The emulsifying capacity of whey protein in b-LGI and
WPF was studied in emulsions containing 4 and 18% fat at
varying concentrations of whey protein. Before recombination,
the whey protein content of b-LGI and WPF was determined
using the Kjeldahl technique. Then, WPF was
concentrated to increase the whey protein concentration to
different values in the 0.15–1.50% range and solutions of
b-LGI were prepared at whey protein concentrations varying
from 0.15 to 0.75%. The efficiency of each WPF
concentrate and each solution of b-LGI in emulsifying anhydrous milk fat at 40–508C was determined by particle
size measurements immediately after processing.
The weight average particle size (d4,3) is shown in
Fig. 3. As fat content did not affect initial particle
size at similar protein-to-fat ratios, particle size was
plotted against protein-to-fat ratio. Increasing the
protein-to-fat ratio led to a rapid decline in d4,3, irrespective
of the whey protein material used in the
system. Thus, whey proteins in WPF and b-LGI were
very effective in covering fat surfaces and consequently, in
inhibiting immediate coalescence. Similar results were
observed by Klemaszewski et al. (1992) for emulsions
(40% peanut oil-in-water) prepared with pure whey protein
material (b-lg, a-la and BSA) and by Agboola and Dalgleish
(1995) for emulsions (20% soya oil-in-water) prepared
with b-lg.