Flashcards
Exam 1
Cards in this deck (37)
- 1Why is butter cut into pea sized chucks for crust?flakes
- 2How might replacing butter with oil affect the texture o the crust?coat all of flour; minimal gluten development through flour absorption of water; no flakes from fat clumps
- 3what reaction eventually takes place when sugar is added to the hot skillet?caramelization
- 4what is the function of the eggs in the pie filling?thickening through denaturation and coagulation in which side groups on proteins rebound to each other and trap liquid in a mesh-like network
- 5why is the hot sugar milk mixture slowly added to the eggs in the filling?to prevent early denaturation and coagulation of eggs which would result in lumps
- 6describe what is happening as the egg whites are beaten to stiff peaks for the meringue.air incorporated, proteins denature; assembled at bubble/liquid interface with hydrophilic part in liquid and hydrophobic in bubble; prevent water from dripping from the foam by holding air and liquid in place
- 7why is cream of tartar added to the meringue? how does it work?cream of tartar is an acid; H ions bond to the sulfur atoms on side groups that would otherwise bond to themselves resulting in over-coagulation
- 8what reaction occurs to brown the meringue and what 3 elements allow this reaction to take place?Maillard: amino group of a protein; reducing sugar; high heat
- 9describe how heat is being conducted from the hot oil to the ginger and garlic during the frying process, and what happens to the moisture in the ginger and garlic?Frying is a dehydration reaction which heat is conducted to the center of a food as water is drawn out. The water is drawn to the surface and escapes as steam.
- 10How might the flavor of the rice be affected if you used old peanut oil?old oil has decomposed and while be high in mono and diglycerides which had to off flavors. If oil old enough and heated high enough could end up with acrolein, which is liberated glycerol and can have irritating effects
- 11the leeks are cooked until very soft. What is happening at a cellular level?cell membranes are damaged which leads to water loss; cell walls are weakened with pectin and hemiceullose gradually breaking down into shorter chains, no longer serving as an effective cement, resulting in soft texture
- 12How will the color of the leeks (which start out bright green) change with heat? Why?Heat damages the chloroplast membranes that contain chlorophyll. This causes acids tired in the vacuole to come into contact with chlorophyll. This acid displaces the magnesium ion in the chlorophyll resulting in production of pheophytin, which is dull olive green color
- 13This recipe calls for day-old rice. How will heating the rice change its texture? Why does this change occur?Rice will get softer our to reversing retrogradation (which is recrystallization of starch granules due to water migration out of the granule). Adding heat disrupts the crystalline structure again, resulting in softer texture.
- 14Why does the white of the fried egg become a solid while the yolk remains liquid?Different proteins coagulate at different temperature; also fat offers a protective effect.
- 15What would you expect to happen if you added the flour to the hot butter-milk mixture instead of adding it at the beginning? Why?Lumpy because starch would gelatinize around the outside, sealing dry flour inside.
- 16How might the outcome of this recipe differ if waxy corn starch was used instead of flour?Waxy corn starch is 100% amylopectin. It would take much longer to thicken and would not be as which as a flour-thickened sauce.
- 17You accidentally spill a large quantity of vinegar directly into your béchemel. What do you expect to happen? Why?Curdling-acid neutralizes the negative charges on micelles in milk, causing them to be attracted to each other and form clumps; also, acid breaks down starch into shorter chains so get thinner paste
- 18Describe what is happening to the sugar solution as the temperature is increasing.Becoming more concentrated. Syrup is cooked to concentrate the sugar (as temp increases, solubility of sugar increase); temperature is increased to the hard crack stage
- 19Why is the candy poured into a pan immediately instead of cooling as was done for the fudge in lab?To prevent crystallization
- 20How might the outcome of this recipe have differed if it wasn't heated high enough? Why?Candy would not have hard texture because enough water would not have been evaporated to reach saturated solution
- 21Other than adding sourness, what is the function of the lemon juice?Prevents enzymatic browning
- 22If you didn't have lemon juice, what other strategies could you use to minimize changes to the appearance from the reaction described above?Heat the mixture to denature the enzymes; add a reducing agent such as vit C; limit exposure to oxygen; create a sugar syrup to coat fruit
- 23You mix the salsa into yogurt to eat from breakfast the next morning. You're surprised by the lump appearance of the yogurt. What happened? Why?The yogurt curdled. Pineapple has enzyme called bromelatin that is a protease and would cut apart the proteins in milk, disrupting the micelle structure, causing them to bond to each other creating lumps.
- 24monosaccharidesany of the class of sugars that cannot be hydrolyzed to give a simpler sugar; glucose, galactose, fructose
- 25disaccharidesare sugars composed of 2 monosaccharides; sucrose, lactose, maltose
- 26amylosethe crystallization form of starch, consisting of long unbranched polysaccharides chains
- 27amylopectina component of starch that has a high molecular weight and branched structure and does not tend to gel in aqueous solution
- 28monoglycerideany of various esters of glycerol in which only one of the 3 hydroxyl groups is esterified and which are often used as emulsifiers
- 29diglyceridean ester formed from glycerol by reacting 2 of its hydroxyl groups with fatty acids
- 30triglyceridean ester formed from glycerol and 3 fatty acids groups
- 31cis- fatty acida natural fatty acid in which the carbon moieties lie on the same side of the double bond
- 32trans- fatty acidan unsaturated fatty acid formed by the partial hydrogenation of vegetables oil, believed to raise blood cholesterol levels
- 33saturated fatty acida fatty acid, such as steric acid whose carbon chain contains no unsaturated linkages between carbon atoms and hence cannot incorporate anymore hydrogen atoms
- 34unsaturated fatty acida fatty acid, the carbon chain which posses one or more double or triple bonds
- 35sucrose polyesteran artificial fat available under the trade names of "Olean" and "Olestra"; molecule is quite large and cannot be absorbed/digested by the human digestive system, it provides no calories to one diet
- 36amino acidany of group of organic compounds containing one or more amino group and one or more carboxyl groups
- 37polypeptidea chain of amino acids linked together by peptide bonds and having molecular weight of up to about 10,000