【作者】 王耀松； 陈洁； 熊幼翎；

【Author】 Yaosong Wang~a Jie Chen~a Youling L.Xiong~(a,b) (a State Key Laboratory of Food Science and Technology,Jiangnan University,Wuxi,214122; b Department of Animal and Food Sciences,University of Kentucky,Lexington,40546,China)

【机构】 江南大学食品科学与技术国家重点实验室； 肯塔基大学动物与食品科学系；

【摘要】 单宁物质大量存在于自然界植物里,具有抗氧化、低毒、能与蛋白反应的性质。本实验重点研究氧化单宁酸对乳清蛋白膜结构与功能的影响,探讨利用它物质来改善乳清蛋白膜的可能性。实验采用5%含量的单宁(单宁与蛋白质量比)加入成膜溶液,铺展法来制备乳清蛋白膜材料,并且对产物膜的交联性、机械性、热密封性、光透性、水汽透性、溶解性以及消化性进行表征。研究结果表明,5%的氧化单宁酸交联乳清蛋白,能提高膜材料的杨氏模量和热塑封性,降低紫外光透过率和膜的光透性;pH6和pH7溶液下膜的浸出度显著上升,SDS-PAGE分析浸出物主要是β-Lg及其二聚物;显著提高在水中的膨胀度,但对水气通透率和胰酶消化率无显著性影响。SDS-PAGE电泳结果显示,经过氧化单宁酸处理后,乳清蛋白膜产生了共价聚集;原子力、红外和扫描电镜以及溶解度的结果表明,酚类共价交联蛋白和物理效应导致蛋白分子形成聚集网络结构,这是导致乳清蛋白膜功能变化的原因。为此,单宁酸可作为一种交联剂取代有毒试剂来改善蛋白生产膜。更多还原

【Abstract】 Tannic acid（TA）,an abundant phenolic compound in plants,exhibits antioxidant activity and can react with proteins.Through cross-linking with proteins,tannic acid might be able to modify the properties of films made from whey protein isolate（WPI,6%）.In this study,mechanical properties（Young’s modulus）,thermal properties（T₀,T_d,T_p）,hydration（swelling and protein leachability）,digestibility,light transmission,and water vapor permeability（WVP）of WPI films were evaluated.Treatments of WPI with 5%tannic acid（w/w,TA/WPI）resulted in higher Young’s modulus,heat sealability,degree of hydration, and protein solubility of WPI films.SDS-PAGE confirmed that the main leached component from both tan- nic acid-treated and untreated WPI films were(3-Lg and its dimers.Tannic acid treatments did not affect WVP and only had a minor impact on film digestibility.These physical properties as influenced by tannic acid were corroborated by the atomic force microscopy（AFM）,scanning electron microscopy（SEM）,and Fourier transform infrared（FT-IR）analyses.The improved WPI film properties can be attributed to the enhanced polymerized network formation due to cross-linking by oxidized tannic acid.Therefore,tannic acid provides a potential alternative to other cross-linkers in the production of edible WPI films.更多还原