摘要
牛奶是一种纯天然饮料,一直以来备受人们喜爱。牛奶可以强化骨骼,补充钙元素,提高机体免疫力。对于不同国家来说,牛奶分有不同的等级。为了提高和严格把控牛奶的质量,建立同位素质谱,同时测定牛奶中酪蛋白的δ^2H、δ^13C、δ^15N和δ^34S值。根据经过优化的等点沉淀法,在牛奶中提取高纯度蛋白质,利用纳升液相色谱-四级杆飞行时间质谱进一步分析提取的蛋白,并确认该蛋白为酪蛋白。根据EA-IRMS检测分离后的酪蛋白δ2H、δ^13C、δ^15N和δ^34S值发现,δ^2H、δ^13C、δ^15N和δ^34S的值和牛奶的产地有一定关联。同一产地的牛奶中酪蛋白的δ^2H、δ^13C、δ^15N和δ^34S值分布范围一致,但不同产地的δ^2H、δ^13C、δ^15N和δ^34S值没有明显的相关性。利用这种方法可以有效简化前期的处理过程,且结果具有很好的重现性,方便进行检测,准确度高,能够用于调查市面上销售牛奶的原产地。
Milk,one kind of natural drink,is wildly accepted by humans,and sometimes even called "white blood". It can supply calcium element,strenthen the immune system for our human bodies. In different countries,milk is also classified in different levels. In order to improve the quality control,a method to determine the casein protein δ^2H、δ^13C、δ^15N、δ^34S that milk contains was established. Firstly,high purity protein is obtained from milk by doing equal point precipitation,and can be proved as casein protein by fulfilling the lift-up time-four rod mass spectrometry. Secondly,the seperation and determination of the δ^2H、δ^13C、δ^15N、δ^34S case in values was made by using the method EA-IRMS,and found that there was a certain correlation between the δ^2H、δ^13C、δ^15N、δ^34S values and the original place of the milk production. The casein δ^2H、δ^13C、δ^15N、δ^34S values of the milk produced in the same region seems similar,but varifys for the ones produced in different regions.The method has the advantages of simple pretreatment,good reproducibility,convenient test and high accuracy. By using this method,we can trace the original producing place of the milk sold in the domestic market.
作者
杨丽萍
Yang Liping(Shanghai Denuo Product Testing Co.,Ltd,Shanghai 200436,China)
出处
《现代食品》
2019年第11期137-140,共4页
Modern Food
