Transcript PROTEINS - Westminster Kingsway College

Culinary Science
Second Years
Lesson 3 – meat and marinades
Do you remember proteins?
In food:
Hydrophilic group (on the outside)
Hydrophobic group (protected inside)
Inner protein bonds
Raw meat/fish is transparent
Denaturation:
What causes this?
Coagulation
Water molecules
Benefits?
Drawbacks?
Acid?
Bulking agents?
Syneresis
Chicken goes dry
Eggs go rubbery
Meat
Meat composition
Meat contains water (75%), protein (18%) and fat (about 3%)
Highly organised structure
Muscle tissue: responsible for how the animal moves when it is
alive, and toughens when it is dead
Contains myoglobin (responsible for the colour of meat)
Connective tissue: acts as a glue to stick muscle to bone.
Made up of collagen, which thickens and toughens as the animal
ages → tougher meat
On cooking, it dissolves to gelatine, tenderising meat
Fat tissue: located between connective tissue and muscle tissue
Reference: Harold McGee on Food and Cooking
Cooking meat
Meat needs to be cooked:
- Kill bacteria
- More digestible (denatured proteins easy to digest v
folded one)
- Improve flavour
- Reduce toughness (Raw meat – not very tender) but
can make it more tough)
Cooking Meat
50-60°C:
Protein start to denature and
coagulate → firm and juicy.
60-65°C:
•Proteins continue to coagulate,
squeezing out water.
•Collagen in connective tissue
denatures and shrinks - exerts new
pressure.
•Meat loses up to 1/6th volume of
water → becomes tough and dry.
70°C:
Collagen converted to gelatine. Less
pressure exerted → less tough.
Reference: Harold McGee on Food and Cooking
Cooking meat
Different meats differ depending on the cut
The old tough cuts
High in collagen, need to be cooked for long times at
temperatures > 70°C, despite the drying out.
Older animals, more fat.
The tender young meats
Cook these pieces at a very high temperature for a very short
times – this greatly reduces cooking time and thus the risk of
excessive coagulation and moisture loss.
Cuts of Beef
For braising (a little
more tender than
stewing)
Very tough bits.
Used frequently
for grazing - builds
up connective and
muscle tissue.
For: mince, or
stewing (slow long
cook)
High fat –
good for
roasting
Fillet & Sirloin –
little fat and
tender. Quick
cook
Rump – not
quite as
tender,
better
flavour.
Quick cook.
Very lean.
Needs
basting/
sold with
fat
Very tough
– mince or
stew or
slow roast
Often
minced –
very tough
Very tough
– mince or
stew or
slow roast
Fish
• Animals – muscles and muscle fibres quite long.
• In fish, very small muscle fibres, merges into connective tissue
• Fish connective tissue is weak, and repeatedly built up and
done, dissolves at 50-55°C (unlike meat) and separates into
distinct flakes
Reference: Harold McGee on Food and Cooking
Marinades
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Pineapple juice pasteurised
Fresh pineapple
Oil
Vodka
Yoghurt
Milk
Vinegar
Wine
Project
• Look up 3 different time/temperature combinations for sous
vide cooking of different cuts of meat
• Look up 1 different time/temperature combinations for sous
vide cooking of different types of fish
Tenderising meat - marinading
Acids (vinegar, wine, lemon juice, tomatoes):
Start to denature the proteins, unwind (as cooking does) so
↓ cooking time
Enzymes (pineapple, papaya, pawpaw, kiwi fruit, figs):
Break down and soften muscle and connective tissue
Work slowly at room temperature, work quickly at 60-70
°C
Dairy (buttermilk, yoghurt):
Mildly acidic – do not toughen outside
Calcium in dairy appears to activate the proteases (like
Now for an experiment....
How do you describe textures?
Bibliography
• McGee on Food and Cooking. By Harold McGee
• The Science of Cooking. By Peter Barham
• Food Preservation: an introduction. Tim Hutton
• Molecular Gastronomy manual from www.inicon.net