chapter 7 -- 2 Flashcards
What is the mechanism responsible for the thickening of emulsion sauces?
Volume fraction of particles increase
Name one aspect which is important in the making of an emulsion sauce, and one aspect which is important in its stabilisation.
Stirring in with small amounts, making small droplets and using the right surfactant
Name three routes to stabilise an emulsion sauce
Thickening the continuous phase, having enough droplets to fill space to the required extent or to induce enough repulsion so to at least effectively fill
space
Why should one be careful with the temperature of the food on which one wants to pour an emulsion sauce
Too high temperature can destroy the sauce
Why can an emulsion sauce that is stored at cold temperature be destabilised upon heating?
Too cold may deprive the droplets from their emulsifiers, thus leading to coalescence while heating again.
How should one start with making a mayonnaise, oil adding to an aqueous solution or vice versa?
Oil to aqueous phase.
What may happen to a mayonnaise while preparing if one adds too much oil at the end of the process?
Oil is separated out.
How can one “save” an emulsion sauce?
By stirring in the phase-separated sauce a surfactant containing liquid phase.
how come the granules become more viscous while heating
When the granulas are disrupted and they are in a sufficient concentration to interact with each other
Why do sauces based on flour or starch become less thick in the mouth and in sauces thickenend with other polymers it doesnt.
the starch is hydrolysed by amylase in the mouth
what does the Laplace equation have to do with emulsion based sauces?
The smaller an oil droplet, the stiffer it will be. Stiffer oil droplets will affect the emulsion in a different way
how does an emulsion based sauce become viscous
If you continue to add oil, you will see that the viscosity of the emulsion starts to increase. There are so many particles in the continuous phase that they start to touch each other. And these interactions are seen as an increase of the viscosity of the system. If you exceed the certain volume fraction of the dispersed phase the continuous phase will not be sufficient anymore to offer space to the newly formed droplets. At this point phase, the inversion of the emulsion will occur.
how come that at a phase inversion that you cannot thicken the oil ?
you do not have enough water droplets
