Fluorescence-based viscosity determination of corn starch using Auramine O.

Area of Science:

• Food Science
• Rheology
• Analytical Chemistry

Background:

• Viscosity is crucial for food hydrocolloids like starch, affecting texture and stability.
• Conventional viscometry methods are time-consuming, require large samples, and lack real-time capabilities.

Purpose of the Study:

• To develop a rapid, non-invasive method for microviscosity determination in corn starch systems.
• To utilize a fluorescence-based approach with Auramine O as a molecular rotor probe.

Main Methods:

• Employed Auramine O, a molecular rotor probe, for fluorescence measurements.
• Correlated fluorescence intensity with bulk viscosity across varying corn starch concentrations (0.1-2.5%).
• Assessed probe stability across pH ranges and over time, evaluating ionic interference.

Main Results:

• A strong linear correlation (R²=0.9929) was found between fluorescence intensity and viscosity, following the Förster-Hoffmann relation.
• Auramine O demonstrated stability across pH 5-9 and 240 minutes, with minimal ionic interference.
• A tenfold increase in fluorescence intensity was observed in 2.5% corn starch compared to water, indicating high sensitivity.

Conclusions:

• The fluorescence-based method provides a sensitive, low-sample-volume, real-time technique for microviscosity determination.
• This platform is versatile for characterizing starch and other hydrocolloids, aiding food quality control and process monitoring.
• The method supports clarification of starch-viscosity relationships and enables scalable, high-throughput analysis.