明胶/淀粉复合膜的界面相容性

采用溶液共混法制备了明胶/淀粉复合膜,探索不同增塑剂对明胶/淀粉复合膜界面相容性的影响。通过紫外可见分光光度计、差示扫描量热分析仪、红外光谱分析仪和扫描电镜,研究了水、甘油、聚乙二醇(polyethylene glycol,PEG)作为增塑剂对明胶/淀粉复合膜界面相容性的影响,采用拉力试验机和透湿性测试仪对其机械性能和水蒸气透过性进行测定。结果表明:甘油和PEG可以显著提高复合膜的透光率和玻璃化转变温度,提高复合膜的拉伸强度,改善其断裂伸长率,但同时也造成其透湿性增加。红外光谱和扫描电镜表明以上原因可能是因为甘油和PEG不仅可以作为增塑剂,还可以作为界面相容剂,改善了明胶/淀粉复合膜的界面,使其相容性更好;相比于甘油,聚乙二醇的效果更佳。     

明胶/L-聚乳酸共混膜的制备与性能表征

L-聚乳酸(PLLA)和明胶共混改性后成膜,分析了共混膜的热性能、力学性能、形貌和亲水性。试验结果表明:明胶与PLLA共混对PLLA的热性能影响较小;当共混膜中明胶质量分数<20%时,可使共混膜保持较好的力学性能;加入甘油可降低共混膜的Tg,并提高其断裂伸长率,起到了一定的增塑作用;聚乳酸与明胶共混后可增加聚乳酸膜的亲水性并降低明胶膜的亲水性,明胶/PLLA共混膜为疏松多孔的结构。     

可食性壳聚糖膜性能的研究

本文研究了壳聚糖膜的制备及对壳聚糖膜进行抗张强度、透湿率、透气系数和吸湿性能的测试。结果表明,1.5%的壳聚糖浓度成膜浓度较适宜; 壳聚糖膜用中温干燥(55℃)时的机械性能相对较佳,并且低温下成的膜较高温下成的膜相对较透明、柔软,高温下成的膜略有淡黄色;随膜厚的增加,膜的透湿率增大;适量的增塑剂可以改善膜的性能,随着甘油浓度的增加,膜的透湿率、透气系数也随之增加,膜的透气系数还随成膜温度的升高而增大。     

脂肪酸脂的加入对淀粉-明胶膜物理性能和稳定性影响

使用甘油(30%)作为增塑剂,获得含25%和50%(在聚合共混物中)的牛皮胶原木薯淀粉膜,也获得了含15%脂质物(脂肪酸甘油酯混合物)的膜配方。为了将共混物膜与纯淀粉或明胶膜进行比较,分析了微观结构和物理性能(光学、阻隔和力学)。明胶和脂质物加入到木薯淀粉膜中明显地影响它们的物理性能,它们表现出了聚合物相和脂质物分散相。明胶的加入使膜更硬,具有更好抗破损性和更强延展性,而脂质物则降低了膜的硬度和抗性,但是提高了可延展性,尤其是当膜的明胶含量为50%时。而且,脂质物改善了膜的水阻隔性能,但是同时降低了膜的光泽度、透明度以及氧渗透性。在5周的贮存后,所有的膜变得更硬、更抗破,特别是那些不含脂质物的膜,在贮存过程中提高了延展性。不论包不包含脂质物,含50%明胶的木薯淀粉膜由于食品涂层或包装均表现出理想性能。     

增塑剂对甘薯淀粉膜机械及渗透性能的影响

鉴于塑料食品包装带来的严重环境问题,研究可食、可降解的包装薄膜非常必要.本文以抗张强度、断裂伸长率、透湿性和透氧性为指标,研究增塑剂对甘薯淀粉膜性能的影响.结果表明,甘油和山梨醇的增塑效果优于聚乙二醇和蔗糖,使膜的断裂伸长率和透湿性更大,透氧性更小.甘油(浓度>5g/100g淀粉)可以显著降低甘薯淀粉膜的抗张强度,较高浓度甘油(浓度>10g/100g淀粉)可以显著改善甘薯淀粉膜的断裂伸长率.甘油的添加使甘薯淀粉膜的透湿性增加.较低浓度甘油(浓度≤7g/100g淀粉)的添加降低甘薯淀粉膜的透氧性,高浓度甘油(浓度>10g/100g淀粉)又使透氧性有所增加,但总体上用甘油增塑的淀粉膜的透氧性均比未增塑的对照膜的透氧性小.     

可食性壳聚糖-淀粉复合膜的研究

本文研究了壳聚糖分别与土豆淀粉、木薯淀粉、玉米淀粉按不同比例复合成膜并研究复合膜的特性,包括透明度、抗张强度、延伸率、水溶性、透湿系数等。结果表明,壳聚糖—玉米淀粉复合膜的透明度较差;随着复合膜中壳聚糖量的增加,膜的抗张强度增强,同时淀粉的种类对膜的抗张强度和延伸率的影响不大;复合膜的透湿系数随壳聚糖含量增加的而增大;随着淀粉含量的增大,复合膜的水溶解度增大。     

肉桂精油抗菌膜的制备及应用

采用肉桂精油、木薯淀粉和壳聚糖为复合膜配方,以抗拉强度、断裂伸长率和水蒸气透过系数为指标,通过正交试验确定复合膜的最佳配方;其次进行肉桂精油最小抑菌浓度试验,最后对确定的配方复合膜进行表征测定,并以红提为原料,进行涂膜保鲜试验。结果表明:当木薯淀粉与壳聚糖的质量比为7︰5,甘油量为30%,热处理温度为50℃,苹果酸量为1.25%时,复合涂膜配方性能最好。肉桂精油最小抑菌浓度为0.68 mL/100 mL,将其添加入膜。感官评价结果表明复合膜对红提具有一定保水、抗菌作用。     

壳聚糖、纳米壳聚糖对聚乙烯醇膜结构与性能的影响

研究添加同一质量分数壳聚糖(chitosan,CS)、纳米壳聚糖(chitosan nanoparticles,NCS)改性聚乙烯醇(polyvinyl alcohol,PVA)膜的性能,利用色差仪与紫外分光光度计探究其光学性能;利用透气性测试仪与透湿性测试仪测试共混膜透气性能与透湿性能;通过等温吸湿实验研究了PVA膜、PVA/CS共混膜、PVA/NCS共混膜的吸湿性能,并将常见的等温吸湿曲线模型与实验数据进行拟合;采用傅里叶变换红外光谱(Fourier transform infrared spectrometer,FT-IR)、差示扫描量热(differential scanning calorimetry,DSC)仪对3种膜的结构与结晶度进行表征。结果表明:CS的加入会使PVA膜对中波紫外线的屏蔽作用增强,NCS的加入会使屏蔽效果更加明显;CS或NCS的加入会使PVA透气性能减弱,透湿性能增强;3种共混膜的等温吸湿曲线与GAB方程的拟合效果最好(R~20.98);FT-IR结果表明,PVA/CS、PVA/NCS共混均匀且共混材料之间形成分子间氢键;DSC结果表明,加入CS或NCS之后PVA分子的结晶速率变慢,结晶度下降,分子结晶的吸热焓值增加。     

抗菌木薯淀粉可食膜的研究

以抗菌性、抗张强度、断裂拉伸应变和透湿性为指标,研究了大蒜油添加对木薯淀粉膜性能的影响。结果表明:大蒜油的融入对木薯淀粉膜的抗菌性能有大的提高。含1.5%大蒜油的木薯淀粉膜对大肠杆菌和金黄色葡萄球菌的抑菌面积分别为171.96mm2和84.07mm2。大蒜油的添加使木薯淀粉膜的抗张强度降低而断裂伸长率增加。含1.5%大蒜油的木薯淀粉膜与对照膜相比,抗张强度下降了56.62%,断裂伸长率升高了84.12%。     

木薯淀粉/壳聚糖可食性复合膜对鲜切菠萝蜜的保鲜研究

主要研究不同的被膜对鲜切菠萝蜜的保鲜效果。分别用壳聚糖、木薯淀粉制成不同的涂膜液对鲜切菠萝蜜进行涂膜处理。在3℃±1℃的条件下贮藏，涂膜后的鲜切菠萝蜜可溶性固形物、总糖、淀粉、总酸、VC的变化均小于对照组，抗菌性能优于对照组。对鲜切菠萝蜜的保鲜作用就不同的膜成分而言，壳聚糖膜的保鲜效果最佳，木薯淀粉-壳聚糖复合膜的保鲜效果优于木薯淀粉膜。     

Stability, solubility, mechanical and barrier properties of cassava starch - Carnauba wax edible coatings to preserve fresh-cut apples

This work aimed at evaluating edible coatings/films formulated with cassava starch, glycerol, carnauba wax and stearic acid, analyzing the stability of emulsion (creaming index and lipid particle size), the barrier properties of coatings applied in fresh-cut apples (respiration rate and water vapor resistance), the solubility and mechanical properties of films prepared with coating solutions. A central composite rotatable design 2³ was used to select optimized formulation. Independent variables used were: cassava starch concentration (2-4% w/w), glycerol content (1-3% w/w) and carnauba wax: stearic acid ratio (0.0:0.0-0.4:0.6% w/w). The creaming index and the lipid particle size of emulsified coatings were strongly affected by the carnauba wax: fatty acid ratio. Glycerol content was the variable that most influenced the respiration rate of coated apple slices, water vapor resistance of coatings and the elastic modulus of films. The water solubility was positively affected by the cassava starch and glycerol contents. Models and response surfaces were obtained for the respiration rate, water vapor resistance of coatings, elastic modulus and solubility of films. According to statistical analysis results, the optimized conditions corresponded to 3.0 g of cassava starch/100 g of coating solution, 1.5 g of glycerol/100 g of coating solution, 0.2:0.8 g of carnauba wax: stearic acid ratio/100 g of coating solution. The models obtained in the experimental design were predictive, which was evidenced by the relative deviations below 10% in validation procedure.     

Constrained mixture design applied to the development of cassava starch-chitosan blown films

Films composed of cassava starch, chitosan and glycerol were produced by blown extrusion and employing a design for constrained surfaces and mixtures. The effects of the components of the mixture on the mechanical properties, water vapor permeability (WVP) and opacity of the films were studied. According to the models generated by the design, the concentration of starch had a positive effect in all properties. The plasticizer glycerol and its interactions with other components had a positive effect on increasing the WVP. The presence of a higher relative concentration of chitosan favored the formation of more rigid and opaque and less permeable films. In general, the concentrations of starch, chitosan and glycerol led to changes in the film properties, potentially affecting their performance. The design for constrained surfaces and mixtures proved to be a useful tool for this type of study due to the complexity of the conditions of film formation.     

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...     

Selection of an Edible Starch Coating for Minimally Processed Strawberry

Edible coatings can represent an alternative for extending post-harvest life of perishable fruits, as strawberries. In this work, the effect of cassava starch edible coatings, added or not of potassium sorbate, on mechanical properties, surface color, sensory acceptance, and respiration rate of strawberries was evaluated in order to choose the best coating conditions to minimally processed strawberries. Integrity and water-vapor resistance of the coatings were also evaluated. Three different concentrations of cassava starch (1%, 2%, and 3%) and two concentrations of potassium sorbate (0.05% and 0.10%) were used in the coatings formulations. Minimally processed strawberries without coating were used as control samples. The strawberries treated with different coatings and control fruits did not present differences regarding mechanical properties, surface color, and all the sensory attributes evaluated. A good integrity of cassava edible coatings on strawberries surface was observed for 2% and 3% starch concentration and the use of coatings, in these concentrations, reduced the strawberries respiration rate, representing a possibility to extend the shelf life of fruits. All coatings showed beneficial effects on increasing the water vapor resistance of the samples, but a significant increase was obtained only with the use of coating with 3% of starch. The potassium sorbate improved significantly the resistance to water vapor, but no differences were observed between the two concentrations studied. Based these results, the coatings with 3% of cassava starch and 3% of cassava starch +0.05% of potassium sorbate were those selected for future shelf life study of minimally processed strawberries.     

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。     

Properties of wheat starch film-forming dispersions and films as affected by chitosan addition

In order to evaluate the impact of chitosan on the physical properties of wheat starch–glycerol films, part of the wheat starch was replaced by chitosan, and the effect of composition on the properties of both the films and the film-forming dispersions was studied. The latter became more stable and viscous as the chitosan proportion was increased in the mixture. Both polymers appeared to integrate homogeneously in the film matrix. The combined effect of the glycerol and chitosan proportions affected the mechanical and barrier properties of the films. The tensile strength and elastic modulus of the films were improved as chitosan ratio increased. The oxygen and water vapor permeability slightly increased in line with the amount of chitosan in the blend although the induced differences were very small. Chitosan ratio directly affected the antimicrobial properties of the films, which showed a significant bactericide activity when the chitosan–starch ratio in the film was 50%. Nevertheless, at a starch:chitosan ratio of 80:20, counts of coliforms did not exceed the initial value in the meat after 7 storage days.     

Antimicrobial activity and physical properties of chitosan–tapioca starch based edible films and coatings

Antimicrobial activity of edible coating solutions based on chitosan and blends of chitosan–tapioca starch with or without potassium sorbate (KS) addition was studied. The agar well diffusion assay showed an antagonist effect on the efficiency of chitosan against Lactobacillus spp. when KS and/or tapioca starch were present. A salmon slice coating assay showed that the chitosan solution was the best coating since aerobic mesophilic and psychrophilic cell counts were reduced, pH and weight loss remained acceptable throughout refrigerated storage, extending global quality to 6-days. Chitosan–tapioca starch based films reduced Zygosaccharomyces bailii external spoilage in a semisolid product but were not effective against Lactobacillus spp. The results suggest that antibacterial action depended on the application technique, due to the fact that chitosan is more available in a coating solution than in a film matrix. Interactions between chitosan–starch and/or KS could affect film physical properties and the antimicrobial activity of chitosan. The addition of chitosan reduced water vapor permeability and solubility of starch films.     

Sucrose and inverted sugar as plasticizer. Effect on cassava starch–gelatin film mechanical properties,hydrophilicity and water activity

The effect of sucrose and inverted sugar as plasticisers on mechanical properties, hydrophilicity and water activity of cassava starch films has been studied. Other additives (gelatin, soybean oil, sodium phosphate and propylene glycol) and pH effect have also been investigated, using the same parameters. Sucrose addition resulted in the highest effect observed on cassava starch films elongation at break, however inverted sugar also had a great effect on this property. The addition of plasticiser and acidic pH increased film water absorption kinesis, while cassava starch concentration had the opposite effect.     

可食性复合涂膜对芒果货架期生理品质的影响

以壳聚糖和可食性淀粉为成膜剂,添加有机酸等亲水性助剂,配制3种可食性复合膜(M1、M2和M3),研究(20±0.5)℃条件货架期内不同可食性复合涂膜处理(以蒸馏水浸泡做空白对照)对芒果转黄率、转色指数、腐烂率、呼吸强度、硬度、质量损失率、可溶性固形物含量(soluble solid content,SSC)、维生素C(VC)和多酚氧化酶(polyphenol oxidase,PPO)活性等生理指标的影响。结果表明：芒果货架期期间,涂膜处理可以有效地抑制果实转黄和腐烂,推迟果实呼吸高峰的到来,显著降低芒果果实的转色指数和软化程度,提高果实硬度。同时,M3处理还可较好地保持果实的质地,有效减缓果实SSC上升的速度和幅度,维持果实较高的VC含量,但对果实PPO活性的抑制与其他涂膜处理间差异不显著。研究表明,涂膜处理可以显著改善芒果货架期期间品质劣变情况,尤以M3涂膜处理效果最好。     

淀粉-壳聚糖可食性复合薄膜保鲜布林的研究

本文主要研究了不同种类的淀粉与壳聚糖复合所形成的被膜对于布林的保鲜效果。分别用木薯淀粉,土豆淀粉,玉米淀粉与壳聚糖制成不同涂膜液对布林进行涂膜处理,在常温(15～25℃)下储藏。涂膜的布林在贮藏期间,其水分损失,硬度,可溶性固形物,总酸度的变化均小于对照组, 并且可延长保质期3～7d。就不同的淀粉成分而言,对于布林的保鲜作用,土豆淀粉-壳聚糖复合薄膜的保鲜作用最佳,玉米淀粉-壳聚糖复合薄膜的作用优于木薯淀粉-壳聚糖复合薄膜。