Topic 2 Flashcards
(135 cards)
1
Q
carb forms include
A
starch
sugar
fliber
glycogen
2
Q
carbs contain what elements?
A
H, C & O
3
Q
how are carbs formed
A
photosynthesis
4
Q
food sources of carbs include:
A
o Cereal grains & flours, Ex: wheat, rye, corn & rice
o Legumes, Ex: peas, beans & lentils
o Starchy roots , Ex: potatoes, yam & cassava
o Fruits, Ex: orange, apple & banana
o Sugars, Ex: Honey, jam & molasses
5
Q
how are carbs classified?
A
number of basic sugar molecules
6
Q
monosaccharide
A
simple sugar
Fructose, galactose, glucose
7
Q
disaccharide
A
simple sugar
Maltose (malt sugar), sucrose (table sugar), lactose (milk)
8
Q
Oligosaccharide
A
simple sugars
3-10 units
9
Q
polysaccharides
A
complex sugars
many units
10
Q
which carbs are simple sugars
A
mono
di
oligo
11
Q
what sugar isn’t considered a simple sugar?
A
polysaccharides
12
Q
monosaccharide sugar units consist of:
A
hexose & pentose
13
Q
hexose
A
6C, sugars such as: glucose, mannose, fructose & galactose
Building blocks of polysaccharides
14
Q
pentose
A
5C, such as: ribose, xylose & arabinose
Building blocks of fibers & gums
15
Q
how do glucose & galactose differ?
A
positioning of the H-OH bond on the
16
Q
what is the most abundant sugar in the world?
A
glucose
17
Q
glucose food source
A
fruits, plant juices & honey
18
Q
what form of sugar circulates in the blood?
A
glucose
19
Q
what are the 3 products of glucose?
A
E
water
CO2
20
Q
what is the storage form of glucose & where is it located?
A
glycogen
liver & muscles
21
Q
what is the sweetest sugar?
A
fructose
22
Q
solubility of fructose? & how does that influence its baking use?
A
very soluble & doesn’t crystallize easily –> not good for making candies
it reduces the freezing point too much thus not an ideal sugar to be used in frozen desserts
23
Q
how is HFCS made?
A
glucose is changed to fructose by adding glucose isomerase
24
Q
glucose isomerase
A
breaks down fructose & changes the isomer of glucose
25
fructose causes ___ times more cell damage than glucose
7
26
fructose is only metabolized by what organ? & what does it lead to the production of?
liver
uric acid --> oxidative damage
27
sucrose contains how much fructose?
50%
28
HFC-42 contains how much fructose?
42%
29
galactose
glucose - galactose
30
galactose is found where?
not free form in foods, fermented in milk where lactose is hydrolyzed into galactose & glucose
31
disccharides occur from what rxn?
condensation
32
common disaccharides include
sucrose (cane/beet sugar)
maltose (corn syrup)
lactose (milk sugar)
33
what sugar unit is accessible to absorption in the blood stream?
monosaccharide
34
hydrolysis
a water molecule enters the region of the functional group of a larger molecule & splits
35
what happens if disaccharides aren't digested?
lead to gas production in the lower gut causing flatulence & abdominal cramps or discomfort
36
lactose intolerance
pancreas doesn't produce lactase
if not enough lactose isn't broken down by bacteria then it leads to abdominal pain
37
sucrose food source
table sugar
extracted from sugar cane & sugar beets
present in fruits, honey & vegetables
38
sucrose composition
glucose & fructose
39
highly concentrated sucrose solutions act as
preservatives & cryoprotectants
40
cryoprotectants
Protects fluid from freezing by lowering the freezing point (lower the temperature at which the liquid would freeze)
41
lactose food source
milk & milk products
42
lactose composition
glucose & galactose
43
maltose composition
2 glucose molecules
44
maltose food source
malt sugar
gaunt in germinating grain & corn syrup
45
what product is used for hydrolysis in malting & how is it made?
alpha-amylase
made by bacteria
46
reducing sugar
a sugar capable of acting as a reducing agent b/c it has a free aldehyde or ketone grp
47
reducing sugars include:
```
all monosaccharides
some disaccharides (not sucrose), oligosaccharides polysaccharides
```
48
is sucrose a reducing sugar?
no
49
Dextrose (glucose) equivalent
a measure for the amount of reducing sugars present in a food/solution
50
when do we use Dextrose (glucose) equivalent
making corn syrup to determine its sweetness
determine the level of degradation of starch
51
increase reducing sugar = ___ hydrolysis = ___ glucose
more & more
52
why is glucose aded to a food?
for its functional properties
sweetness is then adjusted with alternative sweetness
53
sucrose 10% sol'n sweetness
100
54
Glucose syrup 62 DE sweetness
59
55
Glucose syrup 42 DE sweetness
41
56
HFCS (42% fructose) sweetness
100
57
milliard rxn
browning occurs above 150C due to formation of pigments called melanoidins
reduction sugar & AA (no enzyme, no heat)
58
what needs to occur for there to be non-enzymatic browning?
reducing end of reducing sugar & an AA must be present
59
what are the steps in the milliard rxn?
1. Condensation: reducing sugars + AA glycosamine
2. Rearrangement:
Glycosamine Amadori compounds (colourless) --> pyrazines
3. Polymerization: colourless compounds --> brown melanoidins (leads to brown colour & responsible for flavours)
60
why can you smell a bakery?
free AAs react at higher action with reducing sugars
61
caramelization
non-enzymatic, formation of a pigment called caramelin produced due to heat treatment (generally over 160C, diff sugars caramelize at diff temperatures)
62
what inhibits starch gelatinization?
sugars
63
hygroscopic
ability to attract water
sugars
64
why are sugars desirable in food preservation?
sugars absorb more water leaving less available for bacteria
65
inversion & what is the result
hydrolysis of sucrose into its component monosaccharides, achieved by enzyme invertase
sweeter than its original sugar
66
crystallization
the more complex the mix, the slower will be the tendency for crystallization to occur
67
what happens to low DE sugars with the onset of crystallization?
decay b/c their structures are more complex
68
what are the steps of crystallization?
At room temp, about 2 parts sucrose can be dissolved in one part 1 water concentrated solution of ~ 67%
The solution is cooled without agitation, it becomes supersaturated
Clear, hard boiled sweets
Crystals will form & sugar will start to separate
Upon further cooling, especially with agitation, the sucrose crystallizes
Fudges
Agitation = forms small crystals
69
what speeds up crystallization in a supersaturated sol'n?
Sucrose molecule
70
seed crystal
is a surface that sucrose molecules can begin to attach to themselves to, it could even be a few sucrose molecules stuck together, a piece of dust or even an air bubble
71
oligosaccharides composition
10 or fewer monosccarhides
72
oligosaccharides include:
raffinose & stachyose found in dried beans
cause gas in humans if bacteria don't digest it
73
solubility of oligosaccharides
water soluble,le
74
polysaccharides
up to several hundred thousand monosaccharides
75
homopolysaccharides & exs of
polysaccharide composed of the same monosaccharides
starch, cellulose
76
heteropolysaccharides & exs of
composed of 2 or more types of monosaccharides
hectin, hemicellulose
77
what are the 3 kinds of polysaccharides?
starch
fibers
glycogen
78
starch (homoglucan)
basic storage unit in plants (seeds, roots & tubers), consist of glucose molecules
79
what are the 2 kinds of starch molecules
amylose
amylopectin
80
what is the bond in starch molecules
alpha amylose
81
a waxy starch contains how much amylose?
0-5%
82
normal starch contains:
25% amylose & 75% amylopectin
83
what happen to starch granules when they are heated in water?
gelatinize
84
high amylose corn syrup contains how much amylose?
65%
85
what are some starches that only contain amylopectin?
waxy corn
waxy barley
waxy rice
86
which starch molecule gelatinizes better?
amylopectin
87
starch gelatinization
swelling of starch granules when in heated in water
88
what is the movement of starch granules during gelatinization?
Amylose will begin to move out of the granule & amylopectin remains in the granule
When you cool it down, amylose will start h-bonds with water & amylose molecules creates a network trapping water & solidifies (gel)
89
gelation
formation of a rigid thick structure (starch gel) when cooled
90
pasting
when the amylopectin moves out creating a sticky mixture
91
retrogradation
recrystallization of amylose during storage
92
syneresis
leakage of water from the gel
93
what creates a thick paste?
Amylopectin only --> will gelatinize (swelling) quickly but gel will not form b/c there is no amylose & will remain as a thick paste
Gel occurs b/w the h-bonds b/w amylose & water
More amylose = stronger the gel
94
how does granule size influence water movement?
Larger the granule = the faster the water gets into the granule --> not as compact, more space for water retention
will retrograde faster
95
what are the factors effecting gelatinization?
amount of water
temp
duration of cooking
shear
acidity
sugar
rate of cooling
amylose: amylopectin ratio
96
starch dextrinization
heating the starch leads to dextrinization
97
dextrin
sweeter & mobile, broken starch molecules & become brown etc.
98
RS1
Inaccessible to enzymes
Due to high compaction that enzymes are unable to penetrate will not convert to glucose & cannot absorb into blood therefore, becoming excreted
Can be considered a fiber
99
RS2
ungelatinized
Digestive system will be unable to break down (why we cook starch foods before we cook it)
100
RS3
retrograded
Gelatinization start to weep , form crystals which are resistant
101
RS4
chemically modified
102
glycogen
storage form of glucose in animals
103
what happens to surplus glucose?
converted to fat or glycogen
104
dietary fiber is a mix of
```
o Cellulose
o Hemicellulose
o Beta-glucans
o Pectins
o Gums
```
105
fibres found in the cell walls of vegetables, fruits & seeds & provide what to food:
o Physical compactness
o Crispness
o Good mouthfeel
106
vegetable gums with no structural role provide what to food
thickening
viscosity
adhesiveness
gel forming
107
what is finer nutrient for?
bowel health
healthy wt
healthy heart
108
how many finer sources should be chosen a day
1-2 high finer sources
5-7 moderate fiber sources
109
insoluble fibers include
hemicelluloses provide body roughage
110
soluble fibers include
ex: pectin & gums best for inhibiting cholesterol absorption
111
what are the types of fibres ?
cellulose
hemicellulose
beta-glucans
pectic substances
vegetable gums/hydrocolloids
inulin
112
cellulose
homopolysaccharide
glucose units linked with beta bonds to form a linear chain
113
what are modified cellulose products? & why are they modified?
methyl cellulose & carboxymethyl cellulose
more soluble & more useful for thickening, gelling & providing bulk in low cal products
114
hemicellulose
belong to heterogenous polysaccharides
supporting material in cell walls
115
which finer is hydrolyzed in the large intestine by bacteria?
hemicellulose
116
what are the monosaccharide building blocks of hemicellulose?
glucose, xylose, arabinose, mannose
117
which fiber is used in films & gels in packaging & food?
hemicellulose
118
what finer is retardant in staling of bread?
hemicellulose
119
beta - glucans
glucose units linked with beta bonds
less linear than cellulose & more water soluble
120
what are food sources of beta-glucan? & what effect does it have?
oats & barley
lower blood cholesterol when consumed in adequate amounts with a diet low in saturated fats
121
pectic source
found in cell walls & cell space of plants, aid in cementing plant cells together
122
how much beta-glucan is in oats?
0.75g beta-glucan/serving
123
what are the building blocks for pectic substances?
galactruonic acid (derivative of galactose)
124
what fibre is responsible for forming gels?
pectin
125
how is pectin produced commercially?
apple cores (poor quality) & citrus peels (better quality)
126
food source of pectin
fruits
127
Factors affecting gelling of pectin
pH
Sugar
Ca ions
Type of pectic substances
128
vegetable gums/hyrdocolloids
long chain polysaccharides
129
building blocks of vegetable gums/hyrdocolloids
hexose & pentose sugars
130
what increases the growth of bifibacteria?
vegetable gums/hyrdocolloids
131
what are the effects of bifibacteria?
Produces nutrients such as B-grp vitamins & folic acid
Produces digestive enzymes
Reduces food intolerance
Improves nutrient management
Reduces liver toxins, ex: blood amines & ammonia
Competitive elimination of pathogenic microbes
132
what is the result of Vegetable gums/hydrocolloids
| dissolved in water?
thickening or texture building effect
133
when are Vegetable gums/hydrocolloids used in the food industry?
ice cream, low cal salad dressings, low fat foods
134
what are the food sources of Vegetable gums/hydrocolloids?
Seaweed extracts: agar, alginate, carracgeenan
Plant seed gums: locust bean gum, guar gum
Plant exudates: gum Arabic, gum tragacanth
Microbial gums: xanthan gum, dextran
135
inulin
natural plant extract composed of linear fructose chains with mostly one terminal glucose unit, is prebiotic
