Evaluation of the Particle Size of Fat Globules in a Milk Model Emulsion by Photon Correlation Spectroscopy

Abstract

A technique using photon correlation spectroscopy has been developed to measure the average diameter and the relative dispersion of fat globules in a milk model emulsion (sodium caseinate, butter oil, and a lipophilic emulsifier). Dynamic light-scattering experiments were performed on two latex suspensions (261 and 624 nm) to determine relative accuracy (1%), reproducibility (.3 and 1.2%, respectively), experiment duration (20 min), and fit to log-normal distribution (chi-square < 1) of the instrument. The photon correlation spectroscopy sizing technique was used to evaluate particle size in a milk model emulsion obtained through microfluidization before and after suspension in a “dissociating buffer”. Dissociation of proteins facilitated the evaluation of fat globule average diameter (434.6 nm) with a reproducibility (for 12 measurements) of 4.2% and a relative width of 43.1%. © 1991, American Dairy Science Association. All rights reserved.