Carbohydrates Flashcards
(175 cards)
1
Q
Primary source of energy for the body
A
Carbohydrates
2
Q
most abundant in terms of requirement and storage in the body among the three macronutrients
A
carbohydrates
3
Q
named after its chemical components – carbon, hydrogen, oxygen
A
carbohydrates
4
Q
general formula of carbohydrates
A
(CH2O)n
5
Q
simple carbohydrates – (2)
A
monosaccharides & disaccharides
6
Q
complex carbohydrates
A
starches and fiber
7
Q
3 carbohydrate classifications based on monomer units
A
monosaccharides, oligosaccharides, polysaccharides
8
Q
3 types of monosaccharides
A
hexoses, sugar alcohols, pentoses
9
Q
Glucose, Fructose, and Galactose are types of:
A
Hexoses
10
Q
grape, dextrose, or corn sugar are sources of
A
glucose
11
Q
its function: acid hydrolysis of starch
A
glucose
12
Q
digestive end product of sugars and starches
A
glucose
13
Q
levulose or fruit sugar are sources of
A
fructose
14
Q
honey, ripe fruits, HFCS are sources of:
A
fructose
15
Q
digestive end product of sucrose
A
fructose
16
Q
hexose that is not found free in nature
A
galactose
17
Q
digestive end product of lactose
A
galactose
18
Q
monosaccharide used as substitute for therapeutic diets
A
sugar alcohols
19
Q
monosaccharide that yields 2kcal/g
A
sugar alcohols
20
Q
2 types of sugar alcohols
A
mannitol and sorbitol
21
Q
sources of mannitol
A
trees and shrubs
22
Q
4kcal/g absorbed slowly (monosaccharide)
A
sorbitol
23
Q
source of sorbitol
A
fruits and berries
24
Q
monosaccharide not found free in nature
A
pentose
25
C5H10O5
pentose
26
types of pentoses
arabinose, ribose, ribulose, xylose
27
source of arabinose
gum arabic
28
source of ribose
nucleic acid
29
product of metabolism (pentose)
ribulose
30
source of xylose
wood gums
31
structure of glucose
--
32
structure of fructose
--
33
structure of galactose
--
34
refers to 2-10 saccharide units
oligosaccharides
35
structure: glucose and glucose
maltose
36
basic disaccharides occuring in food items
sucrose, lactose, and maltose
37
table or cane sugar, saccharose
sucrose
38
milk sugar
lactose
39
malt sugar
maltose
40
most common form of CHO
sucrose
41
milk and milk products
lactose,
42
malted products
maltose
43
action of diastase on starch
maltose
44
structure: glucose and fructose
sucrose
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structure: glucose and galactose
lactose
46
use in brewing
maltose
47
transport sugar in milk
lactose
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transport sugar in plants
sucrose
49
types of trisaccharides
raffinose and melizotose
50
C18H32O16
trisaccharides
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source of raffinose
sugar beets
52
source of melizotose
honey, poplars, confiers
53
C24H42O21
tetrasaccharide
54
classifications of polysaccharides (3)
digestible, partially digestible, indigestible
55
types of digestible carbohydrates
starch, dextrins, glycogen or animal starch (not found in food items)
56
source of starch
cereal, grains, rice, wheat, rye, sorghum, millet, unripe fruits & veg, legumes, tubers
57
source of dextrins
toasted breads and flour
58
intermediate product of starch digestion
dextrins
59
source of glycogen or animal starch
muscle meat (insignificant source)
60
poysaccharide composed of glucose; manufactured and stored in the liver and muscles
glycogen
61
storage form of energy
glycogen
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two types of partially indigestible carbohydrates
galactogens, inulin
63
source of galactogens
pectin, agar-agar
64
source of inulin
onion, garlic, tuber, artichokes, dandelion
65
types of indigestible carbohydrates
cellulose and hemicellulose
66
source of cellulose
skins of fruits, covering of nuts, stems, leaves
67
types of hemicellulose
agar-agar and pectin
68
source of hemicellulose
cereal fibers
69
source of agar-agar
seaweeds
70
source of pectin
unripe fruits
71
principle sources of carbohydrates
plants
72
only substantial animal source of CHO
milk
73
plant sources of carbohydrates
cereal grains, vegetables, fruits, nuts, sugars
74
term first used in the McGovern report "Dietary Goals for the United States" in 1977
Complex carbohydrates
75
term appeared in the 1980 US Dietary Recommendations
Complex Carbohydrates
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coined to distinguish sugars from other CHO
complex carbohydrates
77
T or F: Complex carbohydrates were coined to distinguish sugars from other CHO
T
78
may create confusion since starches are classified as digestible or indigestible
complex carbohydrates
79
concept introduced by McCancee and Lawrence in 1929
Available & unavailable carbohydrates
80
observed among diabetics; not all CHOs are utilized and metabolized by diabetics
available & unavailable CHOs
81
T or F: Available CHO refers to fiber
F
82
T or F: unavailable CHO refers to soluble sugars and starch
F
83
T or F: available CHO refers to soluble sugars and starch
T
84
T or F: unavailable CHO refers to soluble fiber
T
85
term given to fermentation of CHO in the intestines
available & unavailable carbs
86
new term for available and unavailable CHOs
glycemic and nonglycemic CHOs
87
carbohydrate discovered in the last 20 years
resistant starch
88
starch and starch degradation products not absorbed in the small intestines of humans
resistant starch
89
forms of resistant starch
1. Enclosed starch
2. Some raw starch granules
3. Retrograded amylose
90
metabolic mechanism of resistant starch
---
91
Obtained through
alteration of proportions
of amylose and
amylopectin in starchy
foods by plant breeding
Modified starch
92
Genetic engineering of
high amylose or
amylopectin corn starch
improvement in gelation,
mouthfeel, appearance,
texture, resistance to
heat
Modified starch
93
Structural parts of plants
fibers
94
Non-starch polysaccharides
fibers
95
Bonds between monosaccharides units
cannot be broken down by human
digestive enzymes
fibers
96
what can break cown fibers
some bacteria in GI tract
97
classification of fibers in terms of structure
With Polysaccharides
◦ Cellulose
◦ Hemicellulose
◦ Pectins
◦ B-glucan
◦ Inulin
◦ Gums
◦ Mucilages
With nonpolysaccharides
◦ Lignins
◦ Cutins
◦ Tannins
98
Classification of fibers in terms of
solubility in water
soluble and insoluble
99
Natural gel-forming fibers:
form gel matrix altering
solubility or enzyme hydrolysis
soluble fibers
100
soluble fibers examples
B-glucan, psyllium, pectin and
guar gum and oligosaccharides
101
90-99% fermented in the
colon; Useful in lowering blood
cholesterol, managing obesity,
CVD, DM and preventing
colon cancer
soluble fibers
102
insoluble fibers example
Cellulose, lignin,
hemicelluloses
103
10-15% fermented in the
colon, Contribute bulk to
stools, help prevent
constipation and colon
cancer, and may help control
DM
insoluble fibers
104
Health Benefits of dietary fiber
1. Fermented into short chain fatty acids which stimulate growth of colonic microflora
2. Increase fecal mass & encourages
peristalsis
3. Aids in energy balance & control of body weight
4. Aids to prevent constipation, colorectal cancer, coronary heart diseases, & Type II Diabetes Mellitus (DM)
105
Role of colonic microflora
◦ Act as immunomodulators
◦ Inhibit the growth of harmful microorganisms
◦ Reduce food intolerances and allergies
◦ Stimulate growth of healthy intestinal flora
◦ Reduce undesirable compounds
106
Functions of Carbohydrate for Health
1. Major diet source of energy
2. Serve as the ONLY energy source of our brain cells and the nervous system
3. Digestible carbohydrates with specific roles: lactose, galactose, & ribose and deoxyribose
4. Protein sparer
5. Regulator of fat metabolism
6. Helps to maintain the health and normal
functions of the GIT
7. Cholesterol-lowering effect
8. Promote satiety and delay hunger
9. Serve as one of the constituents of the body
10. Special functions – lactose, galactose, & ribose
107
encourages growth of good bacteria, calcium absorption and synthesis of B-vitamins
lactose
108
serves as a building unit for peripheral nerve cells
galactose
109
digestible carbohydrates for genetic material
ribose and deoxyribose
110
what happens in digestion of carbohydrates in the mouth
chewing food timulates the flow of saliva which contains salivary amylase. salivary amylase starts to break up the polysaccharides
111
what happens in the digestion of carbohydrates in the stomach
bolus mixes with gastric acid
112
T or F: There is good amount of carbohydrate digested in the stomach
F (Very little carbohydrate digestion in the stomach)
113
T or F: presence of fibers delay gastric emptying during carbohydrate digestion in the stomach
T
114
major site of carbohydrate digestion
small intestines
115
what happens during carbohydrate digestion in the small intestine
Pancreatic amylase breaks down polysaccharides to shorter glucose chains and disaccharides, and brush border enzymes break down disaccharides (maltase, sucrase, lactase).
116
T or F: Fiber delays absorption of cabohydrates and fat during digestion of carbohydrates in small intestine
T
117
what happens to monosaccharides during absorption of carbohydrates?
Simple sugars are absorbed directly into the bloodstream and carried to the liver. Fructose and Galactose are changed to Glucose. Glucose is carried to the cells.
118
what happens to disaccharides during absorption of carbohydrates?
Sucrose, Maltose, and Lactose are converted to simple sugars by their corresponding enzymes (sucrase, maltase, lactase). The simple sugars are absorbed into the bloodsteam. Fructose and Galactose are changed to Glucose in the liver, and glucose is carried to cells.
119
what happens to polysaccharides during carbohydrate absorption?
Cellulose wall is broken down, and MAJORITY IS NOT ABSORBED. Starch is changed to intermediate product dextrin then maltose then glucose.
During digestion in mouth, amylase begins to change starch to dextrin.
120
Elaborate the transport of monosaccharides
5 steps:
monosaccharides are absorbed in the mucosal cells
--> into capillaries of the villi
--> into liver via the hepatic vein
--> in the liver: some glucose stored as glycogen in liver and muscle. Fructose and galactose are converted to glucose. --> Glucose enters systemic circulationste
121
refers to all chemical reactions necessary to maintain life
metabolism
122
two categories of metabolism
anabolism and catabolism
123
metabolism where substances are broken down into simpler substances
- energy is released and captured via ATP to energize metabolic rxns
Catabolism
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metabolism wherein larger molecules or structures are built from smaller ones
anabolism
125
hormone that controles glucose metabolism
insulin
125
insulin is secreted by the
pancreas
126
high blood glucose level (hyperglycemia) and low blood glucose level (hypoglycmeia) are results of
impaired or absent insulin secretion
127
a polypeptide secreted from the prancrease in response to hyperglycemia
human insulin (120 mg/100 mL)
128
a hormone which responds to low levels of glucose in the blood
glucagon
129
normal blood glucose level
homeostasis (about 90 mg/100 ml)
130
recommended carb intake based on PDRI 2015
55-75% of TER (70% complex; <10% simple sugars)
-- include 20-25 g dietary fiber and at least 50 g carbs in a day
131
Effects of excessive carb intake
1. Overweight or obesity
2. Increased endogenous synthesis of triglycerides in the liver
(heart disease and diabetes)
3. Occurrence of dental carries for excessive intake of simple
sugars + unhygienic oral care
4. Dietary fiber: abdominal discomfort, increased flatulence,
more frequent bowel movements and slight decrease in the
absorption of some nutrients
132
180-200 x sweeter than sucrose:
aspartic acid + phenylalanine
(not for individuals with PKU)
aspartame
133
decomposes at room T,
sweetness lost during prolonged
cooking and high T
aspartame
134
sources of aspartame
beverages, candiese, etc.
135
Brand Names of aspartame
Nutrasweet and Equal
136
classified as Group 2B, “possibly carcinogenic to humans.” in june 2023
aspartame
137
This category is used when there is
limited, but not convincing, evidence for
cancer in humans or convincing evidence for
cancer in experimental animals, but not both
Group 2B
138
made from sugar in a multi-step chemical process where 3 hydrogen-oxygen groups are replaced with chlorine atoms
Sucralose
139
600x sweeter than sucrose
sucralose
140
T or F: sucralose has a bitter aftertaste and is unstable
F (no bitter-aftertaste and
stable at most conditions)
141
Brand name of sucralose
Splenda
142
aka "polyols"
sugar alcohols
143
formed from the reduction of certain sugars
sugar alcohols
144
mannitol, sorbitol and xylitol
sugar alcohols
145
Ranking of the effect on blood glucose of the consumption of a single food relative to a reference carbohydrate
glycemic index
146
reference food of glycemic index
50g glucose or 50g white bread (GI = 100)
147
a reliable, physiologically based classification of foods according to their post prandial glycemic effect
glycemic index
148
glycemic index formula
(change in blood glucose conc from food)/(change in blood glucose from standard carb) X 100
149
ranges of glycemic index
Low GI: 1-55
Medium GI: 56-69
High GI: 70-100
150
first process in glucose catabolism
glycolysis
151
first process in glucose anabolism
glycogenesis
152
extension of dietary fiber hypothesis of Burkitt and Trowell
glycemic index
153
T or F: dietary fiber hypothesis suggests that foods more slowly absorbed may have metabolic effects in relation to diabetes and the reduction of coronary heart disease (CHD) risk
T
154
rank simple sugar, soluble fiber + sugar, and starch from hight blood glucose level peak to lowest
simple sugar, starch, soluble fiber + sugar
155
Factors which influence glycemic response to food
1. Quantity and digestibility of starches
2. Quantity and sources of sugar in a meal
3. Presence of fat, protein, dietary fiber, anti nutrients and organic acids
4. Degree of processing and cooking
- degree of gelatinization, particle size, food form, cellular structure
156
Types of starch
Amylose and amylopectin
157
T or F: molecules in amylopectin are more open than in amylose
T
158
T or F: amylose is easier to digest than amylopectin
F (amylose is harder to digest)
159
Which has higher GI rating? amylopectin or amylose
amylopectin
160
GI of maltose
close to 100
161
GI of sucrose
87
162
GI of fructose
32
163
T or F: Foods with high fat content have lower GI ratings
T
164
T or F: low GI foods are healthier than high GI foods
F (not always - high fat content also equals lower GI)
165
role of acid in foods
acids present in food slow down body digesting that food
--> slower digestion means slower rise in blood glucose
166
how does cooking increase GI rating of food?
cooking swells starch molecules and softens foods making it faster to digest
167
T or F: Highly processed foods are digested faster and tend to have a higher GI rating
T
168
T or F: Unprocessed grains have lower GI ratings because it takes longer to digest the food
T
169
Eating food with low GI may help to:
1. Control blood glucose levels
2. Control cholesterol levels
3. Control appetite
4. Decrease risk of heart disease
5. Decrease risk of Type 2 diabetes
170
glycemic index of food multiplied by the carbohydrate (available) present in food
glycemic load
171
measures both the quantity and quality of a carbohydrate's effect on blood glucose and insulin release
glycemic load
172
Glycemic load ranges
Low GL: 1-10
Medium GL: 11-19
High GL: 20 or more
173
significant independent predictor of the risk of developing type 2 diabetes, and cardiovascular disease
long term consumption of a diet with high glycemic load
174
may protect againstcolon cancer and breast cancer
GL and Health
