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

¹ Centre de Recherche STELA, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Ste. Foy, PQ, Canada G1K 7P4

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%.

Key Words: photon correlation spectroscopy • fat globule diameter • model emulsion

Submitted on August 13, 1990
Accepted on March 7, 1991