【作者】 单成俊；

【导师】 陈正行；

【作者基本信息】 江南大学 ， 粮食、油脂与植物蛋白工程， 2005， 硕士

【摘要】 本文以大米蛋白浓缩物(RPE)为主要原料制备可食性保鲜膜。实验中以膜的厚度、机械强度、透水率、透氧率为指标,考察了膜的制备工艺、增塑剂的添加量、酶交联和类脂物质这四个因素对膜性能的影响。并在此基础上,对膜的应用进行了初步的探讨。实验表明在以下的实验条件下可以得到性能较好的膜:RPE的浓度为50g/L,甘油的添加量在30±5g/L,pH11±0.5的成膜溶液在80±5℃下处理10～30min,此时膜的物理性能如下:延伸率102.4±18.5%,抗拉强度为2.35±0.54MPa,透水率35.1±1.9 g·mm/kPa·d·m~2,透氧率2.8±0.3 cm~3·ηm/m~2·d·kPa的膜。谷氨酰胺转胺酶(TG)可以通过ε-(γ-glutamyl)-lys异肽键在大米蛋白质分子内部或分子间进行联结,可以明显地改善膜的结构和致密程度,有效地提高大米蛋白可食用膜的阻水性能和抗拉强度。通过单因素和正交实验发现,与未添加TG的膜相比,添加TG的膜的抗拉强度平均提高了43.9%,透水率下降了19.6%,延伸率和透氧率的变化不大。通过扫描电镜照片可以看出通过TG强化后,膜表面的均匀性和内部结构的致密程度得到了提高。针对膜的透水率比较高的缺点,在成膜溶液中添加了不同的类脂物质来提高膜的阻水性能,结果表明:添加硬脂酸、蔗糖脂肪酸酯、蜂蜡后大米蛋白可食用膜的阻水性得到了较大的提高,其中硬脂酸和蔗糖脂肪酸酯的效果比较好,添加质量分数在3g/L比较合适。膜表面和截面的SEM照片表明蜂蜡以小颗粒的形式存在于膜的网络结构中,而硬脂酸和蔗糖脂肪酸酯能与大米蛋白质结合,因而在提高膜的阻水性时对膜的机械性能影响不大。参考以上研究,采用阻氧性比较好的工艺和配方应用于杏仁和核桃仁的保鲜,在陈化40天后杏仁和核桃仁的酸价与对照品相比分别降低了25.8%和51.2%,过氧化值分别下降了25.1%和45.3%。证明大米蛋白可食用膜能够提供比较好的保鲜效果,可以用以延缓果仁中油脂的水解和氧化,延长货架期。更多还原

【Abstract】 In this paper, we prepared the edible films by rice protein extracts. The films were preparedwith thickness, mechanical properties, water vapor and oxygen permeability as index. Theeffects of preparation, content of plasticizer, enzyme polymerize and lipids on the film propertieswere investigated. At last, we did some research of the application of the film.The conditions of preparing the edible films were optimized as following: the content ofRPE: 5g/L;the addition level of glycerin: 3±0.5g/L;pH: 11±0.5;treatment temperature: 80±5℃;treatment time: 10～30min. The physical characteristics of the films were tested: elogationof 102.4±18.5%, tensile strength of 2.35±0.54MPa,water vapor permeability of 35.1±1.9g·mm/ kPa·d·m2 and oxygen permeability of 2.8±0.3 cm3·ηm/m2·d·kPa.Transglutaminase introduced covalent crosslinkage of ε-(γ-glutamyl)-lys between riceproteins, can enhance the films framework and compactness, increase films tensile strength anddecrease water vapor permeability. The result indicated that the tensile strength enhanced by43.9%, water vapor permeability decreased 19.6% without visible change of elongation andoxygen permeability. Scanning electron microscopy was used to investigate the microstructure ofthe films. The results indicated that the uniform and compact of films was enhanced by TG.Various lipids were added into the solution due to RPE films have quite high water vaporpermibility. The presence of stearic acid, sucrose fatty acid ester and bee wax increased the watervapor barrier. And the films contain stearic acid, sucrose fatty acid ester perform better than beewax. The surface and side views indicated that stearic acid and sucrose fatty acid ester caninteract with rice protein, they have little effects on mechanical properties.Almond and peanut kernel were coated with RPE edible films which has low oxygenpermeability. Stored at 40℃ for 40 days, the acid value decreased for 25.8% and 51.2%,peroxide values decreased for 25.1% and 45.3% compared to uncoated samples. So RPE ediblefilms can effectively delay the oil of nuts hydrolyzation and oxidation, extend the shelf life.更多还原