Red emitting fluorogenic dye as an efficient turn-on probe for milk allergen.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Food Science

Background:

• Accurate quantification of milk allergens like beta-lactoglobulin (β-LG) is crucial for food safety and consumer health.
• Existing methods for allergen detection can be time-consuming, complex, or destructive.
• Development of simple, rapid, and non-destructive techniques is highly desirable for dairy product analysis.

Purpose of the Study:

• To develop and validate a novel fluorescence-based assay for the sensitive and selective detection of beta-lactoglobulin (β-LG).
• To utilize the red-emitting fluorogenic dye quinaldine red (QR) as a probe for β-LG quantification.
• To assess the applicability of the QR probe in complex matrices like milk and whey.

Main Methods:

• Spectroscopic investigation of the interaction between quinaldine red (QR) and beta-lactoglobulin (β-LG).
• Fluorometric titration to determine the limit of detection (LOD) in buffer and milk matrices.
• Comparison of results with densitometry methods for validation.

Main Results:

• Quinaldine red (QR) exhibits enhanced fluorescence upon binding to β-LG due to reduced torsional agility and TICT state formation.
• Achieved a limit of detection (LOD) of 52.1 nM in buffer and 0.21 μM in a 5% bovine milk matrix.
• Demonstrated high selectivity, sensitivity, repeatability, and rapid response for β-LG detection.

Conclusions:

• Quinaldine red (QR) serves as an efficient 'turn-on' fluorescent probe for the quantification of beta-lactoglobulin (β-LG).
• The developed method is suitable for analyzing milk allergens in various dairy products.
• This fluorescence-based approach offers a simple, fast, and non-destructive alternative for allergen quantification.