42 research outputs found
The shock compression of microorganism-loaded broths and emulsions: Experiments and simulations
By carefully selecting flyer plate thickness and the geometry of a target capsule for
bacterial broths and emulsions, we have successfully subjected the contents of the capsule to
simultaneous shock and dynamic compression when subjected to a flyer-plate impact
experiment. The capsules were designed to be recovered intact so that post experimental
analysis could be done on the contents. ANSYS® AUTODYN hydrocode simulations were
carried out to interrogate the deformation of the cover plate and the wave propagation in the
fluid. Accordingly, we have shown that microorganisms such as Escherichia coli,
Enterococcus faecalis and Zygosaccharomyces bailii are not affected by this type of loading
regime. However, by introducing a cavity behind the broth we were able to observe limited
kill in the yeast sample. Further, on using this latter technique with emulsions it was shown
that greater emulsification of an oil-based emulsion occurred due to the cavitation that was
introduced
Formulation and characterisation of wheat bran oil-in-water nanoemulsions
Wheat bran oil (WBO) has been reported to have an important content of bioactive compounds, such as
tocopherols, alkylresorcinols, steryl ferulates and other phenolic compounds; however, its poor solubility
in water systems restricts its applications in the food industry. This study is focussed on the formulation
of oil-in-water (O/W) nanoemulsions of WBO in order to improve the bioaccessibility of its active compounds.
The influences of oil concentration, surfactant type and concentration, and emulsification
method, on the droplet size and stability of the nanoemulsions were investigated. Response surface
methodology was used to optimise the conditions for preparing stable nanoemulsions with the minimum
droplet size. The optimal nanoemulsion was obtained when 1% of WBO and 7.3% of a surfactant mixture
of Span 80 (37.4%) and Tween 80 (62.6%) were emulsified in water by high intensity ultrasonication for
50 s after pre-emulsification with a high speed blender during 5 min. The optimal nanoemulsion showed
good stability over time and antioxidant and tyrosinase inhibitory activities, which make it suitable for
use in food applications.This work is part of the GALANG project (Ref.: ITC-20113029)
financed by the Spanish Government through CDTI