Bienzymatic amperometric sensor for protein assay in milk.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Biosensors

Background:

• Accurate protein content determination is crucial for milk quality assessment.
• Existing methods may lack selectivity or efficiency for complex matrices like milk.
• Development of sensitive and selective biosensors is an active area of research.

Purpose of the Study:

• To develop and validate a novel bienzymatic amperometric sensor for milk protein analysis.
• To evaluate the sensor's performance with and without flow injection analysis (FIA).
• To assess the sensor's reliability and recovery rate for protein quantification in milk and milk products.

Main Methods:

• Fabrication of a bienzymatic amperometric sensor utilizing carboxypeptidase A and L-amino acid oxidase.
• Characterization of sensor response, including detection limit and linear concentration range.
• Application of the sensor in flow injection analysis (FIA) for real-time protein assay.
• Determination of protein recovery rates in milk and milk products with and without FIA.

Main Results:

• The sensor exhibited a low detection limit of 1.5 micromol/L.
• Linear concentration ranges were observed between 1.8–2.8 micromol/L (without FIA) and 2–3.5 micromol/L (with FIA).
• High selectivity against milk interferences was achieved, with average protein recovery rates of 99.06% (without FIA) and 99.73% (with FIA).

Conclusions:

• The developed bienzymatic amperometric sensor is highly effective for accurate protein quantification in milk.
• The sensor's performance is enhanced when integrated with flow injection analysis (FIA).
• The sensor demonstrates excellent reliability and recovery, making it suitable for routine analysis of milk and dairy products.