可食性小麦蛋白膜透氧性的研究

一定的条件下 ,以小麦蛋白为原料可以制得具有良好透氧性的薄膜。文中研究了可食性小麦蛋白膜的透氧性能 ,对影响透氧性的 5种因素的影响效果及机理进行了探讨 ,以期望为改善小麦蛋白膜的透氧性提供参考。     

Tensile and Barrier Properties of Edible Films Made from Whey Proteins

ABSTRACT: Whey protein isolate (WPI)-based edible biopolymer films were prepared using a film-forming stage designed to provide heat-induced gelation. Effects of whey-protein ratios, calcium, glycerol (plasticizer), and emulsion droplet incorporation on film tensile and barrier properties were investigated. Protein ratios had less influence on tensile strength, elongation, and water vapor permeability than glycerol and calcium ion concentrations. Semitransparent films with reasonably high tensile and UV-light barrier properties and moderate water vapor barrier properties were prepared from WPI:20% glycerol:10 mM calcium solutions. Microstructure analysis revealed the influence of glycerol and calcium concentrations on gel networks, which could be related to film tensile properties.     

Temperature Effect on Oxygen Permeability of Edible Protein-based Films

Edible films from corn zein, wheat gluten, and wheat gluten/soy protein isolate (2.1:0.9) were produced and their oxygen permeabilities were determined at 7, 15, 25, and 35°C under 0% relative humidity. Mean oxygen permeability values for the 3 films were in the range of 1.8–11.2, 0.9–6.1, and 0.6–3.8 amol/m.s.Pa, respectively. Data for all 3 films showed very good agreement with the Arrhenius activation energy model. No structural transitions were indicated within these films in this temperature range. Calculated activation energy values for the oxygen permeation process were 11.1, 11.9, and 10.8 kcal/mol, respectively. Comparisons with some non-protein edible coatings and plastic packaging materials showed dry protein films were very efficient oxygen barriers.     

Denaturation Time and Temperature Effects on Solubility, Tensile Properties, and Oxygen Permeability of Whey Protein Edible Films

ABSTRACT Whey protein film solubility decreased as film-forming solution heating time and temperature increased. No differences were observed in solubility between films soaked in water at 25 °C for 24 h and 100 °C for 4 min. However, the degree of swelling was significantly larger for films soaked at 100 °C. Films became stiffer, stronger and more stretchable as film-forming solution time and temperature were increased. Oxygen permeability (OP) was lower for films made from heat-denatured whey protein than for films made from native whey protein. Results suggest that an increase in covalent cross-linking, as heat denaturation of the whey protein increases, is accountable for film water insolubility, higher tensile properties and lower OP.     

Development and Characterization of Edible Films from Cranberry Pomace Extracts

The feasibility of using cranberry pomace extract as a new film‐forming material was studied. Cranberry pomaces were extracted using hot water. Low methoxyl pectin (LMP) or high methoxyl pectin (HMP) at a concentration of 0.50% or 0.75% (w/w) and 0.25% (w/w) sorbitol or glycerol was incorporated into film‐forming solutions (FFSs) for improving film functionality. Proximate compositions of cranberry pomace and its extract were determined. The pH and total soluble solid content (SSC) of FFSs, physical and mechanical properties, water vapor permeability, and microstructure of dried films were analyzed. About 1.4% (w/w) of solids was obtained from cranberry pomace water extracts, of which about 93% was carbohydrate. Dried films had bright red color and strong cranberry flavor. Films plasticized with sorbitol were denser in matrix structure and had higher color intensity than those of glycerol plasticized films. In general, LMP and sorbitol incorporated films had higher tensile strength and lower elongation at break and lower water vapor permeability than other films. The higher (0.75%) pectin concentration resulted in increased tensile strength, but decreased elongation at break. Scanning electron microscopy images revealed that sorbitol added films had more regular and compact cross‐section structure than those of glycerol added films. This study demonstrated that it is feasible to create natural colorful and fruit flavor edible films from fruit pomace water extracts. Depending on specific applications of the films, targeted film functionality can be achieved by incorporating proper pectin type and concentration and plasticizer into pomace extracts.     

Physical Properties of Whey Protein–Hydroxypropylmethylcellulose Blend Edible Films

ABSTRACT: The formations of glycerol (Gly)‐plasticized whey protein isolate (WPI)–hydroxypropylmethylcellulose (HPMC) films, blended using different combinations and at different conditions, were investigated. The resulting WPI: Gly‐HPMC films were analyzed for mechanical properties, oxygen permeability (OP), and water solubility. Differences due to HPMC quantity and blend method were determined via SAS software. While WPI: Gly and HPMC films were transparent, blend films were translucent, indicating some degree of immiscibility and/or WPI–HPMC aggregated domains in the blend films. WPI: Gly‐HPMC films were stronger than WPI: Gly films and more flexible and stretchable than HPMC films, with films becoming stiffer, stronger, and less stretchable as the concentration of HPMC increased. However, WPI: Gly‐HPMC blended films maintained the same low OP of WPI: Gly films, significantly lower than the OP of HPMC films. Comparison of mechanical properties and OP of films made by heat‐denaturing WPI before and after blending with HPMC did not indicate any difference in degree of cross‐linking between the methods, while solubility data indicated otherwise. Overall, while adding HPMC to WPI: Gly films had a large effect on the flexibility, strength, stretchability, and water solubility of the film polymeric network, results indicated that HPMC had no effect on OP through the polymer network. WPI–HPMC blend films had a desirable combination of mechanical and oxygen barrier properties, reflecting the combination of hydrogen‐bonding, hydrophobic interactions, and disulfide bond cross‐linking in the blended polymer network.     

Properties of Edible Films from Total Milk Protein

The mechanical properties and water vapor permeability of edible films made from various total milk proteins (TMPs) were investigated. Two TMPs obtained from nonfat dry milk (NDM) by removing lactose and three TMPs obtained from a commercial source were studied. Lactose was extracted from NDM by ultrafiltration or suspension in ethanol followed by filtration. TMP concentrate obtained by ultrafiltration (UF) produced films with the lowest water vapor permeability (WVP) and the highest tensile strength at break. Commercial TMP concentrates produced films more ductile than those from the UF-TMP or retentate from ethanol extraction. Further research is needed to improve mechanical properties of UF-TMP films without increasing the WVP.     

基于响应面分析法的可食性小麦蛋白膜的研究

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。     

基于响应面分析法的可食性小麦蛋白膜的研究

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。     

Plasticized Whey Protein Edible Films: Water Vapor Permeability Properties

Heat treatment, protein concentration, and pH effects on water vapor permeability (WVP) of plasticized whey protein films were examined. The best film formation conditions were neutral pH, aqueous 10% (w/w) protein solutions heated for 30 min at 90°. Isoelectric point adjustment of whey protein with calcium ascorbate buffer increased WVP with increasing buffer concentration, The importance of vacuum application to minimize film pore size was identified using scanning electron microscopy. Polyethylene glycol, glycerol and sorbitol plasticizer concentration affected film WVP. Determining the effects of relative humidity on WVP for plasticized whey protein films enabled prediction of film behavior under any water vapor partial pressure gradient.     

大米蛋白的可食用膜

研究了大米蛋白可食用膜的工艺条件，并测定了膜的抗拉强度、延伸率和透水率．实验表明，大米蛋白的质量浓度为5g／dL，甘油的添加量为3g／dL，谷氨酰胺转胺酶的添加量为质量浓度0．2g／dL，反应时间为90min，膜液在80℃处理40min后能得到性能比较好的膜。     

Use of a Mathematical Model to Describe the Barrier Properties of Edible Films

ABSTRACT: A study on the influence of the solubilization and diffusion process on the barrier properties of 4 different edible films is presented. The water and oxygen barrier properties of zein, alginate, casein, and chitosan films were measured at 25°C. A mathematical model was fitted to the experimental data to obtain quantitative information on both solubilization and diffusion process. Results suggest that alginate film, which shows the highest water and oxygen permeability coefficient, has both higher affinity with water and a higher macromolecular mobility than the other 3 films. The lowest water and oxygen permeability coefficient was detected for chitosan and zein films. The casein film has shown an intermediate behavior.     

Biodegradable Poly(butylene adipate-co-terephthalate) Films Incorporated with Nisin: Characterization and Effectiveness against Listeria innocua

ABSTRACT: Biodegradable poly(butylene adipate-co-terephthalate) (PBAT) films incorporated with nisin were prepared with concentrations of 0, 1000, 3000, and 5000 international units per cm² (IU/cm²). All the films with nisin inhibited Listeria innocua, and generated inhibition zones with diameters ranging from 14 to 17 mm. The water vapor permeability and oxygen permeability after the addition of nisin ranged from 3.05 to 3.61 × 10¹¹ g m m⁻² s⁻¹ Pa⁻¹ and from 4.80 × 10⁷ to 11.26 × 10⁷ mL·m·m⁻²·d⁻¹·Pa⁻¹, respectively. The elongation at break (ɛ_b) was not altered by the incorporation of nisin (P > 0.05). Significant effect was found for the elastic modulus (E) and the tensile strength (σ_s) (P < 0.05). The glass transition and melting temperatures with the presence of nisin ranged from −36.3 to −36.6 °C and from 122.5 to 124.2 °C, respectively. The thermal transition parameters such as the crystallization and melting enthalpies and crystallization temperature were influenced significantly (P < 0.05) by incorporation of nisin into films. The X-ray diffraction patterns exhibited decreasing levels of intensity (counts) as the concentration of nisin increased in a range of 2θ from 8° to 35°. Formation of holes and pores was observed from the environmental scanning electron microscopy images in the films containing nisin, suggesting interaction between PBAT and nisin.     

Protein Structure and Network Orientation in Edible Films Prepared by Spinning Process

Biodegradable film was prepared by spinning soy protein isolate in a coagulating buffer. Tensile properties and molecular structure of the film were investigated. FTIR results showed that no secondary structure differences appeared between protein film and isolate. The protein aggregation observed in the isolate was increased by the immersion and dispersion of the isolate in the isoelectrical pH buffer. Fluorescence spectroscopy did not demonstrate tertiary structural differences between isolate and film. Stretching the film in two orthogonal directions did not result in significant differences of tensile properties (p≤0.05), indicating no network orientation. Therefore, the film structure could be the result of a random aggregation of proteins displaying a globular shape.     

Edible Films and Coatings from Soy Protein

A method was developed by which films could be prepared from commercial isolated soy protein (ISP). ISP was treated with alkali (ATISP) to alter film orooerties. Water vapor oermeability (WVP). oxygen‘permeability (O₂P), tensile strength (TS), percent elongatidn (%E), and appearance of ISP and ATISP were compared. Alkali treatment had no effect on WVP. O₂P, and TS, gave hieher %E, and improved film appearance. Films properties were also compared at pH 6, 8, 10, and 12. In general, pH 6 gave higher WVP and O₂P and lower TS and %E; while higher pH gave lower WVP and O₂P and higher TS and %E. ATISP films could not be produced at pH 6. Film appearance generally improved with increased pH.     

Degradable Wheat Gluten Films: Preparation, Properties and Applications

Degradable films from spray-dried (SD) and flash-dried (FD) wheat gluten prepared at various pHs, salt levels, temperatures, and shearing times were compared. Differences were observed in properties of the films related to processing conditions. Films prepared from SD wheat gluten were thicker, and had higher tensile strengths and Young's moduli. SD wheat gluten solutions applied as coating material resulted in Grade A-quality shell eggs maintaining quality for 30 days at room temperature. Additionally, SD wheat gluten coating increased the water stability of starch-based packaging.     

玉米-小麦淀粉/玉米醇溶蛋白双层膜热学及微观特性

研究了玉米-小麦淀粉成膜液与玉米醇溶蛋白成膜液不同配比制作的5 种可食用复合膜理化特性的差异, 并分别通过扫描电子显微镜观察、热重分析、差示扫描量热分析、X射线衍射分析、傅里叶变换红外光谱分析对其 热学特性和微观结构进行研究。结果表明：添加一层玉米醇溶蛋白后,双层膜阻水性提高,机械性能得到改善,由 扫描电子显微镜观察结果可知双层膜间结合紧密,热重分析和差示扫描量热分析结果显示双层膜热稳定性得到提 高,X射线衍射结果表明生物大分子之间相容性较好,傅里叶变换红外光谱分析结果发现双层膜间产生了新的氢键 等作用力,为玉米-小麦淀粉/玉米醇溶蛋白双层膜在食品包装中的应用提供了重要的参考依据。     

Apple Peel-Based Edible Film Development Using a High-Pressure Homogenization

ABSTRACT:  Biopolymer films were developed from apple peels of apple process co-products and their physical properties were determined. Apple peel-based films with glycerol (23%, 33%, and 44%[w/w, dry basis]) were prepared using high-pressure homogenization (HPH) at different levels of pressure (138, 172, and 207 MPa). An evaluation of the rheological properties (elastic modulus [ G '], viscous modulus [ G "], and viscosity) of the film-forming solutions was performed. For the apple peel films, the water sorption isotherms, the kinetics of water absorption, the water vapor permeability (WVP), the oxygen permeability (OP), and the tensile properties were determined. The  G ' and viscosity of the film-forming solutions decreased significantly with increasing processing pressure ( P  < 0.05). However, no difference was observed in  G " values at different homogenization pressures ( P  > 0.05). The viscosity decreased from 644 to 468 kPa·s as the pressure increased from 138 to 207 MPa at 90 °C. The monolayer water content of the apple peel films decreased with increasing content of glycerol from 23% to 33%. Further increase in glycerol content did not change the monolayer water content. The water diffusion coefficient of the films was highest at the intermediate level of glycerol content. The barrier properties (WVP and OP) of the films increased with increasing level of glycerol, while processing pressure did not influence the gas barrier properties. The films prepared at 207 MPa were less stiff and strong, but more stretchable than those prepared at 138 and 172 MPa.