Separation and quantification of milk proteins with the addition of cheese whey by lab-on-a-chip

Abstract The objective of this work was to evaluate microfluidic chip electrophoresis, known as lab-on-a-chip technique, for the detection of milk adulteration using cheese whey in comparison with SDS-PAGE. Raw, pasteurized, processed at an ultra-high temperature (UHT), and powdered milk samples received increasing concentrations of cheese whey (0, 1, 2.5, 5, 10, 20, 30, 50, and 100% v/v), and were subjected to lab-on-a-chip electrophoresis and SDS-PAGE to detect their mixtures. The lab-on-a-chip methodology was able to separate and quantify milk proteins. In addition, the tested technique is easy, rapid, sensitive, and can detect the addition of cheese whey in milk from the lowest level tested (1%) for milk proteins α-casein and β-casein.

摘要 本研究旨在评估微流控芯片电泳（microfluidic chip electrophoresis），又称芯片实验室技术（lab-on-a-chip technique），并结合十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE），用于检测添加干酪乳清的牛乳掺假情况。研究选取生牛乳、巴氏杀菌乳、超高温（UHT）灭菌乳及乳粉样品，向其中添加梯度浓度的干酪乳清（体积分数为0、1、2.5、5、10、20、30、50及100%），随后分别采用芯片实验室电泳技术与SDS-PAGE对上述混合样品进行检测。芯片实验室电泳技术可实现牛乳蛋白质的分离与定量分析。此外，该检测技术操作简便、快速灵敏，能够针对牛乳中的α-酪蛋白与β-酪蛋白，从最低测试浓度（1%）起检出其中添加的干酪乳清。