环境湿度对植物蛋白膜的影响研究

研究了环境湿度对小麦蛋白膜、大豆蛋白膜以及小麦-大豆复合膜机械性能、通透性等的影响。结果表明,由于蛋白腹为亲水性膜,受环境湿度的影响,其水分含量、分子间作用力有所不同,从而导致蛋白膜的机械性能、透湿性和吸湿率也随之发生变化。膜的阻止水蒸汽渗透的能力下降,吸湿率降低,透氧率呈上升趋势。      

存放时间对植物蛋白膜的影响研究

研究了存放时间对小麦蛋白膜、大豆蛋白膜以及小麦-大豆复合膜机械性能、通透性等性能的影响。结果表明,随着存放时间的延长,蛋白膜的机械性能、透湿性和吸湿率也随之发生变化。并通过电镜扫描分析,发现不同蛋白膜的横截面微观结构有所不同。     

存放时间对植物蛋白膜的影响研究

研究了存放时间对小麦蛋白膜、大豆蛋白膜以及小麦-大豆复合膜机械性能、通透性等性能的影响。结果表明,随着存放时间的延长,蛋白膜的机械性能、透湿性和吸湿率也随之发生变化。并通过电镜扫描分析,发现不同蛋白膜的横截面微观结构有所不同。      

环境温度对植物蛋白膜的影响

研究了环境温度对小麦蛋白膜、大豆蛋白膜以及小麦-大豆复合膜机械性能,通透性等的影响。结果表明,由于蛋白膜易受环境温度的影响,从而导致蛋白膜的机械性能,透湿性和透氧率等也随之发生变化。环境温度对复合膜的抗拉强度影响不大,而延伸率均随着环境温度的上升而增高。其透氧率随着环境温度的升高而上升,水蒸汽透过率随着环境温度的升高先略有下降,而后又呈上升趋势。     

环境湿度对明胶—普鲁兰多糖可食性膜性能的影响

明胶-普鲁兰多糖膜是一种可以快速溶解于热水的可食性包装材料,研究环境湿度对明胶-普鲁兰多糖膜机械性能、氧气透过率、水蒸气透过率、油脂透过率、颜色以及水溶性的影响,并比较环境湿度对明胶膜、明胶-普鲁兰多糖膜和普鲁兰多糖膜性能的影响。结果显示,较高的环境湿度(80%)会降低明胶-普鲁兰多糖膜的抗拉强度,提高其柔韧性,而对其阻氧性、阻油性和透明度没有显著的影响;明胶-普鲁兰多糖膜的各方面性能优于明胶膜和普鲁兰多糖膜。     

脂质对小麦蛋白膜理化特性的影响

研究了脂质对小麦蛋白膜机械性能、通透性等性能的影响。结果表明,脂质由于其疏水性能有效地阻止水分迁移,将其与蛋白质复合能改善蛋白膜的阻湿性。另外,小麦蛋白膜的机械性能、水溶性等也随着脂质的种类和用量的不同而有所不同。将脂质和小麦蛋白复合在一起形成复合膜,使膜的性能有所提高,从而更有利于其在食品体系中的应用。     

不同相对湿度环境条件下玉米醇溶蛋白膜的稳定性研究

以不同蛋白浓度、甘油添加量和成膜温度制备玉米醇溶蛋白膜,研究其在不同相对湿度(RH)条件下24 d储藏过程中的机械性能变化。结果表明:不同条件下制备的玉米醇溶蛋白膜,在中低相对湿度(34%、43%、54%)条件下24 d的储藏过程中,膜的抗拉强度(TS)呈现先增加后减少的趋势,而断裂延伸率(EB)则呈现先减少后增加的趋势。而在80%的高湿度环境中,不同蛋白浓度和不同成膜温度制备的蛋白膜,储藏期间TS呈现逐渐增加的趋势,EB则快速减少;不同甘油含量的膜,在RH80%环境中TS和EB的变化趋势与RH34%、RH43%和RH54%一致。RH65%环境条件下蛋白膜的机械性能的变化受成膜条件的影响较大。整体上看,储藏过程中环境湿度对玉米醇溶蛋白膜的机械性能的影响大于制备条件的影响。因此,在蛋白膜的研究中,应用的环境湿度也是需要考察的重要因素之一。     

脂质对小麦蛋白膜理化特性的影响

研究了脂质对小麦蛋白膜机械性能、通透性等性能的影响。结果表明，脂质由于其疏水性能有效地阻止水分迁移，将其与蛋白质复合能改善蛋白膜的阻湿性。另外，小麦蛋白膜的机械性能、水溶性等也随着脂质的种类和用量的不同而有所不同。将脂质和小麦蛋白复合在一起形成复合膜，使膜的性能有所提高，从而更有利于其在食品体系中的应用。     

增塑剂对小麦面筋蛋白膜机械性能的影响

本文以单因素对比试验,研究甘油、聚乙二醇和戊二醛对小麦面筋蛋白膜机械性能的影响;结果表明,加入甘油、聚乙二醇能较大的提高蛋白膜的断裂延伸率,加入戊二醛能较好的提高蛋白膜的抗拉强度。     

利用酶法修饰小麦面筋蛋白制备食用包装膜研究

该文通过对可食性小麦面筋蛋白成膜特性进行系统研究,探讨小麦面筋蛋白浓度,一定湿度条件下增塑剂用量,酶处理对膜性能的影响。结果表明:小麦面筋蛋白在适当的条件下可制成具有符合机械性能及阻隔性能要求的可食性膜纸。     

可食性小麦蛋白膜透氧性的研究

一定的条件下 ,以小麦蛋白为原料可以制得具有良好透氧性的薄膜。文中研究了可食性小麦蛋白膜的透氧性能 ,对影响透氧性的 5种因素的影响效果及机理进行了探讨 ,以期望为改善小麦蛋白膜的透氧性提供参考。     

Preparation and characterization of proteinous film from lentil (Lens culinaris): Edible film from lentil (Lens culinaris)

This study was conducted to extract protein from lentil seed and prepare edible film from the protein and to determine mechanical, optical and barrier properties of lentil protein concentrate (LPC) film. The film was prepared from LPC (5 g/100 ml water) and glycerine (50%, w/w of LPC). Hunter color value (L, a and b), tensile strength, percentage elongation at break (E), puncture strength, water vapor permeability (WVP), moisture content after conditioning at 50% RH and 25 °C for 48 h and total soluble matter after immersion in water, were measured. In regarding to WVP, in spite of difference in film thickness and relative humidity of experiment in different studies, lentil protein film is comparable with other protein films. Characteristics of the lentil protein-based edible films were comparable with other edible protein films. LPC film had more red and less yellow color; it seems that the film had good mechanical properties and water vapor permeability in concomitant with good solubility.     

Evaluation of the permeability of agricultural films to various fumigants

A variety of agricultural films are commercially available for managing emissions and enhancing pest control during soil fumigation. These films are manufactured using different materials and processes which can ultimately result in different permeability to fumigants. A systematic laboratory study of the permeability of the agricultural films to nine fumigants was conducted to evaluate the performance of commonly used film products, including polyethylene, metalized, and high-barrier films. The permeability, as expressed by mass transfer coefficient (cm/h), of 27 different films from 13 manufacturers ranged from below 1 × 10(-4) cm/h to above 10 cm/h at 25 °C under ambient relative humidity test conditions. The wide range in permeability of commercially available films demonstrates the need to use films which are appropriate for the fumigation application. The effects of environmental factors, such as temperature and humidity, on the film permeability were also investigated. It was found that high relative humidity could drastically increase the permeability of the high-barrier films. The permeability of some high-barrier films was increased by 2-3 orders of magnitude when the films were tested at high relative humidity. Increasing the temperature from 25 to 40 °C increased the permeability for some high-barrier films up to 10 times more than the permeability at 25 °C, although the effect was minimal for several of these films. Analysis of the distribution of the permeability of the films under ambient humidity conditions to nine fumigants indicated that the 27 films largely followed the material type, although the permeability varied considerably among the films of similar material.     

Barrier properties of sodium caseinate films as affected by lipid composition and moisture content

This work analyses the effect of lipid addition (oleic acid, beeswax and oleic acid-beeswax mixtures) as well as the influence of the relative humidity (RH), or the equilibrium water content of the films, on the permeability of sodium caseinate based films to water vapor and gas (oxygen and carbon dioxide). The effect that lipid addition had on the gas and water vapor permeability was dependent both on the composition of oleic acid-beeswax mixtures and the film’s moisture content. The addition of lipid mixtures reduced water vapor transfer as compared to the control films (without lipid), whereas pure oleic acid or beeswax were less effective. Both control films and films prepared with pure beeswax showed the lowest O₂ and CO₂ permeability, whereas the incorporation of oleic acid exponentially increased these values. A linear increase in water vapor and gas permeability was observed when the water content of the film rose, due to its plasticizing effect, which led to an increase in the molecular mobility. Predictive equations for water vapor permeability (WVP) and gas permeability were established as a function of water content and lipid composition.     

Properties of Cysteine-Added Soy Protein-Wheat Gluten Films

Soy and wheat proteins as film ingredients are advantageous due to relative abundance, biodegradability, and their renewable nature. Research objectives were to evaluate effectiveness of gluten and cysteine addition in improving properties of soy protein-based films. Thickness, mechanical, and barrier properties were evaluated. Gluten addition and pH 3.0 lowered water vapor permeability and thickness. Mechanical properties were enhanced at pH 7.0 with cysteine addition. Cysteine increased tensile strength of some treatments due to increase in disulfide bond formation. Best compromise between barrier and mechanical properties was observed for the cysteine-added soy:gluten (4:1) film at pH 7.0. These films could find application as primary packaging for low moisture foods.     

Cellulose-based edible films and their effects on fresh beans and strawberries

 Cellulose-based edible films were applied to fresh beans and strawberries. The moisture loss from these food was measured following the application of films of varying composition under different conditions. The effects of the method of application of film solution, the amounts of polyethylene glycol (PEG), stearic acid (SA), palmitic acid (PA) and lauric acid (LA) in the film, the molecular weights of methyl cellulose (MC) and PEG and, finally, the relative humidity of the environment on moisture loss from fresh beans and strawberries coated with films were investigated. The brushing method for the application of film solution to the foods was found to be better than wrapping and dipping methods in terms of reducing the moisture loss. Recommended amounts of PEG-400 and fatty acids in film solution to reduce moisture loss from foods were found to be 11 ml and 40 g per 100 g MC-20000, respectively. A slight decrease in moisture loss was observed when PEG-400 and MC-20000 in the film solution were replaced by PEG-1000 and MC-41000, respectively. Finally, it was found that moisture loss from fresh beans and strawberries coated with films decreased as the relative humidity of the environment in which they were kept was increased. Received: 19 December 1996 / Revised version: 20 May 1997     

Edible composite films of wheat gluten and lipids: water vapour permeability and other physical properties

Edible composite films comprised of wheat gluten as the structural matrix and various concentrations of different lipids as the moisture barrier component were tested for water vapour permeability, dispersion in water, opacity and mechanical properties. the effects of lipids on the functional properties of gluten-based composite films depended on the lipid characteristics and on the interactions between the lipid and the protein structural matrix. Beeswax, a solid and highly hydrophobic lipid, was the most effective lipid for improving moisture barrier properties of films; but these films were opaque, weak and disintegrated easily in water. Combining wheat gluten proteins with a diacetyl tartaric ester of monoglycerides reduced water vapour permeability, increased strength and maintained transparency.     

Plasticized Whey Protein Edible Films: Water Vapor Permeability Properties

Heat treatment, protein concentration, and pH effects on water vapor permeability (WVP) of plasticized whey protein films were examined. The best film formation conditions were neutral pH, aqueous 10% (w/w) protein solutions heated for 30 min at 90°. Isoelectric point adjustment of whey protein with calcium ascorbate buffer increased WVP with increasing buffer concentration, The importance of vacuum application to minimize film pore size was identified using scanning electron microscopy. Polyethylene glycol, glycerol and sorbitol plasticizer concentration affected film WVP. Determining the effects of relative humidity on WVP for plasticized whey protein films enabled prediction of film behavior under any water vapor partial pressure gradient.