乳清浓缩蛋白-羟丙基甲基纤维素复合膜研究

基于乳清蛋白和羟丙基甲基纤维素2种生物材料的成膜性能,应用羟丙基甲基纤维素和转谷氨酰胺酶(TG)研究乳清浓缩蛋白(WPC)-羟丙基甲基纤维素(HPMC)复合膜的制备和性质。通过比较研究乳清蛋白膜、羟丙基甲基纤维素膜、乳清浓缩蛋白-羟丙基甲基纤维素混合膜和TG交联复合膜的成膜性能,揭示羟丙基甲基纤维素和转谷氨酰胺酶交联作用对乳清浓缩蛋白膜功能性质的修饰作用。结果显示:乳清浓缩蛋白-羟丙基甲基纤维素复合膜较乳清浓缩蛋白膜更坚韧,抗拉强度增大,断裂伸长率降低,并且溶解度增加,对水蒸气和可见光的屏障性能无显著变化。转谷氨酰胺酶促使复合膜的表面微观结构更致密,进一步提升了乳清浓缩蛋白-羟丙基甲基纤维素的机械性能。     

TG酶添加方式对乳清浓缩蛋白-羟丙基甲基纤维素复合膜成膜性能的影响

为了研究转谷氨酰胺酶(TG)改性乳清浓缩蛋白(WPC)-羟丙基甲基纤维素(HPMC)混合膜的最佳成膜方式,文章在制备WPC-HPMC混合膜的不同阶段添加TG酶,研究复合膜和成膜溶液的成膜性能以及结构表征。将WPC与HPMC混合后添加TG酶交联,制备WPC-HPMC-TG膜。调整TG酶的添加方式,将TG酶与WPC交联后添加HPMC,制备WPC-TG-HPMC膜。SDS-PAGE结果证实TG酶可以促进蛋白质分子间发生交联,形成大分子聚合物。FTIR分析结果表明,TG酶交联乳清蛋白能够引起蛋白质二级结构发生改变。与WPC-HPMC-TG膜相比,WPC-TG-HPMC膜具有更好的机械性能和流变性能,这说明TG酶交联WPC的能力强于TG酶交联WPC-HPMC混合物。因此,TG酶合适的添加方式对改善WPC-HPMC混合膜的成膜特性具有积极的影响。     

转谷氨酰胺酶对乳清浓缩蛋白-纳米微晶纤维素复合膜性能的影响

为了研究转谷氨酰胺酶(TG)对乳清浓缩蛋白(WPC)-纳米微晶纤维素(NCC)复合膜性能和结构的影响,本研究以WPC和NCC为原料,利用TG酶处理对WPC-NCC复合膜的机械性能和屏障性能进行优化,并探究TG酶的交联作用对乳清蛋白分子二级结构和复合膜成膜微观结构的作用情况。结果表明,在TG酶的添加量达到12 U/g_蛋白时,WPC-NCC复合膜的抗拉强度达到2.25 MPa,断裂伸长率达到86.75%,水蒸气透过率为4.40×10-12 gmPa-1s-1m-2,有效改善了WPC-NCC复合膜的机械性能性和水蒸气屏障性能。经过TG酶的处理,乳清蛋白结构向稳定有序的方向转变,减少了复合膜的孔洞数量和孔径,使成膜表面结构更加致密,促进了复合膜的机械性能和水蒸气屏障性能的提升。     

乳化剂对高直链玉米淀粉/羟丙基甲基纤维素复合膜性能的影响

本文以高直链玉米淀粉(HACS)、羟丙基甲基纤维素(HPMC)为成膜基材制备可食性食品包装膜。为解决两者在制膜过程中的相分离问题,通过力学性能、水溶性、结晶性能和表面形貌的分析,研究乳化剂的种类(单甘酯、吐温80、十二烷基硫酸钠)和添加量(1%,2%,3%)对HACS/HPMC复合膜性能的影响。X-射线衍射(XRD)分析表明,乳化剂主要通过与直链淀粉形成V型结晶结构而影响HACS/HPMC复合膜的性能。红外光谱(FT-IR)分析表明,添加乳化剂增加HACS与HPMC之间的氢键相互作用。添加2%单甘酯的复合膜综合性能最优,抗拉强度和断裂伸长率分别提高到10.24 MPa和15.86%,复合膜的截面与表面光滑平整。研究证明添加2%的单甘酯可有效的提高HACS与HPMC在成膜过程中的相容性,得到性能优良的复合膜。     

复合大豆分离蛋白膜力学性能研究

在大豆分离蛋白膜制备工艺基础上,添加原纤维素、羧甲基纤维素和羟丙基甲基纤维素三种材料,制备出改性纤维素大豆分离蛋白复合膜.考察不同添加量的三种添加材料对复合膜的膜厚度(FT)、膜完整性(FI)、抗拉强度(TS)、断裂伸长率(E)、透光率(T)、溶解率(D)、水蒸汽透过系数(WVP)七个性能指标的影响效果,并分析了大豆分离蛋白膜和分别添加三种材料所制得的复合膜的扫描电子显微电镜图,筛选出最佳添加材料,最后对其最佳添加量进行了研究.结果表明:当羟丙基甲基纤维素与大豆分离蛋白的质量百分比为4％时,复合膜的抗拉强度达到最大值4.43 MPa,水蒸汽透过系数达到最小值21.0g·mm/(m2·h·kPa),断裂伸长率与透过率均较为理想.     

琥珀酰化改性菜籽蛋白基复合膜制备及其性能研究

琥珀酰化改性菜籽蛋白(SRPI)与羟丙基甲基纤维素(HPMC)复合制得薄膜。通过对复合膜机械性能、水蒸气透过性、透明度、二级结构和微观结构进行表征。结果表明:菜籽蛋白(RPI)经琥珀酰化改性后,SRPI膜与RPI膜相比,拉伸强度提高18. 7%,断裂伸长率提高38. 7%,透明度提高121%,并且蛋白膜的二级结构中β-折叠与α-螺旋占比增大,无规则卷曲占比减小。此外,当SRPI:HPMC=3:1时,复合膜与SRPI膜相比阻水性提高24. 1%,拉伸强度提高101. 3%,α-螺旋与无规则卷曲的占比无明显变化,而β-转角占比提升,有利于蛋白膜的结构稳定,并且复合膜微观结构紧凑,均匀,这表明琥珀酰化改性菜籽蛋白与羟丙基甲基纤维素具有良好的相容性。本研究为菜籽蛋白基复合膜的开发与利用提供了借鉴。     

高直链玉米淀粉/羟丙基甲基纤维素可食性膜的制备及性能研究

以高直链玉米淀粉(HACS)和羟丙基甲基纤维素(HPMC)为主要成膜基材,采用溶液流延法制备了HACS/HPMC可食性膜。研究了不同配比的HACS与HPMC对可食性膜的结晶性能、力学性能、亲水性能和水蒸气阻隔性能等的影响。结果表明,随着HPMC比例的增大,HACS与HPMC之间的氢键作用减弱,复合膜的水溶性增大,连续相由HACS转变为HPMC,但HACS与HPMC的相容性变差。HPMC可有效降低可食性膜的结晶程度并抑制其在储藏过程中的老化。在复合膜中,当HACS与HPMC比例为8∶2时,可食性膜具有最大抗拉强度(7.5 MPa)、断裂伸长率(14.7%)、水接触角(84.33°)和最低水蒸气透过系数(2.17×10~(-10 )g·m·m~(-2)·s~(-1)·Pa~(-1))。纯HACS膜和纯HPMC膜的透光性能均优于HACS/HPMC复合膜。     

乳清浓缩蛋白与卵清蛋白复合膜的制备及其性能

本文以乳清蛋白（Whey protein concentrate,WPC）和卵清蛋白（Egg white protein,EWP）为成膜基质,添加5 U/g_蛋白转谷氨酰胺酶（Transglutaminase,TG）制备WPC/EWP复合膜,分别研究WPC和EWP质量比、膜液pH、甘油添加量对WPC/EWP复合膜结构及性能的影响。结果表明,当WPC/EWP质量比为1:3,成膜液pH为8,甘油添加量为35%时,电镜结果表明形成的复合膜结构致密无孔隙,红外结果显示WPC和EWP有较好的相容性。WPC/EWP复合膜的水蒸气透过率为2.08×10?10 g·s?1m?1Pa?1,透光率为73.90%,抗拉强度为1.60 MPa,断裂伸长率为151.96%。WPC、EWP和甘油在膜液pH为8时具有良好的融合性,能显著（P<0.05）提高WPC/EWP复合膜的机械性能。     

转谷氨酰胺酶改性可食用膜的研究进展

转谷氨酰胺酶可催化蛋白发生交联反应,从而改性可食用蛋白膜和复合膜的组织结构和特性,如抗拉强度、断裂伸长率、阻水性、阻油性、透氧系数等,在食品工业中具有广阔的应用前景.本文介绍转谷氨酰胺酶改性对大豆蛋白可食用膜、乳清蛋白可食用膜、明胶可食用膜和复合膜的特性影响以及应用前景.     

乳清浓缩蛋白可食用包装膜的研制

以乳清浓缩蛋白为基质,通过加入成膜剂、增塑剂制得可食用包装膜。研究了不同成膜剂添加量、不同增塑剂添加量、不同转谷氨酰胺酶添加量对成膜的影响。通过响应面分析表明,制备乳清浓缩蛋白可食用膜的最佳条件是：乳清浓缩蛋白浓度10%、添加山梨醇5%、无水氯化钙1.2166%、转谷氨酰胺酶0.018%,在60~65℃的温度范围成膜。     

Transglutaminase and hydroxypropyl methyl cellulose enhance mechanical properties of whey protein concentrate film

Whey protein and cellulose derivatives are abundant and renewable raw materials that provide an environmentally friendly alternative to fossil fuel sources used for food packaging. A novel biodegradable composite film comprising whey protein concentrates (WPC) aqueous solutions (10%, w/v) with different concentrations of Hydroxypropyl methylcellulose (HPMC) (0, 1, 2, 3, 4 and 5 wt% of WPC) was prepared in the present study. The effect of transglutaminase (TG) on the functional properties of the film was investigated. SDS-PAGE profiles indicated that TG modulated the formation of intermolecular cross-linking of WPC. FT-IR results showed that HPMC modified the mechanical properties of WPC. Incorporation of HPMC decreased the transparency and improved the tensile strength and extensibility of the film. TG addition led to a significant enhancement of the mechanical properties of the film. These findings indicated that TG promoted the formation of WPC-HPMC composite film with improved mechanical properties.     

化学交联与酶法交联对鱼糜-明胶复合膜性质的影响

研究比较了戊二醛和谷氨酰胺转氨酶(TGase)对鱼糜-明胶复合膜的性质改良效果。当戊二醛的含量为蛋白质量的0.025%～0.1%时,膜的抗拉伸强度(TS)没有显著差异,但断裂延伸率(EAB)却随着戊二醛含量的增加而上升,当戊二醛含量增加到0.2%时,TS和EAB都出现了下降。然而,膜的TS和EAB都随着TGase的添加逐渐增加。虽然戊二醛和TGase都可以使蛋白发生交联,导致膜的固形物溶解率(FS)和蛋白溶解率(PS)下降,但是戊二醛的添加效果明显优于TGase。此外,戊二醛的添加会使膜的颜色变黄,而TGase不仅不会影响膜的色泽,还可以提高膜的透明性能。根据SDS-PAGE的结果,发现戊二醛和TGase都会使膜中蛋白分子发生交联形成高分子聚合物。FT-IR的分析结果表明,蛋白分子间的氢键作用随着TGase的添加逐渐减弱,随着戊二醛的添加出现先减弱后增强的趋势。     

酶法改性对各种蛋白膜的溶解特性和体外消化率的影响

以大豆分离蛋白SPI-1、大豆分离蛋白SPI-2、酪蛋白酸钠NaCas-1、酪蛋白酸钠NaCas-2、明胶G-1、明胶G-2、乳清蛋白浓缩物WPC、小麦面筋蛋白WG、花生分离蛋白PPI这9种蛋白质为原料制备蛋白膜,主要研究了谷氨酰胺转移酶(TGase)改性对这9种蛋白膜的溶解特性和体外消化率这2种性能的影响。TGase的作用使SPI-1膜、NaCas膜和WPC膜的水分含量呈显著性降低(P≤0.05)。TGase的处理使各种蛋白质膜的总可溶性物质量均比对照膜明显降低,SDS-PAGE分析表明,TGase作用明显降低了这几种蛋白膜在水溶液中的溶解性。与对照膜相比,TGase改性显著降低了蛋白膜的消化率,其中NaCas、SPI和G蛋白膜的下降幅度较大。这可能是因为TGase催化改性的蛋白膜中产生了新的交联。     

谷氨酰胺转氨酶改性可食性复合膜的研究

研究了以甘油为增塑剂时,谷氨酰胺转氨酶(TGase)对大豆分离蛋白(SPI)和谷朊粉(WG)复合膜功能特性的影响.应用综合评分法得出,当TGase的添加量为0.30%时,综合得分最高,为29.52,此时,复合膜的拉伸强度最大,为56.44 MPa.比对照提高了47.1%;撕裂强度最大,为206.61 N/mm,比对照提高了4.3%;膜的水分含量为12.90%,比对照降低了7.0%;膜的水蒸汽透过率为0.443 g·mm/(kPa·h·m2),比对照降低了12.7%.但添加TGase也使膜的透光率下降.     

Characteristics of edible films made from dairy proteins and zein hydrolysate cross-linked with transglutaminase

The main objectives of this research were to develop whey protein or casein films incorporating zein hydrolysate and also cross‐linked by transglutaminase as to well as characterize the physical and mechanical properties of the film. Zein hydrolysate decreased the solubility of the whey protein film (P < 0.05), while treatment with transglutaminase did not change the solubility of the film significantly. Electrophoresis patterns demonstrated that casein molecules were cross‐linked by transglutaminase and the extent of this cross‐linkage was further increased when zein hydrolysate was added. In addition, the use of zein hydrolysate decreased the tensile strength of the whey protein film by 35–45%. The elongation of the casein film was increased by 41% because of the action of transglutaminase and zein hydrolysate (P < 0.05). The water vapour permeability of the films was not significantly different. As the addition of zein hydrolysate and treatment with transglutaminase improved the flexibility of the films, the level of plasticizer required to maintain film flexibility could be reduced without sacrificing their water vapour permeability.     

Development of nanocomposite biodegradable film containing iron nanoparticles biosynthesised by Saccharomyces cerevisiae

The use of nanoparticles in biodegradable films has been shown to improve their characteristics in food packaging. The study was designed to investigate the effect of iron oxide nanoparticles (IONPs) and lysed yeast cells residue (YSR) on the properties of whey protein concentrate (WPC) films. IONPs (0, 0.5, 1.0 and 1.5 mm ) biosynthesised by Saccharomyces cerevisiae and YSR were used to prepare WPC films. The addition of IONPs and YSR increased the tensile strength (TS) of the films by approximately 2.6 MPa compared with the control films (P < 0.05). Percent elongation and water vapour permeability of the films decreased significantly (P < 0.05) by the contribution of IONPs. All the films did not inhibit the growth of tested microorganisms. The incorporation of YSR in the film also did not make a significant change in any properties of the film (P > 0.05). The results indicated the usefulness of IONPs incorporation into WPC films to enhance mechanical but not antimicrobial properties.     

Effects of microcrystalline cellulose on functional properties of hydroxy propyl methyl cellulose microcomposite films

ABSTRACT:  Edible films and coatings in foods can be used to increase shelf-life and improve organoleptic characteristics of foods by avoiding deterioration of food components and therefore promoting preservation of the final product. This study is the first to investigate the use of different size fillers for the purpose of preparing edible composite films with fillers < 1.0 μm in size. For this purpose, water vapor permeability and mechanical properties of HPMC (hydroxy propyl methyl cellulose) based films with the inclusion of different size MCC (microcrystalline cellulose) fillers were studied. The water vapor permeability of the control HPMC film was 1.2 ± 0.2 g-mm/kPa-h-m² and did not show a significant change with the addition of fillers. A comparison of mechanical properties of the films with a tensile test showed that tensile strength of the control film, which was prepared using a 3 wt% HPMC solution, increased from 29.7 ± 1.6 MPa to 70.1 ± 7.9 MPa with the addition of 500-nm size particles, while it increased only to 37.4 ± 5.5 MPa with the addition of 3-μm size particles. Also important is that the elongation percentage of the control film did not decrease significantly with the addition of submicron size fillers to the HPMC films. This study showed that the increased surface area per weight of smaller size MCC fillers compared to their larger size counterparts was highly beneficial in terms of film mechanical property improvement.