Class #3: Fruits and Vegetables Flashcards
What is a CFG portion of vegetable?
250ml raw leafy veg, or 125ml cooked/raw veg
What is a CFG portion of fruit?
125ml fruit, 125ml fruit juice.
What is contained in the vacuole?
H2O, anthocyanins, flavour compounds, organic acids.
What are the three different types of plastids?
Leucoplasts, chloroplasts, chromoplasts.
True or false: Chromoplasts are unpigmented.
False. Leucoplasts are unpigmented, chromoplasts hold carotenoids (yellow&red)
True or false: Pectic substances are large polysaccharides.
True
Which type of pectin is present in unripe fruit?
Protopectin
Which type of pectin is present in overripe fruit?
Pectic acid
Define fruit (in terms of plant anatomy)
Seed bearing structure, protects seeds
Define seeds (in terms of plant anatomy)
Can create new plants, high in carbohydrate
Define flowers (in terms of plant anatomy)
Responsible for reproduction, all other edible parts of the plant apart from fruit and vegetable.
Define bulbs (in terms of plant anatomy)
Storage organ during plant dormancy.
Define Legumes (in terms of plant anatomy)
Seeds contained in a pod, high in carbohydrate, fibre, protein, and iron.
What is the limiting amino acid in legumes?
Methionine
What are functional foods?
Have potentially positive effects on health other than nutrients.
Where is lutein (yellow phytochemical) found?
Green leafy vegetables.
Where is genistein found, and what does it do?
In soybeans, may decrease risk of breast and uterine cancer.
Where is luteolin found?
Broccoli, Celery, Green Pepper, Herbs
Define degorging.
Removal of bitter compounds using salt and osmosis.
What happens when you cook with acid vs when you cook with base?
Acids precipitate pectins=harder to soften.
Bases: Break down cellulose=mushy
True or False: Calcium salts combine with pectic substances, forming insoluble compounds.
True, firms food and can help make up for lost turgor.
Name 3 ways to retain nutrients when cooking vegetables.
- Short cook time
- minimal H2O use
- cut large chunks (lower surface area)
- Drink cooking liquid, skins
- do not use baking soda
True or false: Higher respiration rate = faster spoiling
True, refrigeration reduces respiration
What is the optimal humidity to store vegetables at?
85-95%
Why does freezing decrease vegetable quality?
The membranes of the plant cells burst if it is not blanched beforehand.
True or False: Refrigeration helps potatoes stay firm.
False. It causes the starch in the potatoes to be converted to glucose. Makes the texture waxy.
Exposing potatoes to light produces which toxic compound?
Solanine, because the potato undergoes photosynthesis.
How does controlled atmosphere packaging keep vegetables fresher longer?
Reduces O2 available and increases CO2 concentration: slower respiration.
What are the 3 major classes of plant pigments?
Carotenoids, chlorophyll and Flavonoids.
True or false: Flavinoids are found in plastids.
False. Chlorophyll and Carotenoids are found in plastids, Flavinoids are found in the vacuole.
What is the structure of chlorophyll?
Porphyrin ring, with Mg in centre. Very heat sensitive.
What colour is chlorophyll a?
Blue Green
What colour is chlorophyll b?
Green
True or false: Chlorophyll is fat soluble.
True
How is green food turned yellow-brown?
- excessive heating ruptures plant cells
- organic acids are released
- H+ ions replace Mg in chlorophyll, forming pheophytin
Why does blanching make greens brighter?
Some chlorophyll may be hidden by air between cells, blanching causes air to bubble away, revealing the chlorophyll.
What are the 3 types of carotenoids?
Carotenes (Yellow-Orange), Lycopene (red), Xanthophylls (Yellow)
True or false: Flavinoids are pH sensitive.
True.
What are the 3 types of Flavinoids?
Anthocyanins, anthoxanthins, betalains
True or False: Anthocyanins are white pigments.
False. Anthocyanins are red-purple-blue, anthoxanthins are white.
What colour are anthocyanins in acidic pH?
a. red
b. purple
c. blue
A
What colour are anthocyanins in basic pH?
a. red
b. purple
c. blue
C
What colour are anthocyanins in neutral pH?
a. red
b. purple
c. blue
B
What colour are anthoxanthins in acidic pH?
a. red
b. Yellow
c. white
C
What colour are anthoxanthins when in contact with Fe or Cu?
a. Blue
b. Yellow
c. White
A
Where are betalains mainly found?
Beets
True or false: Cu and Zn help chlorophyll stay green.
Yes, but we don’t use them bc they’re toxic
What part of the plant do fruits come from?
The flower ovary, matured.
What are the 3 different types of fruits?
Simple, Aggregate, Multiple
Define Aggregate fruit
Formed by joining of multiple ovaries on 1 flower (Ie raspberry)
Define Multiple Fruit
Formed from many flowers, remain together as a single mass.
True or false: Most fruit has a pH above 7
False, most fruit has a pH under 5
Name the 5 organic acids found in fruits.
- Citric Acid (Citrus)
- Malic Acid (Stonefruit)
- Tartaric Acid (Grapes)
- Oxalic Acid (Rhubarb)
- Benzoic Acid (cranberries)
True or False: Low pH fruits are less sweet, but have stronger flavours.
True
Which compounds are responsible for the browning of fruits?
Phenolic compounds (Tannins)-found mostly in unripe fruit, astringent. Decrease as fruit ripens.
True or False: Vitamins reach their peak in fruits at maturity.
True
True or False: Organic acids reach their peak in fruits at maturity.
False, they decrease and their type may change as pH changes.
Why do fruits become sweeter with ripening?
Starch converts to glucose.
Why do fruits become softer with ripening?
Pectic substances degrade.
Define essential oil
An oily substance that is volatile with 100x the flavouring power of where it originated.
Why do fruits become mushy when cooked?
a. Protopectin converts to pectin
b. cellulose and hemicellulose degrade
c. cell membrane proteins denature
d. all of the above
D. When cell membranes denature, they can no longer keep solutes out, so they come in via simple diffusion.
How does sugar maintain firmness in fruit?
Sugar enters cells as H2O leaves, interfering with conversion of protopectin to pectin.
How can you prevent enzymatic browning of fruits?
a. Denaturing the enzyme polyphenol oxidase
b. Cooling the fruit down
c. Cooking the fruit
d. Covering the fruit, reducing O2 exposure
e A,B&D
E. The enzyme can be denatured with acid or base, inhibits activity because optimal pH for enzyme is 7
Cooling the fruit lowers the rate of enzyme activity
Define Climacteric Fruits
Fruits that continue to ripen after harvest.
Define non climacteric fruits
Fruits that do not ripen after harvest.
