壳聚糖/柠檬草精油复合膜的制备及性能研究

以壳聚糖为主要成膜材料,添加适量的柠檬草精油,制备可食性复合膜,测定了柠檬草精油对膜的理化性质和抗菌性能的影响。红外光谱谱图说明柠檬草精油与壳聚糖基质间发生相互作用。扫描电镜结果表明两者共混成膜时柠檬草精油均匀分散。添加柠檬草精油,降低了复合膜的透明度,却能有效提高其抗拉强度、水蒸气阻隔性能和抗菌活性。      

壳聚糖明胶可食用复合膜的制备与抗菌性能研究

以壳聚糖和明胶为复合膜骨架材料,通过加入0.3%(体积比)甘油增塑剂,制备具有显著抗菌性能的可食用复合膜。以较高的抗拉强度、较大的断裂伸长率、较低的水蒸气透过系数为主要性能指标,对成膜骨架材料壳聚糖和明胶的配比进行优化。研究结果表明,当壳聚糖浓度为1.5%、明胶浓度为1.25%时,以6∶4的体积比混合,制备获得机械性能良好(抗拉强度为13.24 MPa,断裂伸长率为112.45%),水蒸气透过系数较低(0.4032 mg·mm·kPa-1·h-1·m-2)的最优化复合膜。通过红外光谱、X射线衍射、扫描电镜等手段对复合膜进行表征。结果表明,与壳聚糖膜和明胶膜相比,复合膜的内部分子之间有较强的氢键和分子间作用力,膜内部致密且水蒸气不易通过,同时复合膜液对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌均具有显著的抑制效果。     

壳聚糖/纤维素硫酸钠复合膜性能的研究

为了研究以壳聚糖和纤维素硫酸钠(NaCS)为材料制备的聚电解质复合膜在药物控制释放上的应用,考察了壳聚糖相对分子质量、NaCS相对分子质量和取代度对该复合膜机械性能(强度、韧性等)和溶胀性能的影响。结果表明,壳聚糖相对分子质量、NaCS相对分子质量和取代度对壳聚糖/NaCS复合膜的机械性质和溶胀性能都有显著的影响。壳聚糖相对分子质量越高,该复合膜的断裂伸长率越大。而NaCS相对分子质量和取代度的增大则会导致该膜的溶胀率降低。此外,溶液pH值对壳聚糖/NaCS复合膜溶胀率也有明显的影响。     

季铵盐壳聚糖/聚乙烯醇复合膜的制备及性能研究

壳聚糖为天然多糖甲壳素脱除部分乙酰基的产物,因其独特的生理功能,能满足很多的应用要求。但由于其水溶性不是很好,在生理pH 6.0以下时溶解度较低,因此限制了壳聚糖在涂膜保鲜上的应用。该研究以季铵盐对壳聚糖进行修饰改性,通过傅里叶红外光谱、核磁氢谱、X-射线衍射对其结构进行表征,并探究不同取代度的季铵盐壳聚糖制备的涂膜的机械性能,最后以季铵盐壳聚糖为原料,采用溶液共混法制备7种不同体积比的季铵盐壳聚糖/聚乙烯醇复合膜,并通过傅里叶红外光谱、热重分析、扫描电镜、水蒸气透过率分析、机械性能测试对复合膜的结构、性能进行分析。得到最佳的复合膜制备体积比,此时复合膜的性能与单纯的聚乙烯醇膜和季铵盐壳聚糖膜相比表现出突出的优越性。复合膜拉伸强度为16.52 MPa,断裂延伸率为56.55%,结晶度为34.60%,水蒸气透过率为98.71 g/（m2·h）,涂膜的最大失重速率为83.20%,最大失重速率温度为347.21℃。该文为后续壳聚糖改性膜材料研究提供了一定的理论参考。     

柑橘皮/壳聚糖复合膜制备及性能研究

柑橘废弃物处理困难是限制柑橘加工业发展的重要因素。为了将柑橘果皮加工成生物基复合薄膜,并研究其结构和性能,先以脐橙皮、壳聚糖和甘油为原料,最大拉伸强度和断裂伸长率为响应值,通过响应面中心组合试验,制备力学性能较佳的脐橙皮/壳聚糖复合膜。再以优化后的配方制备马家柚皮复合膜、南丰蜜桔皮复合膜和纯壳聚糖膜,通过扫描电子显微镜和傅里叶变换红外光谱对壳聚糖膜和3种柑橘皮复合膜进行表征,并测定了薄膜的水蒸气渗透性、光阻隔性和抗氧化能力。响应面优化结果为壳聚糖含量1.10%,脐橙皮含量4.10%,甘油含量0.90%(均为质量分数)。优化后脐橙皮复合膜拉伸强度为(15.76±0.66) MPa,断裂伸长率为(19.23±1.52)%。表征结果显示柑橘皮均匀分散在薄膜结构中,与壳聚糖具有良好的混溶性,两者可能通过氢键进行结合。此外,柑橘皮复合膜在紫外光区和可见光区的光透射率均低于10%,在食品模拟物(体积分数为10%的乙醇溶液和95%乙醇溶液)中能够释放抗氧化物质。综上所述,柑橘皮与壳聚糖能够加工成具有一定力学性能、良好光阻隔性和抗氧化活性的生物基薄膜,为脐橙、南丰蜜桔和马家柚果皮资源化利用提供参考。     

稻壳微晶纤维素/壳聚糖复合膜的制备及表征

采用稻壳粉制备稻壳纤维素和微晶纤维素,并按不同添加比例将其与壳聚糖混和,制得稻壳微晶纤维素/壳聚糖复合膜。考察了不同复合膜的厚度、吸光度、色值和机械性能,并采用红外光谱和扫描电子显微镜进行表征。结果表明：稻壳微晶纤维素添加比例的增加导致复合膜的厚度增加、吸光度减小。当稻壳微晶纤维素/壳聚糖质量比为1.0∶1时,复合膜拉伸强度为6.23 MPa,断裂伸长率为51.49%。复合膜为稻壳微晶纤维素/壳聚糖的共混体系,稻壳微晶纤维素均一嵌入在壳聚糖膜结构中。该研究可为稻壳资源高值化利用和开发新型食品包装材料提供新思路。     

花椒精油/壳聚糖复合膜的制备及其在猪肉冷藏保鲜中的应用

为开发具有优良保鲜效果的复合膜,以壳聚糖(chitosan,CS)为成膜基材,花椒精油(Zanthoxylum essential oil,ZEO)为抑菌剂,制备花椒精油-壳聚糖复合膜(ZEO/CS),探究不同ZEO添加量对复合膜物理性能、结构及猪肉冷藏保鲜效果的影响。结果表明,随着ZEO添加量的增加,复合膜的厚度、总色差逐渐增大,而其透光率、含水率、溶胀性、水溶性、水蒸气透过率、拉伸强度、断裂伸长率显著下降(P<0.05)。扫描电子显微镜(scanning electron microscopy,SEM)结果表明复合膜表面变得不均匀并且会出现乳状现象,热重分析(thermogravimetric analysis,TGA)和差示扫描量热法(differential scanning calorimetry,DSC)表明复合膜的热稳定性下降。将不同ZEO添加量复合膜处理的猪肉在4℃冰箱贮藏8 d,与壳聚糖膜相比,复合膜的感官得分更高,能很好地保持猪肉的色泽和气味,并且能延缓贮藏期间猪肉pH值、硫代巴比妥酸(thiobarbituric acid,TBA)值、高铁肌红蛋白含量(me...     

紫苏精油壳聚糖复合膜的制备及其对鲜切雪莲果的保鲜效果研究

以壳聚糖为基底液,加入紫苏精油等物质,利用溶液共混法制成可食性复合膜。研究紫苏精油添加量对复合膜性能的影响,并比较各复合膜对鲜切雪莲果的保鲜效果。结果表明：随着紫苏精油添加量的增加,复合膜的厚度、不透明度增加,水蒸气透过率、吸水率减小,复合膜的拉伸强度、断裂伸长率、水溶性先增大后减小,O₂透过率、CO₂透过率先减小后增加。紫苏精油壳聚糖复合膜可维持雪莲果较好的感官品质,延长其货架期。     

壳聚糖/纳米蒙脱土复合膜的制备及性能研究

以插层复合法制备壳聚糖/纳米蒙脱土复合膜,测试其机械性能、水蒸气透过率和阻氧性能,同时通过扫描电子显微镜表征其结构。结果表明,添加蒙脱土可提高壳聚糖膜的机械性能与阻氧性,降低水蒸气透过率,应用于枇杷保鲜时,能有效降低果实的腐败程度和VC等成分的损失,对枇杷保鲜效果显著。      

离子液体/壳聚糖复合膜的制备及性能研究

通过溶液蒸发铸膜法制备壳聚糖膜及离子液体/壳聚糖复合膜.利用傅里叶红外光谱仪、原子力扫描探针显微镜和动态热机械分析等测试手段分析了样品的结构、形貌和动态力学性能.结果表明,壳聚糖中加入离子液体形成复合膜,离子液体加入壳聚糖不仅是简单的物理混合,两者之间有氢键等作用力存在;离子液体对壳聚糖膜结晶形貌有较大影响,纯壳聚糖膜结晶为细长针状,且分散均匀,样品表面比较平整;加入离子液体后,呈球形颗粒状,且随着其加入量的增多,颗粒尺寸呈先增大后减小的趋势.当加入量为20%时,颗粒尺寸最大,表面粗糙度达267.74 nm;复合膜的储能模量达到最大,约是纯壳聚糖膜储能模量的1.5倍;但离子液体的加入并未明显改变其玻璃化转变温度.     

Characterization and efficacy of a composite coating containing chitosan and lemongrass essential oil on postharvest quality of guava

This study characterized chemical and physical properties of chitosan (Chi) coatings with or without Cymbopogon citratus (D.C.) Stapf. (CCEO) essential oil (0.6 μL/mL). The effects of Chi-CCEO coating on postharvest quality of guava during storage (15 days, 12 ± 1 °C) were assessed. CCEO improved thermal resistance and surface properties of Chi-coating. Chi-CCEO coating had low water solubility and a_w, high thermal resistance, smooth and low-roughness surface. Chi-CCEO coating delayed weight and firmness losses, changes in soluble solids, titratable acidity, pH, color and phenolics in guava during storage. Chi-CCEO coating decreased polyphenol-oxidase and pectin-methylesterase activity, while increased peroxidase activity after 5 days. Coated guava had lower fructose content and higher citric and succinic acid content than uncoated guava after 10 days. Coated guava had higher scores for texture, color and overall impression but lower scores for odor. Chi-CCEO coating were effective to maintain guava postharvest quality during a 10 day-cold storage.Industrial relevanceThe addition of CCEO in an active concentration to inhibit fungal spoilage in guavas into Chi-coating positively affected its physico-chemical properties, resulting in a flat, smooth and low roughness composite coating. Chi-CCEO coating delayed undesirable postharvest changes caused by physiological processes in guava, maintaining the fruit quality during cold storage. Chi-CCEO coating should be a feasible technology for guava preservation and decrease synthetic fungicide use in this fruit.     

壳聚糖/纳米蒙脱土复合膜的制备及性能研究

以插层复合法制备壳聚糖/纳米蒙脱土复合膜,测试其机械性能、水蒸气透过率和阻氧性能,同时通过扫描电子显微镜表征其结构。结果表明,添加蒙脱土可提高壳聚糖膜的机械性能与阻氧性,降低水蒸气透过率,应用于枇杷保鲜时,能有效降低果实的腐败程度和VC等成分的损失,对枇杷保鲜效果显著。     

Effect of HLB value on the properties of chitosan/zein/lemon essential oil film-forming emulsion and composite film

The properties of film-forming emulsion with emulsifiers of different hydrophilic–lipophilic balance were evaluated, and the performance of chitosan/zein composite film containing lemon essential oil was examined. The retention ratio of lemon essential oil in the film and the release of lemon essential oil from film to food simulation system were also quantitatively analysed. Results showed that the emulsifier with higher hydrophilic–lipophilic balance would make lemon essential oil disperse evenly in the film-forming emulsion, leading to smaller particle size and a lower viscosity of emulsion. Compared with C/Z/L, with the increasing hydrophilic–lipophilic balance value of emulsifier, the tensile strength and water contact angle of films decreased to 28.06 MPa and 23.39°, respectively. Emulsifier with high hydrophilic–lipophilic balance value could effectively increase the initial retention ratio of essential oils in the film, and the maximum initial retention rate of the C/Z/L-15 film was 79.12%. The release of lemon essential oil in each treatment increased rapidly at first and then it slowed down. C/Z/L-15 had the highest retention rate after 12 days, and C/Z/L-11 had the best sustained release effect when lemon essential oil was released into the food simulant.     

Quality changes of sea bass slices wrapped with gelatin film incorporated with lemongrass essential oil

Microbiological, chemical and physical changes of sea bass slices wrapped with gelatin film incorporated with 25% (w/w) lemongrass essential oil (LEO) during storage of 12 days at 4 °C were investigated. Sea bass slices wrapped with LEO film had the retarded growth of lactic acid bacteria (LAB), psychrophilic bacteria and spoilage microorganisms including H?S-producing bacteria and Enterobacteriaceae throughout storage of 12 days in comparison with the control and those wrapped with gelatin film without LEO (G film) (P<0.05). Lowered changes of colour, K value, total volatile base nitrogen (TVB) and TBARS value were also found in LEO film wrapped samples, compared with those wrapped with G film and control, respectively. Therefore, the incorporation of LEO into gelatin film could enhance the antimicrobial and antioxidative properties of the film, thereby maintaining the qualities and extending the shelf-life of the sea bass slices stored at refrigerated temperature.     

Preparation and application of a flaxseed meal protein film containing lemongrass (Cymbopogon citratus) oil

Flaxseed meal protein (FMP) films were prepared, and their mechanical properties (tensile strength (TS) and elongation at break (E) values), water vapour permeability, optical properties and thermogravimetric analysis were evaluated. Briefly, 5 g FMP, 2 g fructose and 0.03 g ferulic acid were required for the optimal preparation of an FMP film. The TS and E values of the FMP film were 13.12 MPa and 61.90%, respectively. Furthermore, different amounts of lemongrass oil (LE) were incorporated into the FMP film to prepare an antimicrobial film. Wrapping pen shell adductor muscle with the FMP film containing 1.0% LE reduced the counts of inoculated Listeria monocytogenes and Escherichia coli O157:H7 compared with those in the control, after storage at 4 °C for 12 day. Consequently, packaging with FMP film containing 1.0% LE can be useful in improving the quality of pen shell adductor muscle during storage.     

北五味子提取物/壳聚糖复合膜的制备及其在肉丸贮藏中的应用

目的 改善纯壳聚糖可食用膜存在的溶胀度高、抗氧化活性不足等缺陷, 使用共混改性的方式提升膜的性能。方法 以壳聚糖为成膜基质, 甘油为增塑剂, 添加北五味子提取物, 采用流延法制备可食用复合膜。研究北五味子提取物的添加量对复合膜的结构特征、物理性能、抗氧化和抑菌活性的影响, 通过傅里叶红外光谱、X-射线衍射、扫描电镜等对复合膜的性能进行表征, 并对经涂膜处理的肉丸进行贮藏实验。结果 北五味子提取物与壳聚糖混合后能保留原有结构, 复合膜的抗氧化活性、阻湿性、阻光性与机械性能得到明显提升。与对照组相比, 在最优添加量时, 复合膜的1,1-二苯基-2-三硝基苯肼自由基清除活性明显提高, 在50%乙醇溶剂中表现最好; 水蒸气透过系数降低了60.20%; 不透明度与北五味子提取物添加量呈正相关; 拉伸强度由7.38 MPa提升至9.92 MPa。将复合膜应用在肉丸贮藏中, 经涂膜处理的肉丸挥发性盐基氮值和菌落总数皆低于对照组, 表现出较好的微生物抑制作用, 肉丸保质期最长可达15 d。结论 北五味子提取物的添加改善了复合膜的性能, 抑菌效果得到提升, 本研究可为壳聚糖基膜的制备及其在肉制品上的应用提供一定数据参考。     

A novel active bionanocomposite film incorporating rosemary essential oil and nanoclay into chitosan

Montmorillonite (MMT) nanoclay and rosemary essential oil (REO) were incorporated into chitosan film to improve its physical and mechanical properties as well as antimicrobial and antioxidant behavior. The MMT weight percent relative to chitosan was varied from 1 to 5 and was activated by three REO levels (0.5%, 1%, and 1.5% v/v), and their impact on physical, mechanical, and barrier properties of the chitosan films was investigated. Total phenolic and antimicrobial activity were also evaluated. Microstructure of chitosan/MMT–REO nanocomposites was characterized through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that incorporating MMT and REO into chitosan improves water gain, water vapor permeability, and solubility of the chitosan film by more than 50%. It was also shown that the combined effect of clay and REO improves significantly the tensile strength and elongation of chitosan (p < 0.05). The XRD and FTIR results confirmed that the improvements are related to the MMT exfoliation and good interaction between chitosan and MMT in the presence of REO. Antimicrobial properties of the films also improved by REO incorporation in 1.5% v/v.     

Improvement of active chitosan film properties with rosemary essential oil for food packaging

Rosemary essential oil (REO) was used to develop an active film from chitosan. The effects of REO concentration (0.5, 1.0 and 1.5% v/v) on film properties were studied by measuring the physical, mechanical and optical properties of the REO‐loaded films. Scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy were used to study microstructure and the interaction of the chitosan‐based films. The solubility and water gain of the chitosan film decreased about 25% and 85%, respectively, by REO incorporation, up to 1.5% v/v, because of the interaction between hydrophilic groups of chitosan and REO as confirmed by FTIR. It was determined that REO improved the transparency of the films from 4.97 in neat chitosan up to 7.61; moreover, it reduced the films’ light transmission in UV light more than 25%. Films containing REO showed more antibacterial activity and total phenol content. The films containing REO showed potential to be used as active film in food preservation.     

ZnO／壳聚糖复合材料的制备与表征

通过在壳聚糖(CS)溶液里掺入乙酸锌制备了Zn~(2 )/CS复合膜,并采用化学溶液沉积法在Zn~(2 )/CS复合膜上生长了氧化锌(ZnO).通过FYIR,XRD,AFM和SEM表征对样品进行分析研究,结果表明,在化学溶液环境中,Zn~(2 )/CS复合膜的表面首先形成了一层ZnO纳米粒子膜,然后部分ZnO纳米粒子长大成长度为0.5～2μm的ZnO纳米棒,具有六角纤锌矿结构,但没有明显的择优取向.ZnO纳米棒和Zn~(2 )/CS复合膜的表面呈一定的角度.复合膜中Zn~(2 )的量越大,ZnO越容易生长在Zn~(2 )/CS复合膜上,Zn~(2 )/CS复合膜表面的ZnO纳米粒子和膜中的Zn~(2 )之间相互作用越强烈.