Table 1 reports the nutrition analysis of cake formulations.
Control cake contained 335 kcal, 10.7 g total fat,
1.7 g saturated fat, and 28.4% energy from fat per 100-g
cake. The 50% oil substituted cake has 36 fewer kcal per
100-g portion than the control and 19.7% of energy from
fat (a reduction of around 62% in actual energy derived
from fat). The effect on energy reduction and on energy
from fat in the cakes where eggs were substituted by chia
gel was less intense than the effect of substituting oil by
chia gel (50% egg substituted cakes have 7 fewer kcal
than control, and a reduction in energy from fat of only
4.7%).
An improvement in the quality of the fat profile in the
cakes was observed as eggs or oil was substituted with
chia gel. As the degree of substitution of oil or eggs increased,
there was less saturated fat (see Table 1), from
1.7 g saturated fat for control to 1.4 g for 50% egg substituted
formula and 1.1 g for 75% oil substituted formula.
Also, the ratio of n-6 to n-3 fatty acids improved as the
substitution increased. Substituting eggs with chia gel
caused the ratio of n-6 to n-3 fatty acids to decrease from
a value of 215.7 (control) to 28.9 (75% substitution). When
oil was substituted with chia gel, the ratio decreased to
13.2 (75% oil substitution). Cholesterol content decreased
as eggs were substituted with chia gel (Table 1).
As shown in Table 2, substituting oil or eggs within the
cake formulation (with chia gel) did not greatly affect the functional properties of the cake. In fact, cake weight was
not statistically different from control at any substitution
level (Table 2), which means that the yield of cake would
not be affected with the use of chia gel. However, cake
volume, an important cake functional characteristic, was
affected when oil or eggs were replaced with chia gel
(Table 2) (P0.05). As substitution increased (above
50%), cakes yielded less volume upon baking, which
means that the product is less aerated and denser. Symmetry
of the product remained unchanged (P0.05) when
substitution levels increased (except for at the 75% egg
substitution level).
The analysis of variance of the sensory evaluation results
(Table 2) showed that there was a statistically significant
effect when replacing oil or eggs with chia gel for
acceptability, color, texture, and taste (P0.05). Post hoc
analysis indicated that the differences appeard when the
percentage of substitution was 50% or 75%, and that
there was no significant statistical difference between the
control formula and the cake made with 25% egg or 25%
oil substitution (P0.05; see Table 2). Despite the statistical
differences observed (Table 2), the sensory results
indicated that the average preference ratings for the 50%
and 75% egg or oil substitution generally ranged from
neutral (“like nor dislike”) to “like slightly,” which indicates
that panelists did not dislike the products that
contained chia gel. Control cake formulation obtained the
highest score for all sensory characteristics evaluated
(Table 2).
For a fat replacer to be successful it should improve or
at least preserve the functional characteristics and sensory
feelings of the food in which it will be used. In this
case, the fat replacer should maintain the functional
characteristics of the product (ie, cake weight, cake volume,
and symmetry) and preserve the taste, texture, and
color of the cake as compared to the traditional formula
(control). This study showed that substituting eggs or oil
within the cake formulation with chia gel up to a level of
25% maintained the functional and sensory characteristics
of the product. Further research is needed to optimize
functional and sensory properties of cakes containing
chia gel. Perhaps less-aggressive fat reductions or combinations
of oil/egg substitution in the same formula may
yield products with acceptable functional and sensory
characteristics.