Properties of gelatin films from giant catfish skin and bovine bone: a comparative study

Edible films were prepared from the gelatin of farmed giant catfish skin (GC) (Pangasianodon gigas), bovine bone gelatin (BB) and their combination. The physical, mechanical, thermal and chemical properties of the resulting films were characterized and compared. The molecular weight distributions of the giant catfish skin gelatin-containing samples had high quantities of α-chains, β-components and high molecular weight cross-links. The bovine bone gelatin-containing samples showed low contents of major bands with high degradation band components. The GC films had higher water activity (0.45) and mechanical properties [tensile strength: TS 41 MPa and elongation at break: EAB 34 (%)] but lower thickness (38 μm) and water vapor permeability than those of BB films. The lowest light transmission (200–800 nm) and film transparency (3.34) were found in the GC films. However, the color attribute (L, a and b) of BB films was closer to the low-density polyethylene commercial film (ΔE 1.2). The highest value of film and protein solubility (100%) was found in BB film, while the lowest value (41–56%) was found in GC film. The GC films showed the most compact, smooth and continuous surface without porous structures, which corresponds to the greater properties of films.     

Effects of essential oil on the water binding capacity,physico-mechanical properties,antioxidant and antibacterial activity of gelatin films

Gelatin films were prepared from gelatin solutions (10% w/v) containing Zataria multiflora essential oil (ZMO, 2, 4, 6 and 8% w/w of gelatin). Scanning electron microscopy observations indicate that ZMO droplets were well dispersed in the film matrix. Water solubility, water swelling, water uptake, water vapor permeability, tensile strength, elongation at break and Young's modulus for gelatin films were 27 ± 0.8%, 391 ± 11%, 135 ± 5%, 0.22 ± 0.014 g mm/m² kPa h, 4.4 ± 0.4 MPa, 125 ± 7% and 8.8 ± 0.4 MPa, respectively. Incorporation of ZMO into gelatin films caused a significant decrease in swelling and water uptake and increase in solubility and water vapor permeability, a significant decrease in tensile strength, increase in elongation at break, decrease in Young's modulus of the films, dose-dependently. Gelatin/ZMO showed UV–visible light absorbance/transmission ranging from 280 to 480 nm with maximum absorbance at 420 nm. Gelatin films exhibited very low antioxidant activity while, gelatin/ZMO films exhibited excellent antioxidant properties. The gelatin/ZMO films also exhibited excellent antibacterial properties against both Gram-positive and Gram-negative bacteria. Our results suggested that the gelatin/ZMO films could be used as an active film due to its excellent antioxidant and antimicrobial properties for food packaging applications.     

Water Solubility, Mechanical, Barrier, and Thermal Properties of Cross-linked Whey Protein Isolate-based Films

Water solubility, hermal properties, tensile strength, percent elongation, oxygen permeability (OP), water‐vapor permeability (WVP) of cross‐linked glycerol plasticized whey protein isolate films were studied to determine the effect of cross‐linkers (glutaraldehyde, formaldehyde, dialdehyde starch, carbonyldiimidazole, and UV irradiation) on film properties. With the exception of UV treatment, solubility of the films decreased (P>0.05) upon treatment of the film‐forming solutions with chemical cross‐linkers. Tensile strength increased (P>0.05), whereas percent elongation was not affected by cross‐linking. Chemical cross‐linking increased (P>0.05) WVP and decreased (P>0.05) OP of the films. UV treatment had no effect on WVP and O P. With the exception of UV‐treated films, both onset temperature and degradation temperatures, as determined by differential scanning calorimetry, were increased upon cross‐linking.     

Active warm-water fish gelatin film containing oxygen scavenging system

An oxygen scavenging system (OSS), composed of oxygen scavenging nanoparticles and iron chloride (II), was incorporated into warm-water fish gelatin film. Surface morphology, cross sectional images, and mechanical, barrier, and optical properties of the oxygen scavenging fish gelatin (OSFG) film were compared to those of the unmodified fish gelatin (UMFG) film. Results indicated that the OSS was well incorporated into the OSFG film structure. The OSFG film had rough film surface, increased water vapor and oxygen permeability, and decreased tensile strength due to the incorporation and agglomerations of the OSS. The incorporation of the OSS also caused color and haze alterations to the OSFG film. In addition, the oxygen scavenging capability of the OSFG film was investigated. The initial oxygen content (%) in the cup headspace, 20.90%, was decreased to 4.56% after 50 days of storage. The OSFG film had good oxygen scavenging capacity, 1969.08 cc O₂/m²/mil, and moisture was used as the activator to trigger the oxygen scavenging reaction.     

Improvement on Physical Properties of Pullulan Films by Novel Cross‐Linking Strategy

Pullulan based films possess several advantages, including high transparency, low toxicity, good biodegradability, good mechanical properties, and low oxygen permeability, are preferable for food packaging. The application of pullulan films on food packaging, however, has inherent disadvantage of high water solubility. In this study, glutaraldehyde and glycerol were used as the cross‐linking reagent and the plasticizer respectively to improve water resistance and physical properties of the pullulan films. Effects of cross‐linking degree on physical properties, including water absorptions, swelling behaviors, water vapor permeability and tensile strengths of films were evaluated. FTIR results demonstrated that the pullulan films were successfully cross‐linked by glutaraldehyde. The tensile strength of pullulan films could be enhanced significantly (P < 0.05) when glutaraldehyde was between 1% and 5% (w/w); nevertheless, the amount of glutaraldehyde above 20% (w/w) led to films brittleness. With the addition of glycerol as a plasticizer enhanced the extensibility of films as well as the hydrophilicity, resulting in higher water vapor permeability.     

Physico-chemical and film-forming properties of bovine-hide and tuna-skin gelatin: A comparative study

A bovine-hide gelatin and a tuna-skin gelatin, both characterized on the basis of their amino acid composition and molecular weight distribution, were used to prepare edible films by casting with glycerol and sorbitol added as plasticizers. The molecular weight distribution of the tuna-skin gelatin exhibited appreciably higher quantities of β-components (covalently linked α-chain dimers), whereas bovine-hide gelatin showed a certain degradation of α₁-chains being indicative of a greater proteolysis. Intrinsic differences in the gelatin attributes affected in diverse manner some of the physical properties of the films. Thus, water vapour permeability was higher in the bovine-hide gelatin film, whereas deformability was considerably higher (10 times higher) in the tuna-skin gelatin film. In contrast, breaking force and water solubility were basically unaffected by gelatin origin. Analysis of the thermal properties revealed both films to be wholly amorphous with similar glass transition temperature values thanks to the plasticizing effects of the glycerol and sorbitol and the low moisture contents.     

Effect of Cross‐linking with Epichlorohydrin on the Properties of Cassava (Manihot esculenta Crantz) Starch

Cassava starch was cross‐linked with epichlorohydrin (EPI) at 45°C for 2 h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N‐dimethylformamide (DMF). The products were characterized by determining their physicochemical, thermal and retrogradation properties. In aqueous medium, the use of a PTC, tetrabutylammonium bromide (TBAB) produced derivatives with higher degree of cross‐linking than those prepared without the use of the catalyst. The degree of cross‐linking was found to be higher using the same concentration of EPI when the reaction was carried out in DMF. At low levels of cross‐linking, the peak viscosity of the cross‐linked starches increased in comparison to that of the native starch. With increasing degree of cross‐linking, the peak viscosity showed a significant reduction. The swelling volume, solubility and light transmittance of the starch pastes were lower for the modified starches. The cross‐linked starches showed slightly reduced values for the gelatinization temperatures, T_onset, T_peak and T_end. The enthalpy of gelatinization of the modified starches increased with increase in the degree of cross‐linking. The modified starches exhibited higher water‐binding capacities (WBC) than the native starch; but with increase in the degree of cross‐linking, there was a gradual decrease in WBC. The in vitro alpha amylase digestibility of the modified starches decreased gradually with increase in the level of cross‐linking.     

Preparation and characterisation of chicken skin gelatin as an alternative to mammalian gelatin

The aims of this study were to report for the first time, the extraction and physico-chemical properties of chicken skin gelatin compared to bovine gelatin. Extracted chicken skin gelatin 6.67% (w/v) had a higher bloom value (355 ± 1.48 g) than bovine gelatin (259 ± 0.71 g). The dynamic viscoelastic profile of chicken gelatin exhibited higher viscous and elastic modulus values compared to bovine gelatin for a range of concentrations and frequencies. Thermal properties studied by differential scanning calorimetry (DSC) showed that the melting temperature of 6.67%, chicken skin gelatin was significantly greater (p < 0.05) than that of bovine gelatin, indicating lower stability of bovine gelatin compared to chicken skin gelatin. Results obtained in this study showed that Gly (33.70%), Pro (13.42%), H.Pro (12.13%) and Ala (10.08%) were the most dominant amino acids in chicken skin gelatin which contributed to the higher gel strength and stability. Raman spectra of chicken skin and bovine gelatin were similar and displayed typical protein spectra. Chicken gelatin showed strong hydrogen bonding compared to bovine gelatin as the tyrosine doublet ratio (I₈₅₅/I₈₃₀) of chicken gelatin was significantly lower than that of bovine gelatin. Significantly, the alpha helix and β-sheet type structures were higher for chicken skin gelatin compared with bovine gelatin. The average molecular weight of chicken gelatin was 285,000 Da. These findings, obtained for the first time for chicken skin gelatin, show that it has high potential for application as an alternative to commercial gelatin.     

Development of Gelatin Bionanocomposite Films Containing Chitin and ZnO Nanoparticles

The gelatin-based nanocomposite films (GNCFs) containing 0, 1, 3, and 5% zinc oxide nanoparticles (N-ZnO) and/or 0, 3, 5, and 10% chitin nanofibers (N-chitin) were prepared, and their water vapor permeability (WVP), chemical structure and microstructure, and their mechanical, thermal, and antifungal properties were investigated. Results showed that incorporation of N-ZnO improved WVP, mechanical, thermal, and antifungal properties of the gelatin-based films. Moreover, physicochemical and antifungal properties of the nanocomposite films improved by increasing N-ZnO concentration. However, applying N-chitin in gelatin films could not enhance barrier properties of the films against water vapor, probably due to the hydrophilic nature of N-chitin. On the other hand, tensile strength of the GNCFs containing N-chitin increased by an increase in nanoparticle concentration, up to 5%, Incorporation of N-chitin in the gelatin film raised both thermal stability and antifungal activity. Simultaneous incorporation of chitin and ZnO nanoparticles in the GNCFs had the interactive effect on improving the physicochemical and antimicrobial properties of GNCFs. For instance, thermograms of differential scanning calorimetry (DSC) showed that the GNCF containing both nanoparticles increased melting point and ?H _m in comparison with net gelatin film. Furthermore, thermograms of thermogravimetric analysis (TGA) indicated that applying both of nanoparticles in gelatin films led to higher thermal stability of polymer against decomposition at higher temperatures, compared to the gelatin film containing each of them.     

Rheological,gelling and emulsifying properties of a glycosylated and cross‐linked caseinate generated by transglutaminase

The impacts of oligochitosan glycosylation and cross‐linking on some properties of a commercial caseinate were investigated in this study. The glycosylated and cross‐linked caseinate with glucosamine content of 4.74 g kg^?1 protein was generated by transglutaminase (TGase) and oligochitosan at pH 7.5 and 37 °C, with fixed substrate molar ratio of 1:3 (acyl donor to glucosamine acceptor), caseinate content of 50 g L^?1, TGase of 10 kU kg^?1 protein and reaction time of 3 h, respectively. In comparison with the caseinate, the glycosylated and cross‐linked caseinate had decreased reactable amino groups (0.58 vs. 0.51 mol kg^?1 protein), higher apparent viscosity, decreased emulsifying activity index (about 14.5%) and statistically unchanged emulsion stability index (92.6 vs. 90.5%). Based on the mechanical spectra of the acid‐induced gels, the glycosylated and cross‐linked caseinate showed shorter gelation time (95 vs. 200 or 220 min) than the caseinate or cross‐linked caseinate. The gels prepared from the glycosylated and cross‐linked caseinate also had enhanced hardness, springiness and cohesiveness. The results indicated that TGase‐mediated oligochitosan glycosylation and cross‐linking has the potential to obtain new protein ingredients.     

Cross‐linking of bovine and caprine caseins by microbial transglutaminase and their use as microencapsulating agents for n‐3 fatty acids

Bovine and caprine caseins were cross‐linked with microbial transglutaminase (mTG). The mTG‐cross‐linked bovine or caprine casein dispersion, mixed with 14.5% maltodextrin (DE = 40), was used to prepare emulsions with 10.5% algae oil. Oxidative stability of emulsions was evaluated by peroxide values (PVs) and anisidine values. Adding liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol lowered the formation of hydroperoxides and their subsequent decomposition products in emulsions. Emulsions stabilised with liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol were spray‐dried at 180/95 °C. Algae oil microencapsulated with mTG‐cross‐linked bovine casein reduced PV by ≈ 34%, while the algae oil microencapsulated with mTG‐cross‐linked caprine casein with low levels of α_s1‐casein reduced PV by ≈ 42% at 4 weeks of storage at 30 °C. The investigation suggests that liposoluble rosemary extract rich in carnosic acid and δ‐tocopherol effectively protected algae oil during the coating process with mTG‐cross‐linked bovine and caprine caseins. The above results clearly indicated that the choice of milk caseins (bovine vs. caprine) cross‐linked with mTG impacts the oxidative stability of spray‐dried algae oil emulsions (microcapsules) enriched with n‐3 fatty acids.     

Effects of acid concentration and the UHP pretreatment on the gelatinisation of collagen and the properties of extracted gelatins

An ultra‐high‐pressure (UHP) transmission medium with HCl was applied as a pretreatment to extract gelatin. The effects of the acid concentration (0–1% (w/v)) on the gelatinisation of collagen and the properties of gelatin were investigated. An increase in the acid concentration decreased the thermostability of collagen and increased the yield of gelatin (from 64% increased to 80%). The content of the subunit components in the pretreated collagen and the gelatin declined slightly as the acid concentration was increased, resulted in slight decrease (P > 0.05) in the gel strength (from 435 g decreased to 408 g). The analysis of Fourier transform infrared spectroscopy (FTIR) spectra showed that the triple‐helical structure, secondary structures of the collagen and covalent cross‐linking in the collagenous fibres were damaged gradually as the acid concentration was increased. The scanning electron microscopy (SEM) images showed that the smooth surface of collagen was partly disrupted with microvoids after UHP/1% HCl pretreatment, which may be related to the damage on the covalent cross‐linking.     

Role of lignosulphonate in properties of fish gelatin films

A commercial low-gelling fish skin gelatin was used to prepare edible films by casting with glycerol and sorbitol added as plasticizers. In order to improve the extremely low water resistance of gelatin films, composite films were prepared with increasing concentrations (wt/wt) of lignosulphonate (LS) from eucalyptus wood (100:0, 85:15, 80:20, 75:25, 70:30 and 65:35, gelatin:LS). How gelatin film properties were affected by the different types of gelatin and LS was determined by comparing bovine gelatin and three different LS (Ca²⁺, Mg²⁺ and Na⁺) in a mixture ratio of 80:20. Physical properties of films were characterized in terms of tensile strength, elongation at break, water solubility, water vapour permeability and opacity. Dynamic oscillatory tests of film-forming solutions revealed strong LS interference with the cold-renaturation ability of gelatin. LS ratios equal to or higher than the 80:20 blend interfered with intermolecular aggregation of gelatin helices. Supposedly, LS acted as a filler, inducing mostly nonbonding interactions with gelatin, as deduced from Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) studies. Lignosulphonate significantly reduced the elongation at break of fish gelatin films, water solubility being drastically reduced with a mixture ratio of 80:20 or higher. The water solubility of bovine gelatin-LS composite films was significantly lower than that for fish gelatin, regardless of the type of LS employed. For potential food packaging applications, the three LS were characterized in terms of cytotoxicity, radical scavenging capacity (DPPH assay) and antimicrobial capacity. The effective antioxidant levels (IC₅₀: 83.4-97.5 μg/mL) were noticeably lower than the cytotoxic ones (IC₅₀: 1480-1745 μg/mL), indicating that these compounds could be used as antioxidants at non-cytotoxic concentrations. No relationship between antioxidant and antimicrobial properties could be observed, the only notable antimicrobial finding being some activity against yeasts.     

Properties of Gelatin Film from Horse Mackerel (Trachurus japonicus) Scale

Optimal conditions for extracting gelatin and preparing gelatin film from horse mackerel scale, such as extraction temperature and time, as well as the protein concentration of film‐forming solutions were investigated. Yields of extracted gelatin at 70 °C, 80 °C, and 90 °C for 15 min to 3 h were 1.08% to 3.45%, depending on the extraction conditions. Among the various extraction times and temperatures, the film from gelatin extracted at 70 °C for 1 h showed the highest tensile strength and elongation at break. Horse mackerel scale gelatin film showed the greatly low water vapor permeability (WVP) compared with mammalian or fish gelatin films, maybe due to its containing a slightly higher level of hydrophobic amino acids (total 653 residues per 1000 residues) than that of mammalian, cold‐water fish and warm‐water fish gelatins. Gelatin films from different preparation conditions showed excellent UV barrier properties at wavelength of 200 nm, although the films were transparent at visible wavelength. As a consequence, it can be suggested that gelatin film from horse mackerel scale extracted at 70 °C for 1 h can be applied to food packaging material due to its lowest WVP value and excellent UV barrier properties.     

Effect of Addition of Halloysite Nanoclay and SiO<Subscript>2</Subscript> Nanoparticles on Barrier and Mechanical Properties of Bovine Gelatin Films

Casting method was used to prepare bovine gelatin based bio-nanocomposite films with halloysite nanoclay and nano-SiO₂ as the reinforcing materials. The composition included gelatin with 20% (w/w) of glycerol (as plasticizer) compounded with halloysite nanoclay and nano-SiO₂ (0%, 2%, 3%, 4%, 5% w/w), respectively. Both types of nanocomposite films showed better mechanical and water solubility than the pristine gelatin films. On comparison with the control, increase in the nanoparticles content resulted in higher tensile strength (9.19 to 13.39 and 12.22 MPa in nanoclay and nano-SiO₂, respectively) and elastic modulus (1.32 to 2.99 and 3.02 MPa% in nanoclay and nano-SiO₂, respectively) with lower elongation at break (80.80 to 55.72 and 40.31% in nanoclay and nano-SiO₂, respectively) and water solubility (85.99 to 69.67 and 69.59% in nanoclay and nano-SiO₂, respectively). Even though a decrease in water vapor permeability was recorded, it was statistically non-significant (1.94 to 1.50 and 1.73 g mm/m² h kPa in nanoclay and nano-SiO₂, respectively). Studies on the heat sealing and peel seal test, conducted to determine the seal strength of the nanocomposite films, revealed lower seal strength compared to control (739.59 to 304.95 and 397.85 N/m in nanoclay and nano-SiO₂, respectively). Between the two nanomaterials used, halloysite nanoclay showed the best results in terms of mechanical properties. The results obtained support the concept of nanocomposite technology and can be employed to improve the barrier and mechanical properties of bovine gelatin films with high potential to be used for food packaging purposes.     

Development of films based on blends of gelatin and poly(vinyl alcohol) cross linked with glutaraldehyde

Both gelatin and poly(vinyl alcohol) (PVA) can be cross linked with glutaraldehyde (GLU). In the case of gelatin, the GLU reacts with each ε-NH2 functional group of adjacent lysine residues, while for PVA, the GLU reacts with two adjacent hydroxyl groups, forming acetal bridges. Thus it can be considered possible to cross link adjacent macromolecules of gelatin and PVA using GLU. In this context, the aims of this work were the development of biodegradable films based on blends of gelatin and poly(vinyl alcohol) cross linked with GLU, and the characterization of some of their main physical and functional properties. All the films were produced from film-forming solutions (FFS) containing 2 g macromolecules (PVA + gelatin)/100 g FFS, 25 g glycerol/100 g macromolecules, and 4 g GLU (25% solution)/100 g FFS. The FFS were prepared with two concentrations of PVA (20 or 50 g PVA/100 g macromolecules) and two reaction temperatures: 90 or 55 °C, applied for 30 min. The films were obtained after drying (30 °C/24 h) and conditioning at 25 °C and 58% of relative humidity for 7 days, and were then characterized. The results for the color parameters, mechanical properties, phase transitions and infrared spectra showed that some chemical modifications occurred, principally for the gelatin. However, in general, all the characteristics of the films were either typical of films based on blends of these macromolecules without cross linking, or slightly higher. A greater improvement in the properties of this material was probably not observed due to the crystallinity of the PVA, which has a melting point above 90 °C. The presence of microcrystals in the polymer chain probably reduced macromolecular mobility, hindering the reaction. Thus more research is necessary to produce biodegradable films with improved properties.     

Properties of bovine gelatin as affected by a cross-linking induced by horseradish peroxidase,glucose oxidase and glucose

Gelatin is an important protein-based hydrocolloid, providing excellent gelling properties in processed foods. Horseradish peroxidase (100 U/g protein), glucose oxidase (1 U/g protein), and glucose (0.025 mmol/g protein) were applied to cross-link bovine gelatin at 37 °C for 3 h, and the gelling properties of cross-linked gelatin were evaluated. Obviously, the cross-linking process did not change the composition of amino acids. The cross-linked gelatin had 39.2% increase in surface hydrophobicity, 54.7% increase in emulsion stability index, but 28.2% decrease in emulsifying activity index, in comparison with bovine gelatin. Laser scanning confocal microscopy observation indicated that cross-linked gelatin rather than bovine gelatin conferred better droplet stability on the generated emulsion after long-storage period of 48 h or 7 days. Moreover, cross-linked gelatin had decreased in vitro digestibility during pepsin hydrolysis (38.5%) and pepsin–trypsin hydrolysis (14.5%) than bovine gelatin. Finally, the gelling and melting temperatures of cross-linked gelatin were 2 °C higher than those of bovine gelatin. Overall, the cross-linking process of bovine gelatin led to easier gelation and improved heat resistance of the subsequently gels.     

Evaluation of mechanical and water barrier properties of transglutaminase cross‐linked zein films incorporated with oleic acid

In this study, four concentrations of transglutaminase were used in zein films incorporated with four oleic acid concentrations, and subsequently, the mechanical and water barrier properties were evaluated. Enzyme concentration significantly affected mechanical and barrier properties of the films. Transglutaminase concentration at 1% improved tensile strength of control sample from 17.5 to 26.9 MPa while solubility decreased from 6.4% to 4.4%. Incorporation of oleic acid into transglutaminase‐treated zein films irrespective of enzyme concentration decreased water vapour permeability and solubility with the 1% transglutaminase‐treated zein films incorporated with 3% oleic acid registering the lowest permeability (0.37 g mm m^?2 h^?1 kPa^?1) and solubility (2.8%) values while elongation at break was not significantly improved. The use of transglutaminase at 1% concentration in cross‐linking zein films coupled with incorporation of controlled concentrations of oleic acid can be an effective approach in improving mechanical and water barrier properties of zein‐based films.     

Mechanical,Physical, Antioxidant,and Antimicrobial Properties of Gelatin Films Incorporated with Thymol for Potential Use as Nano Wound Dressing

The aim of this study was to determine the properties of gelatin films incorporated with thymol. Gelatin films were prepared from gelatin solutions (10% w/v) containing thymol (1, 2, 4, and 8% w/w), glycerol (25% w/w) as plasticizer, and glutaraldehyde (2% w/w) as cross‐linker. Cross‐likened films showed higher tensile strength, higher elongation at break, lower Young's modulus, lower water solubility, lower swelling, lower water uptake, and lower water vapor permeability. Incorporation of thymol caused a significant decrease in tensile strength, increase in elongation at break, decrease in Young's modulus, increase in water solubility, decrease in swelling and water uptake, and increase in water vapor permeability slightly. The films incorporated with thymol exhibited excellent antioxidant and antibacterial properties. The antibacterial activity of the films containing thymol was greatest against Staphylucoccus aureus followed by Bacillus subtilis followed by Escherichia coli and then by Pseudomonas aeruginosa. Thus, gelatin films‐containing thymol can be used as safe and effective source of natural antioxidant and antimicrobial agents with the purpose of evaluating their potential use as modern nano wound dressing. Practical Application : This study clearly demonstrates the potential of gelatin films incorporated with thymol as natural antioxidant and antimicrobial nano film. Such antimicrobial films exhibited excellent mechanical, physical, and water activities and could be used as antibacterial nano wound dressing against wounds burn pathogens.     

玉米淀粉生物降解薄膜的制备及其生物降解特性的研究

以天然高聚物玉米淀粉为原料,经增塑、增强、交联后制备全生物降解薄膜。通过正交实验确定了三种增塑剂的协同作用最佳配比,探索了增强剂、交联剂对薄膜力学性能的影响,研究了该薄膜的生物降解特性,并通过X-衍射对该膜的结构进行表征。结果表明：三种增塑剂的最佳用量为15％水、2％丙三醇、2％尿素,20％增强剂聚乙烯醇、5％交联剂乙二醛,所制备的膜强度达到国标GB4456-84所规定的标准;淀粉经塑化、交联后,次价键断裂,晶区被破坏,使淀粉具备热塑性。该膜微生物生长达到4级,土埋20天后,失重率达到90％。该研究结果为用淀粉制造一次性生物降解膜、消除“白色污染”、提供了理论依据和实际参考。