Chapter 3 Chemistry Of Food Composition Flashcards Preview

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Flashcards in Chapter 3 Chemistry Of Food Composition Deck (115):
0

All foods and humans consist of what 6 basic nutrients?

Water, carbohydrates, lipids, proteins, vitamins, minerals

1

The fundamental purpose of eating and drinking is to ______.

Replace nutrients and obtain calories

2

Humans are composed of ___% water, ___% fat, ___% protein, & ___% minerals

60-70% water, 15-25% fat, 15% protein, 12% minerals

3

Biochemistry

The study of chemistry that occurs in living organisms

4

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

5

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

6

___ grams = 1 teaspoons

5 grams

7

_______grams = 1 ounce

28.35 grams

8

____ grams = 1/2 cup of liquid

100 grams

9

Inorganic Compounds

Substances that do not contain carbon and cannot provide calories (ie water and minerals)

10

This nutrient is the simplest, and most important

Water

11

Explain the rule of 3

Three days without water, three minutes without air, three weeks without food

12

Water is necessary for _______.

All functions

13

The human body is a medium for ______.

Every metabolic process (which uses water)

14

Water content of fruits and vegetables (%)

70-95%

15

Water content of whole milk (%)

80%

16

Water content of most meats (%)

Just under 70%

17

What are the two possible forms of water in food?

Free & Bound

18

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)

19

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)

20

What is the chemical composition of water?

H2O (one oxygen atom flanked by two hydrogen atoms)

21

Heat is measured in the form of ______

Calories

22

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

23

1 kcal = ____ calories

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

26

Heat of Solidification

The removal of heat

27

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

29

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

33

Hard Water

Contains more calcium and magnesium minerals

34

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

41

Solute

Substance that is added to a solvent

42

Solubility

The amount of solute at a specific temperature

43

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

45

Colloids

A particle too large to completely dissolve (ie protein, starch, and fat)

46

The 2 types of dispersions in a universal solvent

Suspension and emulsion

47

Suspension

Particles are too large to dissolve so they just kinda hang out in the solution

48

Emulsion

Liquid is dispersed into another liquid (not completely mixed, like oil and water)

49

When particles dissolve in solvent, solution is either ______ or ______.

Molecular or Ionic

50

Molecular Solution

Cations and anions stay intact

51

Ionic Solution

Cations and Anions separate

52

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.

53

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)

55

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

59

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

60

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)

62

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

68

Lactose is composed of ______.

Galactose and Glucose

69

Maltose is composed of ______.

2 Glucose put together

70

Oligosaccharides

Made up of 3-10 monosaccharides

71

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

73

What are the most common polysaccharides in food?

Starch, glycogen, and fiber

74

Polysaccharides contain _____

Many monosaccharides linked together

75

These are sugar units held together by bonds that cant be broken down, and hence don't provide energy

Fibers (polysaccharides)

76

Dietary Fiber

The undigested portion of carbohydrates remaining in a food sample after exposure to digestive enzymes

77

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

87

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)

90

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