Exam 2: Plant Foods (F&V; Plant Pigments) Flashcards
Structure of parenchyma cells
polyhedral (11-20 faces)
> space, likely to float
intercellular spaces depends on shape & fit between cells
(apples: ~25% air in IC spaces = bobbing for apples)
(potatoes: 1% air = dont float)
-chlorophyll: petropyrowing w/ ____ in center
heat: H gets forced out; britening of color. forcing out air = brighter. heat & time. foce out Mg & replaced w/ hydrogen molecule. not chrophyll, ut pheophyten (olive green).
brigher w/ heat. but >5 mins = olive green.
Functions of parenchyma cells
Their role is largely based on their location in the plant; that can determine whether they will serve in storage, photosynthesis, or damage repair.
storage of food (e.g. starch) and water,; the intercellular air spaces permit gaseous exchange.
supporting tissues
leukoplasts: starch production
- COLLENCHYMA tissue: elongated cells providing structure (esp in veg)
- celery fibers, rhubarb
- SCLERENCHYMA tissue: stone cells in pears, strings in green beans, asparagus
- woody cells that contribute to gritty texture of fruits
climacteric fruits
accelerated respiration just prior to senescence
cont. to ripen ater harvesting
Apple, Apricots, Avo Banana Peach, Pear, Plum Tomato Tropical fruit: Mango, papaya, passion fruits
non-cliacteric fruits
do not ripen after harvesting ( veg )
cherry, citrus Fig Grapes Melons Pineapple Strawberries
ripening of fruit (ways to slow or speed up ripening)
slow:
REF: diff temp / fruit. CO2 lvl
speed:
ETHYLENE GASL ripening hormone
types of plant pigments: (3)
- Carotenoids
- Chlorophyll
- Flavonoids
Cs are fat soluble
chlorphyll A: blue-green
most abundant form
methy r group
Induce color change in chlorpyhll molecules:
ACID: inc the repeadity; how fast the conversion of chrophyll -> pheophyton
ALKALI/BASIC (baking soda): intense color, but not in good way. (1) chorophelum mg remains, but loses the methyl & phyto groups attacked = chrophylin. soluable. bright green but blue/green, unnat color. presence of baking soda: mushy-break down of hemicellulose in plant structure. (1) color & (2) texture
ACID: gray-green
BASIC: bright green (chorophyllin)
HEAT: 1st bright green -> dull olive/brown
METALS: copper & zinc help retain green, not used bc of toxicity
carotenoids: yellow-orange
ex: carrots
more heat & acid stable ACID: ligher (yellow-orange) BASIC: brownish HEAT: lighter orange METALS: no effect
3 kinds of flavonoids: (1) anthocyanin: red-purple (brightly colored)
ex: purple cabbage
ACID: red
BASIC: blue, purple, green (funky blue)
HEAT: dull red-brown
METALS: copper, iron, aluminum, tin
-red-purple -> green-slate blueenzymatic browning:
can brown/blacken due to enzymes
can occur in many F&V when they are bruised, cut, or exposed to air
phenolic compound + enzyme + O2 -> melanin (dark brown pigment)
how can enzymatic browning be reduced?
- BLANCHING: deactivates enzymes
- ACID: reduces/slows enzymatic activity
- WATER IMMERSION
- SULFUR COMPOUNDS
- REFRIGERATION
- ASCORBIC ACID (antiox)
process of cooking beans (soaking, CA, basic, acidic)
SOAKING BEANS: softens outer surface, absorption of water, inc tenderness
ACID on cooked beans: firmer
ALKALI/BASIC on cooked beans: mushy; when you go above the pH of 8, you will end up with mushy beans
CA will affect beans when cooked: harder;
-CA acetate powder, milk, molasses
adding to beans that inc acidity: onions & garlic, peppers, & TOMATOES (wait til beans softens, then add tomatoes at end like lime, lemon, & salt)
recognize diff soy products (TSP, TVP, soy milk, tofu, tempeh, natto)
refer to 021 book
TVP: Textured Vegetable Protein
TSP: Textured Soy Protein.
SOY MILK: plant milk produced by soaking dried soybeans and grinding them in water.
Tofu: bean curd, is a food made by coagulating soy milk and then pressing the resulting curds into soft white blocks.
TEMPEH: soy product. made by a natural culturing & controlled fermentation process that binds soybeans into a cake form, similar to a very firm vegetarian burger patty.
NATTO: Japanese food made from soybeans fermented with Bacillus subtilis var. natto.smell, strong flavor, and slimy texture.
flavonoids: (2) anthoxanthin: cream/white
ex: cauliflower
ACID: whiter
BASIC: yellow/white
HEAT: lil change, possible yellowing
METALS: aluminum= loss of white; iron darkens pigment
