Final Flashcards
2 types of protein in milk
Casein - precipitated from solution
Whey - coagulate by heat
2 types of protein in milk
Casein - precipitated from solution
Whey - coagulate by heat
Consumer use definition of fruits and vegetables
Fruits are more sweet/used in desserts
Vegetables are more savoury
Botanical definition of fruits and vegetables
Fruits are mature plant ovaries and their seeds
Some fruits that are considered to be vegetables - tomatoes, cucumbers, avocados
True or false - In general, f&v have a high water and protein content
False. Low in protein, high water content, variable in carbohydrates
What gives broccoli it’s structure?
Cellulose and hemicellulose
Post harvest changes
Growth to maturity –> Ripening –> Senescence
Senescence
Over ripening/deterioration/programmed cell death
Two post-harvest metabolic processes
Respiration and Transpiration - management of these determines food quality
“Mature Green”
Mature but not ripe - when picked
Climacteric fruits
Fruits that will continue to ripen after harvest
e.g. bananas apples tomatoes
Why do climacteric fruits continue to ripen after picked?
Because they produce ethylene
e.g. green bananas and apples in a bag
If a banana won’t ripen?
Either chill injury or not mature when picked
Chill injury
Won’t ripen, will go straight to senescence
eg. chilled bananas
Chill injury
Won’t ripen, will go straight to senescence
eg. chilled bananas
Non climacteric fruits
Fruits that are picked when mature and will senescence after being picked.
E.g. berries (metabolize quickly), citrus (metabolize slowly)
Do not respond to ethylene
Whichever maturity the fruit is picked is where it stays
Purpose of post harvest storage methods
to manage respiration and transpiration
Controlled Atmosphere
Storage with reduces oxygen and increase carbon dioxide
e.g. refrigeration, keeping apples and bananas at low temperature and low oxygen environment
Modified Atmosphere
Packaging with reduced oxygen and added nitrogen
e.g. pre packaged veggies
What happens if oxygen levels are too low in the atmosphere?
Respiration becomes anaerobic and results in an undesirable taste and quick degradation
Grades of fresh f&v
extra fancy, fancy, commercial
Grades of processed f&v
fancy, choice, standard
True or false - there is no nutritional difference between grades
True
Canned vegetable production
grading, solubility testing, washing/peeling/cutting, blanching, inspection, can filling, addition of brine, sealing cans, thermal processing, labeling
What heat medium is added to canned f&v
Brine for vegetables
syrup/juice for fruit
Blanching
Inactivation of enzymes by controlled heating
e.g. 90 degrees for 3-4 minutes
Blanching
Inactivation of enzymes by controlled heating
e.g. 90 degrees for 3-4 minutes
What are the enzymes that are inactivated by blanching?
Polyphenol oxidase
Pectinase - breaks down pectin which hold plant cells together
Chlorophyllase
Perozidase - causes oxidative reactions
True or false - blanching is an effective thermal preservation technique
False. Destroys enzymes but does not inactivate pathogens and spoilage microbes
Polyphenol oxidase (PPO)
Browning upon exposure to oxygen
Polyphenols + O2 + PPO –> tissue browning
Good for black tea
How can PPO be inhibited?
Blanching (in processed)
Remove O2 add sulphites, decrease pH (in fresh)
Benefits of Blanching
Softens tissues
removes air from tissue
washes cut surfaces
reduces microbial load
True baby carrots vs manufactured
True - immature carrots
manufactured - cut from slender carrots, peeled and immersed in a chlorine bath
True baby carrots vs manufactured
True - immature carrots
manufactured - cut from slender carrots, peeled and immersed in a chlorine bath to destroy pathogens
Sauerkraut Production
Removal of core, outer and green leaves washed/sliced Layered with salt Fermented (by floral succession) canned
Floral Succession
Bacteria that work and build one after another
No starter culture is added
E.g. sauerkraut fermentation
Tea production
Not microbial
Green - PPO inactivated
Oolong - partial oxidation
black - oxidation (fermentation)
Black Tea production
withering leaves plucked
rollers rupture cell walls
ferment
dry
Phytochemicals
Plant chemicals with health related effects that are not essential nutrients (e.g. not macros or micros)
- act as antioxidants to stop free radical damage
Examples of phytochemicals
Lutein/Beta carotene - dark green and orange
Anthocyanins - red/purple
Lycopene - tomatoes
Polyphenols - white/cream
Hybrid f&v
Made by crossbreeding
add flavour and novelty for consumers
Three major classes of grains
Cereals - wheat, barely, corn, oat
Oilseeds - canola, soybean, flax
Pulses
2 major advantages of grain consumption
Fiber and antioxidants
Value added processing
Enhancing a product and adding value before selling it to customers
e.g. wheat to bread
Primary - milling, pearling, cleaning
Secondary - starch extraction, protein modifications
3 parts of grain cereals
Bran - fruit/seed coat
Germ - rich in protein/oil/vitamins
Endosperm - rich in starch
Starch
The main component in cereals
Composed of amylose and amylopectin
- form granules
Why is native starch not soluble in cold water?
Needs heat to loosen the molecules (gelatinization)
Amylase enzymes break down starch into sugars more easily because molecules open up when heat added
Dietary Fibre
Components of plant material in the diet which are resistant to digestion by enzymes produced by humans
3 main plant sources of dietary fibre
Cereal grains, vegetables, fruits
Hard wheat
high protein (12/14%) elastic dough i.e. bread
Soft wheat
low protein (8-10%) weak dough i.e. cakes and pastries
Durum wheat
very high protein (15-18%)
semolina
i.e. pasta
Wheat processing
Dry milled into whole grain flour, white flour, bran and germ
wet milled into starch, vital gluten and fibre
Whole wheat flour
flour, germ and bran
white flour
made from the endosperm, does not include bran and germ
Gluten protein network
produced during dough kneading and helps with dough rising, holds structure and shape
Oat processing
Dehulling into hull and groat
Heat treatment
processed into whole oat flour, bran and bran flour, oat flakes and steel cut oats
Saturated fats
No double bond
monounsaturated fats
one double bond
polyunsaturated fats
more than one double bond
Why does flax oil spoil faster than canola?
Because there are more polyunsaturated double bonds in flax oil.
The more unsaturated a fat is the more vulnerable it is to autooxidation and rancidity.