Workshop 9 Flashcards
Omega 3 FA are primarily found in
- oily fish (salmon, lake trout, herring, mackerel, sardines)
- plant sources: walnuts, flaxseed, hemp
Why is fish muscle more tender than meat
because of the small quantity of CT
What happens when overcook fish?
leads to dry, tough, shrunken texture
Compare fat and protein content of fish & meat
fish:
- lower fat
- same protein
walnuts, flaxseed, hemp rich in:
alpha-linolenic acid
Most fish need __ cooking
little
require little heat to coagulate
What is a major difference in cooking between fish & meat?
Fish doesn’t become more tender the longer it is cooked (excepted cephalopods: squid, octopus)
Flesh of fish =
= very short, delicate muscle fibers and connective tissue that expand and release protein when cooking
What are the wet methods for cooking fish?
- poaching/boiling
- steaming
- braising
Benefits of steaming
minimal mineral and vitamin loss
When should the fish be seasoned when steaming?
Before
What is a form of indirect steaming?
Microwaving
In papillote
What is braising?
Cross between stewing & steaming
ex: paella
Dry methods of cooking fish
- frying
- grilling
Pan-searing salmon
- preheat the oil
- Dry the flesh before adding it to the pan
- Hold the fillets firmly
- reduce the heat once fish is added
- Aim for 120°F, gets chalky and dry above 140°C
- Cook most of the fish though skin side down, briefly on the other
What is the secret to successful grilling?
Intense heat
Which fish should not be grilled?
Thicker than 5cm
fat-soluble vitamins
ADEK
Fats of animal origin
Butter
Lard (pork)
Vegetable fats:
- Oils
- Margarine (hydrogenated or non-hydrogenated trans-fat free)
- All-vegetable shortening (hydrogenated oil)
Vegetable shortening = __ oil
hydrogenated
Margarine = __ oil
hydrogenated or non-hydrogenated trans-fat free type
Oils can serve as : (3)
Cooking medium
Binding agent
Preserving agent
Medium chain triglyceride (MCT) oil =
- contains medium chain fatty acids (easily, rapidly hydrolysed and absorbed)
(ex: coconut oil)
When are MCT oil used?
Conditions of fat malabsorption
Which oils are highly valued for their flavour?
- olive oil
- sesame oil
but low smoke point
Which oils are consumed unheated due to their low smoke points?
- cold pressed oils and flax or linseed oil
High smoke points oils:
- peanut, canola, sunflower, clarified butter
used for frying
What happens when fat is heated to its smoke point?
TG break down into FFA + acrolein
Acrolein
a substance irritating to the eye, nostrils, lungs, digestive system
What occurs at the flashpoint?
smoke at the surface of heated oil
Factors that decrease the smoke point of fats:
- Emulsifiers
- Length or number of times it is used for frying
- Food particles (crumbs, eggs)
- Shallow pan: exposes larger surface to O2
- Copper, bronze, iron, brass
- Temperature above smoke point (above 230°C)
- Cold pressed oils
What makes fats more susceptible to oxidation?
- length or number of times the same fat is used for frying
- heating oil to temperature above smoke point (or above 230°C)
Fried foods should be fried once they have been __
dried
-> to avoid water & fat from spattering
How to minimise greediness when frying?
- fry in small batches
- high temperature
- decrease sugar, and fat in food
What is crispiness due to
Moisture loss
What happens in fried potatoes?
Heat causes moisture in the starch granules to swell and cook them
When does Browning occur?
When the steam has escaped
The browning of the outer portion of the food during frying is the result of the __ involving sugars and proteins, and caramelisation
Maillard reaction
What does the degree of browning depend on?
Time, temperature, chemical composition of foo
Does browning depend on the type of fat used?
No
How to extend shelf-life of fat used for frying
- if frying is below the smoke point
- strained food particles
- stored in cool, dark place or in fridge
How many times can ion be reused?
5-7 times
When is it a health concern to reuse it?
if oil contains mono and diglycerides
How to maximise the lifespan of oil?
- Watch the temperature: don’t let oil get past smoke point
- Remove excess batter and breading during and after frying
- Remove debris after frying
- Store oil in a cool, dark place
Past smoke point:
rapid breakdown
Breadcrumbs, flour at the bottom cause oil to
breakdown
When should you discard oil ?
If oil has smoked, smells rancid, produces foam, doesn’t bubble upon addition of food
What contamination can you get if don’t acidify homemade oil?
Clostridium botulinum
How long do homemade oils last?
2 weeks
What can replace fat?
fruit/veg purees
Does reduced-fat margarine work to replace fat?
It contains water and may be inappropriate
Does using wax paper help reduce fat?
Not appropriate as it smokes when heated to high temperature
Emulsion =
Dispersion of one liquid in another, both liquids are antagonistic or immiscible
How are emulsions classified?
According to the degree of stability
Stability increases with thickness
What are the types of emulsions?
- Temporary emulsions: thin viscosity and stability
- Semi-permanent emulsions: thick viscosity, more stability
- permanent emulsions: very thick viscosity (semi-solid), very stable
How to make the most basic vinaigrette?
- 1 part acid (or 1/2 acid, 1/2 water)
- 1/3 part emulsifier
- 3 parts neutral oil
