Class #3: Fruits and Vegetables

Question 1

What is a CFG portion of vegetable?

Answer 1

250ml raw leafy veg, or 125ml cooked/raw veg

Question 2

What is a CFG portion of fruit?

Answer 2

125ml fruit, 125ml fruit juice.

Question 3

What is contained in the vacuole?

Answer 3

H2O, anthocyanins, flavour compounds, organic acids.

Question 4

What are the three different types of plastids?

Answer 4

Leucoplasts, chloroplasts, chromoplasts.

Question 5

True or false: Chromoplasts are unpigmented.

Answer 5

False. Leucoplasts are unpigmented, chromoplasts hold carotenoids (yellow&red)

Question 6

True or false: Pectic substances are large polysaccharides.

Answer 6

True

Question 7

Which type of pectin is present in unripe fruit?

Answer 7

Protopectin

Question 8

Which type of pectin is present in overripe fruit?

Answer 8

Pectic acid

Question 9

Define fruit (in terms of plant anatomy)

Answer 9

Seed bearing structure, protects seeds

Question 10

Define seeds (in terms of plant anatomy)

Answer 10

Can create new plants, high in carbohydrate

Question 11

Define flowers (in terms of plant anatomy)

Answer 11

Responsible for reproduction, all other edible parts of the plant apart from fruit and vegetable.

Question 12

Define bulbs (in terms of plant anatomy)

Answer 12

Storage organ during plant dormancy.

Question 13

Define Legumes (in terms of plant anatomy)

Answer 13

Seeds contained in a pod, high in carbohydrate, fibre, protein, and iron.

Question 14

What is the limiting amino acid in legumes?

Answer 14

Methionine

Question 15

What are functional foods?

Answer 15

Have potentially positive effects on health other than nutrients.

Question 16

Where is lutein (yellow phytochemical) found?

Answer 16

Green leafy vegetables.

Question 17

Where is genistein found, and what does it do?

Answer 17

In soybeans, may decrease risk of breast and uterine cancer.

Question 18

Where is luteolin found?

Answer 18

Broccoli, Celery, Green Pepper, Herbs

Question 19

Define degorging.

Answer 19

Removal of bitter compounds using salt and osmosis.

Question 20

What happens when you cook with acid vs when you cook with base?

Answer 20

Acids precipitate pectins=harder to soften.

Bases: Break down cellulose=mushy

Question 21

True or False: Calcium salts combine with pectic substances, forming insoluble compounds.

Answer 21

True, firms food and can help make up for lost turgor.

Question 22

Name 3 ways to retain nutrients when cooking vegetables.

Answer 22

• Short cook time
• minimal H2O use
• cut large chunks (lower surface area)
• Drink cooking liquid, skins
• do not use baking soda

Question 23

True or false: Higher respiration rate = faster spoiling

Answer 23

True, refrigeration reduces respiration

Question 24

What is the optimal humidity to store vegetables at?

Answer 24

85-95%

Question 25

Why does freezing decrease vegetable quality?

Answer 25

The membranes of the plant cells burst if it is not blanched beforehand.

Question 26

True or False: Refrigeration helps potatoes stay firm.

Answer 26

False. It causes the starch in the potatoes to be converted to glucose. Makes the texture waxy.

Question 27

Exposing potatoes to light produces which toxic compound?

Answer 27

Solanine, because the potato undergoes photosynthesis.

Question 28

How does controlled atmosphere packaging keep vegetables fresher longer?

Answer 28

Reduces O2 available and increases CO2 concentration: slower respiration.

Question 29

What are the 3 major classes of plant pigments?

Answer 29

Carotenoids, chlorophyll and Flavonoids.

Question 30

True or false: Flavinoids are found in plastids.

Answer 30

False. Chlorophyll and Carotenoids are found in plastids, Flavinoids are found in the vacuole.

Question 31

What is the structure of chlorophyll?

Answer 31

Porphyrin ring, with Mg in centre. Very heat sensitive.

Question 32

What colour is chlorophyll a?

Answer 32

Blue Green

Question 33

What colour is chlorophyll b?

Answer 33

Green

Question 34

True or false: Chlorophyll is fat soluble.

Answer 34

True

Question 35

How is green food turned yellow-brown?

Answer 35

- excessive heating ruptures plant cells - organic acids are released - H+ ions replace Mg in chlorophyll, forming pheophytin

Question 36

Why does blanching make greens brighter?

Answer 36

Some chlorophyll may be hidden by air between cells, blanching causes air to bubble away, revealing the chlorophyll.

Question 37

What are the 3 types of carotenoids?

Answer 37

Carotenes (Yellow-Orange), Lycopene (red), Xanthophylls (Yellow)

Question 38

True or false: Flavinoids are pH sensitive.

Answer 38

True.

Question 39

What are the 3 types of Flavinoids?

Answer 39

Anthocyanins, anthoxanthins, betalains

Question 40

True or False: Anthocyanins are white pigments.

Answer 40

False. Anthocyanins are red-purple-blue, anthoxanthins are white.

Question 41

What colour are anthocyanins in acidic pH? a. red b. purple c. blue

Answer 41

A

Question 42

What colour are anthocyanins in basic pH? a. red b. purple c. blue

Answer 42

C

Question 43

What colour are anthocyanins in neutral pH? a. red b. purple c. blue

Answer 43

B

Question 44

What colour are anthoxanthins in acidic pH? a. red b. Yellow c. white

Answer 44

C

Question 45

What colour are anthoxanthins when in contact with Fe or Cu? a. Blue b. Yellow c. White

Answer 45

A

Question 46

Where are betalains mainly found?

Answer 46

Beets

Question 47

True or false: Cu and Zn help chlorophyll stay green.

Answer 47

Yes, but we don't use them bc they're toxic

Question 48

What part of the plant do fruits come from?

Answer 48

The flower ovary, matured.

Question 49

What are the 3 different types of fruits?

Answer 49

Simple, Aggregate, Multiple

Question 50

Define Aggregate fruit

Answer 50

Formed by joining of multiple ovaries on 1 flower (Ie raspberry)

Question 51

Define Multiple Fruit

Answer 51

Formed from many flowers, remain together as a single mass.

Question 52

True or false: Most fruit has a pH above 7

Answer 52

False, most fruit has a pH under 5

Question 53

Name the 5 organic acids found in fruits.

Answer 53

- Citric Acid (Citrus) - Malic Acid (Stonefruit) - Tartaric Acid (Grapes) - Oxalic Acid (Rhubarb) - Benzoic Acid (cranberries)

Question 54

True or False: Low pH fruits are less sweet, but have stronger flavours.

Answer 54

True

Question 55

Which compounds are responsible for the browning of fruits?

Answer 55

Phenolic compounds (Tannins)-found mostly in unripe fruit, astringent. Decrease as fruit ripens.

Question 56

True or False: Vitamins reach their peak in fruits at maturity.

Answer 56

True

Question 57

True or False: Organic acids reach their peak in fruits at maturity.

Answer 57

False, they decrease and their type may change as pH changes.

Question 58

Why do fruits become sweeter with ripening?

Answer 58

Starch converts to glucose.

Question 59

Why do fruits become softer with ripening?

Answer 59

Pectic substances degrade.

Question 60

Define essential oil

Answer 60

An oily substance that is volatile with 100x the flavouring power of where it originated.

Question 61

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

Answer 61

D. When cell membranes denature, they can no longer keep solutes out, so they come in via simple diffusion.

Question 62

How does sugar maintain firmness in fruit?

Answer 62

Sugar enters cells as H2O leaves, interfering with conversion of protopectin to pectin.

Question 63

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

Answer 63

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

Question 64

Define Climacteric Fruits

Answer 64

Fruits that continue to ripen after harvest.

Question 65

Define non climacteric fruits

Answer 65

Fruits that do not ripen after harvest.