Abstract:
Freezing can adversely affect the quality of liquid egg through co
mplex inter
-
particle
interactions of egg micro
-
particles. The effect of pectin, PG
-
Alginate (PGA), Arabic Gum,
maltodextrin and defrost temperature on the rheological properties, microstructure and
color of frozen egg was studied. The fresh sample exhibite
d a light yellow color with high
values of
L
and positive values of
a
and
b
. Freezing resulted in a reduced
L
value with
slight changes in a and b. The additives could enhance the lightness with the closest values
of
L
to that of the fresh sample detected
for PGA and pectin. Fresh egg with a low
viscosity exhibited near
-
Newtonian flow behavior. However, the freezing
-
thawing
significantly increased the viscosity. Accordingly, the flow behavior index of the frozen
samples was decreased significantly along wit
h a sharp increase in the consistency index,
revealing a pseudo
-
plastic behavior. All frozen samples exhibited higher viscosities than
the fresh sample. Fresh samples contained evenly distributed micro
-
particles ranging
from 0.05 to 5.50
m centering at 1.
27
m. Freezing resulted in aggregated particles with
significantly larger sizes. Maltodextrin significantly reduced the particle size. Further
reduction was achieved by the addition of pectin, PGA, and Arabic gum.
Smallest
particle
size distributions were
achieved at pectin and PGA concentrations of 0.25 and 0.1%,
respectively. The results of this study can be employed for the development of new
products based on frozen egg with no added sugar or salt, while maintaining the physical
and functional properti
es of the final product.
Keywords
:
Arabic gum,
Flow behavior,
Microstructure,
Pectin
,
PG
-
Alginate
.
