Composition/Nutrition Flashcards
OP is:
TP is:
osmotic pressure
turgor pressure
What is dietary fibre?
What purpose do they serve in the plant? How do they differ?
cellulose, hemicellulose, pectin, lignin.
part of cell wall
differ in structure and bond types
What is the role of fibre in nutrition?
Humans cannot digest -> pass through system
acts as bulking agent and laxative, prebiotic
prevent appendicitis, constipation, diabetes, gallstones, obesity, rectum tumors
What is the factor and the effects (4) that give fibre its nutritive qualities?
absorb water and swell
- non-digestible bulk -> feel full
- increase retention time for nutrients, more absorption
- restrict calorie intake
- delay fat/glucose absorption after meal
2 categories of fibre:
insoluble: cellulose, hemicellulose, lignin
soluble: pectin, gums
What is a new class of carbs that is now considered fibre (nutritionally)? What benefits does it have (3)?
resistant starch
- not easily digestible
- remains longer in system
- good for diabetic patients
Ripe fruits are higher in ____ than unripe fruits, which are higher in ____.
sugar
starch
common sugars in fruits:
glucose, fructose, sucrose
starch is found in:
What is the structure?
mature vegetables, unripe fruits
long chains of glucose (polysaccharides)
The 2 digestible starch types:
amylose (a 1-4) straight chains
amylopectin (a 1-4 and a 1-6) branched chains
How does cellulose differ from starch?
also made of glucose units, but b 1-4 bonds
industrial sources of starch:
corn, potato
What enzymes are used to hydrolyze starch and why?
b-galactosidase, a-amylase
produce sugar/syrup
starches are used industrially as:
thickener
source of glucose/fructose
4 types of resistant starch:
give examples
RS1: physically inaccessible or digestible RS (seeds, legumes, unprocessed grains)
RS2: natural granular form (uncooked potato, green banana flour)
RS3: formed when starchy foods are cooked and cooled (bread, cold potatoes, cold rice)
RS4: chemically modified to resist digestion (not in nature)
Rich sources of pectin:
apple, citrus
What is the chemical structure of pectin?
polymer of methyl ester of GALACTURONIC ACID
pectin is important in the production of: ____ due to its ability to ___
what is the general procedure?
jams, jellies; form gel/viscous colloidal suspension
pectin + sugar + acid + cook -> jam
What can be used to make diabetic jelly/jam? Why?
low methoxyl pectin (LMP)
form gel with Ca, no sugar needed
What is the effect of pectin in juice?
cloudiness, thickening
What is “PME?”
natural enzyme in fruit and veg that hydrolyzes pectin
Pectin methyl esterase
Is PME inactivated in juice? Why or why not?
YES: if want cloudy juice
NO: if want to clarify -> then inactivated in pasteurization
NO: if need to filter
What is the role of Ca chloride in fruit? Why?
firming of fruit slices
forms gel with LMP -> increased gel strength, structural rigidity
____ are the major component of the plant cytoplasm
proteins
True False: fruit and vegetable contain significant amounts of protein
false; not major contributors fruit<1% veg 2% peas 7% cereal/pulses 12%
during storage, proteins will lower the _____ of _____, and increase ____ of crops
OP; amino acids
nutritive value
common plant proteins:
albumins globulins, gliadins, glutenins
gluten is form from:
It is important in:
gliadins, glutenins
dough rheology, baking, bread, etc
Where are fats and oils found in plant cells?
in cytoplasmic layers
are fruit/veg major contributors of fats?
no; <2% (dry weight basis)
Fat content of produce is usually expressed in: ____
Why?
dry weight basis (remove water)
very small %
What fruits are high in fats?
avocado, palm kernel, olive
fats and oils are higher in what plant tissues?
cuticle, epidermis, corky layers
nutritional value of fats/oils depends on: (3)
degree of unsaturation, double bonds (omega 3 and 6), structural orientation
intake of ___ and ____ fats should be limited.
trans
saturated
plant oils rich in saturated fats
Which fatty acids are common?
palm kernel
coconut
lauric, myristic
What plant oils are rich in unsaturated fats?
peanut corn olive sunflower soybean
common unsaturated fatty acids:
if these are fully hydrogenated, it becomes:
linoleic
linolenic
oleic
stearic (C18)
___ fatty acids are important in ___ function and in high quantity in the ____.
What are sources in plants?
omega 3; immune; brain
flax, walnuts, pumpkin seeds
True/False: fruit/veg contain excesses of organic acid, more than needed for metabolic activity
True
Why do fruit/veg contain so many organic acids?
by products of metabolic activities
accumulated in vacuoles
What are the dominant organic acids?
citric, malic
Grapes and avocado are rich in ___ acid
blackberry contains ___ acid
spinach contains ___ acid
tartaric
isocitric
oxalic
___ and ____ contain 3% acid
lime, lemon
F&V are important sources of: (vitamins)
vitamin C (best source)
vitamin A precursors
folic acid
Important minerals in F&V:
iron, calcium
what factors need to be considered when evaluating miineral and vitamin content in F&V?
Amount consumed
bioavailability
concentration
is spinach a rich source of calcium?
No, bound to oxalate (not bioavailable)
3 major classes of pigments;
chlorophylls (green)
carotenoids (yellow orange)
flavonoids (various colors)
role/location/properties of chlorophylls:
need for photosynthesis
in chloroplasts (chlorophyll a and b)
heat in acid -> turn brown/olive
Difference between types of chlorophylls:
a: CH3
b: CHO group
The enzyme ____ will remove the ____ group on chlorophyll, which will turn the color bright green
chlorophyllase
phytol
carotenoids are ___ soluble, and found in ____.
fat; chromoplasts
True/False: green leaves do not contain carotenoids
False; hidden by chlorophyll
What carotenoids are found in carrots, tomato, and radish? what benefits do these compounds have?
carrot: b-carotene (pre vitamin A)
tomato: lycopene (pharmaceutical properties)
radish: xanthophylls
Types of flavonoids:
anthocyanins (red/blue/purple)
anthoxanthins (yellow)
catechins
leucoanthocyanins (colorless, can form brown)
color of anthocyanins depends on _____.
What is the color in different conditions?
pH
acid: red
slightly basic: purple
basic: blue
Anthoxanthins can have nutraceutical properties as _____.
anti-hemorrhage factor
What are tannins?
astringent compounds, can react with metal ions to give dark color (tan)
“Tan” is produced by:
catechins polymerizing
tannins reacting with metal ions
