Compression test: an aluminum cylinder probe (Fig. 2A) was
used, with diameter 25 mm, test speed of 1 mm/s and compression
of 50% of the sample height. The necessary force to compress
50% of the sample height, in newtons, was taken to be
the result from the test.
– Cut test: a Warner–Bratzler shear blade with guillotine probe
(Fig. 2B) was used, with test speed of 1 mm/s. The cut was performed
perpendicularly to the main axis of the snack until completely
breaking it. The peak force obtained, in newtons, was
taken to be the result from the test.
– Cut test: a Warner–Bratzler shear blade with a ‘‘V’’ shape probe
(Fig. 2C) was used, with test speed of 1 mm/s. The cut was performed
perpendicularly to the main axis of the snack until completely
breaking it. The peak force obtained, in newtons, was
taken to be the result from the test.
– Puncture test: a needle probe (Fig. 2D) was used, with test speed
of 1 mm/s and perforation of 50 % of the sample thickness. The
peak force obtained, in newtons, was taken to be the result from
the test.
– Shear test: a Kramer shear cell five-blade probe (Fig. 2E) was
used, with test speed of 1 mm/s. Sufficient quantity of snack
was used to cover the bottom of the cell, without overlapping
of the pieces, and shearing was performed until the probe had
completed its travel. The peak force obtained, in newtons, was
taken to be the result from the test.
Before the analyses, the snacks were carefully cut to achieve
standardization regarding the shape for the instrumental test:
– Compression test: all snacks were cut into squares of side length
1.5 cm (smaller than the probe);
– Cut test with guillotine, cut test with ‘‘V’’ shape probe and puncture
test: the cylindrical and ring-shaped snacks were standardized
with lengths of 3 cm; the pellet snacks were cut into rectangles
of length 2 cm and width 1.5 cm; the shell-shaped snacks were
cut to have a diameter of 1.5 cm.
– Shear test: the original shape of all the snacks was preserved.
All analyses were performed at ten replicates.
2.4. Statistical analysis
The means of the sensory attributes were compared using variance
analysis followed by the Tukey test (significant difference