不同类型蛋白质及其添加量对牛乳介电特性的影响  

Influence of Different Proteins and Their Additive Amounts on Permittivities of Milk

作　　者：郭文川[1] 孔繁荣[1] 

机构地区：[1]西北农林科技大学机械与电子工程学院,陕西杨凌712100

出　　处：《农业机械学报》2016年第8期248-254,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(31671935);江苏省农产品物理加工重点实验室开放基金项目(JAPP2014-2)

摘　　要：为了了解不同类型蛋白质及其添加量对生鲜牛乳介电特性的影响规律,为牛乳蛋白质掺假提供新的检测手段,采用同轴探头技术测量了20~4 500 MHz范围内乳清蛋白、大豆蛋白和三聚氰胺的蛋白质添加量（0~4.70%）对生鲜牛乳相对介电常数ε＇和介质损耗因数ε″的影响规律,分析了不同类型蛋白质及其添加量对介电特性的影响机理。结果表明：在所测频率范围内,牛乳的ε＇随频率的增加而减小,牛乳的ε″在2 000 MHz附近有最小值;当蛋白质添加量相同时,添加大豆蛋白的牛乳具有最大的ε＇,而添加三聚氰胺的牛乳具有最小的ε＇;添加乳清和大豆蛋白的牛乳的ε＇和ε″均随蛋白质添加量的增加呈线性增大,但添加三聚氰胺的牛乳的ε＇和ε″与蛋白质添加量之间的相关性不明显。研究说明,不同类型的蛋白质及其添加量对牛乳介电特性的影响规律不同,这种差异使基于介电特性识别牛乳中不同类型的蛋白质及其添加量成为可能。To understand the influence of different proteins and their additive amounts on permittivities of milk,and to explore a method for detecting the adulteration of milk protein,the open-ended coaxial-line probe technology was used to study the influence of frequency（ 20 ~ 4 500 MHz） and protein additive amounts（ 0 ~ 4. 70%） of different proteins, including whey protein, soybean protein and tripolycyanamide,on permittivities（ dielectric constant ε＇ and dielectric loss factor ε″） of milk,and the influence mechanism of different proteins and their additive amounts on permittivities were analyzed. The results showed that over the frequency range of 20 ~ 4 500 MHz,ε＇ was decreased with the increase of frequency,and ε″ decreased firstly and then increased with the increasing frequency. The minimum value of ε″ observed at around 2 000 MHz. With the same protein additive amount,the milk added with soybean protein had the largest ε＇,while the milk added with tripolycyanamide had the smallest ε＇. ε″ of the milk added with whey protein and soybean protein were higher than the values of milk with tripolycyanamide at the same protein additive amount. The permittivity values（ ε＇ and ε″） of milk were increased linearly with the increase of additive amounts of soybean and whey protein,and all the linear correlation coefficients were greater than 0. 92. However,the correlation between the permittivities values and tripolycyanamide content was not obvious,and all the linear correlation coefficients were less than0. 51. The study results indicated that different proteins and their additive amounts had different influence on dielectric properties of milk,which made it possible to identify the different protein types and their additive amounts in milk based on dielectric properties.

关 键 词：牛乳 乳清蛋白 大豆蛋白 三聚氰胺 介电参数 

分 类 号：TS252.2[轻工技术与工程—农产品加工及贮藏工程]