Gold nanoparticle aggregation-based colorimetric assay for β-casein detection in bovine milk samples

Area of Science:

• Analytical Chemistry
• Biotechnology
• Food Science

Background:

• The traditional Kjeldahl method for bovine milk quality evaluation is time-consuming and requires multiple steps.
• Accurate determination of protein content, specifically beta-casein (β-CN), is crucial for milk quality assessment.
• Existing methods for β-CN detection can be complex and unsuitable for rapid, on-site analysis.

Purpose of the Study:

• To develop a rapid, sensitive, and specific colorimetric assay for detecting beta-casein (β-CN) in bovine milk.
• To overcome the limitations of traditional methods like the Kjeldahl analysis.
• To enable on-site detection of β-CN in milk samples.

Main Methods:

• Utilized antibody-functionalized gold nanoparticles (AuNPs) for a colorimetric detection approach.
• Developed a method based on β-CN triggered AuNP aggregation.
• Validated the assay by comparing results with the established Kjeldahl method.

Main Results:

• Achieved a linear dynamic range of 0.08-250 μg mL⁻¹ for β-CN detection.
• Established a limit of detection (LOD) of 0.03 μg mL⁻¹.
• Demonstrated high correlation between the developed assay and the Kjeldahl method for real milk samples.

Conclusions:

• The developed AuNP-based colorimetric assay provides a simple, highly sensitive, and specific method for β-CN detection.
• This assay eliminates the need for complicated sample preparation, making it suitable for on-site applications.
• The method offers a significant improvement over the traditional Kjeldahl method for bovine milk quality evaluation.