改性抗菌聚乙烯醇包装薄膜的性能研究

为了开发新型的食品抗菌包装薄膜,以聚乙烯醇(PVA)为基膜,添加季铵盐壳聚糖,茶多酚,丙酸钙/对羟基苯甲酸乙酯几种抗菌剂制备成改性抗菌PVA薄膜。研究结果表明,加入质量分数为2%季铵盐壳聚糖,0.5%茶多酚,1.5%丙酸钙/0.5%对羟基苯甲酸乙酯均不同程度减小了PVA薄膜的断裂伸长率;加入0.5%茶多酚减小了薄膜的抗拉强度,其他抗菌剂则增大了薄膜的抗拉强度;所有抗菌剂均增加了薄膜的摩擦系数、雾度,降低了其透光率;提高了薄膜的水蒸气透过系数、溶胀率和溶解率;改变了PVA薄膜的颜色;几种抗菌剂改性PVA薄膜均对金黄色葡萄球菌和大肠杆菌产生了较好的抑菌效果。经研究,改性后的PVA薄膜具有较好的包装和抑菌性能,是一种新型的功能型活性食品包装。     

Cu-PAN@G-CS/PVA制备及在虾肉鲜度检测中的应用

以1-(2-吡啶偶氮)-2-萘酚(1-(2-pyridylazo)-2-naphthol,PAN)合铜(Ⅱ)络合物(Cu-PAN)为H₂S指示剂,壳聚糖(chitosan,CS)/聚乙烯醇(polyvinyl alcohol,PVA)为膜基材料,石墨烯为增敏材料,采用流延法制备比色复合薄膜(Cu-PAN@G-CS/PVA),通过指示剂置换法,实现对虾肉中H₂S的检测。利用扫描电子显微镜和傅里叶红外光谱考察Cu-PAN@G-CS/PVA的形貌和官能团特征,通过紫外-可见吸收光谱考察鲜度膜对H₂S的响应性能。结果表明,随H₂S质量浓度增加,Cu-PAN@G-CS/PVA薄膜由紫红色变成黄色。利用Cu-PAN@G-CS/PVA薄膜监测明虾(Penaeus chinensis)在4℃和25℃贮藏的鲜度变化,色差变化值与总挥发性盐基氮含量有很好的相关性,可准确、快速指示虾肉的新鲜度,为水产品智能包装的开发提供参考。     

聚乙烯醇/壳聚糖/芒果皮提取物复合膜的制备与表征

为了探究芒果皮废弃物的高值化利用,采用微波工艺制备了芒果皮提取物（MPE）。壳聚糖（CS）使用冰醋酸（AAG）或柠檬酸（CA）溶解后,将MPE与聚乙烯醇（PVA）、CS共混,采用溶液浇铸法制备了PVA/CS/MPE复合膜。利用UV、FT-IR、SEM和TG对复合膜的结构、形貌和热性能进行表征分析,对复合膜的力学性能、耐水性、抗菌性、抗氧化性和降解性能进行了测定。实验结果表明:相比于普通搅拌提取（35 °C,500 r/min,4 h,产率13.86%）,微波工艺（35 °C,300 r/min,1 h）下MPE的产率提升至38.26%;复合薄膜各组分之间主要通过氢键作用结合,相容性较好,无明显的相分离;复合膜均表现出良好的抗菌活性和可降解性;CA体系的复合膜拉断伸长率较纯PVA膜提升近一倍,添加MPE后拉断伸长率更高;而MPE能显著改善AAG体系复合膜的耐水性,同时,MPE提高了复合膜的抗紫外、抗氧化能力。因此,所制备的PVA/CS/MPE复合薄膜在医药、食品包装等行业有着广泛的应用前景。     

常压等离子体退除PVA浆料机理探讨

通过常压等离子体处理进行PVA失重、PVA浆料在水中溶解率的变化、等离子体处理与常规H₂O₂退浆比较分析以及PVA薄膜的XPS和FT-IR分析,讨论常压等离子体对PVA作用的机理。结果表明,常压等离子体作用使部分PVA大分子氧化成小分子如CO₂、H₂O而直接消失在空气中,另一部分PVA大分子被氧化降解成分子链较短的分子,提高了其在水中的溶胀、溶解性。     

广西产铁皮石斛花提取物的细胞毒性及体外抗氧化活性研究

目的：探讨广西产铁皮石斛花不同提取物的细胞毒性及体外抗氧化活性。方法：以乙醇和水提取并通过冷冻和热风干燥获得铁皮石斛花提取物，测定提取物的总酚、总黄酮含量，以DPPH、 ABTS自由基清除率和FRAP总还原能力评价抗氧化活性并进行相关性分析；以MTT法测定提取物的细胞毒性；以丙二醛(MDA)含量、ABTS总抗氧化活性、过氧化氢酶(CAT)、谷胱甘肽过氧化氢酶(GSH-Px)和总超氧化物歧化酶(T-SOD)的活性水平评价提取物对H₂O₂诱导细胞氧化应激的保护作用。结果：乙醇提取物的总酚和总黄酮含量均高于水提取物，且抗氧化活性总体优于水提取物，冷冻干燥乙醇提取物(DEF)最优；总酚、总黄酮含量与抗氧化指标的相关系数均高于0.7；提取物在100～800μg/mL下对HepG2细胞毒性低；经H₂O₂诱导HepG2细胞的氧化应激后，提取物干预能降低MDA含量，提高ABTS、CAT、GSH-Px和T-SOD的活性水平。结论：铁皮石斛花乙醇提取物的总酚、总黄酮含量及抗氧化活性最优，细胞毒性低，可通过提高抗氧化活性...     

PVA/海藻酸钠/TiO2纳米纤维膜的制备及其抗菌性能

以聚乙烯醇(PVA)和海藻酸钠为二元聚合物基体,掺杂纳米TiO₂,利用静电纺丝技术制备了具有生物亲和性和抗菌性的纳米纤维复合膜。讨论了海藻酸钠和纳米TiO₂的加入对纺丝溶液性能的影响,并通过扫描电镜(SEM)、傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、热失重(TGA)等分析了纤维膜的微观结构、内部物质之间的相互作用和热学性能,最后对纳米纤维膜进行了抗菌测试。结果表明：海藻酸钠的加入使纤维的直径减小且分布更为集中;纳米TiO₂的加入使得纳米纤维膜获得了抗菌性能,在光照条件下对大肠埃希菌和金黄色葡萄球菌的24 h抗菌率都达到了90%以上。     

柠檬汁纳米银抗菌复合膜的制备工艺优化及性能研究

本研究以聚乙烯醇（PVA）和可溶性淀粉（SS）为原料,甘油为增塑剂,柠檬汁（LJ）为还原剂将硝酸银原位还原成纳米银（AgNPs）,制得抑菌性能良好的PVA-SS-LJ-AgNPs复合膜。经单因素及正交试验得出,最佳制膜工艺为PVA 3 g、SS 0.5 g、甘油3 g、LJ 7 mL、硝酸银130 mmol/L,最优工艺下,膜的抗拉伸强度、断裂伸长率、水蒸气透过系数、吸湿性、透光率分别为12.16 MPa、1111.59%、0.09 g/0.01 h·m2、12.56%、48.05%。通过对膜的物理性能和结构进行分析得出,柠檬汁可成功地将纳米银原位还原至保鲜膜中。与PVA-SS膜比较,柠檬汁和硝酸银的加入使复合膜的抗拉伸强度提高到11.51 MPa,断裂伸长率提升至1470.20%。与PVA-SS-LJ膜比较,AgNPs的加入使膜水蒸气透光系数和吸湿性得到有效平衡,纳米银颗粒均匀地分散于复合膜中,该复合膜的抑菌性能良好,对大肠杆菌、金黄色葡萄球菌、沙门氏菌、枯草芽孢杆菌、铜绿假单胞菌均具有较好的抑制效果。综上,PVA-SS-LJ-AgNPs复合膜符合当前食品包装材料新要求,有潜在的应用前景。     

负载小麦醇溶蛋白纳米银胶体颗粒的抗菌壳聚糖复合膜构建及表征

本研究采用浇筑法,成功构建了Ag NPs/小麦醇溶蛋白/壳聚糖复合抑菌膜,实现了Ag NPs的稳态化和协同增效。自组装的小麦醇溶蛋白(gliadin),同时充当AgNPs的螯合剂和稳定剂,有效抑制了纳米银颗粒(AgNPs)团聚。与其他复合膜相比,gliadin/Ag NPs复合膜透明度良好。SEM和EDS证实Ag NPs均匀分布于复合膜。此外,gliadin/AgNPs复合颗粒具有优异的缓释特性。人皮肤成纤维细胞评估结果表明复合膜具有更好的生物相容性,激光共聚焦显微镜(CLSM)显示gliadin/Ag NPs复合膜对大肠杆菌与金黄色葡萄球菌具有更强的抗菌效果。这些薄膜在抗菌食品包装材料、伤口敷料以及植入物的开发方面极具应用价值。     

聚乙烯醇/海藻酸钠/黄连素医用敷料制备及其性能

为提高聚乙烯醇(PVA)/海藻酸钠(SA)医用敷料的抗菌性和耐水性能,采用黄连素(BR)为天然抗菌剂负载在医用敷料上,通过静电纺丝法制备PVA/SA/BR纳米纤维膜,并在氯化钙无水乙醇溶液中进行交联处理,对PVA/SA/BR纳米纤维膜的化学结构、抗菌性能、吸液性能以及力学性能进行表征与分析。结果表明:BR负载在PVA/SA纳米纤维上形成明显串珠,且与PVA/SA结合良好,氯化钙交联处理后PVA/SA/BR纳米纤维膜由网状变为平滑膜状;当BR质量分数为6%时,PVA/SA/BR纳米纤维膜断裂强度为1.76 MPa,其对大肠杆菌和金黄色葡萄球菌的抑菌率分别为99.41%、97.89%;当氯化钙质量分数为4%,交联时间为4 h时,PVA/SA/BR纳米纤维膜的断裂强度为4.17 MPa,吸液倍率为1 257%。     

聚偏氟乙烯/FeCl3复合纤维膜柔性传感器的制备及其性能

为制备灵敏度高的柔性传感器,将六水合三氯化铁(FeCl₃·6H₂O)加入聚偏氟乙烯(PVDF)中,采用静电纺丝法制备PVDF/FeCl₃复合纤维膜并组装成传感器。借助扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、接触角分析仪等对纤维膜的形貌、结构、润湿性、力学性能及压电性能进行表征。结果表明:适量的FeCl₃·6H₂O 添加可增加纤维膜中β晶型的相对含量,进而有效提高传感器的压电输出性能,但过多FeCl₃·6H₂O会抑制β晶型的形成;当FeCl₃·6H₂O质量分数为0.5%时,纤维晶体结构中β晶型的比例达到最大值68.74%,最高输出电压达到约5 V;传感器对激振过程的反应时间可达0.025 s,且在不同激振频率下的响应时间基本一致,动态高频时具有较高的压电输出。     

Nano-TiO2 particles and high hydrostatic pressure treatment for improving functionality of polyvinyl alcohol and chitosan composite films and nano-TiO2 migration from film matrix in food simulants

This study investigated the impact of nano-TiO₂ and high hydrostatic pressure (HHP) treatment on microstructure, water vapor and gas barrier, antibacterial and mechanical properties of polyvinyl alcohol (PVA)–chitosan (CHI) biodegradable films and determined the migration behavior of TiO₂ nanoparticles from the films to food simulants. Apart from the effect of filler, TiO₂ nanoparticles also could improve the antibacterial activity of the films and play a role as a plasticizer in the films. HHP treatment promoted the interaction between PVA and chitosan molecules, resulting in the formation of more compacted network structures in PVA–CHI films. The migration of TiO₂ from the films was investigated in food simulants including distilled water, acetic acid, ethanol and olive oil, in which the trace amount of TiO₂ (< 4.20 × 10^− 3‰) was only detected in olive oil. HHP treatment at 200–400 MPa significantly reduced migration of TiO₂ nanoparticles from the films.Industrial relevanceResults from this study provide a new application direction of high hydrostatic pressure (HHP) in the field of food packaging materials for improving the functionality of materials. Due to the non-thermal characteristic, HHP in combination with nano-TiO₂ not only improved the mechanical and barrier properties of the biodegradable PVA–CHI composite films (polyvinyl alcohol and chitosan based materials), but also enhanced the antibacterial activity of the films. The HHP treated PVA–CHI–TiO₂ films are very stable in food simulants, such as olive oils. Therefore, the utilization of HHP and nano-TiO₂ is promising in the preparation of food packaging materials with desirable functionalities.     

Effect of Sorbitol Plasticizer on the Structure and Properties of Melt Processed Polyvinyl Alcohol Films

Poly (vinyl alcohol) (PVA) possesses wide applications as food packaging materials, but is difficult to melt process for its strong inter/intra hydrogen bonding. In this work, flexible PVA films with different content of sorbitol plasticizers were prepared by melt processing with the assistance of water. And the influence of sorbitol plasticizer content on the crystallinity, optical transparency, water‐retaining capability, mechanical properties, thermal stability and oxygen and water permeability were investigated. The results indicated that sorbitol dramatically improved the melt processing ability of PVA. Sorbitol could interact with PVA to form strong hydrogen bonding interactions, which would decrease the original hydrogen bonding of the matrix, resulting in the decrease of crystallinity degrees. The glass transition, melting and crystallization peak temperatures decreased with the increase of sorbitol. All the films exhibited fine optical transparency. The water retaining capability were improved with the increase of sorbitol. Especially, an increase in elongation at break and decrease in Young's modulus and tensile strength were observed indicating good plasticizing effect of sorbitol on PVA films. In addition, the PVA films prepared in this work exhibited fine barrier properties against oxygen and water, suggesting wide application potential as packaging materials.     

Development of cellulose-based bactericidal nanocomposites containing silver nanoparticles and their use as active food packaging

The use of nanomaterials, including metallic as active fillers in polymeric nanocomposites for food packaging has been extensively investigated. Silver nanoparticles (AgNPs), in particular, have been exploited for technological applications as bactericidal agents. In this paper, AgNPs were incorporated into a hydroxypropyl methylcellulose (HPMC) matrix for applications as food packaging materials. The average sizes of the silver nanoparticles were 41 nm and 100 nm, respectively. Mechanical analyses and water vapor barrier properties of the HPMC/AgNPs nanocomposites were analysed. The best results were observed for films containing smaller (41 nm) AgNPs. The antibacterial properties of HPMC/AgNPs thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The disk diffusion studies revealed a greater bactericidal effectiveness for nanocomposites films containing 41 nm Ag nanoparticles.     

Development of antimicrobial whey protein-based film containing silver nanoparticles biosynthesised by Aspergillus Niger

Applications of whey protein concentrate (WPC)-based films have been limited in the food industry due to their poor mechanical properties. This research aims to evaluate the effect of silver nanoparticles (AgNPs) synthesised by Aspergillus niger on the mechanical and antimicrobial properties of WPC-based films. The biosynthesised AgNPs solution was added into the WPC film formula at the concentration of 0, 0.25 and 1.25 mm . The film samples containing AgNPs inhibited the growth of Staphylococcus aureus, Escherichia coli O157:H7, Salmonella Enteritidis, Listeria monocytogenes, Williopsis saturnus or Aspergillus sydowii with zones of inhibition ranging from 13 to 19.7 mm. Incorporation of AgNPs improved tensile strength and water barrier properties of the films by 84% and 67%, respectively. However, per cent elongation at the break of the film decreased from 37% to 11% by the addition of 1.25 mm AgNPs. This work provides a protocol for preparing improved antimicrobial WPC films with AgNPs.     

Recent advances in biobased and biodegradable polymer nanocomposites,nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs—this is biosynthesized from plant extracts–showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.     

聚乙烯醇/纳米纤维素/石榴皮多酚复合抗菌薄膜性能研究

目的:开发绿色抗菌抗氧化食品包装薄膜。方法:以石榴皮多酚为功能活性物质,采用共混法制备聚乙烯醇/纳米纤维素晶体/石榴皮多酚复合抗菌薄膜,并对其性能进行表征。结果:石榴皮多酚的添加影响了薄膜表面的连续性;当石榴皮多酚添加量为5倍最小抑菌浓度时,薄膜的透水气性增加了28.79%,拉伸强度、断裂伸长率、疏水性及透光率分别降低了44.97%,29.37%,36.36%,22.35%,同时总酚含量为(5.92±0.17) mg/L,DPPH自由基清除率达到(13.31±0.22)%;薄膜表现出良好的抑菌性,对白色念珠菌的抑菌效果最好,其次为金黄色葡萄球菌、大肠杆菌。结论:聚乙烯醇/纳米纤维素晶体/石榴皮多酚复合抗菌薄膜是一种新型活性食品包装材料。     

纳米蒙脱土含量对聚乙烯醇基纳米复合膜包装性能的影响

以聚乙烯醇（polyvinyl alcohol,PVA）和纳米钠基蒙脱土（montmorillonite,MMT）为原料,通过溶液
插层-流延成膜法制备不同MMT含量（0、2.5%、5%、10%、15%、20%,以PVA干质量计）的PVA-MMT纳米复合
膜,研究纳米MMT含量对聚乙烯醇基纳米复合膜包装性能的影响。X射线衍射图谱及扫描电镜结果表明,低含量
（5%以下）MMT在纳米复合膜内分散均匀,形成剥离型纳米复合材料,其他含量则形成插层型的纳米复合材料,
PVA结晶形态受纳米材料含量的影响。纳米复合膜的包装性能受纳米MMT含量的影响,随着纳米MMT含量的升
高,PVA-MMT纳米复合膜的水蒸气阻隔性能（水蒸气透过率）和耐水性能（溶解质量损失率、溶胀率和吸湿率）
显著提高（P＜0.05）,而透光性能显著降低（P＜0.05）;在0～5% MMT含量范围内,纳米复合膜拉伸强度随着
纳米MMT含量的增加而提升,而纳米MMT含量高于5%之后,纳米复合膜拉伸强度低于纯PVA膜的拉伸强度,并
且加入纳米材料后,复合膜韧性降低。     

Active chitosan–polyvinyl alcohol films with natural extracts

Active films were prepared from chitosan (Ch) and polyvinyl alcohol (PVA) containing aqueous mint extract (ME)/pomegranate peel extract (PE). The effect of these extracts on the physical, mechanical, antimicrobial and antioxidant properties of the films were studied. Increased protection against UV light was observed in the films containing the extracts. Addition of ME/PE improved the tensile strength of the films without affecting their puncture strength. Ch–PVA films incorporated with PE had the highest tensile strength (41.07 ± 0.88 MPa). Permeability characteristics of the films were not altered due to addition of extracts. ME/PE conferred antioxidant properties to Ch–PVA films as determined by DPPH radical scavenging activity. The films also exhibited antibacterial activity against Staphylococcus aureus and Bacillus cereus. PE containing films totally inhibited the growth of B. cereus and reduced the number of S. aureus by 2 log cycles. These results suggest that Ch–PVA film containing ME/PE can be used for development of active food packaging materials.