Microcrystalline cellulose effects on the rheology of mixed oleogels
structured with candelilla wax and saturated fat
The structuration processes of mixed oleogels produced with candelilla
wax (CW, 0 or 3%), fully hydrogenated soybean oil (FH, 5-15%), and
microcrystalline cellulose (MC, 0-9%) were studied to define their
rheological effects. During the cooling CW crystals performed as
nucleation sites for FH. The elastic modulus (G’) of oleogels with FH
and 3% CW were more than two orders of magnitude higher than those
produced with 0% CW. Adding MC to the oleogels increased slightly the
G’. Independently of the amount of MC, oleogels structured with
increasing amounts of FH and 0% CW showed the elastic properties
scaling of colloidal gels. This behavior was lost by adding 3% CW,
implying that in mixed FH-CW oleogels, the CW crystal network dominated
the oleogel rheology. The flow point and the mechanical reversibility of
oleogels and commercial butter (CB) was also determined. CB showed flow
points at 44 and 59% strain and mechanical reversibility values of 29
and 35% of G’ measured in a pre-shear step. Adding MC to oleogels
structured with FH and 0% CW increased their flow point (37.2%) near
those of CB. This effect was not produced in mixed FH-3% CW oleogels.
The mechanical recovery of oleogels produced with FH, MC, and 0% CW
tend to decrease as the FH content increased. CW and MC did not show a
simple concentration–effect relationship for the mechanical recovery.
Nonetheless, oleogels structured with 3% CW and 10% FH and 6-9% MC
showed mechanical recovery (~60%) close to that of CB.