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Edible films applied in food packaging must possess excellent inhibitory and mechanical properties. Protein-based films exhibit a high capacity for film formation and offer good gas barrier properties. However, they have weak mechanical and water barrier characteristics. The objective of this research was to develop active composite films based on reinforced soy protein isolate (SPI)/Kappa-carrageenan (K) with varying concentrations of bacterial cellulose nanofibrils (BCN). Increasing the BCN concentration improved the morphological, structural, mechanical, water vapor barrier, and moisture content properties. In comparison to the pure SPI film (S), the film with a high BCN concentration demonstrated a significant decrease in WS (22.98 ± 0.78 %), MC (21.72 ± 0.68 %), WVP (1.22 ± 0.14 g mm-1 S-1 Pa-1 10-10), and EAB (57.77 ± 5.25 %) properties. It should be emphasized that there was no significant alteration in the physicomechanical properties of the optimal film (SKB0.75) containing Zenian-loaded metal-organic frameworks (ZM). However, it substantially enhanced the thermal stability of this film, which can be attributed to the strong interfacial interactions between polymer chains and ZM. Furthermore, the ZM films inhibited the growth of pathogenic bacteria and increased the DPPH antioxidant activity. Thus, SKB0.75-ZM2 films can be utilized as practical components in food packaging.

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Gelatin-based electrospun fibers are promising materials for food packaging but suffer from high hydrophilicity and weak mechanical properties. To overcome these limitations, in the current study, gelatin-based nanofibers were reinforced by using oxidized xanthan gum (OXG) as a crosslinking agent. The nanofibers' morphology was investigated through SEM, and the observations showed that the fibers' diameter was decreased by enhancing OXG content. The resultant fibers with more OXG content exhibited high tensile stress so the optimal sample obtained showed a tensile stress of 13.24 ± 0.76 MPa, which is up to 10 times more than neat gelatin fiber. Adding OXG to gelatin fibers reduced water vapor permeability, water solubility, and moisture content properties while increasing thermal stability and porosity. Additionally, the nanofibers containing propolis displayed a homogenous morphology with high antioxidant and antibacterial activities. In general, the findings suggested that the designed fibers could be used as a matrix for active food packaging.

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Enzymes are one of the main biocatalysts with various applications in the food industry. Stabilization of enzymes on insoluble carriers is important due to the low reuse, low operational stability, and high cost in applications. The immobility and the type of carrier affect the activity of the immobile enzyme. Hydrogels are three-dimensionally cross-linked macromolecular network structures designed from various polymers. Hydrogels can provide a matrix for an immobile enzyme due to their extraordinary properties such as high water absorbing capacity, carrier of bioactive substances and enzymes, biocompatibility, safety, and biodegradability. Therefore, this study mainly focuses on some enzymes (lactase, lipases, amylases, pectinase, protease, glucose oxidase) that are of special importance in the food industry. These enzymes could be immobilized in the hydrogels constructed of macromolecules such as kappa-carrageenan, chitosan, Arabic gum, pectin, alginate, and cellulose. At last, in the preparation of these hydrogels, different enzyme immobilization methods in macromolecular hydrogels, and effect of hydrogels on enzyme activity were discussed.

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Recently, the improvement of gelatin-based films for usage in food packaging has attracted more attention owing to their non-toxicity, biodegradability, availability, and renewability. In the current study, the improved gelatin-based films were produced using covalent interaction through dialdehyde kappa-carrageenan (DAK-car) and thymol-loaded zein nanoparticle content. The influences of DAK-car into the matrix of gelatin films (GEL) on the structural, total soluble matter (TSM), moisture content (MC), and water vapor permeability (WVP), and mechanical properties were investigated. After the formation of covalent crosslinking amongst the amino groups of GEL and the dialdehyde groups of DAK-car with the blending ratio of 1:2 (GEL 4% w/v): (DAK-car 1% w/v), a remarkably (p < 0.05) reduction was saw in TSM, MC, and WVP of film. The tensile strength of this film (72.26 ± 0.3 MPa) was ~20-fold higher compared with pure GEL film. It should also be noted that the presence of zein nanoparticles (ZNPs) did not have a notably effect on improving the attributes of gelatin-based film. However, the presence of thymol in concentrations of 0.25 and 0.5 mg/mL showed acceptable antioxidant and antimicrobial activities. As a result, GEL/DAK-car with blending ratio of 1:2 containing thymol-loaded ZNPs films demonstrated the valuable potential for application in active food packaging.

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The goal of tissue engineering is to assemble functional constructs that restore, maintain, or improve damaged tissues or organs. Hydrogels formed with natural polymers display high potential in artificial scaffolds for tissue repair as they can resemble the extracellular matrices. Thus, the aim of this study was to design nanocomposite hydrogels of chitosan/oxidized-modified quince seed gum/curcumin-loaded in halloysite nanotubes (CS/OX-QSG/CUR-HNTs) for tissue engineering applications. The produced hydrogels were analyzed for thermal stability, degradation, swelling ratio, gelling time and mechanical properties. The results showed that with increasing content of OX-QSG, thermal stability, swelling ratio, and degradation rate of hydrogels were improved. Notably, the optimal CS/OX-QSG hydrogel with ratio of 25:75 exhibited rapid gelation behavior (<50 s) and improved compressive strength (3.96 ± 0.64 MPa), representing the suitable hydrogel for application in tissue engineering. The MTT test showed that these hydrogels were non-toxic and any reduction or stop of NIH-3 T3 cells growth wasn't observed over time. In addition, CS/OX-QSG 25:75 hydrogels containing CUR-HNTs with 10 and 30% content was significantly (P < 0.05) enhanced cell growth and proliferation (around 150%). Obtained results illustrated that CS/OX-QSG hydrogels with ratio of 25:75 and the content of 30% CUR-HNTs can be an effective scaffold for application in tissue engineering.

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Newly, fabrication of scaffolds along with the therapeutic agent of tetracycline hydrochloride for application in wound healing and anti-inflammatory effect could interest consideration. In this work, we developed a novel drug delivery mat composed of gum tragacanth (GT), zein, poly lactic acid (PLA) and tetracycline hydrochloride (TCH) (zein/GT/PLA/TCH) in different blending ratios of zein/GT. Scanning electron microscope (SEM) images of mats showed interconnected pores with beadles nanofibers. The results of SEM showed that by increasing the ratio of zein/GT, the average diameter of nanofibers increased from 253.22 ± 15.36 to 547.78 ± 56.48 nm for the ratios of 80:20 and 90:10, respectively. Moreover, the successful loading of TCH and was approved by Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA). By addition of TCH and increasing the GT content to the developed nanofibrous mats, the tensile strength, swelling degree and porosity of zein/GT/PLA/TCH nanofibers increased. Furthermore, this scaffold also displayed appropriate antibacterial properties and suitable degradability for skin tissue engineering. The results of cytocompatibility and SEM micrographs proved that zein/GT/PLA/TCH scaffold had promising proliferation and adhesion against NIH-3 T3 fibroblast cell.

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