ice cream was evident by cryo-SEM for different sources of fat
(Figure 3). Milk fat ice cream (Figure 3A) shows the presence
of a large number of spherical droplets that protrude out of the
air bubble interface. Ice cream formulated with HOSO was also
investigated as a control sample (Figure 3B). The smooth membrane
visible around the air cell was indicative of oil spreading at
the interface. A fat network was not formed in that case, thereby
compromising incorporation of air and stabilization of the air cell.
RBW oleogel seemed to aggregate at the interface forming a rough
membrane but with no definition of droplet shape (Figure 3C).
RBW oleogel samples also showed platelets of fat that protruded
from the fat layer around the air interface. The aggregation of fat
at the air cell interface in RBW oleogel ice cream at different
concentrations of emulsifier was also evident (Figure 4). Samples
formulated with lower concentration of emulsifier (0.05%) had almost
no aggregation of fat at the air cell interface (Figure 4A). The serum of the same sample, however, displayed a large number of
separate spherical fat droplets instead of clusters. When emulsifier
was added at higher concentration (0.2%), more fat aggregation at
the air interface was observed and the presence of single fat droplets
at the serum phase was reduced (Figure 4B). An increase in fat
concentration at the air cell interface was observed at lower magni-
fication, which increased the distortion of the air cell (Figure 4D)
when compared to an ice cream with lower fat aggregation at the
air cell (Figure 4C).