高直链玉米淀粉-壳聚糖复合膜透气透水性能研究

本文以高直链玉米淀粉(HACS)和壳聚糖(CS)为基本材料,甘油为增塑剂,甲基纤维素(MC)为增强剂制备可食性复合膜,研究了高直链玉米淀粉与壳聚糖的配比、甘油的添加量以及甲基纤维素的添加量对复合膜的透气透水性能的影响.结果表明,HACS:CS为2:1时,膜的CO2透过量和O2透过量最低,水蒸气透过量(WVT)也处于较低...     

高直链玉米淀粉/壳聚糖可食性复合膜的制备与性能的研究

以高直链玉米淀粉和壳聚糖为成膜基质,添加适量的增塑剂,采用流延法制备可食性复合膜。研究了复合膜中淀粉与壳聚糖的不同比例(1:0,3:1,1:1,0.5:1与0:1)对可食性复合膜的力学性能、透湿性、透光率及其颜色的影响。结果表明:随着壳聚糖添加比例的增加,复合膜的抗拉强度逐渐降低;断裂伸长率则先增大,在淀粉与壳聚糖质量比为1:1时达到最大值,然后下降;透湿性逐渐升高,而透明度则逐渐降低;膜的颜色值L*与a*值逐渐减小,b*及ΔE*逐渐增加,即膜的明度值逐渐下降,黄色值逐渐增加。     

壳聚糖-乳清蛋白双层膜制备工艺优化

以壳聚糖和乳清蛋白为原料制作双层膜,通过研究辅料添加(增塑剂甘油的添加量)和制膜条件(乳清蛋白溶液浓度、乳清蛋白水浴处理温度、壳聚糖溶液p H)对双层膜力学性能(抗拉强度和断裂伸长率)的影响规律。结果表明:在添加辅料方面,随甘油添加量的增加,壳聚糖-乳清蛋白膜的抗拉强度逐渐降低,断裂伸长率逐渐升高。在制膜方面,随乳清蛋白浓度的增大,膜的抗拉强度和断裂伸长率都先升高后下降;随水浴处理温度的升高,膜的抗拉强度降低,而断裂伸长率升高;随壳聚糖溶液p H的增加,膜的抗拉强度和断裂伸长率都是先缓慢升高后下降。利用正交试验优化制膜工艺,确定最佳制膜条件:甘油添加量为0.45 m L、蛋白浓度为6.0%、水浴处理温度为75℃、壳聚糖溶液为p H4.8,此条件下抗拉强度为(97.39±2.25)MPa,断裂伸长率为(11.53±1.04)%。该研究为其在食品保鲜中的应用提供了重要参考依据。     

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.     

魔芋葡甘聚糖-甲基纤维素可食膜的制备及其性能研究

利用魔芋葡甘聚糖和甲基纤维素制备可食膜,研究甲基纤维素添加量、甘油添加量、均质时间和干燥温度对可食膜性能的影响。首先进行单因素实验,得到了各个变量甲基纤维添加量、甘油添加量、均质时间、干燥温度对可食膜水蒸气透过系数(WVP)、断裂伸长率(E)、抗拉强度(TS)的影响。在单因素的基础上确定了各变量的范围,选择WVP和E作为响应值,进行了响应面优化实验。研究结果:在最优水平下,甘油添加量0.963%(V/V),甲基纤维素添加量0.238%(W/V),干燥温度59.6℃,均质时间8.91min,WVP可达到8.4511×10-10g/m·s·Pa;甘油添加量0.985%(V/V),均质时间7.68min,干燥温度40℃,甲基纤维素添加量0.363%(W/V),E可达到130.25%。     

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。     

玉米淀粉/壳聚糖/魔芋葡甘露聚糖复合膜的制备及物性研究

以玉米淀粉、壳聚糖、魔芋葡甘露聚糖(KGM)为成膜基材。通过研究成膜配方中壳聚糖与KGM质量比、玉米淀粉、甘油、吐温-80等材料的质量分数对复合抗拉强度(TS)、断裂伸长率(EAB)、水蒸气透过系数(WVP)和不透明度(Opacity)的影响,以主成分分析法计算复合膜综合分为评价指标,利用正交实验对复合膜成膜配方进行优化。结果表明:当壳聚糖与KGM质量比1.0∶0.6、玉米淀粉质量分数10%、甘油质量分数0.50%、吐温-80质量分数0.30%时,复合膜TS为(22.53±0.16)MPa,EAB为(20.07±1.18)%,WVP为(1.87±0.01)×10~(-12)g·cm~(-1)·s~(-1)·Pa~(-1),不透明度为(4.13±0.07)mm~(-1),复合膜性能最优。     

柚皮精油食品包装材料的制备及性能

以柚皮精油、玉米淀粉、甘油和壳聚糖为复合膜配方,以抗拉强度、断裂生长率和水蒸气透过量等机械性能为指标,通过单因素和正交试验确定复合膜的最佳配方,最后对复合膜结构表征和外观进行分析.结果 表明:复合膜的最佳配方为壳聚糖添加量1.25％、玉米淀粉添加量0.4％、甘油添加量0.6％、柚皮精油添加量0.2％.表征和外观分析表明...     

微晶纤维素的醚化改性及其在淀粉膜中的应用

为改善微晶纤维素（microcrystalline cellulose,MCC）在淀粉膜中的分散性,通过对MCC进行阳离子醚化改性,制得改性微晶纤维素（modified-microcrystalline cellulose,MD-MCC）,并对其化学结构、结晶性、热稳定性和微观形貌进行表征。采用溶液流延法制得淀粉-微晶纤维素复合膜（淀粉-MCC,淀粉-MD-MCC）,分别研究MCC和MD-MCC添加量对淀粉膜结构和性能的影响。结果表明,与MCC相比,MD-MCC的基本化学结构未改变,仍然保持纤维素的基本结构,但其结晶度和热稳定性略有降低,表面呈多孔结构。随着MCC和MD-MCC添加量的增加,淀粉膜的表面粗糙度增大,透光率和断裂伸长率降低,水接触角、水分含量和厚度增大,抗拉强度和水蒸气渗透系数先增加后减小。MD-MCC在淀粉膜中的分散性优于MCC,淀粉-MD-MCC复合膜的力学性能和阻水性能优于淀粉-MCC复合膜,其中MD-MCC添加量为5%时,复合膜具有最大的抗拉强度和阻水性能。     

响应面试验优化玉米淀粉-壳聚糖可食膜的制备工艺

通过响应面法优化玉米淀粉、壳聚糖和甘油的质量分数来制备可食膜,以机械性能（伸长率、抗拉强度）和透湿性（water vapor permeability,WVP）为评价指标,得出二次响应预测模型。结果表明：玉米淀粉、壳聚糖和甘油的质量分数分别为3.71%、0.95%和0.64%时,抗拉强度最大;3 种物料质量分数分别为3.82%、0.50%和1.00%时,伸长率最大;3 种物料质量分数分别为3.52%、0.52%和0.50%时,WVP最小。综合考虑,玉米淀粉、壳聚糖和甘油质量分数分别为3.50%、0.50%和0.67%时,可食膜的性能最优。     

Effect of Molecular Weight,Acid, and Plasticizer on the Physicochemical and Antibacterial Properties of β‐Chitosan Based Films

Abstract: Effects of chitosan molecular weight (1815 and 366 kDa), type of acid (1% acetic, formic, and propionic acid, or 0.5% lactic acid) and plasticizer (0, 25% glycerol or sorbital w/w chitosan) on the mechanical, water barrier, and antibacterial properties of β‐chitosan films were investigated. Tensile strength (TS) of high molecular weight (Hw) films was 53% higher than that of low molecular weight (Lw) ones, acetate, and propionate films had the highest TS (43 and 40 MPa) among tested acids, and plasticizer‐reduced film TS 34%. Film elongation at break (EL) was higher in Hw films than in Lw ones, in which formate and acetate films were the highest (9% and 8%, respectively), and plasticizer increased the film EL 128%. Molecular weight of chitosan did not influence water vapor permeability (WVP) of the films. Acetate and propionate films had lower WVP than other acid types of films, and plasticizer increased film WVP about 35%. No difference was found between glycerol and sorbitol films in terms of film mechanical and water barrier properties. Lw β‐chitosan films showed significant antibacterial activity against E. coli and L. innocua. This study demonstrated that β‐chitosan films are compatible to α‐chitosan films in physicochemical properties and antibacterial activity, yet with simple sample preparation. Practical Application: β‐chitosan based edible films at molecular weight of about 300 kDa showed great antibacterial activity against Gram‐positive and Gram‐negative bacteria. The films have similar mechanical and water barrier properties to α‐chitosan based films at the similar molecular weight, but simple sample preparation procedures and more attractive color. The release of active chitosan fragment from the film matrix acts as an antibacterial agent, making β‐chitosan films suitable as intelligent food wraps or coatings for a wide range of food products to control moisture loss and prevent surface bacterial growth.     

Mechanical Properties, Water Vapor Permeabilities and Solubilities of Highly Carboxymethylated Starch-Based Edible Films

ABSTRACT: Tensile strength (TS), elongation (E), water vapor permeabilities (WVP) and solubilities were determined for highly carboxymethylated starch (HCMS)-based edible films plasticized with sorbitol (S), xylitol (X), mannitol (M) and glycerol (G). TS and E of HCMS-based film increased as the concentration of plasticizer S, M or × increased. TS of the HCMS-based film containing combined plasticizers were higher than those of films containing single plasticizer. The WVP of HCMS-based films seemed to decreased as the concentration of M, X or G plasticizer increased. Increasing plasticizer concentrations in HCMS-based film resulted in decreasing solubility of the films.     

Permeability and Mechanical Properties of Cellulose-Based Edible Films

Factors affecting barrier properties [oxygen permeability (OP) and water vapor permeability (WVP)] and mechanical properties [tensile strength (TS) and elongation (E)] were investigated for methyl cellulose (MC) and hydroxypropyl cellulose (HPC) films. OP, WVP and TS of MC and HPC films increased as the molecular weight (MW) of the cellulose increased. E of MC films increased as MW increased, but E of HPC films was highest for the intermediate MW of 370,000. OP, WVP and TS of MC films were not a function of thickness, but E slowly increased as film thickness increased. OP and WVP of HPC films were not relatable to film thickness, but TS and E of HPC films slowly increased as film thickness increased. TS decreased and E increased for both film types as concentration of plasticizers was increased. Plasticizers enhanced or retarded OP and WVP of cellulose-based films, depending on their concentrations.     

Effect of the presence of glycerol and Tween 20 on the chemical and physical properties of films based on chitosan with different degree of deacetylation

Chitosans with two different deacetylation degree (DD) (60.9% and 96%) were used to elaborate edible films. The influence of the degree of deacetylation and the presence of glycerol and Tween 20 in the formulation on the surface tension of the film forming solutions as well as on the chemical structure, optical and mechanical properties and water vapor permeability (WVP) of the resulting films were studied.IR spectra showed no significant differences on the chemical structures of chitosan of the different films. However, X-ray diffraction analysis indicated that the use of chitosan with higher DD and the use of glycerol as additive resulted in higher crystallinity. Films made of chitosan with the lower DD (60.9%) were found to have higher tensile strength (TS) and elongation (E) in a tensile test. Degree of deacetylation did not have any effect on WVP. The presence of glycerol resulted in less resistant, more elastic and more permeable films.The presence of Tween 20 improved the wettability of film solutions and affected significatively mechanical, optical and barrier properties of the films. A positive interaction between glycerol and Tween 20 was observed for WVP.     

膜液质量浓度对MC/WG可食性复合膜性能的影响

研究膜液质量浓度对甲基纤维素(MC)/小麦面筋蛋白(WG)可食性复合膜性能的影响。结果表明：MC/WG复合膜的抗拉强度、阻氧性能随着膜液质量浓度的增大而显著提高;断裂伸长率、透光率随着膜液质量浓度的增大而降低;水蒸气透过系数则随着膜液质量浓度的增大先减小后增大,在膜液质量浓度为50g/L时最小。各个质量浓度下的复合膜均可完全溶于水,具有良好的水溶性。综合比较复合膜在不同质量浓度下的性能,MC/WG质量浓度以50g/L为宜。     

OPTIMIZATION OF GLYCEROL EFFECT ON THE MECHANICAL PROPERTIES AND WATER VAPOR PERMEABILITY OF WHEY PROTEIN-METHYLCELLULOSE FILMS

Biopolymer films and coatings are generally designed using biological materials such as proteins, polysaccharides, lipids and their derivatives. The use of plasticizers is also required to improve the mechanical properties (tensile strength and elongation) of the films. For application of films to food systems, it is important for the developed films to possess favorable mechanical and permeability characteristics. Therefore, knowledge of optimum conditions where the water vapor permeability (WVP) is minimized while the mechanical properties are enhanced would be significant depending on the application of the edible films. In this study, the effects of glycerol, as a plasticizer, and methylcellulose (MC) ratios on WVP and mechanical properties of the whey protein films were investigated. Optimum properties of edible films were obtained by applying the complex method optimization algorithm to this multiobjective function problem, and glycerol to total polymer ratio (MC and whey protein concentrate [WPC]) of 0.356 and 0.45 was found for the films with MC : WPC ratios of 0.3 and 0.8, respectively. With respect to the results of this study, it might be concluded that optimum conditions for different edible film‐forming agents can be determined via the use of a good experimental design.     

Properties of Chitosan Films as a Function of pH and Solvent Type

ABSTRACT: Two different deacetylated chitosans were dissolved in formic, acetic, lactic, or propionic acid to prepare chitosan films. The pH values of the film-forming solutions were adjusted to 3, 4, and 5. Water vapor permeability (WVP), tensile strength (TS), elongation (E), and total soluble matter (TSM) were significantly ( P < 0.05) affected by acid type, pH, and degree of deacetylation (DA). Low DA (LDA) chitosan films had lower WVP and TSM, higher TS compared with high DA (HDA) chitosan films. The E values were not affected by DA. As pH increased, WVP and TSM of chitosan films tended to increase while TS decreased significantly ( P < 0.05). Chitosan films with acetic and propionic acid solvents had low WVP and TSM and high TS, while films with lactic acid solvent had high E and TSM and the lowest TS. Fourier-transform infrared showed peak shifting in the spectra with different solvents and at different pH values. Chitosan films with lactic acid solvent showed a peak shift to a lower frequency range. The NH₃⁺ band was absent in the pH 5.0 chitosan film spectra.     

Development and characterization of cassava starch and soy protein concentrate based edible films

The sensory attributes, mechanical, water vapour permeability (WVP) and solubility properties of cassava starch and soy protein concentrate (SPC)‐based edible films of varying levels of glycerol were studied. Addition of SPC and glycerol up to 30% and 20%, respectively, reduced stickiness and improved colour and appearance of the films. Tensile strength (TS), elastic modulus (EM) and elongation at break (EAB) of films increased, while film solubility (FS) and WVP decreased with SPC and glycerol up to 50% and 20% level, respectively, ranging from 20.33 to 26.94 MPa (TS), 41.33 to 72.76 MPa (EM), 7.90 to 12.28 MPa (EAB), 15.07 to 31.90% (FS) and 2.62 to 4.13 g H₂O mm m^?2 day kPa (WVP). The TS, EAB and WVP were higher for the biofilms than for low‐density polyethylene and cellophane films.