Error estimation, validity and best practice guidelines for quantifying coalescence frequency during emulsification...

Area of Science:

• Chemical Engineering
• Colloid and Surface Science
• Food Science & Technology

Background:

• Emulsification processes are critical in food and pharmaceuticals, often involving high disperse phase volumes.
• Droplet coalescence significantly impacts emulsion stability and processing outcomes.
• The step-down technique is widely used to measure coalescence frequency, but its accuracy is debated.

Purpose of the Study:

• To theoretically validate the step-down technique for measuring coalescence frequency.
• To quantify systematic errors arising from experimental non-idealities.
• To provide best practice guidelines for accurate emulsification studies.

Main Methods:

• Derivation of error estimates for limited sampling rates.
• Analysis of errors due to non-instantaneous step-down.
• Assessment of errors from residual fragmentation post-step-down.

Main Results:

• Limited sampling rate, non-instantaneous step-down, and residual fragmentation introduce systematic errors in coalescence rate estimation.
• These errors can be minimized by careful selection of experimental parameters.
• The step-down technique remains a valid method under optimized conditions.

Conclusions:

• The step-down technique is a suitable method for quantifying coalescence frequency in emulsification.
• Best practice guidelines are provided to mitigate systematic errors.
• Recommendations are tailored for general and specific (stirred tank oil-in-water) emulsification systems.