玉米淀粉/壳聚糖/魔芋葡甘露聚糖复合膜的制备及物性研究

以玉米淀粉、壳聚糖、魔芋葡甘露聚糖(KGM)为成膜基材。通过研究成膜配方中壳聚糖与KGM质量比、玉米淀粉、甘油、吐温-80等材料的质量分数对复合抗拉强度(TS)、断裂伸长率(EAB)、水蒸气透过系数(WVP)和不透明度(Opacity)的影响,以主成分分析法计算复合膜综合分为评价指标,利用正交实验对复合膜成膜配方进行优化。结果表明:当壳聚糖与KGM质量比1.0∶0.6、玉米淀粉质量分数10%、甘油质量分数0.50%、吐温-80质量分数0.30%时,复合膜TS为(22.53±0.16)MPa,EAB为(20.07±1.18)%,WVP为(1.87±0.01)×10~(-12)g·cm~(-1)·s~(-1)·Pa~(-1),不透明度为(4.13±0.07)mm~(-1),复合膜性能最优。     

明胶-壳聚糖共混复合膜的逾渗研究

为探讨明胶-壳聚糖复合膜的性能,确定复合体系的逾渗阈值,为生产实践提供依据。试验以共混的方法制备了明胶-壳聚糖复合膜,测定了壳聚糖质量分数不同(0～21%)时复合膜的抗拉强度(2.3～12.5 MPa)、断裂伸长率(203.1%～108.2%)和热缩性(3.7%～1.9%)。当添加壳聚糖到一定量时,复合膜的抗拉强度、断裂伸长率和热缩性均发生突变。结果表明,明胶-壳聚糖共混复合膜存在逾渗现象,逾渗阈值为壳聚糖质量分数约15%。     

可食性复合膜在水蜜桃保鲜中的应用研究

以木薯淀粉、壳聚糖、明胶为原料,按不同比例研制可食性复合膜,测试其性能,同时将其应用于容易腐败变质的水蜜桃保鲜中,定期对硬度、多酚氧化酶、可溶性固形物等生理生化指标进行测定。研究结果表明:当1%木薯淀粉与2%壳聚糖溶液的配比为1∶1时,复合膜的综合性能较优。该复合膜包装冷藏水蜜桃,各项生理生化指标均优于未包装复合膜的水蜜桃,并且差异显著(p<0.05)。     

绿豆改性淀粉复合膜阻水性的研究

研究了绿豆改性淀粉复合膜的阻水性;采用绿豆改性淀粉、壳聚糖为主要材料制备复合膜,选择了改性淀粉用量、壳聚糖与改性绿豆淀粉的比例、甘油用量、淀粉糊化温度、干燥温度、干燥时间等6个因素进行单因素试验,确定甘油用量为2.5%,糊化温度为70℃,对其中4个主要因素进行正交试验;得出:以共混液质量为100%计,改性淀粉用量2%,壳聚糖与改性淀粉为6∶4,干燥温度80℃,干燥时间4h,此条件下,淀粉复合膜阻水性最强,膜的透湿系数达到5.03×10~(-11)g/(m·s·Pa)。     

可降解壳聚糖淀粉抗菌复合膜对红提葡萄保鲜效果的研究

目的研究可降解壳聚糖淀粉抗菌复合膜对红提葡萄的保鲜效果。方法设置可降解壳聚糖淀粉抗菌复合膜组、可降解壳聚糖淀粉复合膜组、市售PE保鲜膜组和空白组4个组进行红提葡萄保鲜效果研究。果蔬保鲜效果用失重率、好果率、呼吸强度、可溶性固形物和总酸等指标评定,其中失重率、好果率、呼吸强度和总酸采用常规方法测定;可溶性固形物的测定应用手持折光仪。结果红提葡萄贮藏60 d((3±1)℃)后,空白组的失重率超过30%,好果率仅为18%;市售PE保鲜膜组的好果率为20%;可降解壳聚糖淀粉复合膜组的失重率达到23%,好果率约为40%;可降解壳聚糖淀粉抗菌复合膜组的失重率仅为18%,好果率可达到60%以上。结论可降解壳聚糖淀粉抗菌复合膜具有良好的保水、抗菌功效,可应用于葡萄保鲜。     

可食性淀粉复合膜的制备及性能

以改性淀粉为成膜基材,甘油和羧甲基纤维素钠(CMC)为添加剂制备可食膜,研究了改性淀粉及复合膜的相关结构和性能。将壳聚糖与淀粉共混,进行干热改性得到改性淀粉,采用溶液共混法将改性淀粉糊化液、甘油及CMC搅拌混合,随后流延成膜;通过红外光谱、X射线衍射方法对改性淀粉的结构进行了分析,通过热重分析、扫描电镜对改性淀粉及复合膜的结构进行了分析,并研究了甘油及CMC含量对复合膜性能的影响。结果表明,壳聚糖干热改性淀粉属于以物理反应为主的改性,其有助于改善复合膜的物理性能,甘油降低了复合膜的机械强度和阻水性,但CMC可增强膜的机械强度。当甘油含量为20%,CMC含量为60%时,壳聚糖干热改性淀粉复合膜的综合性能达到最佳。     

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。     

抗菌性玉米醇溶蛋白/壳聚糖复合膜的制备与性质

采用分步法,先配制壳聚糖/醋酸/乙醇溶液体系,再向其中加入玉米醇溶蛋白,最后利用流延法制成玉米醇溶蛋白/壳聚糖(zein/chitosan,Z/C)复合膜,探讨壳聚糖质量分数对Z/C复合膜理化性质与抗菌特性的影响。结果表明:在壳聚糖质量分数为2%~8%范围内,混合溶液的黏度和电导率随壳聚糖质量分数变化成阶梯状变化,且壳聚糖的添加对复合膜性质有显著影响,Z/C复合膜的断后伸长率从1.00%提高到6.67%,接触角从65.97°减小到53.61°,水蒸气透过率从5.23 g·m/(m2·h·Pa)提高到9.16 g·m/(m2·h·Pa);扫描电子显微镜观察,复合后薄膜保持光滑、均一;大肠杆菌抑菌实验表明添加壳聚糖使复合膜具有较强的抗菌特性。     

添加巴西甜橙油对壳聚糖膜性质的影响

使用浇铸-蒸发-碱浸法制备壳聚糖-巴西甜橙油复合膜,采用红外光谱、X射线衍射对复合膜进行表征,考察巴西甜橙油添加量对膜的厚度、拉伸强度、断裂伸长率、接触角、水蒸气透过系数、总溶解物质量分数、溶胀指数等性质的影响。结果表明：巴西甜橙油占据了壳聚糖骨架中的部分官能团的位置,打乱了壳聚糖骨架的有序性,使膜中壳聚糖乙酸盐的含量增大。巴西甜橙油添加量为2%时,膜的断裂伸长率取得最大值（10.07%）。膜的接触角和总溶解物质量分数随着巴西甜橙油添加量的增加而增大,最大值分别为81.15 °和4.24%。膜的水蒸气透过系数在巴西甜橙油添加量为6%时最小,为313.32 mg•mm/（kPa•h•m2）。壳聚糖-巴西甜橙油（8%）复合膜的溶胀指数最小,为0.49。巴西甜橙油的加入改善了由浇铸-蒸发-碱浸法制备的壳聚糖膜的力学性质和物理性质,研究结果可为壳聚糖-巴西甜橙油复合膜的生产和应用提供技术依据。     

天然防腐剂淀粉复合膜的抑菌性研究

为探究天然防腐剂淀粉复合膜的抑菌性能,将不同比例的壳聚糖及丁香油分别添加到马铃薯淀粉和玉米淀粉中,研究两者复配后的淀粉膜的抑菌性能。结果表明:添加壳聚糖和丁香油的马铃薯淀粉复合膜和玉米淀粉复合膜对大肠杆菌、酵母菌均具有明显的抑制作用,且复合膜抑菌效果与壳聚糖和丁香油的浓度成正比,与淀粉的种类无关。同浓度下的壳聚糖淀粉复合膜对大肠杆菌、酵母菌的抑制效果优于丁香油淀粉膜。     

Classification of cassava starch films by physicochemical properties and water vapor permeability quantification by FTIR and PLS

ABSTRACT:  Cassava starches are widely used in the production of biodegradable films, but their resistance to humidity migration is very low. In this work, commercial cassava starch films were studied and classified according to their physicochemical properties. A nondestructive method for water vapor permeability determination, which combines with infrared spectroscopy and multivariate calibration, is also presented. The following commercial cassava starches were studied: pregelatinized (amidomax 3550), carboxymethylated starch (CMA) of low and high viscosities, and esterified starches. To make the films, 2 different starch concentrations were evaluated, consisting of water suspensions with 3% and 5% starch. The filmogenic solutions were dried and characterized for their thickness, grammage, water vapor permeability, water activity, tensile strength (deformation force), water solubility, and puncture strength (deformation). The minimum thicknesses were 0.5 to 0.6 mm in pregelatinized starch films. The results were treated by means of the following chemometric methods: principal component analysis (PCA) and partial least squares (PLS) regression. PCA analysis on the physicochemical properties of the films showed that the differences in concentration of the dried material (3% and 5% starch) and also in the type of starch modification were mainly related to the following properties: permeability, solubility, and thickness. IR spectra collected in the region of 4000 to 600 cm⁻¹ were used to build a PLS model with good predictive power for water vapor permeability determination, with mean relative errors of 10.0% for cross-validation and 7.8% for the prediction set.     

Physicochemical and Mechanical Properties of Bambara Groundnut Starch Films Modified with Stearic Acid

The physicochemical and mechanical properties of biofilm prepared from bambara starch modified with varying concentrations of stearic acid (0%, 2.5%, 3.5%, 5%, 7%, and 10%) were studied. By scanning electron microscopy, bambara starch films modified with stearic acid (≥3.5%) showed a progressively rough surface compared to those with 2.5% stearic acid and the control. Fourier transform infrared spectroscopy spectra revealed a peak shift of approximately 31 cm^?1, suggesting the promotion of hydrogen bond formation between hydroxyl groups of starch and stearic acid. The addition of 2.5% stearic acid to bambara starch film reduced water vapor permeability by approximately 17%. Bambara starch films modified with higher concentration of stearic acid were more opaque and showed significantly high melting temperatures. However, mechanical properties of starch films were generally negatively affected by stearic acid. Bambara starch film may be modified with 2.5% stearic acid for improved water vapor permeability and thermal stability with minimal effect on tensile strength.     

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.     

Mechanical properties of pea starch films associated with xanthan gum and glycerol

The aim of this study was to evaluate the effect of the addition of xanthan gum and glycerol to the starch of green pea with high content of AM (cv. Utrillo) in the preparation of films and their physical characteristics. Filmogenic solution (FS) with different levels of pea starch (3, 4, and 5%), xanthan gum (0, 0.05, and 0.1%), and glycerol (glycerol–starch ratio of 1:5 w/w) were studied. The FS was obtained by boiling (5 min), followed by autoclaving for 1 h at 120°C. The films were prepared by casting. Films prepared only with pea starch were mechanically resistant when compared to other films, prepared with corn, cassava, rice, and even other pea cultivars (yellow, commercial). The tensile strength of these films is comparable to synthetic films prepared with high‐density polyethylene and linear low‐density polyethylene. However, they are films of low elasticity when compared to other films, such as rice starch films, and especially when compared to polyethylene films. The increased concentration of starch in the solution increased the puncture force. The increased concentration of glycerol slightly decreased the film crystallinity and interfered in the mechanical properties of the films, causing reduction of the maximum values of tensile strength, strain at break, and puncture force. The plasticizer also caused an increase of elongation at break. Xanthan gum was important to formation of films; however, it did not affect their mechanical properties.     

Comparative study on the properties of flour and starch films of plantain bananas (Musa paradisiaca)

Biodegradable films were prepared by using the flour and starch isolated from plantain bananas of the variety “Terra” (Musa paradisiaca). Since the non-starchy fraction present in the banana flour represents 29.4% (on dry basis) of its composition, we considered it would be interesting to compare the properties of the film elaborated from this natural blend with that of the film produced from the banana starch only. Both films were characterized on the basis of their mechanical, barrier, optical, structural, and thermal properties. The banana flour film was less mechanically resistant but more flexible than the banana starch film. Despite the differences in the microstructure of the flour and starch films, the former was slightly soluble in water, and its water vapor permeability was similar to that of the starch film. Regarding the optical properties, the flour film was yellowish, which can be attributed to its protein content and the presence of phenolic compounds. The starch film, on the other hand, was lighter and less opaque. The FTIR spectra revealed the presence of the amide I group related to proteins only in the case of the flour film. Both plantain banana films displayed a C-type X-ray pattern and one glass transition temperature each, which was higher for the starch film (46.4 °C) as compared to the flour film (30.2 °C). The presence of other components (protein, lipids, and fiber) in the flour film had important effects on its properties. In general, the banana flour and starch are very promising materials for the formulation of coatings and films.     

Thermoplastic Starch–PVA Nanocomposite Films Reinforced with Nanocellulose from Oil Palm Empty Fruit Bunches (OPEFBs): Effect of Starch Type

ABSTRACT

This research studied the effect of three types of starch on the properties of thermoplastic starch (TPS)–Poly (vinyl alcohol) (PVA)–cellulose nanocomposite films. Three different types of starch with amylose and amylopectin contents used were corn starch, cassava starch, and sago starch. Meanwhile, the nanocellulose was isolated from oil palm empty fruit bunches (OPEFBs) by mechanical treatment using ultrafine grinder. The nanocomposite films were made by evaporation casting method. It was found that the difference of amylose content in the native starch affected the properties of nanocomposite films. Meanwhile, the nanocellulose added into matrix TPS–PVA could increase tensile strength of TPS–PVA nanocomposite films.     

Physical and Mechanical Properties of Pea Starch Edible Films Containing Beeswax Emulsions

ABSTRACT:  Hydrophobic beeswax emulsions were incorporated into hydrophilic starch films to modify physical, mechanical, and thermal properties of the films. Beeswax was added in the film-forming solution of high-amylose pea starch (35% to 40% amylose w/w) at the level of 0%, 10%, 20%, 30%, and 40% w/w of starch with glycerol as a plasticizer (40/60 of glycerol/starch). Addition of beeswax affected mechanical properties, significantly reducing tensile strength and elongation and increasing elastic modulus. Beeswax addition decreased water vapor permeability and increased oxygen permeability. However, the addition of hydrophobic wax particles in starch films marginally affected these physical properties below 30% beeswax in the films. Beeswax addition at the 40% concentration formed amylose–lipid complex that caused the dramatic changes of physical and thermal properties of the films.     

Effects of Extrusion Temperature and Plasticizers on the Physical and Functional Properties of Starch Films

Cornstarch, at 20% moisture content (dry basis, d.b.), was mixed with glycerol at 3:1 ratio to form the base material for extruded starch films. Stearic acid, sucrose and urea, at varying concentrations, were tested as secondary plasticizers for the starch‐glycerol mixture. The ingredients were extruded at 110 and 120°C barrel temperatures to determine the effects of extrusion temperature, plasticizer type and their concentrations on the film‐forming characteristics of starch, as well as their effects on selected physical and functional properties of the films. The physical and mechanical properties of the films were studied by scanning electron microscopy (SEM) and tensile testing, while the glass transition and gelatinization properties were analyzed using differential scanning calorimetry (DSC). The interactions between the functional groups of starch and plasticizers were investigated using Fourier‐transform infrared (FTIR) spectroscopy. The water vapor permeability (WVP) properties of starch films were determined using ASTM standard E96‐95. Scanning electron micrographs exhibited the presence of native and partially melted starch granules in the extruded films. The tensile stress, strain at break and Young's modulus of starch films ranged from 0.9 to 3.2 MPa, 26.9 to 56.2% and 4.5 to 67.7 MPa, respectively. DSC scans displayed two glass transitions in the temperature ranges of 0.1 to 1°C and 9.6 to 12°C. Multiple melting endotherms, including that of amylose‐lipid complexes, were observed in the thermoplastic extrudates. The gelatinization enthalpies of the starch in the extruded films varied from 0 to 1.7 J/g, and were dependent largely on the extrusion temperature and plasticizer content. The shift in the FTIR spectral bands, as well as the appearance of double‐peaks, suggested strong hydrogen bonding interactions between the starch and plasticizers. The WVP of starch films ranged from 10.9 to 15.7 g mm h^‐1 m^‐2 kPa^‐1, depending on the extrusion temperature and the type of plasticizer used.     

Classification,modeling and prediction of the mechanical behavior of starch-based films

The starch-based film properties database was created with 8 variables and 322 observations collected from the literature. The selected variables were: (1) the starch origin (potato, cassava (tapioca), corn (maize), wheat, yam), (2) the starch concentration, (3) the amylose content, (4) the glycerol concentration, (5) the ambient relative humidity during storage, (6) the aging time of films and two mechanical properties of the starch films at break, (7) tensile strength at break (s_b) and (8) strain at break (e_b). The main objective of this work was to classify the data set and to predict mechanical properties (tensile strength (s_b) and strain at break (e_b) of starch-based films using a Rival Penalized Competitive Algorithm to find the clusters and, for each class, an artificial neural network (ANN) model from 6 parameters (starch origin, starch concentration (%), amylose content (%), glycerol content, ambient relative humidity (RH) and the aging of films). Each ANN was optimized using a genetic algorithm. The root-mean square error (RMSE) and the coefficient of determination B allowed to choose the best ANN. The results showed that it was possible to distinguish five classes where the composition of each class C_i could be described accurately and connected with the mechanical behavior of the films. This work also showed that it was useful firstly to classify the database before attempting to predict the mechanical properties of the starch-based films.     

Composition and Film Properties of Temperature Responsive,Hydrophobically Modified Potato Starch

The film‐forming properties of hydrophobically modified potato starch were studied to optimize coating and surface sizing formulations for improvement of barrier properties of paper and paperboard. The spontaneous fractionation of a potato starch hydrophobically modified with a quaternary dodecylammonium chloride resulted in an amylose‐rich precipitate with properties differing from those of the original starch. Film formation was investigated in the presence of glycerol and poly(vinyl alcohol) plasticizers. Anti‐plasticization was found to occur at low and intermediate plasticizer levels but highly flexible, continuous films were obtained when 30 parts of plasticizer were added to 100 parts of dry starch. The highest transparency and greatest flexibility were obtained with glycerol, while the hydrophobic film properties were maintained with poly(vinyl alcohol). A study of the glass transition temperatures and melting behavior of starch‐plasticizer films by differential scanning calorimetry gave useful information about the crystallinity of the films.