摘要
采用L-组氨酸(L-His)作为蛋白凝胶功能性的增强剂,将其加入乳清分离蛋白溶液中制备热诱导凝胶,研究L-His对乳清蛋白结构及其凝胶特性的影响。结果表明:在乳清蛋白等电点(pI 5.2)时蛋白形成尺度约1700 nm、具有极小比表面积且几乎不带电的蛋白聚集体,远离蛋白等电点时则所形成的聚集体大小约为400 nm;L-His抑制蛋白聚集体的形成而减小粒径、显著提高聚集体比表面积,促进蛋白分子结构展开并提高其带电量。在经历热诱导后,乳清蛋白在其等电点时形成持水性差的白色凝胶,而在其他pH值时则形成持水性高的黄色凝胶且越远离等电点,胶体黄度值越大;L-His的加入对凝胶颜色变化无显著影响,但能够显著提高凝胶的持水性(P<0.05);有效提高凝胶的质地特性,特别是在pH 7.59和pH 9.74时显著提高乳清蛋白凝胶的弹性及咀嚼性(P<0.05)。这些质构变化可能主要归结于L-His改变了凝胶内的氢键、二硫键和疏水作用力的重排。总之,L-His修饰乳清蛋白结构而改变其凝胶性能且同时受到pH值的影响。
L-Histidine(L-His)was added as a functional enhancer of protein gels to whey protein isolate in aqueous solutions to prepare heat-induced gels.The effects of L-His on the structure and gel properties of whey protein were investigated.The results showed that aggregates with a diameter of about 1700 nm and a very small specific surface area,which were found to be almost uncharged,were formed at the isoelectric point(pI 5.2)of whey protein.However,the aggregate size was~400 nm at pH away from the pI.L-His inhibited whey protein aggregation,reduced the aggregate size but dramatically increased the specific surface area,promoted protein unfolding and increased the amount of charge carried by the protein molecule.Whey protein formed a heat-induced white gel with a low water-holding capacity(WHC)at the pI,whereas the gels formed at other pH values were yellow with higher WHC than at the pI and the yellowness was increased as pH was farther away from the pI.Despite having no obvious impact on the color,L-His significantly enhanced the WHC(P<0.05)and improved the textural properties of gels.More notably,the elasticity and chewiness of the gels that were formed at pH 7.59 and 9.74 were significantly improved by L-His(P<0.05).These changes in gel functional properties could be mainly attributed to the fact that L-His could impel the rearrangement of hydrogen bonds,disulfide bridges and hydrophobic interactions involved the gel matrix.Overall,L-His changed the structure of whey protein and improved the gel properties,and its effect was affected by pH.
作者
王耀松
马天怡
胡荣蓉
张唯唯
应瑞峰
黄梅桂
唐长波
WANG Yaosong;MA Tianyi;HU Rongrong;ZHANG Weiwei;YING Ruifeng;HUANG Meigui;TANG Changbo(College of Light Industry and Food Engineering,Nanjing Forestry University,Nanjing 210037,China;Key Laboratory of Meat Processing and Quality Control,Ministry of Education,College of Food Science and Technology,Nanjing Agricultural University,Nanjing 210095,China;Key Laboratory of Animal Products Processing,Ministry of Agriculture and Rural Affairs,Synergetic Innovative Center of Food Safety and Nutrition,College of Food Science and Technology,Nanjing Agricultural University,Nanjing 210095,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2021年第6期16-23,共8页
Food Science
基金
国家自然科学基金青年科学基金项目(31401530,31501509)
江苏省优势学科建设项目青年创新基金项目(80900604)。
