chapter 7 Flashcards
name three flour based sauces
espagnole
veloute
bechamel
name three emulsion based sauces
hollandaise
bearnaise
mayonnaise
Describe the mechanism responsible for the thickening of flour based sauces
The starch (the amylose and amylopectin) molecules get into the solution and effectively fill up space, leading to thickening
What is a starch granule
Granule consisting of amylose and amylopectin molecules, that is being made
within the plant
What determines the crystallinity of the starch granule?
Ratio between amylose and amylopectin
Describe what happens to a starch granule in water when it is heated (distinguish two stages, and mention the temperatures that define these two stages).
below melting point (60-70 degrees) the granules start swelling. During the absorption, the amylopectin in the cystallized loses its order structure and the crystals are broken.
Then above the melting point (80-90 degrees) more swelling occurs and the granules are disrupted
What happens at the second stage when heating an initial starch granule solution in terms of opaqueness and thickening
More opaque, and thicker.
Why is the thickening process due to starch molecules, once at the right temperature, so efficient? Illustrate the answer with a drawing of the colloidal structure present when thickening is occurring
Very long molecules, leading to a high radius of gyration, thus efficient way
of filling up the liquid space
Give one important distinction between wheat starch and corn starch in terms of their ingredients, and explain how that affects their appearance once they are thickening the solution they are in.
Wheat starch contains proteins, while corn starch does not. First is non-transparent, while the second is transparent and glossy upon cooling
What type of sauce should one use to pour over food in order to establish a glossy look, a wheat type of starch or a corn starch?
corn starch
