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120 Cards in this Set
- Front
- Back
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2 main components of starch
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amylose-linear 1,4
amylopectin-branched 1,4 and 1,6 |
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starch gelatinization
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starch granule absorbs water and swells
loss of maltese cross irreversible swelling rapid increase in viscosity |
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pasting
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additional swelling, amylose leaches into the cooking water
thickness due to enlarged granules, amylose exudate |
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Ingredients on gelatinization
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Sugars, salts, fats and surfactants--all increase gelatinization temperature
Acids-reduces viscosity |
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Acid-modified starch
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thin boiling starch-heating starch below gelatinization temperature in acid
when hot low viscosity so you can pump it when hot but when cold a clear gel forms (gumdrops) |
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Cross linked starch
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starches containing molecules that have been cross-linked with one another with ether/ester links
minimizes breakdown of starch in acid frozen foods |
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pregelatinized starch
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starch that is precooked and dried-instant
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functions of fat in food
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crystal modification
medium for heat transfer flavor and tenderness in protein foods tenderness in baked products body and mouthfeel |
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Antioxidant names
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BHA, BHT, TBHQ
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Purposes of antioxidants
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Delay rancidity
Increase shelf life Bind metal pro-oxidants Stop free radical reactions |
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Rancidity types, enzymes
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Oxidative-lipoxygenase
Hydrolytic-lipase |
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When does hydrolytic rancidity occur
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Short fatty acids are hydrolyzed from the glycerol
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When does oxidative rancidity occur
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happens at double bonds
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specific gravity indication of texture
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floaters-waxy, sinkers-mealy
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loss of minerals from vegetables
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leaching into water
paring-trimming, removing peel |
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loss of vitamins from vegetables
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leaching
paring heat (hastens chemical reaction) air (oxidation) enzymes (oxidation) |
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fruit (part of vegetables)
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cucumber, okra, squash
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flowers
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broccoli, cauliflower
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bulb
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onion, garlic
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tubers
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short, thickened fleshy part of an underground stem
irish potato, jerusalem artichoke |
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roots
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carrots, rutabaga
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seeds
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peas, beans, corn
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preventing enzymatic browning
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avoid oxygen-required as substrate
add salt-Cl ion interferes with enzyme keep product cool-inhibits enzyme alter pH-inhibits enzyme blanch-heat inactivates enzyme add reducing agent-reverses reaction |
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enzymatic browning reaction
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polyphenols + O2 -phenolase-> quinones + H2O -polymerization-> brown pigments
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post-harvest factors affecting quality of fruit
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moisture loss
exposure to oxygen bruising time before processing processing: cutting, peeling, washing |
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slowing fruit ripening
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low temperature
controlled atmosphere storage-low oxygen, high CO2 modified atmosphere packaging-excludes oxygen, builds up CO2 |
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ethylene gas
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plant hormone, induces ripening in some fruits
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during ripening (pectin substances)
__ --> __ --> __ |
protopectin --> pectin --> pectic acid
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pectic substances
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polymers of galacturonic acid and its methyl ester
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acidity change in ripening
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acidity decreases
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pectic substances in ripening
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remain constant-pectin decreases and pectic acid increases
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lignin
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polymers containing benzene derivatives
not soften when heated, woody characteristic to plants dietary fiber |
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Total acidity, instrument used
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all ionized and unionized protons
titrating |
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Active acidity
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only ionized protons, pH meter
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Normality
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total acidity, molarity x ionizable H+
n=mol/L x [H+] |
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4.6-how to cook at diff pHs
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lower than 4.6 won't have microbes, use boiling water
greater than 4.6 pressurize steam by pressure cooker |
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buffer system
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weak acid and salt
resists pH change |
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aggregate fruit
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fleshy fruit, several ovaries in one flower
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simple fruit
drupes pomes |
developed from one ovary in one flower
pomes-simple fruit containing a core plus seeds drupes-simple fruit containing a stone or pit enclosing a seed |
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multiple fruit
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cluster of several flowers
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ex of aggregate fruit
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raspberries, strawberries, blackberries
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ex of simple fruit
pomes drupes |
apples, pears,
plums, cherries, peaches |
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ex of multiple fruit
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pineapple, figs
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pomes-
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simple fruit containing a core plus seeds
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drupes-
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simple fruit containing a stone or pit enclosing a seed
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Parenchyma cells
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edible parts of plant tissue, food synthesized or stored
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Factors inc hard to cook phenomenon
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time
high storage temperature high rh storage |
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Cooking legumes
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Soak beans-water enters in hillum
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Fat soluble plant pigment
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chlorophyll-green
carotenoids-yellow, orange, red/orange carotenes xanthophylls |
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water soluble plant pigment
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Flavanoids-
anthocyanins (red/blue) anthoxanthins (colorless white/yellow) Betalains betacyanin (purplish red) betaxanthin (yellow) |
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chlorophyll + heat + soda ->
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chlorophyllin- bright green
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chlorophyll + heat + acid ->
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pheophytin-olive green
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chlorophyll + phytyl ->
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chlorophyllide-light green
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pheophytin + phytyl ->
chlorophyllide + heat + acid -> |
pheophorbide-olive green
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influence of heat on color
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changes trans to cis bonds
duller, no resonance acids come out |
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Oxygen oxidation state determines
+ charge - charge |
color
red, purple, blues colorless, white, yellow |
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influence of pH on color
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differing colors at different pH
cabbage red-blue-yellow |
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Biological concern
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bacteria, mold, yeasts
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chemical concern
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food additives
pesticides |
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physical concern
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glass stuff in food
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bacteria
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one celled
shape: round, rod, spiral spores |
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yeast
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one celled
oval or spherical spores |
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mold
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multicellular
fuzzy or cotton like aerobes spores |
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faculatative
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with or without O2
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thermophiles
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40-70 C
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mesophiles
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10-50 C
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psychrotrophs
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0-30 C
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psychrophiles
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-10-20 C
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danger zone
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40-140 F
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microbial growth requirements
bacteria |
pH 3.5-9
thermophiles, mesophiles, psychrophiles Aw.91 aerobic, anaerobic, faculatative |
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microbial growth requirements
yeasts |
pH 2-10
mesophiles Aw .88 mostly aerobic |
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microbial growth requirements
molds |
pH 2-10
mesophiles Aw .75 aerobic |
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Fight BAC 4 things
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Clean
separate chill cook |
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useful molds
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soy sauce
cheeses |
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useful yeast
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bread
beer wine |
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useful bacteria
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yogurt
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HALT
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Humidity, Air, Light, Temperature
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Humidity effect
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nutrient loss
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Air effect
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vitamin loss
off flavors bugs |
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light effect
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speeds up reactions
off colors off flavors vitamin loss |
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effect of temperature
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color changing
wheat doesn't rise changes texture |
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food storage tests
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sensory
nutritious safe-mutagenicity |
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protect food
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good seams on cans
off floor |
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Sundrying
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free!
exposed to elements, animals |
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spray drying
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liquid to powder
spray liquid into a current of dry, heated air new/off flavors |
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freeze drying
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product frozen then ice is sublimed by a vacuum
expensive good texture/quality |
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drum drying
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product turned to slurry, turned on surface of a drum, heated inside by steam, dries, product scraped off
not as economical |
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tunnel drying
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dry air blown cross current at a high velocity around food, dry air provides heat
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deep fat frying
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hot oil replaces hot air
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osmotic dehydration
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product tossed in bed of sucrose crystals pull water from cells
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extrusion drying
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slurry of cereal
passes through heated tube under pressure, product exits under pressure, release causes water to evaporate |
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baking
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water vaporized
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factors required to determine appropriate processing methods and time
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time-temp combination to inactivate most heat resistant pathogens/spoilage organisms
heat penetration properties of each food in container |
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clostridium botulinum
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anaerobic
Aw .92 temp 3.3-97 C protein or carbs favor growth low salt content |
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D-value
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time at a given temp to reduce microbes by 90%
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sterilization
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treatment to destroy all microbes and spores
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commercial sterilization
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treatment to destroy all pathogenic and spoilage organisms
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pasteurization
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treatment to destroy pathogenic organisms
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blanching
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steaming or boiling water immersion for a short period
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r enamel
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red
berries, cherries |
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c enamel
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corn has sulfur
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can bulging
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hydrogen swelling-harmless, acid in food
botulism-fatal |
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headspace
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contents to expand
partial vacuum maintain seal, sealed well for consumers |
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asceptic packing
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food is commercially sterilized, cooled, filled into separate sterilized containers
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hot fill and hold
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hot food filled in container, sealed, inverted and held to sterilize lid
only when acidic foods used, botulism not a concern |
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cellar/common storage
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<15C
short term roots, potatoes, apples |
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refrigeration
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0 to 10C
weeks to months most foods |
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freezing
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<-18 C
0 F months to 2 years most foods |
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potatoes refrigerated?
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NO starches change to sugars
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blanching storage
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vegetables blanched
good color, flavor, texture microbial load packing good nutrients no odors, flavors |
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how to blanch
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salted boiling water and ice bath
vegetables into boiling water wait a minute crisp foods, plunge into ice bath |
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commercial D-value
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12-D
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changes in food during cool storage
microbial growth |
slowed but continues
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changes in food during cool storage
chemical changes |
starch to sugar in potatoes
staling of bread |
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changes in food during cool storage
off flavors |
when stored with certain foods
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changes in food during cool storage
chill injury in some foods |
bananas
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changes in food during frozen storage
ice crystal formation and growth |
large crystals can disrupt cell walls and membranes
lose texture |
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changes in food during frozen storage
movement of water from cells |
higher concentration of solutes in remaining unfrozen liquid
oxidation of fats, polyphenols, pigments loss of flavor and color quality freezer burn |
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changes in food during frozen storage
microbial load |
no major change
slow freezing may allow more destruction from large ice crystals or some growth if not cold enough |
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cold point
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point in can where it takes the longest to heat up
conduction-in middle convection-bottom middle |
