substrate and reaction process optimization. The structure of saccharide b-Cel is regulated by modifying the carboxyl group of cellulose molecules, the kind of saccharide molecules (including glucose, galactose, lactose, cellobiose, and cellulose), and the degree of branching. The branched structure of saccharide b-Cel greatly influenced its rheological characteristics and solubility. This work presents a practical method for the synthesis of artificial branching polysaccharides and is crucial for the development of innovative materials based on biomass.

Hybrid biodegradable materials from starch and hydrocolloid: fabrication, properties and applications of starch-hydrocolloid film, gel and bead

The potential for utilizing starch and hydrocolloids as sustainable biomaterials has garnered significant attention among researchers. The biodegradability and functional properties of composite films, gels, and beads, as well as their environmental friendliness, make them attractive options for a variety of applications. However, the hydrophilicity, brittleness, and regeneration limitations of starch materials can be addressed through the incorporation of non-starch hydrocolloids. This article summarizes the formation mechanisms and interactions of starch-hydrocolloid films, gels, and gel beads, evaluates the factors that affect their structural and functional properties, and presents an overview of the progress made in their physicochemical and functional applications. The structure of starch-hydrocolloid composites is primarily formed through hydrogen bond interactions, and the source, proportion, and preparation conditions of the components are critical factors that affect the properties of the biomaterials. Starch-hydrocolloid films are primarily used for extending the shelf life of food products and detecting food freshness. Starch-hydrocolloid gels are utilized as adsorption materials, wound dressings, and flexible sensors, and starch-hydrocolloid beads are primarily employed for the controlled release of bioactive substances. It is clear that starch-hydrocolloid composites have the potential to develop novel advanced materials for various applications in the food, biological, and materials industries.

Encapsulation of tea polyphenols into high amylose corn starch composite nanofibrous film for active antimicrobial packaging

Starch-based composite nanofibrous films loaded with tea polyphenols (TP) were successfully fabricated through electrospinning high amylose corn starch (HACS) with aid of polyvinyl alcohol (PVA), referred as HACS/PVA@TP. With the addition of 15 % TP, HACS/PVA@TP nanofibrous films exhibited enhanced mechanical properties and water vapor barrier capability, and their hydrogen bonding interactions were further evidenced. TP was slowly released from the nanofibrous film and followed Fickian diffusion mechanism, which achieved the controlled sustained release of TP. Interesting, HACS/PVA@TP nanofibrous films effectively improved antimicrobial activities against Staphylococcus aureus (S. aureus) and prolonged the shelf life of strawberry. HACS/PVA@TP nanofibrous films showed superior antibacterial function by by destroying cell wall and cytomembrane, and degrading existing DNA fragments, stimulating excessive intracellular reactive oxygen species (ROS) generation. Our study demonstrated that the functional electrospun Starch-based nanofibrous films with enhanced mechanical properties and superior antimicrobial activities were potential for the application in active food packaging and relative areas.

Effect of Cymbopogan citratus Fibre on Physical and Impact Properties of Thermoplastic Cassava Starch/Palm Wax Composites

Cymbopogan citratus fibre (CCF) is an agricultural waste plant derived from a natural cellulosic source of fibre that can be used in various bio-material applications. This paper beneficially prepared thermoplastic cassava starch/palm wax blends incorporated with Cymbopogan citratus fibre (TCPS/PW/CCF) bio-composites at different CCF concentrations of 0, 10, 20, 30, 40, 50 and 60 wt%. In contrast, palm wax loading remained constant at 5 wt% concentration using the hot moulding compression method. TCPS/PW/CCF bio-composites were characterised in the present paper via their physical and impact properties. The addition of CCF significantly improved impact strength by 50.65% until 50 wt% CCF loading. Furthermore, it was observed that the inclusion of CCF resulted in a little decrement in biocomposite solubility compared to neat TPCS/PW biocomposite from 28.68% to 16.76%. Water absorption showed higher water resistance in the composites incorporating 60 wt.% fibre loading. The TPCS/PW/CCF biocomposites with different fibre contents had 11.04-5.65% moisture content, which was lower than the control biocomposite. The thickness of all samples decreased gradually with increasing fibre content. Overall, these findings provide evidence that CCF waste can be utilised as a high-quality filler in biocomposites due to its diverse characteristics, including improving the properties of biocomposites and strengthening their structural integrity.

Preparation and characterization of starch-based composite films reinforced by quinoa (Chenopodium quinoa Willd.) straw cellulose nanocrystals

The development of green and biodegradable nanomaterials is significant for the sustainable utilization of renewable lignocellulosic biomass. This work aimed to obtain the cellulose nanocrystals from quinoa straws (QCNCs) by acid hydrolysis. The optimal extraction conditions were investigated by response surface methodology, and the physicochemical properties of QCNCs were evaluated. The maximum yield of QCNCs (36.58 ± 1.42 %) was obtained under the optimal extraction conditions of 60 % (w/w) sulfuric acid concentration, 50 °C reaction temperature, and 130 min reaction time. The characterization results of QCNCs showed that it is a rod-like material with an average length of 190.29 ± 125.25 nm, an average width of 20.34 ± 4.69 nm, excellent crystallinity (83.47 %), good water dispersibility (Zeta potential = -31.34 mV) and thermal stability (over 200 °C). The addition of 4-6 wt% QCNCs could significantly improve the elongation at break and water resistance of high-amylose corn starch films. This study will pave the route for improving the economic value of quinoa straw, and provide relevant proof of QCNCs for the preliminary application in starch-based composite films with the best performance.

Carboxymethyl cellulose/poly(vinyl alcohol) blended films reinforced by buckypapers of carbon nanotubes and 2D material (MoS2): Enhancing mechanical strength, toughness, and barrier properties

Plastic waste is one cause of climate change. To solve this problem, packaging films are increasingly produced from biodegradable polymers. Eco-friendly carboxymethyl cellulose and its blends have been developed for such a solution. Herein, a unique strategy is demonstrated to improve the mechanical and barrier properties of carboxymethyl cellulose/poly(vinyl alcohol) (CMC/PVA) blended films for the packaging of nonfood dried products. The blended films were impregnated with buckypapers containing different combinations of multiwalled carbon nanotubes, two-dimensional molybdenum disulfide (2D MoS₂) nanoplatelets, and helical carbon nanotubes (HCNTs). Compared to the blend, the polymer composite films exhibit significant increases in tensile strength (~105 %, from 25.53 to 52.41 MPa), Young's modulus (~297 %, from 155.48 to 617.48 MPa), and toughness (~46 %, from 6.69 to 9.75 MJ m^-3). Polymer composite films containing HCNTs in buckypapers offer the highest toughness. For barrier properties, the polymer composite films are opaque. The water vapor transmission rate of the blended films decreases (~52 %, from 13.09 to 6.25 g h^-1 m^-2). Moreover, the maximum thermal-degradation temperature of the blend rises from 296 to 301 °C, especially for the polymer composite films with buckypapers containing MoS₂ nanosheets that contribute to the barrier effect for both water vapor and thermal-decomposition gas molecules.

Effects of primary, secondary and tertiary structures on functional properties of thermoplastic starch biopolymer blend films

To better understand the correlation between structure and properties in thermoplastic starch biopolymer blend films, the effects of amylose content, chain length distribution of amylopectin and molecular orientation of thermoplastic sweet potato starch (TSPS) and thermoplastic pea starch (TPES) on microstructure and functional properties of thermoplastic starch biopolymer blend films were studied. After thermoplastic extrusion, the amylose contents of TSPS and TPES decreased by 16.10 % and 13.13 %, respectively. The proportion of the chains with the degree of polymerization between 9 and 24 of amylopectin in TSPS and TPES increased from 67.61 % to 69.50 %, and from 69.51 % to 71.06 %, respectively. As a result, the degree of crystallinity and molecular orientation of TSPS and TPES films increased as compared to sweet potato starch and pea starch films. The thermoplastic starch biopolymer blend films possessed a more homogeneous and compacter network. The tensile strength and water resistance of thermoplastic starch biopolymer blend films increased significantly, whereas thickness and elongation at break of thermoplastic starch biopolymer blend films decreased significantly.

The relationship between molecular structure and film-forming properties of thermoplastic starches from different botanical sources

To illustrate the correlations between molecular structures and the film-forming properties of thermoplastic starch from various botanical sources, starches from cereal, tuber and legume were modified by thermoplastic extrusion and the corresponding thermoplastic starch films were prepared including thermoplastic corn starch (TCS), thermoplastic rice starch (TRS), thermoplastic sweet potato starch (TSPS), thermoplastic cassava starch (TCAS) and thermoplastic pea starch (TPES) films. TPES film displayed a higher tensile strength (6.28 MPa) and stronger water resistance, such as lower water solubility (15.70 %), water absorption (42.35 %), and water vapor permeability (0.285 g·mm·h-1·m-2·kPa-1) due to higher contents of amylose and B1 chains. TCAS showed a smoother and more amorphous film due to higher amylopectin content, resulting higher elongation at break and larger opacity. TCS film was the most transparent due to a compacter network and more ordered crystallinity structure, which was suit for the packaging of fresh vegetables and aquatic products, whereas TCAS film was the opaquest, which protected package foods from light such as meat products, etc. The outcome would provide an innovative theory to regulate accurately the functional properties of thermoplastic starch films for different food needs.

Structure and properties of flexible starch-based double network composite films induced by dopamine self-polymerization

Starch-based packaging materials are being developed to alleviate environmental pollution and greenhouse gas emissions associated with plastic-based ones. However, the high hydrophilicity and poor mechanical properties of pure-starch films limit their widespread application. In this study, dopamine self-polymerization was used as a strategy to improve the performance of starch-based films. Spectroscopy analysis showed that strong hydrogen bonding occurred between polydopamine (PDA) and starch molecules within the composite films, which significantly altered their internal and surface microstructures. The composite films had a greater water contact angle (> 90°), which indicated that the incorporation of PDA reduced their hydrophilicity. Additionally, the elongation at break of the composite films was 11-fold higher than pure-starch films, indicating that PDA improved film flexibility, while the tensile strength decreased to some extent. The composite films also exhibited excellent UV-shielding performance. These high-performance films may have practical applications in food and other industries as biodegradable packaging materials.

Physicochemical Properties of Water-Based Copolymer and Zeolite Composite Sustained-Release Membrane Materials

A nitrogen fertilizer slow-release membrane was proposed using polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), epoxy resin, and zeolite as raw materials. The effects of the water-based copolymer (PVA:PVP) solution ratio A (A1−A4) and zeolite amount B (B1−B4) on the water absorption rate (XS), water permeability (TS), fertilizer permeability (TF), tensile strength (KL), elongation at break (DSL), and viscosity (ND) of the membrane were explored using the swelling method, a self-made device, and a universal testing machine. The optimal combination of the water-based copolymer and zeolite amount was determined by the coefficient-of-variation method. The results show that the effects of the decrease in A on KL and the increase in B on KL and DSL are promoted first and then inhibited. DSL and ND showed a negative response to the A decrease, whereas XS, TS, and TF showed a positive response. The effect of increasing B on ND, TS, and TF showed a zigzag fluctuation. In the condition of A1−A3, XS showed a negative response to the B increase, whereas in the condition of A4, XS was promoted first and then inhibited. Adding PVP and zeolite caused the hydroxyl stretching vibration peak of PVA at 3300 cm−1 to widen; the former caused the vibration peak to move to low frequencies, and the latter caused it to move to high frequencies. The XRD pattern shows that the highest peak of zeolite is located at 2θ = 7.18° and the crystallization peak of the composite membrane increases with the rise in the proportion of zeolite. Adding PVP made the surface of the membrane smooth and flat, and adding a small amount of zeolite improved the mechanical properties of the membrane and exhibited good compatibility with water-based copolymers. In the evaluation model of the physicochemical properties of sustained-release membrane materials, the weight of all indicators was in the following order: TF > ND > TS > KL > XL > DSL. The optimal membrane material for comprehensive performance was determined to be A2B3.

Biodegradable active packaging: Components, preparation, and applications in the preservation of postharvest perishable fruits and vegetables

The consumption of fresh fruits and vegetables is restricted by the susceptibility of fresh produce to deterioration caused by postharvest physiological and metabolic activities. Developing efficient preservation strategies is thus among the most important scientific issues to be urgently addressed in the field of food science. The incorporation of active agents into a polymer matrix to prepare biodegradable active packaging is being increasingly explored to mitigate the postharvest spoilage of fruits and vegetables during storage. This paper reviews the composition of biodegradable polymers and the methods used to prepare biodegradable active packaging. In addition, the interactions between bioactive ingredients and biodegradable polymers that can lead to plasticizing or cross-linking effects are summarized. Furthermore, the applications of biodegradable active (i.e., antibacterial, antioxidant, ethylene removing, barrier, and modified atmosphere) packaging in the preservation of fruits and vegetables are illustrated. These films may increase sensory acceptability, improve quality, and prolong the shelf life of postharvest products. Finally, the challenges and trends of biodegradable active packaging in the preservation of fruits and vegetables are discussed. This review aims to provide new ideas and insights for developing novel biodegradable active packaging materials and their practical application in the preservation of postharvest fruits and vegetables.

Preparation of sodium alginate/konjac glucomannan active films containing lycopene microcapsules and the effects of these films on sweet cherry preservation

In this study, lycopene microcapsules (LMs) were prepared using chitosan (CS) and carboxymethyl CS (CMCS) as the wall materials. Sodium alginate (SA) and konjac glucomannan (KGM) were used as substrates to fabricate LM/SA/KGM composite films. Results showed that when 2.0 % CMCS was employed, the resulting LMs had the maximum embedding rate of 83.17 %, smallest particle sizes, and stable zeta potentials. The LMs still had a high retention rate after 10 days of storage at 4 and 25 °C. When 2.0 % LMs were used, the corresponding composite film exhibited the best antibacterial properties, oxidation resistance, a high transparency (82.3 %), and a strong water vapor barrier (2.39 × 10^-10 g/m·s·Pa). Finally, the effects of the as-prepared composite films on the preservation of sweet cherries stored at 0 °C for 15 days were investigated. The results indicated that the LM/SA/KGM composite film effectively prolonged the shelf lives of sweet cherries and efficiently delayed the decline in the decay rate, pH, contents of soluble solids, and other indicators. The application of LM/SA/KGM composite films in fruit and vegetable preservation has development prospects and provides a reference for expanding the application range of lycopene and enhancing fruit and vegetable preservation.

Effect of Different Ratios of Glycerol and Erythritol on Properties of Corn Starch-Based Films

The demand for biodegradable products has increased; hence, a suitable method for producing green composites is essential. This study prepared corn starch-based films using the solution casting method, and the physicochemical properties of the prepared films were investigated using a mixture of glycerol (GLY) and erythritol (ERY) at different ratios (4:0, 3:1, 2:2, 1:3, and 0:4) as plasticizing agents. The crystallinity, hydrophilicity, mechanical properties, oxygen and water vapor, surface roughness, and thermal stability of corn starch-based films were analyzed using small-angle X-ray diffraction, water contact angle, automatic tensile testing machine, oxygen permeability tester and water vapor permeability analyzer, atomic force microscope, and thermogravimetric analyzer. With the increase in GLY ratio, the thickness, water-solubility, water content, water vapor permeability, elongation at break, oxygen permeability and V-shaped crystallization of the corn starch-based films increased. The tensile strength and the thermal stability decreased with increasing the GLY ratio. We developed a new plasticizer using glycerol and erythritol to improve the properties of starch films and provided the basis for the industrial production of corn starch-based films.

Mimic Pork Rinds from Plant-Based Gel: The Influence of Sweet Potato Starch and Konjac Glucomannan

This study investigated the effect of sweet potato starch (SPS) and konjac glucomannan (KGM) on the textural, color, sensory, rheological properties, and microstructures of plant-based pork rinds. Plant-based gels were prepared using mixtures of soy protein isolate (SPI), soy oil, and NaHCO₃ supplemented with different SPS and KGM concentrations. The texture profile analysis (TPA) results indicated that the hardness, cohesiveness, and chewiness of the samples improved significantly after appropriate SPS and KGM addition. The results obtained via a colorimeter showed no significant differences were found in lightness (L*) between the samples and natural pork rinds after adjusting the SPS and KGM concentrations. Furthermore, the rheological results showed that adding SPS and KGM increased both the storage modulus (G’) and loss modulus (G’’), indicating a firmer gel structure. The images obtained via scanning electron microscopy (SEM) showed that the SPS and KGM contributed to the formation of a more compact gel structure. A mathematical model allowed for a more objective sensory evaluation, with the 40% SPS samples and the 0.4% KGM samples being considered the most similar to natural pork rinds, which provided a comparable texture, appearance, and mouthfeel. This study proposed a possible schematic model for the gelling mechanism of plant-based pork rinds: the three-dimensional network structures of the samples may result from the interaction between SPS, SPI, and soybean oil, while the addition of KGM and NaHCO₃ enabled a more stable gel structure.

High Amylose-Based Bio Composites: Structures, Functions and Applications

As biodegradable and eco-friendly bio-resources, polysaccharides from a wide range of sources show steadily increasing interest. The increasing fossil-based production of materials are heavily associated with environmental and climate concerns, these biopolymers are addressing such concerns in important areas such as food and biomedical applications. Among polysaccharides, high amylose starch (HAS) has made major progress to marketable products due to its unique properties and enhanced nutritional values in food applications. While high amylose-maize, wheat, barley and potato are commercially available, HAS variants of other crops have been developed recently and is expected to be commercially available in the near future. This review edifies various forms and processing techniques used to produce HAS-based polymers and composites addressing their favorable properties as compared to normal starch. Low toxic and high compatibility natural plasticizers are of great concern in the processing of HAS. Further emphasis, is also given to some essential film properties such as mechanical and barrier properties for HAS-based materials. The functionality of HAS-based functionality can be improved by using different fillers as well as by modulating the inherent structures of HAS. We also identify specific opportunities for HAS-based food and biomedical fabrications aiming to produce cheaper, better, and more eco-friendly materials. We acknowledge that a multidisciplinary approach is required to achieve further improvement of HAS-based products providing entirely new types of sustainable materials.

The relationship between linear chain length distributions of amylopectin and the functional properties of the debranched starch-based films

The relationship between linear chain length distributions and the functional properties of the starch-based films after pullulanase debranching treatment of corn (CS), rice (RS) and wheat (WS) were investigated. The results indicated that the film thickness was negatively correlated with A chains content (r = -0.939) and apparent amylose content (r = -0.926), and was positively correlated with B3 chains content (r = 0.847). The tensile strength of the debranched starch-based films were positively correlated with apparent amylose content (r = 0.813), and the elongation at break were inversely proportional to B3 chains content (r = -0.817). The hydrophobicity of the starch-based films was positively and negatively correlated with the proportions of linear chains with DP 6-12 (r = 0.892) and DP 25-36 (r = -0.863), respectively. On the contrary, no significant correlation was noticed between chain length distribution of amylopectin and transparency and thermal stability.

Degradable photo-crosslinked starch-based films with excellent shape memory property

With the increasingly serious plastic pollution, people's demand for the multi-functional biodegradable plastics is becoming more and more urgent. Inspired by the crosslinked shape memory polymers, the crosslinked starch films were synthesized by inducing the decomposition of benzophenone into free radical and depriving hydrogen on starch macromolecules under UV irradiation, in order to gain a high shape memory performance. The results showed that a three-dimensional crosslinking network between starch macromolecule chains was formed. Compared with the uncrosslinked starch films, the photo-crosslinked films not only had higher mechanical property (tensile strength increased by 154%), but also had better water resistance (water contact angle from 60° to 87°) due to the reduction of free hydroxyl groups. In addition, the stable covalent bonds serving as netpoints endow photo-crosslinked films with great improvement in shape memory property, with nearly 180° bending recovery. More importantly, the maximum shape memory fixity ratio (R_f) and shape memory recovery ratio (R_r) under stretch deformation were 96.5% and 99.8%, respectively. And the R_f and R_r could reach 94.6% and 79.8% even at higher strain. In all, the excellent shape memory performance and good degradability crosslinked starch films, which have great potential application in disposable heat-shrinkable packaging materials.

Processing and characterization of thermoplastic corn starch-based film/paper composites containing microcrystalline cellulose

BACKGROUND

Different thermoplastic starch (TPS) films were prepared with or without the addition of microcrystalline cellulose (MCC) obtained via the melt-extrusion method, and then the hot-press method was used to produce environmentally friendly TPS-based film/paper composites to replace petroleum-based materials.

RESULTS

The paper-plastic composites exhibited good interfacial adhesion from the scannign elctron microscopy images. It was seen that 5 wt.% MCC was added to reinforce the mechanical properties of TPS films, such that it also improved the barrier properties of MCC@TPS/paper composites and extended the path of water vapor through TPS films, which decreased the water vapor transmission rate of MCC@TPS/paper composites. TPS/paper composites and MCC@TPS/paper composites have better physical properties (i.e. smoothness, flexibility and folding resistance) than only paper. In particular, it was found that the water contact angle of MCC@TPS/paper composites and TPS/paper composites were higher than single-layer paper. Furthermore, MCC reinforced paper-plastic composites demonstrated good barrier properties which can meet the requirement of the need for lower water sensitive materials in the food packaging industry.

CONCLUSION

Thermoplastic corn starch-based film/paper composites have good application properties as a potential source of bioplastic materials. © 2021 Society of Chemical Industry.