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1.
基于响应面分析法的可食性小麦蛋白膜的研究   总被引:7,自引:0,他引:7  
梁桂兆  卞科 《食品科学》2004,25(5):70-75
应用响应面分析法研究了谷朊粉浓度、甘油浓度、pH值、成膜温度对成膜特性的影响。实验结果表明,甘油浓度与pH值及其交互作用对蛋白膜抗拉强度和延伸率影响比较显著;对膜的透水性影响比较大的因素是甘油浓度、温度、谷朊粉浓度及甘油浓度与温度的交互作用;谷朊粉浓度、甘油浓度、pH值、温度以及它们的交互作用对蛋白膜的透氧性的影响都是比较显著的。  相似文献   

2.
Gelatin film from blue shark (Prionace glauca) skin was investigated in order to utilize what is one of the most serious marine wastes in Japan. Film properties from shark skin such as tensile strength (TS), elongation at break (EAB) were evaluated. The TS of gelatin film from shark skin was affected by the protein concentration (1, 2 and 3%) of the film-forming solution (FFS). TS of the film from a 2% protein FFS was the highest. EAB and water vapor permeability (WVP) increased with increasing FFS protein concentration. WVP of shark skin gelatin was evidently low as compared to gelatin films from other fish. An increase in the FFS protein concentration decreased transparency at almost all wavelengths. Furthermore, opacity at 280 nm was characteristically high as compared to films from bony fish skin. The addition of glycerol improved flexibility and enhanced the UV barrier property at 280 nm. However, transparency at the visible range and WVP increased with increasing glycerol content.From the above, it was suggested that shark skin gelatin film technology can be applied to pharmaceutical products or rich-fat food due to its excellent water and UV barrier properties.  相似文献   

3.
Rheological properties of the film-forming solutions of tapioca starch/decolorized hsian-tsao leaf gum (dHG) as well as the structural properties and viscoelasticity of the resulting films were characterized as a function of dHG and glycerol concentrations. As compared to film-forming solutions with tapioca starch alone, the apparent viscosity, storage modulus and loss modulus of starch/dHG film-forming solutions increased, and tan δ decreased with increasing dHG. After casting of the film-forming solutions, all starch/dHG films showed relatively low opacity values. SEM and X-ray diffraction analysis revealed that all starch/dHG films exhibited homogeneous and highly amorphous structure. The extensional creep compliance of starch/dHG films increased with increasing glycerol concentration, implying weaker mechanical strength and higher mobility of polymer chains by the plasticizing effect of glycerol. However, addition of dHG pronouncedly increased the mechanical and elastic properties of tapioca starch films as evidenced by a decrease in extensional creep compliance and retardation time. Such results implied that dHG may possibly modify the network structure of tapioca starch film.  相似文献   

4.
The effects of processing parameters, including the applied amount of microbial transglutaminase (MTGase), the pH of film-forming solution, air-drying temperature, as well as the additional pre-incubation, on the properties of MTGase-treated soy protein isolate (SPI) films were investigated. The treatment with low concentration of MTGase (4–10 units per gram of SPI, U g 1) significantly increased the tensile strength (TS) values of SPI films, while high concentration of MTGase (over 20 U g 1) resulted in significant decrease in the TS values (P  0.05). The elongation at break (EB) values of corresponding films gradually decreased, and the contact angle values persistently increased with the enzyme concentration. At alkaline pH range, the TS and EB values of MTGase-treated SPI films were significantly higher than that at pH 7.0 (P  0.05). Meanwhile, the contact angle values significantly decreased with increasing pH from 7.0 to 10.0 (P  0.05). The TS, EB and contact angle values of MTGase-treated films gradually but insignificantly decreased with increasing the air-drying temperature from 18 to 50 °C (P > 0.05). The properties of MTGase-treated films were also affected by the additional pre-incubation of film-forming solutions with MTGase before casting. Furthermore, the aggregation of SPI or its components induced by MTGase has been proved to mainly account for the influence of processing parameters on the properties of SPI films (MTGase-treated). Thus, low concentration of enzyme, alkaline pH range and low air-drying temperature, at which conditions the MTGase-induced aggregation of SPI in film-forming solutions could be in some extent inhibited or delayed, might facilitate the improvement of the properties of SPI films by MTGase, especially the mechanical and surface hydrophobic properties.Industrial relevanceThe development of biodegradable protein film has attracted a lot of attention worldwide. The enzymatic cross-linking induced by transglutaminase has been confirmed to improve mechanical and surface hydrophobic properties of cast films from most of food proteins, including soy proteins. Results of this study show that, the improvement of properties of cast films of soy proteins by transglutaminase treatment is largely dependent upon many processing parameters, e.g., enzyme concentration, the pH of film-forming solution and temperature.  相似文献   

5.
The addition of nisin into a gelatin matrix can change properties of the film. The aim of this work was to develop gelatin-based films containing different nisin concentrations in order to study their influence on the film's antimicrobial and physical properties and their rheological properties as a film-forming solution (FFS). The FFS was characterised by rheological assays, and the gelatin-based active films were characterised and assessed by the effects of nisin concentrations on their various properties, including antimicrobial activity. Nisin's concentration affected not only its viscoelastic properties of FFS but also its film solubility in water, film surface roughness and light barrier. The addition of nisin also slightly modified the water contact angle and the mechanical properties of the gelatin films. Finally, the films demonstrated activity against Staphylococcus aureus and Listeria monocytogenes at concentrations above 56 mg of nisin g−1 of gelatin.  相似文献   

6.
Effects of glycerol (3-7% w/w) and sorbitol (4-8% w/w) concentration, pH (7.0, 9.0, 11.0) and heating (90 °C, 20 min) of film-forming solution (FFS) on the water vapor permeability (WVP), moisture content (MC), solubility, light transmission and transparency of pea protein isolate (PPI) films were investigated. Films plasticized with sorbitol exhibited significantly lower WVP, lower MC and higher solubility, in comparison with glycerol-plasticized films. Increasing glycerol content of the films led to increases in WVP and MC but did not affect film solubility. In contrast, increase in sorbitol content had no effect on permeability and MC but resulted in increased film solubility. Moisture sorption isotherms of PPI films suggested that the difference in WVP observed among films plasticized with glycerol and sorbitol might be due to the different hygroscopicity of these plasticizers. The pH of FFS did not have a significant effect on WVP and MC. Solubility of PPI films formed from non-heated FFS was not affected by pH, whereas solubility of films formed from heat-treated FFS generally increased when pH was increased from 7.0 to 11.0. Heating of FFS resulted in improved film transparency. All tested films were characterized by excellent ability to absorb UV radiation. Microstructural observation by scanning electron microscopy did not show differences between sorbitol- and glycerol-plasticized films.  相似文献   

7.
D Kim  SC Min 《Journal of food science》2012,77(9):E240-E246
Edible biopolymer films were developed from gelatin extracted from trout skin (TSG) using thermal protein denaturation conditions and plasticizer (glycerol) concentration as variables. The amino acid composition of the TSG, elastic modulus, viscous modulus, and the viscosity of film-forming solutions, and tensile properties, water vapor permeability, solubility in water, and color of TSG-based films were determined. A 6.8% (w/w, wet basis) trout skin-extracted gelatin solution containing 9, 17, or 23% (w/w, dry basis) glycerol was heated at 80, 90, or 100 °C for 30, 45, or 60 min to prepare a film-forming solution. TSG can be characterized as a gelatin containing high contents of methionine and aspartic acid. The gelation temperature of the film-forming solution was 7 °C and the solution was subjected to heating to form a stable matrix for a film. Increased heating time of the film-forming solution reduced the film solubility (P < 0.05). Heating at 90 °C for 30 min was suggested as the requirement for film formation. As the concentration of glycerol in the film increased, film strength and moisture barrier properties decreased, while film stretchability increased (P < 0.05). Trout skin by-products can be used as a natural protein source for fabricating biopolymer films stable at ambient conditions with certain physical and moisture barrier properties by controlling thermal treatment conditions and glycerol concentrations. Practical Application: The fishing industry produces a significant amount of waste, including fish skin, due to fish processing. Trout skin waste has potential value as a protein source that can be used to form biopolymer edible films for packaging low and intermediate water activity food products, and thus may have practical applications in the food industry, which could be one way to cut waste disposal in the trout processing industry.  相似文献   

8.
The properties of porcine plasma protein-based films as influenced by some factors and pretreatment were studied. Both protein concentrations (20 and 30 g L−1) and glycerol contents (50, 60 and 70 g/100 g protein) had the impact on film properties. Film prepared from film-forming solution (FFS) containing protein (30 g L−1) and glycerol (60 g/100 g protein) possessed the highest tensile strength (TS) (2.48 MPa), while that containing protein (30 g L−1) and glycerol (70 g/100 g protein) exhibited the greatest elongation at break (EAB) (18.33%). Protein and glycerol contents affected water vapor permeability (WVP) and transparency of the resulting films. No differences in protein solubility were found among all films (p > 0.05). Pretreatment of FFS by adjusting pH (2-11) and heating at different temperatures (40, 55 and 70 °C) on the properties of the resulting films was investigated. TS and EAB became higher but WVP decreased with decreasing or increasing pH value of FFS. Heat treatment of FFS with pH 3 and 10 had no impact on TS of the resulting film (p > 0.05). On the other hand, EAB and WVP increased with increasing temperature of FFS at both pHs (p < 0.05).  相似文献   

9.
大豆分离蛋白与谷朊粉可食性复合膜研究   总被引:1,自引:0,他引:1  
该文报道影响大豆分离蛋白与谷朊粉复合膜成膜因素,分析各种因素对复合膜性能影响,并对正交试验结果采用极差分析和综合评分法进行评定,得到制备综合性能良好的可食性膜最佳条件为:谷朊粉与大豆分离蛋白比例为1∶5,甘油量为20%,pH为11,预热处理温度和时间分别为80℃和40min;此时,膜的透光率、拉伸强度、撕裂强度、水分含量和水蒸汽透过率依次为60.5%、38.38MPa、198.02N/mm、13.87%和0.507g·mm/kPa·h·m2。  相似文献   

10.
ABSTRACT:  This study investigated the antimicrobial activities of chitosan-lysozyme (CL) composite films and coatings against tested microorganisms inoculated onto the surface of Mozzarella cheese. CL film-forming solutions (FFS) with a pH of 4.4 to 4.5 were prepared by incorporating 0% or 60% lysozyme (per dry weight of chitosan) into chitosan FFS with or without a pH adjustment to 5.2. Sliced cheese was subjected to 3 CL package applications: film, lamination on a multilayer coextruded film, and coating. Cheese was inoculated with Listeria monocytogenes , Escherichia coli , or Pseudomonas fluorescens at 104 CFU/g, or with mold and yeast at 102 CFU/g. Inoculated cheese was individually vacuum packaged and stored at 10 °C for sampling at 1, 7, and 14 d for bacteria, and at 10, 20, and 30 d for fungi. Inoculated bacteria survived but failed to multiply in untreated cheese during storage. Treated cheese received 0.43‐ to 1.25‐, 0.40‐ to 1.40‐, and 0.32- to 1.35-log reductions in E . coli , P. fluorescens , and L . monocytogenes , respectively. Incorporation of 60% lysozyme in chitosan FFS showed greater antimicrobial effect than chitosan alone on P. fluorescens and L . monocytogenes . The pH adjustment only affected the antimicrobial activity on L . monocytogenes , with lower pH (unadjusted) showing greater antimicrobial effect than pH 5.2. Mold and yeast increased to 105 CFU/g in untreated cheese after 30 d storage. Growth of mold was completely inhibited in cheese packaged with CL films, while 0.24‐ to 1.90‐ and 0.06‐ to 0.50-log reductions in mold populations were observed in cheese packaged with CL-laminated films and coatings, respectively. All CL packaging applications resulted in 0.01- to 0.64-log reduction in yeast populations.  相似文献   

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