Fruits Flashcards
What are the three types of flowers?
- Simple
- Aggregate
- Multiple
Define simple fruits.
Derived from the ovary of one pistil : from a simple blossom.
What are the three subcategories of simple fruits?
1) Drupes
2) Pomes
3) Citrus fruits
Define aggregate fruits.
Formed by a single flower with many stamens and pistils
Define multiple fruits.
Formed from many flowers and remain together as a single mass
What are the three subcategories of berries?
- True berries
- Pepo
- Hesperidium
Give examples of true berries.
Currants, tomatoes, cranberry, kiwi, banana, graphes, avocado
Give examples of pepo berries.
Curcurbits: hard skin - melon, squash
Give examples of hesperidium berries.
Rind, juicy interior - citrus
What is the difference between animal and plant cells?
Plant cells have a cell wall, a vacuole and intercellular air
Compare the primary cell wall and the secondary cell wall.
Primary: thin and contains cellulose, hemicellulose, and pectic substances
Secondary: relatively thick and may contain lignin
Define lignin.
a non carbohydrate material with a chemical
structure derived from benzene (carrots, broccoli, asparagus)
Define cellulose.
indigestible polymer
Define hemicellulose. What is it degraded by?
less polymerized than cellulose (degraded by alkali)
Define pectic substances.
protopectin, pectin
Define intercellular air.
fills empty spaces between cell walls in plants and contributes to volume and crispness and textural differences
What kind of cell are vegetables and fruits composed of?
Parenchyma cells
The cytoplasm of parenchyma cells contains compounds for what?
Starch Content Color
Water Volume Flavor
What are plastids?
Storage organelles for substances (starch and pigments)
Name the 3 plastids.
- Leucoplasts
- Chloroplasts
- Chromoplasts
Define leucoplasts.
Starch and Water Major Digestible Portion
Define chloroplasts.
Chlorophyll Essential for CHO Synthesis Green Color
Define chromoplasts.
Carotene or Xanthophyll Pigments Orange-Yellow Color
What are the components of the parenchyma cells of VEGETABLES?
- Cytoplasm (all parenchyma cells)
- Plastids (all parenchyma cells)
- Vacuoles
- Organic acids
What do vacuoles provide?
Store Water & Other Compounds Turgor
Rigid Firmness of Plant Cell Resulting From Being Filled w/ Water
What do organic acids provide in parenchyma cells?
Cell pH
Flavor and Acidity
What is used commercially to polish fruits? What can it contain?
- Additional wax
- May contain preservatives or colour
What does the skin of fruits secrete? What does it do?
waxy cutin- that: -protects the surface
-retards loss of water
How many portions of fruits and vegetables should individuals over the age of 14 consume?
7-10 portions
What constitutes a vegetable portion?
1 cup raw leafy vegetable
1⁄2 cup cut-up raw or cooked vegetable 1⁄2 cup vegetable juice
What constitutes a fruit portion?
1 medium fruit
1⁄2 cup fresh, frozen, or canned fruit
1⁄4 cup dried fruit 1⁄2 cup fruit juice
How much water does fruit contain? Protein, fat and carb?
70-95% water
Less than 1% protein and fat (but there are exceptions)
Solids are primarily carbohydrates
What is contained in smaller amounts in fruits?
Cellulose, hemicellulose, pectic substances
What do fruits provide in terms of nutrients?
Carbohydrates, calories, fibre, vitamins, minerals, phytochemicals
Name 3 fruits that are high in fat.
Coconut, avocado, olive
Define phytochemicals.
Nonnutrient components of plants that are beneficial in fighting disease
How are phytochemicals emerging as potential regulators of health?
Antioxidants
Regulate protein synthesis
Mimic hormones
Alter blood chemistry
What do blueberries provide in terms of phytochemicals?
Flavonoids: anthocyanins, flavinols
What do cranberries provide in terms of phytochemicals?
Proanthocyanins
What do raspberries and strawberries provide in terms of phytochemicals?
Ellagitannins
What do watermelon, pink grapefruit and tomatoes provide in terms of phytochemicals?
Lycopene
What are the components of the parenchyma cells of FRUITS?
- Cytoplasm (all parenchyma cells)
- Plastids (all parenchyma cells)
- Organic acids (volatile and nonvolatile)
- Pectic substances
- Phenolic compounds
Name 2 phenolic compounds.
Tannins and polyphenols
Name 3 pectic substances.
Protopectin, pectin and pectic acid
Compare the acidity of fruits and vegetables.
Fruits: pH below 5.0
Vegetables: pH above 4.5 (generally)
What is tartness in fruit related to?
Acidic content
Least acidic = more bland and sweet
Compare volatile and nonvolatile organic acids.
Volatile: vaporize during heating
Nonvolatile: do not vaporize, leach out when cooked in water
What are citric acids found in?
Citrus fruits and tomatoes
What are malic acids found in?
Apples, apricots, cherries, peaches, pears, strawberries
What are tartaric acids found in?
Grapes
What are oxalic acids found in?
Rhubarb
What are benzoic acids found in?
Cranberries
What is the function of pectic substances?
Cell cement, firmness and structure
How do pectin substances change during ripening?
1) Protopectin (immature fruit - no gel)
2) Pectin (ripe fruit - gel)
3) Pectic acid (overripe fruit - no gel)
How does the food industry use pectin?
Emulsifier, stabilizer, thickener, texturizer
What are phenolic compounds responsible for?
browning and bruising
What do tannins provide in unripe fruits?
bitter taste - astringent
Name 4 ways to prevent enzymatic browning.
1) Denaturing enzymes: boiling water, blanching harms fruit
2) Add acid: polyphenol oxidase inhibited
3) Lowering storage temp: cold slows enzyme inhibition
4) Blocking oxygen: coating with sugar or water or antioxidants
Name the 6 changes that arise during ripening of fruit.
1) Increase in vitamin content
2) Organic acids decrease and increase in pH
3) Changes in colour: carotenoids and anthocyanins
4) Starch decreases
5) Texture softens
6) Flavour substances develop
When is the peak vitamin content?
At maturity of fruit
What does the organic acid decrease during ripening influence?
fruit flavor and color pigments
anthocyanins
Why are there changes in colour during ripening?
pigments are unmasked (chlorophyll degradation) or synthesized (increased)
Why does organic acids decreasing cause their type to change? What does that influence?
Due to increase in fruit sugar
- Influence fruit flavour and colour pigments (anthocyanins)
Why does starch decrease during ripening?
present in immature fruits and gradually disappears as fruit ripens and its sugar content increases (starch = source of sugar)
Why does texture soften during ripening?
due to the degradation of the cementing pectic substances and Ca 2+ (mushy)
protopectin ⇒ water-soluble pectin ⇒ pectic acid
Why do flavour substances develop during ripening?
- fruit becomes less tart as sugar increases
- organic acids decrease, so does astringency (polyphenol compounds decrease)
How are fresh fruit and vegetables graded on?
Uniformity of size and shape Minimum and maximum diameter Minimum length Color Maturity Freedom from disease, injury, and other defects and damage; and cleanliness
Name 4 ways to make fruit available all year.
Canning
Freezing
Juicing
Drying
What are some signs of refrozen fruit?
Heavy frost, flaccid, less flavourful, often no sugar added
What are frozen fruit juice concentrates?
3/4 water removed
How can you rehydrate dried fruit?
1/2 cup liquid per 1 cup dried fruit
What are aromatic oils?
- Delicate, volatile with heat
- Colourful outer layer of citrus fruits “zest”
- More flavour than fruit’s juice
How can you collect zest?
- Grater: smallest hole then pastry brush to remove
- Five-hole zester
How much zest can you gain from one lime? Lemon? Orange?
Lime: 1-1 1/2 tsp
Lemon: 1/2-1Tbsp
Orange: 1 Tbsp
Texture is affected by what?
Cooking medium
What happens when heat is applied to plant tissues?
1) Cell membranes are disrupted
2) Lose their selective permeability
What happens when cell membranes are disrupted?
- expulsion of air
- protopectin transformed into pectin
What happens when cell membranes lose their selective permeability?
- protein denaturation
- no more osmotic pressure but simple diffusion for water and solutes to pass through membranes
What happens when fruits are heated in water alone?
sugar diffuses out of the fruit and water moves into the fruit
What substances will help fruit keep their texture during cooking?
1) Calcium ions
2) Acids and sugar
How do calcium ions help fruit maintain a solid texture during cooking?
- reduce the tissue breakdown of fruits.
- Ca 2+ reacts with structural polysaccharides in the tissues (pectic substances) to form insoluble salts that strengthen tissues
What does adding an alkali to fruit do? What can you add to help maintain a firm texture?
Solubilize hemicellulose -> mushy texture
- Acids and sugar do the opposite
How does the nutritive value of fruit change?
Mainly loss of ascorbic acid
How does flavour change when fruit is cooked?
Off-flavour if cooked too long in sugar syrup (ex: strawberries)
Name 4 ways fruit can be prepared.
- Dry-heat (baking, broiling, frying/sautéing, grilling)
- Moist-heat (stewing/poaching)
- Dried fruit (soaked in water, simmered in covered pan)
- Fruit spreads (fruit preserves, jams, conserves, chutneys, jellies, marmalades, butters
Which fruit are the exceptions that cannot be made into spreads?
Bananas and melons
Differentiate climateric and non-climateric fruits.
Climateric fruits: continue to ripen after harvest
Non-climateric fruits: best ripened before harvest
How long before you should consume fresh fruit?
3 days after purchase
How do you increase storage time of ripe fruit?
Placing in plastic bags with air holes
Refrigerating
How do you store canned fruit?
Store in dry places (temp at 21oC)
Define a fruit.
a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering.
What are classification exceptions of fruits? Why?
Tomato, nuts, rhubarb
Give examples of drupes.
Fruits with seeds encased in a pit: apricots, cherries, peaches, plums
Give examples of aggregate fruits.
Blackberries, raspberries, strawberries
Give examples of multiple fruits.
Pineapple and figs
Give examples of pomes.
Fruits with seeds contained in a central core, such as apples and pears.
Give examples of citrus fruits.
Oranges, grapefruits, lemons, limes, kumquats and mandarins
What are ground or mashed whole cooked fruit?
Jams
What are mixtures of fruits (usually including citrus) to which nuts and raisins but no sugar are added
Conserves
What is made from the juice of cooked fruit with added sugar and pectin?
Jellies
What is juice combined with thin slices of fruit and rind?
Marmalades
What fruit should not be left in the refrigerator?
Bananas will turn brown
Is the percentage of fruit juice lower or higher in nectar compared to juice?
Nectar is lower (30-40%)
What fruits contain more vitamin C than oranges?
Papaya, kiwifruit, strawberries
