Quantification of proteins in dairy products using an optical biosensor

Area of Science:

• Dairy Science
• Analytical Chemistry
• Biotechnology

Background:

• Accurate quantification of milk proteins is crucial for dairy product quality control.
• Existing methods for milk protein analysis can be time-consuming or require sample pretreatment.
• Developing rapid and sensitive techniques is essential for efficient dairy processing.

Purpose of the Study:

• To develop and validate novel optical immunosensor techniques for milk protein quantification.
• To simultaneously quantify major intact caseins (alpha(s1), beta, kappa) in milk.
• To assess the severity of heat treatment in milk by quantifying native and denatured alpha-lactalbumin.

Main Methods:

• Utilized a 2-step sandwich assay with specific monoclonal antibodies for casein quantification.
• Employed optical immunosensor technology for rapid detection of protein forms.
• Developed assays to differentiate native and heat-denatured alpha-lactalbumin.

Main Results:

• Simultaneous quantification of intact alpha(s1)-, beta-, and kappa-caseins achieved in 10 minutes with a detection limit of 0.87 microg/mL.
• Successfully applied the casein quantification assay to raw and drinking milks.
• Discriminated various heat treatments (pasteurization, UHT, sterilization) by analyzing alpha-lactalbumin denaturation in 4 minutes.
• Demonstrated high repeatability and automation for both techniques with no milk pretreatment required.

Conclusions:

• Optical immunosensor technology offers a rapid, sensitive, and specific platform for milk protein analysis.
• The developed methods provide accurate quantification of intact caseins and effective assessment of milk heat treatment.
• These techniques have significant potential for application in the dairy industry for quality control and process monitoring.