Preparation and Characterization of Soy Protein Isolate-Based Nanocomposite Films with Cellulose Nanofibers and Nano-Silica via Silane Grafting

A Soy Protein-Based Film Based on Chemical Treatment and Microcrystalline Cellulose Reinforcement Obtained from Corn Husk Byproducts

Developing an environmentally friendly soy protein-based film that offers excellent performance has garnered considerable interest while also posing a significant challenge. Herein, we propose the strategy of covalent and noncovalent cross-linking to improve the mechanical properties of the films. First, chemical denaturation was carried out under the combined action of sodium sulfite, sodium dodecyl sulfate, sodium hydroxide, and urea to reshape the structure of the protein to improve the solubility of protein and release active groups. Then, microcrystalline cellulose (MCC) derived from low-cost agro-industrial byproducts (corn husk) was employed to balance the covalent cross-linking reaction between proteins and the noncovalent reaction between MCC and protein. The results indicate that the structure and properties of the soy protein-based films were modified and improved through chemical treatment in conjunction with biomass enhancement. It is concluded that the addition of 1% MCC improves the tensile strength, elastic modulus, water solubility, and water vapor permeability of "MCC-1%" by 64.7, 75.9, 22.7, and 12.9%, respectively. Additionally, the resulting film of "MCC-1%" exhibits better resistance to thermal degradation and improved thermo-stability. However, the elongation at break decreased by increasing the addition of MCC. Thus, this work may provide a simple and affordable approach to preparing a high-performing soy protein-based film.

Natural polysaccharides and proteins-based films for potential food packaging and mulch applications: A review

Conventional nondegradable packaging and mulch films, after reaching the end of their use, become a major source of waste and are primarily disposed of in landfills. Accumulation of non-degradable film residues in the soil leads to diminished soil fertility, reduced crop yield, and can potentially affect humans. Application of degradable films is still limited due to the high cost, poor mechanical, and gas barrier properties of current biobased synthetic polymers. In this respect, natural polysaccharides and proteins can offer potential solutions. Having versatile functional groups, three-dimensional network structures, biodegradability, ease of processing, and the potential for surface modifications make polysaccharides and proteins excellent candidates for quality films. Besides, their low-cost availability as industrial waste/byproducts makes them cost-effective alternatives. This review paper covers the performance properties, cost assessment, and in-depth analysis of macromolecular structures of some natural polysaccharides and proteins-based films that have great potential for packaging and mulch applications. Proper dissolution of biopolymers to improve molecular interactions and entanglement, and establishment of crosslinkages to form an ordered and cohesive polymeric structure can help to obtain films with good properties. Simple aqueous-based film formulation techniques and utilization of waste/byproducts can stimulate the adoption of affordable biobased films on a large-scale.

Influence of silylated nano cellulose reinforcement on the mechanical, water resistance, thermal, morphological and antibacterial properties of soy protein isolate (SPI)-based composite films

The aim of this research work is to improve the mechanical and water-resistance properties of soy protein isolate (SPI) biofilm. In this work, 3-aminopropyltriethoxysilane (APTES) coupling agent modified nanocellulose was introduced into the SPI matrix in the presence of citric acid cross-linker. The presence of amino groups in APTES facilitated to form cross-linked structures with soy protein. The incorporation of a citric acid cross-linker made the cross-linking process more productive, and the surface smoothness of the film was confirmed by a Scanning Electron Microscope (FE-SEM). From the study of the mechanical and thermal properties and water resistance of the film, it was confirmed that the results were highly satisfactory for the modified nanocellulose incorporated film compared to the non-modified one. Additionally, coating of citral essential oil onto SPI nanocomposite film displayed antimicrobial properties due to the presence of various phenolic groups in the citral oil. The Tensile Strength and Young's Modulus of silane-modified nanocellulose containing film were enhanced by ~119 % and ~ 112 %, respectively on incorporation of 1 % APTES-modified nanocellulose. Consequently, this work is expected to offer an effective way for silylated nano-cellulose reinforcing soy protein isolate (SPI) based bio nanocomposite films for packaging applications. As an example, we have demonstrated one of the application as wrapping films for packing black grapes.

Investigation of wound healing efficiency of multifunctional eudragit/soy protein isolate electrospun nanofiber incorporated with ZnO loaded halloysite nanotubes and allantoin

One significant aspect of the current therapeutic agents employed in wound healing involves the engineering of nano polymeric scaffolds to mimic the properties of extracellular matrix (ECM). The present work aimed to prepare and evaluate Eudragit® L100 (EU) nanofibers in combination with soy protein isolate (SPI). Allantoin (Ala) with a 2 wt% was encapsulated as a model drug renowned for its anti-inflammatory and antioxidant agents. Moreover, the synthesized ZnO-halloysite nanotubes (ZHNTs) with different concentrations of 1, 3, and 5 wt% were incorporated into the EU/SPI/Ala nanofiber as a reinforcing filler and a remarkable antibacterial agent. The scanning electron microscope (SEM) analysis showed that by increasing the weight percentage of SPI from 1 % to 2.5 %, the average diameter of nanofibers decreased from 132.3 ± 51.3 nm to 126.7 ± 47.2 nm. It was 223.5 ± 95.6 nm for nanofibers containing 5 wt% ZHNTs (the optimal sample). The evaluation of in vitro release kinetics of Ala for 24 h, showed a burst release during the first 2 h and a sustained release during the subsequent times. Moreover, the structure, crystallinity, and thermal stability of synthesized nanofibers were characterized by Fourier Transform Infrared Spectrometry (FTIR), X-ray diffraction (XRD), and Thermo gravimetric analysis (TGA), respectively. In vitro degradation and mechanical characteristics of these nanofibers were studied. Furthermore, the capability of the nanofibers for cell proliferation was revealed through the MTT test and field emission scanning electron microscopy (FESEM) images of cell attachment. The antimicrobial activity of EU/SPI/Ala/ZHNTs showed that this sample with high ZHNTs content (5 w%t) had the most remarkable antibacterial activity against S. aureus. The results revealed that EU/SPI/Ala/ZHNTs mats could be promising potential wound dressings.

Fabrication of edible and biodegradable cutlery from morning glory (Ipomoea aquatic) stem fiber-reinforced onto soy protein isolate

This study aimed to investigate the preparation of soy protein isolated (SPI) cutlery incorporated with 5–20% (w/w) crude morning glory stem fiber (MGSF). SPI cutlery samples without and with MGSF were subjected to hydraulic hot press molding at 160 °C for 5 min pressing time. SPI with 5% MGSF showed decreased lightness values compared to the control SPI (without MGSF) (p < 0.05). Flexural modulus attained in SPI with 5% MGSF was higher and subsequently showed decreases in impact strength and compression load compared to the control SPI (p < 0.05). SPI with 5% MGSF sample showed slightly lower water absorption followed by decreases in degree of swelling and solubility with that of the control SPI (p < 0.05). Micrographs revealed a 5% MGSF formed uniform matrix with SPI in comparison to the control and other treatments that showed cracks with the increased fiber addition. Additionally, stiffness decreased with the addition of 5% MGSF to SPI thereby increasing deflection in comparison to the control SPI and other treatments. Thus, SPI cutlery added with 5% MGSF potentially retained the physical and mechanical properties of edible and biodegradable cutlery for food applications.

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MGSF at 5% level improved water resistance properties than the control SPI.

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Mechanical properties were enhanced in SPI sample treated with MGSF.

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Impact strength decreased with the increments of MGSF fiber in SPI cutlery.

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SEM micrographs confirmed the uniform fiber distribution in SPI treated with 5% MGSF.

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SPI at 5% MGSF can be exploited to produce edible and eco-friendly cutlery.

Effect of Maltodextrin and Soy Protein Isolate on the Physicochemical and Flow Properties of Button Mushroom Powder

In this investigation, the effect of different drying techniques, such as freeze-drying and cabinet drying, with two different carrier agents, such as maltodextrin (MD) and soy protein isolate (SPI), at different levels (10, 15, and 20%) on button mushrooms has been revealed. The results showed that the button mushroom powders (BMPs) formulated with SPI as a carrier agent had significantly higher powder yield, hygroscopicity, L *, a *, and b * values, whereas BMP formulated with MD had significantly higher water activity, solubility index, tapped density, bulk density, and flowability. The highest retention of bioactive compounds was reported in freeze-dried mushroom powder compared to cabinet dried powder using SPI as a carrier agent. Fourier transform infrared (FTIR) analysis confirmed that certain additional peaks were produced in the mushroom button powder-containing SPI (1,035-3,271 cm-1) and MD (930-3,220 cm-1). Thus, the results revealed that SPI showed promising results for formulating the BMP using the freeze-drying technique.

Plant protein-based nanocomposite films: A review on the used nanomaterials, characteristics, and food packaging applications

Consumer demands to utilize environmentally friendly packaging have led researchers to develop packaging materials from naturally derived resources. In recent years, plant protein-based films as a replacement for synthetic plastics have attracted the attention of the global food packaging industry due to their biodegradability and unique properties. Biopolymer-based films need a filler to show improved packaging properties. One of the latest strategies introduced to food packaging technology is the production of nanocomposite films which are multiphase materials containing a filler with at least one dimension less than 100 nm. This review provides the recent findings on plant-based protein films as biodegradable materials that can be combined with nanoparticles that are applicable to food packaging. Moreover, it investigates the characterization of nanocomposite plant-based protein films/edible coatings. It also briefly describes the application of plant-based protein nanocomposite films/coating on fruits/vegetables, meat and seafood products, and some other foods. The results indicate that the functional performance, barrier, mechanical, optical, thermal and antimicrobial properties of plant protein-based materials can be extended by incorporating nanomaterials. Recent reports provide a better understanding of how incorporating nanomaterials into plant protein-based biopolymers leads to an increase in the shelf life of food products during storage time.

Cellulose Nanofiber-Assisted Dispersion of Halloysite Nanotubes via Silane Coupling Agent-Reinforced Starch–PVA Biodegradable Composite Membrane

HNTs (halloysite nanotubes) are widely used in reinforcing material, often used in material reinforcement and particle loading. However, their easy agglomeration causes them to have great limitations in application. In this work, two kinds of silane coupling agents (KH560 and KH570) were introduced to graft the CNF/HNT (cellulose nanofiber) nanoparticles used to reinforce the starch-polyvinyl alcohol (PVA) composite membranes. The mechanical properties, water resistance properties and thermal performance of the composite membrane were tested. The results showed that the CNF/HNTs nanoparticle system modified by two silane coupling agents enhanced the tensile strength (TS) of the starch–PVA composite membranes by increments of 60.11% and 68.35%, and, in addition, the water resistance of starch–PVA composite membrane improved. The introduction of chemical bonds formed associations and a compact network structure, which increased the thermal stability and the crystallinity of the starch–PVA composite membrane. In the study, we creatively used CNF to disperse HNTs. CNF and HNTs were combined under the action of the silane coupling agent, and then mixed into the starch–PVA membranes matrix to prepare high-performance degradable biological composite membranes.

The control of fungi and mycotoxins by food active packaging: a review

Conventionally used petrochemical-based plastics are poorly degradable and cause severe environmental pollution. Alternatively, biopolymers (e.g., polysaccharides, proteins, lipids, and their blends) are biodegradable and environment-friendly, and thus their use in packaging technologies has been on the rise. Spoilage of food by mycotoxigenic fungi poses a severe threat to human and animal health. Hence, because of the adverse effects of synthetic preservatives, active packaging as an effective technique for controlling and decontaminating fungi and related mycotoxins has attracted considerable interest. The current review aims to provide an overview of the prevention of fungi and mycotoxins through active packaging. The impact of different additives on the antifungal and anti-mycotoxigenic functionality of packaging incorporating active films/coatings is also investigated. In addition, active packaging applications to control and decontaminate common fungi and mycotoxins in bakery products, cereal grains, fruits, nuts, and dairy products are also introduced. The results of recent studies have confirmed that biopolymer films and coatings incorporating antimicrobial agents provide great potential for controlling common fungi and mycotoxins and enhancing food quality and safety.

Preparation and characterizations of antibacterial–antioxidant film from soy protein isolate incorporated with mangosteen peel extract

The mangosteen peel extract (MPE) was used to obtain soy protein isolate (SPI) films. The results show that MPE exhibited a high content of total phenolics and antioxidant activity. Moreover, the MPE can enhance the antibacterial–antioxidant properties, UV-visible light barrier properties, and water-resistant properties of the SPI films. The presence of MPE resulted in an increase in water vapor permeability and hydrophobicity. The extract addition also reduced the film’s crystallinity along with a decrease in the mechanical property and lowering of the maximum degradation temperature. Attenuated total reflectance Fourier transform infrared spectroscopy revealed that the polyphenols in MPE could interact with SPI through hydrogen bonds and hydrophobic interactions, and the addition of MPE changed the secondary structure of SPI with a decrease in β-sheets and an increase in β-turns and random coils. Scanning electron microscopy showed that all the films exhibited smooth and homogenous morphology on the surface and on some layers through cross-sectional images. Our results suggested that the MPE would be a promising ingredient to make SPI films used as an active packaging material.

Ultrasonic-modified montmorillonite uniting ethylene glycol diglycidyl ether to reinforce protein-based composite films

A novel biodegradable protein-based material (UMSPIE) that consists of natural polymer soy protein isolate (SPI), ultrasonic-modified montmorillonite (UMMT), and ethylene glycol diglycidyl ether (EGDE) was produced by solution casting. Fourier infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) were used to characterize the chemical structure and micro-morphologies of as-synthesized protein-based composite films. The results showed that the interlayer structure of MMT was destroyed by ultrasonic treatment, and the hydrogen bonding between SPI chains and the ultrasound-treated MMT plates was enhanced. The synergistic effect of UMMT and EGDE on SPI molecules made the network structure of the UMSPIE film denser. In addition, the mechanical and barrier properties of the as-synthesized films were explored. Compared with pure soy protein film, the tensile strength of the UMSPIE film has an increase of 266.82% (increasing from 4.4 to 16.14 MPa). From the above, the modified strategy of layered silicates filling combining crosslinking agents is considered as an effective method to improve the functional properties of bio-based polymer composites.