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

[Display omitted] •Liquid Egg adulteration (Awd, Aeyr, Advw or Advy) was fully detected.•Egg water dilution (Awd) is tested by colorimetry (color, opacity, density).•Egg yolk ratio (Aeyr) is tested by electrochemistry (conductivity, salinity, TDS, pH).•Interfacial fingerprinting was developed for the first time to test Advw.•Interfacial fingerprinting mechanism was described by fluorescence microscopes, etc. 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.