Principles Of Dietetics - topic A: food nutrition and supporting sciences Flashcards
Climacteric fruits
ripen post-harvest
examples: peach, pear, banana, apple, tomato
Non-climacteric fruits
best when ripened before harvest
examples: grapes, melon, citrus
olive green in acid
pheophytin
bright green in alkaline
chlorophyllin (mushy: hemicellulose broken down)
one dozen oranges will yield
one quart of juice
cooking method - frozen
shorter cooking time than fresh because blanching and freezing have made them tender
blanching
immersion in boiling water for a short time
10, #6/CASE
13 CUPS
canned fruits and vegetable grades USDA
grade A - desserts, salads (fancy)
grade B - processed (choice)
grade C - puddings, pies (standard
fresh produce grades USDA
fancy, extra #1, #1, combination, #2
vitamins and minerals in meat, poultry, fish, and meat alternatives
thiamin, niacin, riboflavin, iron, copper, trace minerals
pork is a good souce of what
thiamin
(high heat destroys thiamin)
fish paste
good source of nondairy calcium
pigments - meat - green colors
green colors are due to further myoglobin breakdown, oxidation of pigment myoglobin
post-mortem changes and aging
- change in muscle protein brought about by enzymes which increase the water-holding capacity of the muscle
- acid (vinegar) and salt also increase tenderness by increasing water-holding capacity of muscle
- MAP (modified atmosphere packaging) prevents deterioration by slowing respiration
inspection and grading
shown with a round purple inspection stamp/sticker “USDA Inspected and Passed”
cookery principles and temepratures
temp - 325’F for roasting
- high temp increases shrinkage, toughen
- a slow-cooked roast yields less waste
- insert meat thermometer BEFORE cooking
- safe minimum internal temperatures
- 145’F: pork, beef, veal, lamb, steaks, roast, fish
- 160’F ground beef, ground veal, ground lamb
- 165’F turkey, chicken, duck
vacuum wrapped meats
cured meats are pink from nitrites (inhibit botulism)
tempering meat
allows it to cook more evenly
- Letting meat sit out at room temperature before cooking it
method of cooking determined by cut of meat - dry heat
no water involved, for tender cuts near backbone (loin, sirloin)
method of cooking determined by cut of meat - frying
heat the fat before it smokes
- desirable property of fat used in frying is a high smoke point > 400’F
- highest = safflower 513’F
- lowest = butter 350’F
rancidity in an unsaturated fatty acid
involves the uptake of oxygen in an unsaturated fatty acid
- healthiest plant oils are all highly unsaturated (olive oil has more MUS; less susceptible to rancidity than soybean oil which has more PUS)
- greater # of double bonds, greater risk of rancidity
fish cookery- smell
fresh fish should not smell fishy
egg yolk
is a naturally occurring oil in water emulsion and has more protein by weight
egg freshness
old eggs float, fresh eggs sink
eggs - preparation and processing - syneresis
syneresis (weeping) - liquid released from a coagulated product
- occurs when cooked at too high a temperature, or too low a temperature for too long a time; creates a tough watery product
egg substitutes
- lower in fat, kcal, cholesterol; often higher in sodium than fresh eggs
- when cooking with egg substitutes, there will be color (added carotenoid) and flavor differences - eliminated yolk
when eggs are held in the refrigerator for too long
loss of carbon dioxide makes eggs more alkaline, old eggs = need to increase acidity
milk and milk products - whey
whey has lactose
milk and milk products - composition and nutritive value
low in iron and vitamin C
milk and milk products - processing- where to store if unopened?
dry storage if unopened
buttermilk in place of regular milk in a recipe
increase the baking soda
- buttermilk is more acidic = need to increase base
sweet acidophilus milk
skim milk plus lactobacillus acidophilus bacteria which reduces lactose
use of milk in food preparation- when milk is heated & to prevent curdling
- when milk is heated, whey protein precipitates out on bottom of pan or on surface of milk
- to prevent curdling, add an acid slowly and agitate - an acid precipitates casein in milk
butter
at room temp, hydrolytic rancidity (uptake of water) leads to flavor changes in butter (saturated fat)
- saturated fats take up water
- unsaturated oils are more subject to oxidative rancidity (soybean oil) (uptake of oxygen at a double bond in an unsaturated fat)
cream
heavy or thick > 36% fat
medium 30-36% fat
whipped cream 35% fat
cheese
- uncured - refrigerate immediately (cottage cheese, cream cheese)
- cured - additional whey removed, salt added, ripened over time
- %moisture content high to low: cottage (79), cream, mozzarella (45-55), camembert, bleu, Swiss, cheddar, gorgonzola, parmesan (31)
wheat flours
graham, whole wheat - entire grain, use freshly ground, spoils quickly due to fat in germ
hard wheat bread
strong gluten; bread highest in protein - 11.8%
all-purpose (blend of hard and soft wheat)
less gluten; 10.5% protein, used in bakery
pastry (soft wheat)
weaker gluten; 7.9% protein, used in bakery
cake (soft wheat)
least and weakest gluten, more starch, 7.5% protein, used in bakery, least amount of protein