Synergistic effects of EDTA and lysozyme on the properties of hydroxypropyl starch nano antibacterial films.

Hydroxypropyl starch (HPS) nano antibacterial films incorporating Ethylene Diamine Tetraacetic Acid (EDTA) and lysozyme (LY) were fabricated via solvent casting method. The synergistic effects of EDTA and LY on the microstructure, component interactions, color, optical, mechanical, barrier and antibacterial properties of HPS nano antibacterial films were evaluated. The results indicated that EDTA and LY were well dispersed in the matrix of the HPS nano antibacterial films, the film-forming substrates have good compatibility, resulting in a dense multi-layer structure of the HPS nano antibacterial films. The addition of EDTA and LY increased the color parameters (L*, a*, b* and △E*) of the HPS nano antibacterial films. The synergistic effects of EDTA and LY significantly decreased the light transmission of the HPS nano antibacterial films. The presence of EDTA and LY increased the tensile strength (TS) and the elongation at break (EAB) of the HPS nano antibacterial films. The TS and EAB of E2.5L1 reached the highest values of 6.329 MPa and 50.24 %, respectively. The incorporation of EDTA and LY had positive effects on the improvement of water vapor permeability (WVP) and oxygen permeability (OP). The WVP and OP of E2.5L1 reached the highest values of 0.9350 × 10-12 g cm/cm2•s•Pa and 0.297 × 10 -2 g m/m2 •d, respectively. In addition, EDTA and LY had significant synergistic effects on the antibacterial activity against S. aureus (Gram-positive bacteria) and E. coli (Gram-negative bacteria). E2.5L1 exhibited the highest antibacterial activity and the inhibition zone diameters of S. aureus and E. coli were 3.69 mm and 4.28 mm, respectively. The HPS nano antibacterial films incorporating EDTA and LY are potential functional packaging materials.

Effect of bovine bone collagen and nano-TiO2 on the properties of hydroxypropyl methylcellulose films.

Hydroxypropyl methylcellulose (HPMC) film containing bovine bone collagen (BC) and nano-TiO2 were developed via casting method. The films were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), and their mechanical properties, barrier properties, thermal stability and surface color were investigated. The results showed that polymer matrices of HPMC and BC had good compatibility. The nano-TiO2 could be well embedded and dispersed in the matrix of HPMC/BC films, resulting in homogeneous, continuous and compact structure of the composite films. The addition of BC and nano-TiO2 significantly (p < .05) changed the surface color parameters of the films (p < .05). In addition, the introduction of BC and nano-TiO2 had a positive effect on the improvement of mechanical properties, barrier properties and thermal stability of the HPMC based films. The results suggest that HPMC based films containing BC and nano-TiO2 are more suitable for active packaging in the food industry.

Mechanical, barrier and antimicrobial properties of corn distarch phosphate/nanocrystalline cellulose films incorporated with Nisin and ε-polylysine.

Antimicrobial bio-nanocomposite films were prepared by incorporating nisin (0.25-0.5% W/W) and ε-polylysine (PL, 0.2% W/W) into corn distarch phosphate/nanocrystalline cellulose based films (CN) via casting method. Nisin and PL had significant effects on color parameters (L*, a*, b* and ∆E*) and improved the mechanical, barrier properties, thermal stability of the films. The CN bio-nanocomposite films incorporation the combination of nisin and PL had synergistic antimicrobial activity against Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). Structural property assessment by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) revealed that a clear interaction between the hydroxyl groups of corn distarch phosphate and the amino groups of nisin and PL, leading to the microstructure of the CN bio-nanocomposite films with appropriate content of nisin and PL was more continuous and compact. These results indicate that the CN bio-nanocomposite films containing nisin and PL is a potential active packaging material with enhanced physicochemical properties in food industry.

Mechanical and barrier properties of corn distarch phosphate-zein bilayer films by thermocompression.

Corn distarch phosphate-zein bilayer films (C-Z) fabricated from corn distarch phosphate-based films (C) laminated on zein-based films (Z) by thermocompression. The strong interaction between starch and zein molecules was formed by hydrogen bonding, which resulted in good thermal stability of bilayer films. Moreover, bilayer films exhibited better mechanical properties and ductility than monolayer Z films, and concomitantly enhanced the moisture barrier and oxygen barrier for monolayer C films. The tensile strength (TS) and elongation at break (EAB) of the C-Z bilayer films (the ratio C:Z was 6:4) increased by 74.04% and 348.13% over the Z films, respectively. Compared with C films, the water vapor permeability (WVP) and oxygen permeability (OP) of the C-Z bilayer films (the ratio C:Z was 6: 4) decreased by 31.53 and 24.26%, respectively.

Mechanical and moisture barrier properties of corn distarch phosphate film influenced by modified microcry stalline corn straw cellulose.

BACKGROUND: In this paper, a novel modified microcrystalline corn straw cellulose (MMCSC) was prepared by ultrasonic/microwave-assisted treatment. Effective incorporation of MMCSC into corn distarch phosphate (CDP)-based composite films was investigated. RESULTS: As the proportion of MMCSC was increased, tensile strength increased initially before decreasing, and the elongation at break always decreased. The composite film of MMCSC20 showed the lowest water vapor permeability (2.917 × 10-7 g m-1 h-1 Pa-1 ). The measurement of surface color showed that by the increasing of the MMCSC proportion in composite films, the L* and b* values and the total color difference (ΔE* ) increased, while a* values decreased. Fourier transform infrared spectroscopy and X-ray diffraction analysis indicated that, with the incorporation of MMCSC, the stable structure of the films was enhanced through cross-linking and the crystallinity was increased. A scanning electron microscopy study revealed the surface microstructure of films (MMCSC0-MMCSC30) was smooth and homogeneous, and there was no distinct separation in the matrix of composite films. CONCLUSION: The incorporation of suitable MMCSC could improve the properties of composite films. The CDP-MMCSC films, which are completely biodegradable and environmental friendly, have a high potential to be used for food packaging. © 2018 Society of Chemical Industry.

Effects of ultrasonic/microwave-assisted treatment on the properties of corn distarch phosphate/corn straw cellulose films and structure characterization.

Edible films were casted using aqueous solutions of corn distarch phosphate (CDP, 3 wt%) and corn straw cellulose (CSC, 0.5 wt%). The effects of ultrasonic, microwave and ultrasonic/microwave-assisted treatment on mechanical properties and light transmittance, as well as the water vapour permeability (WVP) of edible films, were evaluated. It was found that corn distarch phosphate/corn straw cellulose (CDP/CSC) films treated using ultrasonic waves/microwaves for a certain condition has a distinct increase in tensile strength, elongation at break and light transmittance and a drastic decrease in WVP. Moreover, scanning electron microscopy demonstrated that the surface and cross-section morphology of CDP/CSC films after ultrasonic/microwave-assisted treatment were smoother, denser and without a notable phase separation compared with control films. The results of mechanical properties and barrier properties were in agreement with the changes in molecular interactions detected by Fourier transform infrared spectroscopy and X-ray diffraction analysis. These findings indicate that ultrasonic/microwave-assisted treatment can improve the application of biodegradable films.

Effect of Incorporation Nanocrystalline Corn Straw Cellulose and Polyethylene Glycol on Properties of Biodegradable Films.

This work aimed to study the effect of nanocrystalline corn straw cellulose (NCSC) and polyethylene glycol (PEG) on the properties of biodegradable corn distarch phosphate (CDP) films. The mechanical properties and barrier properties were investigated. Meanwhile, the compatibility, crystallization, thermal stability, and morphological structure of the films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (X-RD), thermogravimetric (TGA), and scanning electron microscopy (SEM). In contrast with the CDP films, incorporation of NCSC in the films improved their tensile strength (TS) significantly, and incorporation of PEG improved their elongation at break (EAB) significantly else. PEG, CDP, and NCSC (P-CDP/NCSC) blend films had the best barrier properties. The thermal stability of the films was increased by the incorporation of NCSC. X-RD showed that CDP and NCSC (CDP/NCSC) films had higher crystallinity. SEM revealed that all films had smooth surface, while the films presented a uniform network structure through the incorporation of NCSC.