Topic 4: Part B Flashcards
1
Q
Carbohydrates (CBO) includes
A
sugars, starches and fibres
2
Q
Carbs consist of..
A
carbons, hydrogen, oxygen
3
Q
Carbs are formed in ..
A
green plants through photosynthesis whereby the sun energy converts carbon dioxide form atmosphere and water form soil into glucose
4
Q
Oxygen is given off by the ..
A
plant during photosynthesis
5
Q
Carb foods include
A
- Cereal grains and flours (wheat, rye, corn)
- Legumes (pease, beans, lentils)
- Starchy roots or tubers, (potatoes, yam cassava)
- Fruits (orange, apple, banana)
- Sugars, honey, jams, molasses.
- Milk products
6
Q
Carb are classified according to number of ..
A
basic sugar (saccharide) units
7
Q
4 types of carbs and how many sugars are in them
A
- Monosaccharides- simple sugars, _1 unit.
- Disaccharides- simple sugars, 2 units.
- Oligosaccharides- simple sugars, 3-10 units.
- Polysaccharides- complex sugars, many units.
8
Q
Monosaccharides
A
include 6 carbon hexose and 5 carbon pentose
9
Q
Hexose
A
Hexose sugars such as glucose, mannose, fructose and galactose are building blocks of polysaccharides.
10
Q
Pentose
A
Pentose sugars such as ribose, xylose and arabinose are the building blocks of fibers and gums.
11
Q
Glucose
A
- most abundant sugar in the world
- found in fruits, plant juices and honey
- present w other sugars
12
Q
The form of glucose that circulates the bloodstream, it is broke down in the body to give 3 products
A
- energy
- water
- carbon dioxide
13
Q
Many complex carbs such as starch and cellulose have..
A
glucose as basic unit
14
Q
Glucose is major component of corn syrup which is formed by
A
hydrolysis of starch
15
Q
Corn syrup and crystalline glucose are widely used in
A
baking industry
16
Q
Fructose
A
- found in fruits, plant juices and honey
- sweetest of all common sugars
- very soluble and doesn’t crystallize easy
17
Q
In food industry glucose is changed too..
A
fructose by addition of enzyme glucose isomerase
18
Q
High fructose corn syrup
A
glucose changed to fructose and sweetener used in soft drinks
19
Q
Galactose
A
- not found in its free from in foods
- forms bond with glucose to produce lactose (milk sugar)
- basic unit off some complex carbs such as vegetable gums
20
Q
Some galactose is found in ..
A
freeform in fermented milk products where hydrolysis of lactose has occurred
21
Q
Disaccharides
A
-consist of 2 monosaccharides linked together
22
Q
Common disaccharides in food are..
A
sucrose (cane/beet sugar), maltose from corn syrup and lactose from milk
23
Q
Disaccharides are not absorbed into ..
A
the bloodstream from small intestines and hence are not available as energy sources to human body
24
Q
Disaccharides must be hydrolyzed to ..
A
monosaccharides which then can be absorbed ti bloodstream
25
Non-hydrolyzed disaccharides pass through the ..
small intestine to the large intestine where they are hydrolyzed by bacteria to produce acetic and lactic acids/gases
26
When produced in sufficient quantities these acids form disaccharides have a..
laxative effect and cause dirrahea (gas production can cause flatulence and abdominal cramps/discomfort)
27
Sucrose
- table sugar
- extracted from sugar cane and beets.
- consists of glucose and fructose chemically bonded
- present w other sugars in fruits, honey and vegetables
28
Lactose
- milk sugar
- consists of glucose and galactose chemically bonded to each other
- only found in milk and products of milk
29
Maltose
- found in germinating grain, corn syrup
- product pf starch hydrolysis
- important of production of malted beverages
- consists of 2 glucose molecules chemically bonded to each other
30
Oligosaccharides
- carb molecules that contain 10 or fewer monosaccharides
- includes raffinose and stachyose
- gas formation (commonly found in dried beans)
- not digested by humans but broken down by bacteria in intestinal tract resulting in gas formation
31
Polysaccarides
- complex carbs
- up 2 several hundred thousand monosaccarides joined together
- homoglucans are composed of the same type of monosaccharides
32
Heteroglucans are composed of ..
at least 2 types of monosaccharides (may be straight chains or highly branched chains)
33
Starch (homoglucan)
- basic storage form of carbs in plants
- found in abdunace of seeds, roots, and tubers
- consist of only glucose molecules
34
2 kinds of starch molecules
- amylose
| - amylopectin
35
Amylose
near chain structure
36
Amylopection
highly branched structure
37
Most natural starched consist of a mixture of..
amylose and amylopectin
38
Normal starch consist of ...
25% amylose and 75% amylopectin
39
Starch granules swell when..
heated in water (called gelatinization)
40
Gelatinization
is responsible for the thickening that occurs when a starch pudding or sauce is cooked.
41
Commercial varieties of high amylose corn contains..
65% amylose and are difficult to gelatinize some requiring temp of 100C
42
Some starched consist only of amylopectin such a ..
waxy corn, waxy barley, and waxy rice gelatinize easily and produce clear pastes
43
Dextrins (homoglucans)
produced when starch molecules are partially broken down by enzymes, acid or dry heat.
44
Dextrins are formed from ..
corn starch when corn syrup is made, when bread is toasted or flour heated
45
Dextrins have a less..
thickening power than starch and are brown in colour
46
Glycogen (humoglucan)
- storage form of glucose in animals.
- during digestion, carbohydrates (e.g., starch) is hydrolyzed to glucose which is absorbed into the blood.
- surplus glucose is converted into either fat or glycogen.
47
Glycogen is stored in the ..
liver and muscles temporarily until hydrolyzed to help maintain blood glucose levels or used as fuel by muscles
48
Dietary fibre is not digested by humans since there is no..
enzyme in the digestive tract that can hydrolysis the molecules that makeup plant fibre.
49
Dietary fibre is a complex mixture of ..
cellulose, hemicellulose, beta-glucans, pectins and gums
50
Some fibre components are found in the ..
cell walls of vegetables, fruits, and seeds and give physical compactness, crispiness and good mouthfeel
51
Other fibre components such as vegetable gums have no..
structural role but impart thickening, viscosity, adhesiveness and gel forming ability to foods
52
Public health promotion has emphasized the importance of ..
fibre in our diets for the prevention or control of several chronic disorders (colon cancer, cardiovascular disease, and diabetes)
53
Benefits of fibre
- bowel health: prevent colon cancer
- healthy weight: slow digestion of food and maintains fullness for longer
- heart health: beneficial for heart health and inhibits cholesterol
54
How many fibres should you ingest
1 or 2 high fibre sources AND 5 or 7 moderate fibre sources EACH DAY ** Canadians don't consume enough
55
Insoluble fibres ..
ex: hemicelluloses provide body w roughage
56
Soluble fibres ..
ex: pectin and gum best for inhibiting cholesterol absorption
57
A high fibre diet requires a..
high water intake and large amount of fibre and bind minerals
58
Recommended daily intake of fibre for women and men
women: 25g
men: 38g
59
How much fibre Canadians consume
approx: 20-25 grams/day
60
How much fibre Americans consume
approx: 15-20 grams/day
61
Types of fibres
- cellulose (homoglucan)
- hemicellulose (heteroglucan)
- beta-glucan (homoglucan)
- pectic substances
- vegetable gum/hydocolloids
- modified cellulose
62
Cellulose
consist of many glucose linked together by beta bonds to form a linear chain.
63
Cellulose found in
cell was of plants and are important for physical structure.
64
Cellulose can be chemically modified to make it more..
soluble and useful for thickening, gelling and providing bulk in low calorie products (diets)
65
Modified cellulose products include ..
methyl cellulose and carboxymethyl cellulose
66
Hemicellulose (heteroglucan)
- found in plant cell walls
| - contain a variety of different monosaccharides building blocks (pentoses and hexoses)
67
Hemicellulose has greatest effect is in..
baked goods where they improve the water binding of flour
68
In bread dough, hemicellulose they improve mixing quality and ..
reduce mixing energy, aid incorporation of protein and improve loaf volume
69
Hemicellulose great retards ..
staling of bread compared to bread with no hemicellulose
70
Beta-glucans
- composed of glucose units that are linked together by beta bonds
- less linear than cellulose and more soluble in water
71
Beta-glucans in the gastrointestinal tract
it forms a viscous hydrated mass that traps bile acids and reduces the amount of cholesterol absorbed into the body.
72
Beta-glucans decrease the rate of...
digestion of starch into glucose and the rate of absorption of glucose from the gastrointestinal tract into the bloodstream.
73
Beta-glucan may be good for diabetics as a means of..
controlling level of blood sugar
74
Health claim for ..
oat beta-glucan is: 0.75 g beta-glucan/serving (3 servings /day).
75
Pectic substances found in ..
both cell walls and in space between plant cells. aid in cementing plant cells together.
76
Galaturectic acid
(derivative of galactose) is the basic building block of pectic substances
77
Pectic is a ..
pectic molecule common in fruits and responsible for forming gels in various jam, jellies and preserves (commonly pectin is produced from apple cores or citrus peel)
78
Vegetable gums/hydrocolloids
long chain polysaccharides, various hexose and pentose sugar are the basic building blocks. widely used in food industry (ice cream, salad dressing)
79
Vegetable gums/hydrocolloids dissolved in water produce ..
thickening or texture building effect
80
Gums can help to ..
retain water, reduce evaporation rates and modify ice crystal formation
81
Examples of gums/hydrocolloids
1. Seaweed extracts: agar, alginate, carrageenan
2. Plant seed gums: locust bean gum. Guar gum
3. Plant exudates: gum Arabic, gum tragacanth
4. Microbial gums: xanthan gum, dextran
82
Modified cellulose 2 examples
- Carboxymethlycellulose which is used as a bulking agent in low calorie foods and in fruit fillings.
- Methyl cellulose is used in reformed potato products and in coating and batters to reduce oil absorption
