Chapter 3 Chemistry Of Food Composition Flashcards
The fundamental purpose of eating and drinking is to ______.
Replace nutrients and obtain calories
All foods and humans consist of what 6 basic nutrients?
Water, carbohydrates, lipids, proteins, vitamins, minerals
Humans are composed of ___% water, ___% fat, ___% protein, & ___% minerals
60-70% water, 15-25% fat, 15% protein, 12% minerals
Biochemistry
The study of chemistry that occurs in living organisms
All living things contain what 6 key elements? Why are they important?
Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur; they are the building blocks for organic material
Are there calories in carbohydrates? Protein? Fiber? Alcohol? Vitamins? Minerals? Fat? Water? If yes, how much per gram?
Carbs=4 kcal per gram, protein=4 kcal per gram, fat=9 kcal per gram, alcohol=7 kcal per gram. The rest are no’s
___ grams = 1 teaspoons
5 grams
_______grams = 1 ounce
28.35 grams
____ grams = 1/2 cup of liquid
100 grams
Inorganic Compounds
Substances that do not contain carbon and cannot provide calories (ie water and minerals)
This nutrient is the simplest, and most important
Water
Explain the rule of 3
Three days without water, three minutes without air, three weeks without food
Water is necessary for _______.
All functions
The human body is a medium for ______.
Every metabolic process (which uses water)
Water content of fruits and vegetables (%)
70-95%
Water content of whole milk (%)
80%
Water content of most meats (%)
Just under 70%
What are the two possible forms of water in food?
Free & Bound
Free Form of Water
It is the largest form of water in foods and can be separated from food (like when squeezing a peach or orange)
Bound Form of Water in Food
Smallest form of water in food, cannot be separated (like bread, you cant squeeze the water out of it)
What is the chemical composition of water?
H2O (one oxygen atom flanked by two hydrogen atoms)
Heat is measured in the form of ______
Calories
In calories, uppercase C means ___________. Lowercase c means _________.
C = amnt of energy to raise 1kg of water by 1 degree celsius c = amnt of energy to raise 1g of water by 1 degree celsius
1 kcal = ____ calories
1,000
Specific Heat
The amount of heat required to raise the temperature by 1 degree celsius
Freezing Point
The temperature at which a liquid turns into a solid. Water becomes less dense. Occurs at 32 degrees F, or 0 degrees celsius
Heat of Solidification
The removal of heat
Melting Point
The temperature at which water turns from a solid to a liquid. 32 degrees F or 0 degrees celsius
Boiling Point
Temperature at which water boils. 212 degrees F or 100 centigrade
Heat of Vaporization
The amount of heat required to turn a liquid into a gas
As altitude increases, boiling point _______. Why does this happen?
Decreases; Occurs because there is less pressure.
Artificial pressure can be created by pressure cookers, which does what to your heating time?
Speeds it up
______ determine whether water is HARD or SOFT.
Minerals
Hard Water
Contains more calcium and magnesium minerals
Soft Water
Contains higher sodium content
Does the hardness or softness of water affect the boiling point?
Nope!
The 2 most important functions of water in food? What are twp other functions that are not necessarily as important?
It is a transfer medium for heat, and it is a universal solvent.
It is an agent in chemical reactions, and it is a factor in perishability/preservation of food.
Define moist-heat cooking, and name the methods
A cooking method that uses water to transfer heat.
Boiling, simmering, steaming, stewing, and braising
Define dry-heat cooking, and name the methods
Cooking method that uses heat in a form of radiation.
Baking, grilling, broiling, and frying
Microwaves use ______ & _______ cooking methods. Explain why.
Moist AND dry heat methods. Radiation heats up the water that is in the food, which then heats the food
Solvent
Liquid (like water) which solute (like NaCl) is added to
Solute
Substance that is added to a solvent
Solubility
The amount of solute at a specific temperature
Solution
Completely homogenous mixture of a solute (usually a solid) dissolved in a solvent (usually a liquid)
Biochemical interactions could not occur in _________.
absence of solvent environment
Colloids
A particle too large to completely dissolve (ie protein, starch, and fat)