Starch (1/31) Flashcards
What food products can starch be found in?
breads, cereals, grains, potatoes, and other foods
What percent of the world’s calories does starch provide?
70-80%
Other than starch, what does breads and cereals offer?
vitamins and minerals
What part of the plant does starch come from?
seeds, roots, tubers, cereal grains, and legumes
What is the storage energy of the plant?
starch
T/F: starch is a polysaccharide
true, many glucoses that are chemically bound together
What are the two fractions of starch?
amylose and amylopectin
What are characteristics of amylose?
long and linear and can thicken or gel
What are characteristics of amylopectin?
compact and branched and only thickens
What is the difference between a gel and a thick liquid?
gels hold their shape when you leave them alone and thick liquids take the shape of the container they are put in
What are examples of native starches?
cornstarch, tapioca, wheat, potato, rice, and arrowroot
What are examples of the modified starches?
hydrolyzed (chopped up), cross-linked (stuck together), substituted (new stuff added), and arrowroot
What are examples of the somewhere in between starches?
genetically engineered and physically modified (pre-gelatinzed starch, cold water swelling, and heat treated)
What is physically modified starch?
instant starch, don’t need to cook for it to think/gel, will absorb cold water, and is useful in “instant pudding”
What is hydrolysis or acid-converted starch?
“thin-boiling starch”, low viscosity paste, produces stiff gel, and useful in confectionary industry
What is cross-linked or cross-bonded starch?
lower viscosity and increase temp for hydration, resistant to shear or stirring, greater tolerance of heat, and usful for canned soup, spaghetti sauces, and pie fillings
What is substitution or stabilization good for?
prevents retrogradation, improves clarity, reduces syneresis, and useful for frozen or refrigerated starch-thickened foods
What is syneresis?
when the water comes back out of a gel doe to retrogradation
T/F: resistant starch is not digested by human body
true
What are the four main types of resistant starch?
RS1, RS2, RS3, RS4
What happens when you cook starch granules?
changes in the starch structure
What happens when you cook starch with dry heat?
starch becomes more soluble, reduces the thickening ability, dextrinization, and brown/nutty/toasted flavor develops
What are examples of dry heat?
brown roux and espagnole sauce. a higher proportion of starch to liquid is needed
What happens when you cook starch with moist heat?
starch granules are insoluble in cold water, colloidal dispersion produced with heating, starch paste forms
What happens when starch is heated with moisture?
the granules absorb the water and change shape
What is gelatinization?
with heat, starch granules absorb water and swell which increases viscosity and increases translucency
What is gelation?
when something, anything, forms a gel
T/F: retrogradation is a fast process
false, happens to starch gels over time
What happens during retrogradation?
starch gels reorganize, losing water and becoming dense
What are the factors affecting starch pastes?
temperature and time of heating, agitation or stirring, acidity (pH), addition of sugar or fats & proteins
What is a roux?
starch + fat + heat and cook till thick and smooth and add liquid to hot roux
What is a slurry?
starch + cold water and mix until smooth and add slurry to hot liquid
What mother sauces can be thickened with starch?
bechamel, veloute, espagnole
What mother sauces may be thickened with starch?
tomato
What mother sauces are thickened with an emulsion?
hollandaise
What do cream soups use for flavoring?
mirepoix
What are cream soups thickened with?
starch (roux or slurry), cream, pureed starchy vegetables
What are typical starch choices for starch thickened desserts?
corn starch (clear and glossy), flour, and tapioca
How are starch-thickened desserts made?
by separating starch by mixing with sugar then cold liquid and then cook starch mixture before adding eggs
How do we do microwave cooking of starch?
best for small batches and stop microwaving and stir in (approximately once every 1 minute)
