Recent advances on emerging biosensing technologies and portable analytical devices for detection of dairy proteins

Dairy products are an important part of a daily diet, and the dairy protein they contain is not only a key nutrient but also possesses biological activity. However, dairy proteins (such as casein, β-lactoglobulin (β-LG), and α-lactalbumin (α-LA) in dairy products are likely to cause some allergic reactions. In addition, dairy proteins are also used as important markers for identifying dairy product adulteration. Therefore, the detection of dairy proteins is extremely significant for preventing food allergy and identifying dairy product adulteration. Although traditional detection methods (such as chromatography-based methods) can obtain sensitive detection results, they usually suffer from several limitations to some extent, such as time-consuming procedures, expensive equipment, and the requirement of specialized personnel. Recently, emerging biosensing technologies and portable analytical devices have been successfully applied to the detection of dairy proteins, enabling rapid, highly sensitive trace analysis with a remarkable sensitivity level reaching picogram per milliliter (pg/mL) or even femtogram per milliliter (fg/mL). In this review, we summarized the latest advancements on emerging biosensing technologies and portable analytical devices for dairy protein detection. Firstly, several common traditional detection techniques for detecting dairy proteins were briefly introduced and compared. Subsequently, we summarized the design and development of emerging biosensing technologies (e.g., electrochemical, colorimetric, fluorescence, surface-enhanced Raman spectroscopy (SERS), and photoelectrochemical biosensors) for detection of dairy proteins, as well as portable detection devices (test strips and microfluidic devices). In addition, the advantages and disadvantages of these detection technologies for dairy protein detection were also discussed. Most importantly, the remaining challenges and future prospects in this field were proposed.