THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph

initial soy biomass; SNF and SMF. The differing characteristics between them were mainly
exhibited through water retention, opacity and colour.
Figure 5.1c displays the SNF obtained from the second stage filtration step after acid
hydrolysis. These fibers were first observed in the second stage filter due to its self-aggregating
properties which created translucent gel-like structures. The SNF’s is thought to be released
from the main SF mass which accumulated on the second stage filter over time. The gel-like
appearance was observable in both the first and second stage indicating that SNF was also
present in the final SF after chemical treatment. It should be noted that the appearance of these
fibers were only observable after the acid hydrolysis step. Both the Alkaline 1 and Alkaline 2
treatments yielded no observable gel-like structures in the second stage filter. In addition,
preliminary trials found that the release of SNF was highly dependent on the rehydration of the
starting biomass. Without rehydration, gel-like structures and loose fibers were not observed
after acid hydrolysis.
After decanting the liquid portion from centrifugation, the gelled SNF had a fiber
concentration of 0.03 ± 0.01% w/w indicating the highly hydrophilic nature of the fibers.
Preliminary trials showed that these gelled structures were relatively weak and could be broken
easily but were able to reform back into a gelled structured after ultrasonication for at least 1
min. This suggests that the fiber-water interaction could be re-established by shear which is
unconventional of typical gelling behaviour. The colloidal gel was stable and progression of
syneresis was not evident even after 2 weeks of storage in a sealed beaker.
After the chemical treatment, the bulk SF’s were visibly loose and fluffy in comparison to
the initial SF (Figure 5.1e). The presence of bigger fiber fractions could be clearly seen with
distinct solid and liquid phases. After both mechanical treatments, the SF was transformed into
a homogenously distributed suspension with a viscous liquid consistency as shown in Figure
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