明胶/普鲁兰酶改性淀粉膜的制备与性能研究

研究了普鲁兰酶对淀粉膜性能的影响及明胶对普鲁兰酶改性淀粉膜性能的影响。结果表明:与原淀粉膜相比,普鲁兰酶改性淀粉膜的表面更平滑;膜的热稳定性增大,热封性能增强;抗拉强度、水蒸气透过率和透光率分别增加了75%、18%和35%,断裂伸长率降低了53%。与未添加明胶的酶改性淀粉膜相比,添加明胶后,膜的表面变粗糙;膜的阻水性能与阻光性能增强,热封性能变差。当明胶添加量为10%时,膜的抗拉强度增加了17.6%;当明胶添加量为25%时,膜的断裂伸长率增加了54.3%;在明胶添加量为15%时,膜的热稳定性最大。     

柚皮纳米微晶纤维素的制备及其用于改进羧甲基淀粉膜性能的研究

以柚皮纤维素为原料,采用硫酸酸解法制备柚皮纳米微晶纤维素,对纳米微晶纤维素的形貌、结晶结构进行表征分析,以复合膜表面形貌、力学性能、水蒸气透过率和透光率为指标,研究不同添加量柚皮纳米微晶纤维素对羧甲基淀粉膜性能的影响。研究发现：柚皮纳米微晶纤维素为长度为60~180 nm,直径为3~15 nm的棒状晶体;X-射线衍射表明其仍为纤维素I型结构;复合膜电镜图光滑平整;纳米微晶纤维素添加量为5%时,复合膜的拉伸强度较原膜提高最大（52.22%）;而随着纳米微晶纤维素的添加,复合膜的断裂伸长率呈下降趋势;当添加量为7%时,复合膜水蒸气透过率降低最大（23%）;纳米微晶纤维素的添加量大于3%时显著降低复合膜的透光率,但未改变原膜在不同波长下的透光率。因此,添加柚皮纳米微晶纤维素能有效改善复合膜的性能,制备出综合性能优良的羧甲基淀粉复合膜。     

微晶纤维素对大豆分离蛋白可食性复合膜性能的影响

以大豆分离蛋白(SPI)为主要成膜基材,添加微晶纤维素(MCC),研究不同微晶纤维素质量分数对复合膜力学性能、表观性能和阻气性能的影响.通过差示扫描量热分析(DSC),研究大豆分离蛋白与微晶纤维素的相互作用.结果表明:微晶纤维素质量分数为30%～40%时,复合膜的力学性能较好;微晶纤维素质量分数为30%时,复合膜的阻气性能最佳.因此,微晶纤维素能够改善大豆分离蛋白膜的性能;当微晶纤维素质量分数为30%时,复合膜综合性能最佳.     

甘油与甲基纤维素对高直链玉米淀粉- 壳聚糖复合膜性能的影响

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,研究高直链玉米淀粉与壳聚糖的质量比,甘油的添加量以及甲基纤维素的添加量对复合膜物理性能的影响,包括抗拉强度(TS)、断裂伸长率(E)、水蒸气透过系数(WVP)和色度。结果表明,壳聚糖添加量的增大与甘油添加量的增加都使高直链玉米淀粉- 壳聚糖复合膜的抗拉强度降低,断裂伸长率和WVP 显著增大,膜颜色变黄;甲基纤维素的添加改善了复合膜的机械性能和WVP,随着甲基纤维素添加量的增加,复合膜的抗拉强度和断裂伸长率都随之增大,WVP 逐渐降低,且对膜的颜色没有显著影响。     

改性方式及马来酸酐添加量对淀粉/聚羟基脂肪酸酯复合膜性能的影响

以羟丙基交联木薯淀粉、聚羟基脂肪酸酯（polyhydroxyalkanoate,PHA）为成膜基材,马来酸酐（maleic anhydride,MAH）为增容剂,采用挤压吹塑法制备淀粉/PHA复合膜。马来酸酐通过两种不同方式加入淀粉/PHA 体系中,即淀粉、PHA与MAH直接共混挤出（直接添加处理）和PHA先与MAH干法改性,再与淀粉共混挤出（干 法改性处理）,且MAH的添加量分别为1%、3%和5%。研究改性方式及MAH添加量对膜性能的影响。结果表明： PHA质量分数为12%时,由直接添加处理1% MAH所成膜具有较高的抗拉强度和透光率,较好的阻水性、热稳定性 和相容性,且具有较为平滑均匀的微观结构;由干法改性处理5% MAH所成膜的断裂伸长率较高,膜表面较为平整 光滑。PHA质量分数为24%时,由直接添加处理3% MAH所成膜具有较高的抗拉强度,较好的阻水性、热稳定性, 且微观结构较为平滑均匀;由干法改性处理3% MAH所成膜具有较好的机械性能;由干法改性处理5% MAH所成 膜具有较高的透光率。傅里叶变换红外光谱表明MAH的添加能够增强各分子间的相互作用。综合膜的各项性能得 出,当PHA质量分数为12%时,由直接添加处理1% MAH所成膜具有较优的性能;当PHA为24%时,由直接添加处 理3% MAH所成膜的性能较优。     

脱脂棉纳米微晶纤维素的制备及其作为海藻酸盐-淀粉复合薄膜增强剂的应用

探究了纳米微晶纤维素对海藻酸盐-淀粉复合薄膜的增强效果。以脱脂棉为原料,采用化学预处理结合超声破碎法制备纳米微晶纤维素（NCC）;以马铃薯淀粉与海藻酸钠为成膜基材,以甘油为增塑剂,将NCC作为增强组分,通过流延法制备复合薄膜。微观形貌观察表明,脱脂棉NCC呈棒状,直径30 nm左右,长径比约为8;对复合膜的机械性能、阻隔性能、光学性能、水溶性、热稳定性和红外光谱检测表明,当NCC的添加量为5%（w/w）时,可以有效提高复合膜的拉伸强度、水溶时间和热稳定性,降低复合膜的透湿系数,而对复合膜的透光性影响不大。      

羧甲基纤维素强化胶原纤维膜的制备及其性能分析

基于静电相互作用（离子键、范德华力）的蛋白质-多糖聚合现象成为改良可食膜的重要手段。本实验以酸溶胀胶原纤维（正电性）为基料,研究带负电性的羧甲基纤维素（carboxymethyl cellulose,CMC）对胶原纤维膜性能的影响。结果表明：当CMC添加量（以胶原纤维质量计,下同）过多（大于10%）,成膜液发生絮凝甚至分层现象而不能成膜;随着CMC添加量（范围为0%～5.0%）的增加,成膜液ζ-电势显著下降,pH值无明显变化,复合膜表面越来越粗糙,膜厚度增加,透光率显著降低（P＜0.05）;复合膜拉伸强度和杨氏模量随CMC添加量增加而显著增加（P＜0.05）,而断裂延伸率显著降低（P＜0.05）;当CMC添加量达5.0%时,复合膜的水蒸气透过率达到（32.41±0.86）g/（m·s·Pa）,阻氧性与膜溶胀动力学性能显著提高（P＜0.05）;此外,热稳定性分析表明添加CMC能够提高复合膜热稳定性。由此可知,CMC能够通过静电相互作用促进与胶原纤维的结合,提高胶原纤维膜相关机械强度和阻隔性能,从而为可食膜性能提升提供了一种可行手段。     

改性甘蔗渣微晶纤维素特性及其对明胶膜性能的影响

该研究以甘蔗渣微晶纤维素为原料，制备了醚化微晶纤维素和乙酰化微晶纤维素，利用扫描电镜、X-射线衍射、傅里叶变换红外光谱及差示扫描量热分析了2种改性甘蔗渣微晶纤维素性质。同时以明胶为成膜基质，研究了2种改性甘蔗渣微晶纤维素对复合膜性能的影响，结合上述方法分析复合膜的结构及热稳定性。结果表明，甘蔗渣微晶纤维素改性后，形貌未发生明显变化，改性基团成功被接入，结晶度、熔融温度均有降低。明胶与甘蔗渣微晶纤维素、醚化微晶纤维素、乙酰化微晶纤维素的复合膜透水透气性及机械性能均低于明胶膜，乙酰化微晶纤维素的相关性能最好，3种微晶纤维素均与明胶有良好的相容性，结构致密，稳定性增强。     

鱼皮胶原纤维-淀粉复合膜的制备及性能研究

为明确鱼皮胶原纤维尺寸及其添加量对鱼皮胶原纤维-淀粉复合膜性能的影响,本研究利用醋酸预处理鱼皮(3、6、9、12 h)获得了不同尺寸的胶原纤维(CF3、CF6、CF9、CF12),考察了不同类型胶原纤维及其添加量对共混膜性能的影响。采用傅里叶红外光谱技术、差示扫描量热法及扫描电子显微镜对复合膜进行结构表征。结果表明:添加鱼皮胶原纤维后,复合膜的断裂伸长率和水蒸气透过系数均增加,溶解性降低;当CF3和CF6添加量分别为7.5%和10%时能增强复合膜的抗拉强度,而且以10% CF6制备的复合膜抗拉强度性能最好,添加CF9和CF12时,复合膜的抗拉强度呈降低现象。对添加10% CF6制备的复合膜和纯淀粉膜进行表征,发现胶原纤维与淀粉相容性良好,在成膜过程中,胶原纤维交错在淀粉膜中,两者之间形成了氢键,但复合膜的热稳定性下降。     

可食性狭鳕鱼皮明胶-褐藻胶复合膜的性质与结构表征

采用狭鳕鱼皮明胶与褐藻胶共混法制备可食性复合膜,以改善鱼皮明胶膜的性能。结果表明:狭鳕鱼皮明胶具有很好的成膜性,但是其力学性能和热稳定性较低,阻水性差。褐藻胶与鱼皮明胶混合后,二者相容性较好,复合膜的透光率达80%以上,力学性能增大,添加60%褐藻胶后,膜的抗拉强度和伸长率分别提高67.4%和112.6%,热变性温度提高8℃,水溶性和吸湿性都显著降低,说明复合膜的力学性能、热稳定性和阻水性都明显优于两种单一膜。红外光谱、X射线衍射和扫描电镜对其结构进行表征,表明两者通过化学结合生成了新的大分子化合物,得到稳定的复合膜。      

Structure and phase behaviour of microcrystalline cellulose in mixture with condensed systems of potato starch

It has been suggested that microcrystalline cellulose (MCC) can be used in biodegradable films to improve techno‐functionality by providing bulk and enhancing mechanical strength. This study aimed to investigate the effect of MCC addition on the structural properties of potato starch films. Samples were prepared by hot pressing at 120 °C for 7 min to produce systems that covered a broad range of moisture content and relative humidity. Complimentary experimental techniques, including thermomechanical analysis, FTIR, wide‐angle X‐ray diffraction and SEM, were employed to examine the micro‐ and macromolecular characteristics in these mixtures. Both moisture content and the presence of MCC have a plasticising effect on the composites yielding a reduction in its glass transition temperature. It appears that there is no specific and nontrivial interaction between potato starch and MCC, an outcome which indicates that the cellulose fibres act as inert filler in the polymeric composite.     

聚乳酸/乙酰化纳米纤维素薄膜制备及性能研究

为改善聚乳酸(PLA)薄膜的力学及阻隔性能,采用纳米纤维素(NCC)对其进行改性。以微晶纤维素(MCC)为原料,用硫酸法制备NCC,进而制备乙酰化纳米纤维素(ANCC),然后将PLA与ANCC按不同比例混合后制备复合薄膜。采用透射电子显微镜(TEM)、傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)对其微观结构和形态进行观测。采用拉伸仪和氧气透过率仪对其力学和气体阻隔性能进行分析。结果表明,使用酸法制备的纳米纤维素长度为100~200 nm,直径范围为10~20 nm。乙酰化处理对纳米纤维素的外观形态没有明显改变。与纯聚乳酸膜相比,ANCC添加量为1%时制备的复合薄膜的拉伸强度增加了29.09%,进一步增加ANCC含量则会导致复合薄膜力学性能下降。添加ANCC有效降低了复合薄膜的氧气透过量,ANCC添加量为0.5%时,薄膜的氧气透过率与纯PLA薄膜相比降低42%。添加ANCC对于薄膜的透光率和雾度没有明显影响。      

Conductive Polyaniline/Cellulose/Graphite Composite Films with High Thermal Stability and Antibacterial Activity

Functional composite films were successfully prepared from cellulose, graphite (GP), and polyaniline (PANI) using a combination of physical and chemical processes. Cellulose was dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO) and regenerated in water to form the matrix. GP was dispersed in the NMMO solvent prior to the dissolution of the cellulose, and PANI was deposited on the surfaces of the cellulose/GP films by in situ chemical polymerization. The structures of the PANI/cellusose/GP composite films were investigated using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and SEM/energy-dispersive X-ray spectroscopy. The mechanical strengths, thermal stabilities, conductivities, and antibacterial activities of the films were studied in detail. The results showed that GP formed a multilayered structure in the cellulose matrix and that the PANI nanoparticles were tightly wrapped on the film surface. The film thickness increased from 40 m to 100 m after the addition of GP and PANI. The tensile strength of the composite films was 80~107 MPa, with the elongation at break being 3%~10%. The final residual weight of the composite films was as high as 65%, and the conductivity of the composite films reached 14.36 S/m. The cellulose matrix ensured that the films were flexible and exhibited desirable mechanical properties, while the GP filler significantly improved the thermal stability of the films. The PANI coating acted as a protective layer during burning and provided good electrical conductivity and antibacterial activity against Escherichia coli; both of these characteristics were slightly enhanced by the incorporation of GP. These PANI/cellulose/GP composite films should be suitable for use in electronics, antistatic packing, and numerous other applications.     

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.     

淀粉醛强化大豆分离蛋白/槲皮素复合膜制备及性能研究

目的 探究淀粉醛(dialdehyde starch,DAS)对大豆分离蛋白(soy protein isolate,SPI)/槲皮素(quercetin,QR)复合膜特性的影响。方法 以青稞淀粉为原料,通过高碘酸钠氧化制备了DAS,以SPI为基质,以DAS和QR为添加物,以拉伸强度、水分阻隔性能、抗氧化性能为指标进行单因素试验,通过响应面优化试验筛选出DAS强化的SPI/QR复合膜最佳制备条件后,对复合膜的微观结构进行表征,并对其物理学性能进行测试。结果 DAS强化的SPI/QR复合膜最佳制备条件为每100 mL蒸馏水中添加SPI 6.00 g、pH为8、DAS 5%、QR 4%、DES 25%(DAS、QR、DES以SPI质量计)。在此条件下,薄膜的拉伸强度为(7.37±0.39) MPa、水蒸气透过系数为(3.54±0.29)×10^-11 g/(m·s·Pa)、抗氧化活性为(70.88±0.40)%。结构表征结果表明, DAS的添加使得该复合膜分子间形成了共价亚胺键,表面结构及横断面结构更加致密。此外,该复合膜具有较好的热稳定性、紫外阻隔性、疏水性。结论 D...     

食品胶对甘薯淀粉膜性能的响应面法优化实验

以机械性能(抗张强度、断裂拉伸应变)和透湿性为指标,研究食品胶对甘薯淀粉膜性能的优化。结果表明：羟丙基羧甲基纤维素(HPCMC)添加量为3.5～4.0g/100g 淀粉、甘油添加量小于2.0g/100g 淀粉及黄原胶添加量小于2.0g/100g 淀粉时,膜的机械性能较好;HPCMC 添加量小于2.0g/100g 淀粉、甘油添加量大于4.0g/100g 淀粉和黄原胶添加量小于1.5g/100g 淀粉时,膜的透湿性较小。由于不同性能的优化值范围不完全相同,在实际应用中可根据对不同性能的要求进行选择。     

Preparation and properties of starch nanocrystals/carboxymethyl chitosan nanocomposite films

Waxy maize starch was hydrolyzed with sulfuric acid in aqueous solution. The remaining starch granules after acid hydrolysis were characterized by TEM and wide‐angle XRD. Starch nanocrystals with size between 40 to 80 nm and relative crystallinity of 63% were obtained after 6 days of hydrolysis. Starch nanocrystals/carboxymethyl chitosan composite films were prepared by casting‐evaporation method. When the starch nanocrystals content was below 30 wt%, the filler dispersed uniformly in the carboxymethyl chitosan matrix, whereas aggregation of starch nanocrystals and phase separation between aggregates and matrix were observed when the starch nanocrystals content was higher than 30 wt%. The maximum tensile strength (TS) of composite films approached ∼29 MPa, which was two times higher than that of the carboxymethyl chitosan film without filling starch nanocrystals. The percentage elongation at break (EB%) of nanocomposite films decreased with the increasing of the starch nanocrystals content. The water absorption and water vapor barrier property of carboxymethyl chitosan film were significantly improved by adding starch nanocrystals.