糊化条件对柠檬酸淀粉酯成膜性能影响

糊化是淀粉成膜必不可少的环节,它可使淀粉膜具有更好的应用性能。以机械活化柠檬酸淀粉酯为原料,断裂伸长率和吸水性为评价指标,并结合SEM、XRD和接触角分析,探讨糊化条件对柠檬酸淀粉酯成膜性能的影响。结果表明,糊化温度50 ℃、糊化时间30 min时,柠檬酸淀粉酯膜的断裂伸长率和吸水率较好;SEM表明,糊化时间和糊化温度的增加,柠檬酸淀粉酯表现出更好的成膜性;XRD分析可知,柠檬酸淀粉酯膜变成了V型结晶结构;接触角分析可知,随着糊化时间的增加,柠檬酸淀粉酯膜的亲水性变强,但随着糊化温度升高,柠檬酸淀粉酯膜亲水性下降。机械活化柠檬酸淀粉酯具有更低的糊化温度和更短的糊化时间,有望广泛应用在淀粉膜领域。     

木薯氧化淀粉-壳聚糖复合膜的成膜特性研究

利用木薯氧化淀粉为成膜主要材料,添加增塑剂甘油和增强剂壳聚糖,制备了一种新型可食性淀粉膜。通过研究膜组分和成膜工艺参数对抗拉强度、断裂伸长率、水溶性和透明度等膜性能的影响,确定了制膜最佳工艺条件。正交实验结果表明,氧化淀粉的用量对膜的力学性能起主要影响作用,当m(木薯氧化淀粉)∶m(壳聚糖)∶V(甘油)=6∶2∶3时,在60℃下烘干4h,可制得较为理想的淀粉膜,抗拉强度为4.86MPa,断裂伸长率为130.88%,水溶性和透明度分别为50.31%和87%。      

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。      

响应面法优化阿魏酸淀粉酯膜制备工艺

采用单因素试验和响应面法考察阿魏酸淀粉酯取代度、干燥温度和甘油添加量对阿魏酸淀粉酯膜抗张强度（tensile strength,TS）和断裂伸长率的影响。结果表明：随着取代度的增大,阿魏酸淀粉酯膜的TS逐渐增大,断裂伸长率逐渐减小;当干燥温度不大于60 ℃时,阿魏酸淀粉酯膜的TS随着温度的升高略微增大,当温度升高到60 ℃以上时,TS显著降低（P＜0.05）,阿魏酸淀粉酯膜的断裂伸长率随着温度的升高显著降低（P＜0.05）;随着甘油添加量的增大,阿魏酸淀粉酯膜的TS逐渐减小,断裂伸长率逐渐增大。综合考虑各因素对阿魏酸淀粉酯膜机械性能的影响,在取代度0.068、干燥温度40 ℃、甘油添加量1.20 g/4.0 g条件下制备阿魏酸淀粉酯膜,膜的TS较高,为10.23 MPa;在取代度0.023、干燥温度41 ℃、甘油添加量1.30 g/4.0 g条件下制膜,膜的断裂伸长率较高,为321.65%。     

高速混合条件下不同增塑剂对热塑性淀粉结构及性能的影响

目的:研究在一定高速混合温度下增塑剂种类对材料的结构与性能产生的影响,为今后TPS在降解材料领域的应用提供依据。方法:通过高速混合的方法制得三种不同增塑剂(甘油、甲酰胺、尿素)增塑的热塑性淀粉(TPS)样品,对保存在室温及65RH%湿度下的样品的各项性能进行测试。结果:SEM结果说明:增塑剂能在一定程度上破坏和改变淀粉颗粒的形态。XRD测试表明:甲酰胺塑化的TPS(FPTPS)和尿素塑化的TPS(UPTPS)的耐回生性能好于甘油塑化的TPS(GPTPS)。TG测试表明:三种塑化剂塑化的热塑性淀粉的热稳定性次序为甘油<甲酰胺<尿素。FTIR谱图可得出几种塑化剂与淀粉形成氢键的能力为:尿素>甲酰胺>甘油。结论:甲酰胺和尿素作为淀粉增塑剂,其塑化的热塑性淀粉的综合性能要优于甘油。     

增塑剂对壳聚糖-明胶复合膜物理性能的影响

研究了增塑剂(甘油、乙二醇、聚乙二醇400)对壳聚糖-明胶复合膜性能的影响.结果表明:增塑剂的加入对膜的物理性能产生了显著的影响,三种增塑剂都使膜的拉伸强度和吸水性降低、断裂伸长率和透水气率增大,但不同的增塑剂对断裂伸长率的影响表现出较大不同.甘油和乙二醇对膜的透光率影响不大,聚乙二醇400会使膜的透光率大大降低.综合各种指标,甘油对壳聚糖-明胶复合膜的增塑效果最好.     

壳聚糖-甘油-丝素共混膜的制备及性能研究

采用流涎法制备壳聚糖-甘油-丝素共混膜,以膜的伸长强度和断裂伸长率为指标,考察各组分混配比例对膜性能的影响.结果显示:壳聚糖可增强膜的拉伸强度,但当壳聚糖浓度≥10 g/L,膜的断裂伸长率出现下降;添加甘油可提高膜的拉伸强度和断裂伸长率;丝素蛋白的添加可使膜的拉伸强度略有上升,同时较明显地提升了断裂伸长率.进一步采用10 g/L壳聚糖、10 g/L甘油、0～20 g/L丝素蛋白成膜,并考察其抑菌性能.结果表明:含5 g/L丝素蛋白的共混膜即可完全抑制金黄色葡萄球菌的生长,含20 g/L丝素蛋白的共混膜可完全抑制大肠杆菌的生长,丝素蛋白的添加大大提高了壳聚糖共混膜的抑菌性能.     

高速混合条件下不同增塑剂对热塑性淀粉结构及性能的影响

目的:研究在一定高速混合温度下增塑剂种类对材料的结构与性能产生的影响,为今后TPS在降解材料领域的应用提供依据。方法:通过高速混合的方法制得三种不同增塑剂(甘油、甲酰胺、尿素)增塑的热塑性淀粉(TPS)样品,对保存在室温及65RH%湿度下的样品的各项性能进行测试。结果:SEM结果说明:增塑剂能在一定程度上破坏和改变淀粉颗粒的形态。XRD测试表明:甲酰胺塑化的TPS(FPTPS)和尿素塑化的TPS(UPTPS)的耐回生性能好于甘油塑化的TPS(GPTPS)。TG测试表明:三种塑化剂塑化的热塑性淀粉的热稳定性次序为甘油<甲酰胺<尿素。FTIR谱图可得出几种塑化剂与淀粉形成氢键的能力为:尿素>甲酰胺>甘油。结论:甲酰胺和尿素作为淀粉增塑剂,其塑化的热塑性淀粉的综合性能要优于甘油。      

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。     

L-阿拉伯糖、增塑剂复合改性鱼皮明胶可食用膜制备工艺研究

以鱼皮明胶为成膜基质,L-阿拉伯糖、甘油和山梨醇为改性剂,采用浇铸法制备可食用膜,以拉伸强度和断裂伸长率为目标优化指标,通过单因素试验及正交试验确定薄膜最佳制备工艺。结果表明：在L-阿拉伯糖和鱼皮明胶质量比2 ∶8、增塑剂（甘油∶山梨醇）质量比为2 ∶1、增塑剂浓度20%、水浴温度60 ℃、水浴时间40 min 条件下,可食用膜机械性能最佳,拉伸强度和断裂伸长率分别达到（17.46±2.59）MPa、（116.95±13.05）%。     

Edible films made from blends of manioc starch and gelatin – Influence of different types of plasticizer and different levels of macromolecules on their properties

The interest in the development of edible and biodegradable films has increased because it is every day more evident that non-degradable materials are doing much damage to the environment. In this research, bioplastics were based on blends of manioc starch (native and modified) and gelatin in different proportions, added of glycerol or sorbitol, which were used as plasticizers. The objective was to study the effect of two different plasticizers, glycerol and sorbitol, and different concentrations of starch and gelatin on the barrier (water vapor permeability – WVP), mechanical (tensile strength and elongation at break), physicochemical (solubility in water and in acid) and physical properties (opacity and thickness) of the obtained bioplastics samples. As a result, all of them showed transparency and resistance to tensile strength, as well as increasing in thickness values and in the WVP, as the gelatin content increased in the formulations. Finally, all results for tensile strength and elongation at break obtained for those samples plasticized with sorbitol were better than those plasticized with glycerol.     

增塑剂改性明胶膜的制备与表征

研究了不同增塑剂对明胶膜性能的影响。采用流延法制备了不同增塑剂增塑剂改性明胶膜,并对其结构力学、热稳定性及光学性能进行表征,结果表明:当乙二醇、丙三醇、山梨醇的质量浓度为12.5%时,断裂伸长率达到最大值,分别为113.00%、145.33%、120.63%;随增塑剂乙二醇、丙三醇、山梨醇的加入,改性明胶膜的热缩性呈增加趋势,分别增加1.70%、2.84%、1.94%;在可见光中心点600 nm处,乙二醇、丙三醇、山梨醇改性明胶膜的透光率分别增加8.8%、11.9%、8.3%。结果表明,增塑剂可以优化明胶的性能以使其应用到实际生产中。      

增塑剂对高直链淀粉基生物降解薄膜力学性能的影响

以高直链玉米淀粉为原料,利用微波辐射加热工艺将淀粉糊化,通过溶液浇铸法制备淀粉基薄膜。探讨了不同增塑剂以及复合增塑剂对高直链淀粉基薄膜性能的影响。结果表明,甘油、山梨醇和木糖等增塑剂对淀粉的塑化作用是比较显著的。与单一的增塑剂相比,复合增塑剂所制备的材料的力学性能更加优良,尤其是甘油与木糖复合增塑所制备的淀粉基薄膜性能更好。     

Effect of Plasticizers on Mechanical and Barrier Properties of Rice Starch Film

The effect of plasticizers, glycerol, sorbitol and poly(ethylene glycol) 400 (PEG 400), on mechanical and barrier properties of rice starch film has been investigated. Sorbitol‐ and glycerol‐plasticized starch films appeared homogeneous, clear, smooth, and contained less insoluble particles compared to unplasticized rice starch films. PEG 400 did not form plasticized films of suitable characteristics. The softness and stickiness of films improved with increasing concentrations of glycerol and sorbitol. In general, films plasticized with glycerol and sorbitol displayed a better solubility in water than unplasticized films, i.e. 35% (w/w) glycerol and 45% w/w (sorbitol) (optimum solubility). The tensile strength of films decreased especially in the high concentration regime of plasticizers, between 20–45% (w/w) of plasticizer/rice starch film. Through the entire concentration regime, the tensile strength of glycerol‐plasticized films was significantly lower than that of sorbitol‐plasticized films, but their elongation was larger. The water vapor transmission rate (WVTR) through plasticized films and the oxygen transmission rate (OTR) increased with glycerol and sorbitol concentrations, however, glycerol was revealed to be significantly more effective in reducing the tensile strength as well as increasing the WVTR and the OTR compared to sorbitol. With the higher tensile strength and the smaller OTR and WVTR, the 30% sorbitol‐plasticized film reveals an improved coating performance in terms of a reduction of coating failures.     

Starch-Polyvinyl Alcohol Films –Effect of Various Plasticizers

Various polyols were evaluated as plasticizers for starch-polyvinyl alcohol films. Glycol glycoside, an experimental polyol made from starch and ethylene glycol, and sorbitol were highly effective plasticizers alone and in combination with small amounts of glycerol. Glycol glycoside is an especially attractive plasticizer because of its low production cost. Glucose and sucrose performed well in combination with glycerol or sorbitol.     

马铃薯淀粉/海藻酸钠复合交联可食膜阻湿性影响因素研究

研究不同膜液配比、不同增塑剂及用量、不同油脂及用量对马铃薯淀粉/海藻酸钠复合交联可食膜阻湿性能的影响。马铃薯淀粉含量高的膜样比海藻酸钠含量高的膜样具有更低的水蒸气透过系数,但水溶性增加;增塑剂(甘油、山梨醇、甘油山梨醇混合物)用量提高,复合交联可食膜的水蒸气透过系数和水溶性均增加,以质量比为1∶1的甘油与山梨醇混合物为增塑剂的膜样具有较低的水蒸气透过系数和水溶性;油脂可以提高复合交联可食膜的疏水性,降低复合交联可食膜的水溶性,添加橄榄油的复合交联可食膜比添加硬脂酸具有更低的水蒸气透过系数。      

Mechanical and Thermal Characteristics of Pea Starch Films Plasticized with Monosaccharides and Polyols

Edible starch films were produced from pea starch and various plasticizers (mannose, glucose, fructose, and glycerol and sorbitol) at the ratio of 4.34, 6.50, 8.69, and 10.87 mmol plasticizer per gram of starch. After film specimens were conditioned at 50% relative humidity, mechanical properties (tensile strength, elongation, and modulus of elasticity), water vapor permeability (WVP), moisture content, and thermomechanical properties (G’ and tan8) were determined as a function of plasticizer concentration. At all concentration levels, monosaccharides (mannose, glucose, and fructose) made the starch films stronger (higher tensile strength) and more stretchable than polyols (glycerol and sorbitol), while WVP of monosaccharide‐plasticized starch films were lower than those of polyol‐plasticized starch films, especially at higher plasticizer concentration levels. Except for 4.34 mmol/g of mannose‐plasticized film, all the other films showed similar modulus of elasticity at the same plasticizer concentration. Polyol‐plasticized films had lower T than the monosaccharide‐plasticized films. Glucose‐ and sorbitol‐plasticized films needed more activation energy to go through glass transition than others. After all, research results showed that not only the polyols but also the monosaccharides were effective in plasticizing starch films. It is concluded that molecular size, configuration, total number of functional hydroxyl group of the plasticizer as well as its compatibility of the plasticizers with the polymer could affect the interactions between the plasticizers and starch molecules, and consequently the effectiveness of plasticization.     

Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation

Cassava starch-chitosan films were obtained by melt bending and compression molding, using glycerol and polyethylene glycol as plasticizers. Both the starch/chitosan and the polymer/plasticizer ratios were varied in order to analyze their effect on the physical properties of the films. Additionally, the antimicrobial activity of 70:30 polymer:plasticizer films was tested in cold-stored pork meat slices as affected by chitosan content. All film components were thermally stable up to 200 °C, which guaranteed their thermostability during film processing. Starch and chitosan had limited miscibility by melt blending, which resulted in heterogeneous film microstructure. Polyethylene glycol partially crystallized in the films, to a greater extent as the chitosan ratio increased, which limited its plasticizing effect. The films with the highest plasticizer ratio were more permeable to water vapor, less rigid, and less resistant to break. The variation in the chitosan content did not have a significant effect on water vapor permeability. As the chitosan proportion increased, the films became less stretchable, more rigid, and more resistant to break, with a more saturated yellowish color. The incorporation of the highest amount of chitosan in the films led to the reduction in coliforms and total aerobic counts of cold-stored pork meat slices, thus extending their shelf-life.     

Effect of banana and plasticizer types on mechanical,water barrier,and heat sealability of plasticized banana‐based films

Unripe banana flour and starch were used to formulate plasticized banana‐based films (flour film, PBF; starch film, PBS) with two types of plasticizers (glycerol, Gly; sorbitol, Sor) and a mixture of Gly‐Sor on film properties. PBS showed greater water barrier, elongation at break, toughness, and transparency, but lower efficiency in heat sealability than PBF. However, the easier and a higher yield in the preparation process of PBF lead to higher UV and visible light barrier than PBS which could be due to its protein content and the presence of phenolic compounds in PBF. Both banana films plasticized with Sor showed high glossiness, high efficiency in heat sealability, and mechanical and water barrier properties; however, the undesirable recrystallization of white crystals resulted in lower film flexibility. Thus, Gly‐Sor was preferred without change of water barrier but strengthened heat sealability. Therefore, banana‐based film might be considered as a green food packaging material.

Practical applications

Banana flour and starch from unripe bananas can be used as safe food ingredients for food products and as green biodegradable packaging materials. Banana flour film showed similar mechanical properties as banana starch film but involved easier processing and higher yield in the preparation of banana flour. Moreover, banana flour films had higher efficiency in heat sealability with the potential to protect the packed food from UV–visible light deterioration. Furthermore, an easier way to modify proper film properties is by the proper selection of the plasticizer. A mixture of plasticizers (glycerol and sorbitol) showed high potential to improve long‐term physical stability such as through UV–visible light prevention, and improved mechanical properties and heat sealability of plasticized banana‐based films. Briefly, plasticized banana flour film with a mixture of plasticizer will be potential, alternative biodegradable packaging material to reduce the use of nonbiodegradable synthetic plastic materials in food applications.     

Physical Properties of Gelatin Films Plasticized by Blends of Glycerol and Sorbitol

ABSTRACT: The addition of plasticizers increases the flexibility and workability of films based on biopolymers. However, the use of some plasticizers cause undesirable results, such as the migration of these additives out the film or crystallization during shelf life. Thus, the aim of this study was to evaluate the effect of blends with different ratios of sorbitol and glycerol, at 2 plasticizer concentrations, on mechanical, viscoelastic, and water vapor barrier properties of films based on gelatin. The films were prepared with 2 g gelatin/100 mL of water and with 25 or 55 g plasticizer/100 g gelatin. The ratio, glycerol to sorbitol, was studied as 0:100, 20:80, 40:60, 60:40, 80:20, and 100:0. The increase of plasticizer concentration from 25 to 55 g plasticizer/100 g gelatin caused an increase of flexibility and reduction of resistance and water vapor barrier as expected. In relation to the effect of the mixture, the increase in the proportion of glycerol caused a reduction of the puncture force, tensile strength, modulus of elasticity, and an increase of the puncture deformation, elongation at break, and water vapor permeability due to the higher plasticizing effect of glycerol. This behavior was explained in terms of molecular weight of the plasticizers, which demonstrated that the studied properties could be considered as functions of the number of molecules of plasticizers in the films.