Testing adulterated liquid-egg: developing rapid detection techniques based on colorimetry, electrochemistry, and interfacial fingerprinting

Abstract

To develop rapid detection techniques for liquid eggs' adulteration, three types of adulterations were considered: water dilution, manipulation of yolk ratio in whole egg, and blending different varieties of egg white or yolk. Objective: Establish detection techniques utilizing colorimetry, electrochemistry, and interfacial fingerprinting for these adulterations, respectively. Results: Colorimetry allows for detection (1 min·sample^-1) of water dilution through linear (R² ≥ 0.984) and exponential fitting (R² ≥ 0.992); Electrochemistry enables detection (6 min·sample^-1, R² ≥ 0.979) of the adulteration of yolk ratio in whole egg; Interfacial fingerprinting technique effectively detects (detection duration: 10 min·sample^-1, detection limit: 1.0-10.0 wt%) the adulteration of different varieties of egg white. Subsequently, through 3D-fluorescence microscopy (interface height variation: 22.49-573.45 μm), interfacial tension variation (65.54-35.48 mN·m^-1), contact angle variation (89.7°-32.9°), particle size range (free water: 0.94-14.29 μm; protein aggregation: 6.57-10.76 μm), and etc., interfacial fingerprinting mechanism was elucidated. This research contributes novel insights into the detection of adulteration in liquid eggs.

Keywords: Adulteration detection; Colorimetry; Electrochemistry; Interfacial fingerprinting; Liquid egg.