Chapter 3 Chemistry Of Food Composition Flashcards
(115 cards)
0
Q
The fundamental purpose of eating and drinking is to ______.
A
Replace nutrients and obtain calories
1
Q
All foods and humans consist of what 6 basic nutrients?
A
Water, carbohydrates, lipids, proteins, vitamins, minerals
2
Q
Humans are composed of ___% water, ___% fat, ___% protein, & ___% minerals
A
60-70% water, 15-25% fat, 15% protein, 12% minerals
3
Q
Biochemistry
A
The study of chemistry that occurs in living organisms
4
Q
All living things contain what 6 key elements? Why are they important?
A
Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur; they are the building blocks for organic material
5
Q
Are there calories in carbohydrates? Protein? Fiber? Alcohol? Vitamins? Minerals? Fat? Water? If yes, how much per gram?
A
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
6
Q
___ grams = 1 teaspoons
A
5 grams
7
Q
_______grams = 1 ounce
A
28.35 grams
8
Q
____ grams = 1/2 cup of liquid
A
100 grams
9
Q
Inorganic Compounds
A
Substances that do not contain carbon and cannot provide calories (ie water and minerals)
10
Q
This nutrient is the simplest, and most important
A
Water
11
Q
Explain the rule of 3
A
Three days without water, three minutes without air, three weeks without food
12
Q
Water is necessary for _______.
A
All functions
13
Q
The human body is a medium for ______.
A
Every metabolic process (which uses water)
14
Q
Water content of fruits and vegetables (%)
A
70-95%
15
Q
Water content of whole milk (%)
A
80%
16
Q
Water content of most meats (%)
A
Just under 70%
17
Q
What are the two possible forms of water in food?
A
Free & Bound
18
Q
Free Form of Water
A
It is the largest form of water in foods and can be separated from food (like when squeezing a peach or orange)
19
Q
Bound Form of Water in Food
A
Smallest form of water in food, cannot be separated (like bread, you cant squeeze the water out of it)
20
Q
What is the chemical composition of water?
A
H2O (one oxygen atom flanked by two hydrogen atoms)
21
Q
Heat is measured in the form of ______
A
Calories
22
Q
In calories, uppercase C means ___________. Lowercase c means _________.
A
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
23
Q
1 kcal = ____ calories
A
1,000
24
Specific Heat
The amount of heat required to raise the temperature by 1 degree celsius
25
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
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Heat of Solidification
The removal of heat
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Melting Point
The temperature at which water turns from a solid to a liquid. 32 degrees F or 0 degrees celsius
28
Boiling Point
Temperature at which water boils. 212 degrees F or 100 centigrade
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Heat of Vaporization
The amount of heat required to turn a liquid into a gas
30
As altitude increases, boiling point _______. Why does this happen?
Decreases; Occurs because there is less pressure.
31
Artificial pressure can be created by pressure cookers, which does what to your heating time?
Speeds it up
32
______ determine whether water is HARD or SOFT.
Minerals
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Hard Water
Contains more calcium and magnesium minerals
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Soft Water
Contains higher sodium content
35
Does the hardness or softness of water affect the boiling point?
Nope!
36
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.
37
Define moist-heat cooking, and name the methods
A cooking method that uses water to transfer heat.
| Boiling, simmering, steaming, stewing, and braising
38
Define dry-heat cooking, and name the methods
Cooking method that uses heat in a form of radiation.
| Baking, grilling, broiling, and frying
39
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
40
Solvent
Liquid (like water) which solute (like NaCl) is added to
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Solute
Substance that is added to a solvent
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Solubility
The amount of solute at a specific temperature
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Solution
Completely homogenous mixture of a solute (usually a solid) dissolved in a solvent (usually a liquid)
44
Biochemical interactions could not occur in _________.
absence of solvent environment
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Colloids
A particle too large to completely dissolve (ie protein, starch, and fat)
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The 2 types of dispersions in a universal solvent
Suspension and emulsion
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Suspension
Particles are too large to dissolve so they just kinda hang out in the solution
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Emulsion
Liquid is dispersed into another liquid (not completely mixed, like oil and water)
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When particles dissolve in solvent, solution is either ______ or ______.
Molecular or Ionic
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Molecular Solution
Cations and anions stay intact
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Ionic Solution
Cations and Anions separate
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pH scale
Measure of acidity or basicity based on a scale of 1-14. Below 7 is considered acidic, above 7 is considered basic. Center is neutral.
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Hydrolysis
Chemical breakdown of a compound due to an interaction with water
54
Carbon dioxide release
Using baking soda in water (important for bread to rise)
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Water Activity
Amount of water available for microbial growth. Most molds grow at .85 and above
56
To extend shelf life of foods, you _______.
Take water out of the food
57
Osmosis and Osmotic Pressure
Osmosis is the movement of water from an area of high water concentration to an area of lower water concentration.
Osmotic pressure is the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution.
58
The 3 types of carbohydrates
Monosaccharides, Disaccharides, and Polysaccharides
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Monosaccharides are divided into what two groups? Name all of them in each group
Hexoses (6 carbons long): glucose, fructose, and galactose
| Pentoses (5 carbons long): ribose, arabinose
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Name the disaccharides
Sucrose, maltose, and lactose
61
Polysaccharides are separated into what two groups? Name them in each of the groups
Digestible: plant starch (amylose and amylopectin), animal starch (glycogen)
Undigestible: fiber (cellulose, hemicellulose, pectin, gums, insulin, etc)
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Monosaccharides
The simplest of the sugars, classified by its number of carbons (pentose & hexose are the most common in food)
63
Glucose. What is it called when it is refined?
6-C sugar, called dextrose when refined
64
Fructose
Aka fruit sugar or levulose, found primarily in fruits and honey, sweetest of all sugars but not used in cooking because of problems such as stickiness and overbrowning.
65
Name 2 sugars a part of DNA and RNA
Ribose and Aravinose
66
What is the difference between the hexose carbohydrates?
Same chemical signature but different orientation of space
67
Sucrose is composed of _______.
Glucose and fructose
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Lactose is composed of ______.
Galactose and Glucose
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Maltose is composed of ______.
2 Glucose put together
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Oligosaccharides
Made up of 3-10 monosaccharides
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What are the two most common oligosaccharides and how many monosaccharides are they made of?
Raffinose (3 monosaccharides) & Stachyose (4 monosaccharides)
72
Oligosaccharides are used as _________, and the do not produce cavities and are therefore ________.
Agents in food; cariogenic
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What are the most common polysaccharides in food?
Starch, glycogen, and fiber
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Polysaccharides contain _____
Many monosaccharides linked together
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These are sugar units held together by bonds that cant be broken down, and hence don't provide energy
Fibers (polysaccharides)
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Dietary Fiber
The undigested portion of carbohydrates remaining in a food sample after exposure to digestive enzymes
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Soluble Fiber
Dissolves in water. (Insoluble fiber does not dissolve in water)
78
What kind of bonds are in fiber (polysaccharides)
1, 4 alpha bonds
79
What are the 3 common fibers? Where are they found?
Cellulose, hemicellulose, and pectic substances. Found in every cell in a plant food syste
80
Hemicellulose is composed of _____
A mixture of monosaccharides
81
What group do oils and fats belong to?
Lipids
82
How are oils and fats different?
1. Fats are solid at room temp, oils aren't
2. Fats are usually from animal sources, whereas oils come from plants
EXCEPTIONS: coconut and palm oils are solid at room temp, and fish oils liquid at room temp
83
What are the three groups of edible lipids?
Triglycerides, phospholipids, sterols
84
Triglycerides make up about ____% of all lipids, and consist of the three fatty acids _____, ______, & ______.
95% ; saturated, monosaturated, polyunsaturated
85
How do you differentiate between the three fatty acids?
Carbon length and degree of saturation
86
How many double bonds in the carbon chain of a saturated fatty acid?
No double bonds
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How many double bonds in the carbon chain of a monounsaturated fatty acid?
1 double bond
88
How many double bonds in the carbon chain of the polyunsaturated fatty acid?
2 double bonds
89
Name some good resources of saturated fatty acids
Meats, dairy (milk and butter), plants (coconut, coconut oil, palm oil)
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Name some good resources for monounsaturated fatty acids
Olives, olive oil, peanuts, peanut butter, avocado
91
Name two good resources for polyunsaturated fatty acids
Vegetable oils and fish
92
Phospholipids are similar to triglycerides except that________.
One fatty acid is replaced with a compound containing phosphorus
93
What is the function of phospholipids in the human body?
To move water-soluble vitamins and hormones
94
Foods that contain phospholipids
Egg yolks, liver, soybeans, wheat germ, and peanuts
95
Best known phospholipid
Lecithin
96
Sterols
Large molecules, interconnected rings of carbon atoms with a variety of side chains attached
97
Name sterols that are within your body
Cholesterol, bile, testosterone, estrogen, adrenal hormones, vitamin D
98
Are sterols found in plants or animals?
Both
99
6 functions of lipids in our food
They contribute to:
1. Heat transfer during food prep
2. Tenderness
3. Mixing (emulsifying)
4. Texture
5. Flavoring food
6. Increases ones feeling of fullness after eating (satiety)
100
How many amino acids are there? How many of those are essential?
22; 9 essential
101
What is the major difference between lipids/CHOs and protein?
Protein contains nitrogen
102
5 Functions of protein in food
They allow the follwing during prep:
1. Hydration
2. Denaturation/coagulation
3. Enzymic reactions
4. Buffering (keeping acids and bases balanced)
5. Browning
103
Meat is a good source of _____
B vitamins, iron, and zinc
104
Dairy foods are a good source of ______
Calcium (provide 80% of daily value)
105
Vitamin C is found _____
Only in plants
106
What are the fat-soluble vitamins? Where are they found?
Vitamins A, D, E, & K. Found in egg yolk
107
Where is vitamin B12 found?
Only in foods of animal origin or fermented foods
108
What are the two major sources of sodium?
Processed foods and saltshakers
109
The two major groups for vitamins and minerals
Fat soluble and water soluble
110
Two major groups for minerals
Macro (Ca), and micro (Fe)
111
What is the function of vitamins and minerals in our food?
They are antioxidants, a compound that inhibits oxidation which causes deterioration and rancidity. Antioxidants are used to neutralize free radicals (unstable molecules that can damage the cell)
112
The most important antioxidants
Vitamins A, C, and E, and the Mineral Selenium
113
The only mineral directly consumed
Sodium
114
What is sodium used for?
Preservative, enhances flavor
