FN: Science of Food Flashcards
Name the 3 ways in which protein structure can be denatured
- Heat
- Manual Agitation
- Acid
What are the 2 functions of strong plain flour in rough puff pastry
1) Bulk ingredient
2) Contains the gluten which makes the pastry elastically
What are the 2 functions of lard in rough puff pastry
1) Traps air in between it creating layers when cooked
2) Gives the pastry a short crisp texture
What are the 3 functions of butter in rough puff pastry
1) When cooked gives the pastry a golden brown colour
2) Gives a richer flavor
3) Traps air in between creating layers when cooked
What are the 2 functions of Salt in rough puff pastry
1) Strengthens the gluten
2) Gives flavour
What are the function of lemon juice in rough puff pastry
1) Strengthens the gluten
What are the 3Wha functions of water in rough puff pastry
1) Binds all the ingredients together
2) Reacts with the glutenin and gliadin to form the gluten
3) Creates steam in the oven letting the pastry rise
What are the main 9 types of pastry
- Shortcrust
- Sweet Shortcrust
- Rough Puff
- Puff
- Choux
6, Flakey - Suet
- Filo
- Hot Water Crust
Fat to flour ratio in shortcrust pastry
1:2
Fat to flour ratio in flaky, puff and rough puff pastry
3:4
Fat to flour ratio in choux pastry
1:3
What are the 4 types of rasing agents
- Mechanical
- Physical
- Chemical
- Biological
What are the 5 types of a mechanical raising agents
- Sieving
- Whisking
- Rubbing In
- Creaming
- Lamination
What is the physical raising agent
Steam
What are the 2 types of chemical raising agents
- Bicarbonate of Soda
- Baking Powder
What is the biological raising agent
Yeast
What 2 things must be present for gelatinisation to occur
Heat and Liquid
What are the 3 types of starch to make sauces
- Wheat Flour
- Corn Flour
- Arrowroot
What are the 7 stages for gelatinisation of an all in one sauce
- When the ingredients are mixed, they do not dissolve, instead they form a suspension
- Stirring the liquid keeps the starch particles suspended. If the suspension is not stirred, the particles will sink to the bottom and stick together forming a lumpy sauce
- At 60c the starch granules absorb the liquid and swell
- Gelatinisation is when the liquid reaches 80c they burst and release starch making the mixture thick
- Gelatinisation is complete when the liquid reaches 100c for 1 min (this will stop the sauce tasting raw)
- When cool, the starch forms a gel and solidifies
- When reheated the sauce is converted back to its liquid state
When a starch sauce is frozen, what occurs
Syneresis
What is syneresis
When the sauce weeps and starts to go back to it’s original state
What is it called when the sauce weeps and goes back to its original state
Retrogradation
What happens when acid or sugar is added to a sauce
It goes runny, and the desired consistency cannot be reached
What are the advantages of smart starches
- They aren’t affected by freezing, or the addition of sugar and acid
- They can thicken a liquid without applying heat
- They can change the appearance of a sauce (pulpy, smooth, opaque)
What is the ratio of butter and flour to milk for a pouring roux
15:250
What is the ratio of butter and flour to milk for a coating roux
25:250
What is the ratio of butter and flour to milk for a panada roux
50:250
What is not added to a blended sauce
Fat
What is the main purpose of arrowroot sauces
Glaze sweet foods as it is transparent
What are the standard ingredients of a cornflour blended sauce
275ml Liquid
15g Cornfour
25g Sugar (if sweet)
What are the standard ingredients for a arrowroot blended sauce
150ml Liquid
2-2.5g Arrowroot
What is enzymic browning also known as
oxidation
What are the 4 ways to prevent enzymic browning
1) Add an acid that will denature the enzymes
2) Cooking it as the heat will denature the enzyme
3) Submerge the food in water which prevents oxygen reaching the food
4) Blanching the vegetables before they are frozen
What is dextrinisation
When starch is broken down into smaller molecules and exposed to dry heat, it turns a brown colour and produces a nice aroma and flavour
What is caramalisation
When heated, the sugar becomes brown and develops in colour and flavour
What is the function of flour in a starch based sauce
Gelatinise
What are the 2 functions of flour in a starch based sauce
Enrich the sauce and make it shine
What are the 2 functions of milk in a starch based sauce
Liquid bulk ingredient, and thins the sauce
What is the does the word ‘short’ mean in shortcrust pastry
Light and crumbly
What are the 2 functions of flour in shortcrust pastry
Bulk ingredient and forms the structure
What are the 3 functions of fat in shortcrust pastry
Adds colour, coats the fat granules and gives the pastry flavour
What is the function of water in shortcrust pastry
Binds the ingredient to make a soft but not sticky dough
What are the 2 functions of salt in shortcrust pastry
Strengthens the gluten, and flavours the pastry
What are the 3 ways to make shortcrust pastry healthier and how does it improve the healthiness
Wholemeal flour - More NSP
Hard margarine instead of butter - same amount of calories but less saturated fat
Remove salt and replace with herbs or spices - lower sodium content
What are the 4 main nutrients in fruit
Vitamin C, Vitamin A, NSP, Starchy carbohydrates
What is fridge temperature
1-4’c
Freezer temperature
-18’c
Why should shelf life in a freezer be limited to 3 months
The cell walls of the products get burnt by the ice crystals, so when you thaw the food water seeps out, affecting the sensory qualaties
Why should frozen food not be re-frozen
Sensory qualities are reduced and you may lose track of how long it has been in there
2 types of bacteria
Spoilage - Makes food go bad
Pathogenic - Cause food poisoning or foodborne disease
What conditions do bacteria need to multiply
- Time (every 20 mins - binary fission)
- Temperature - 5-63’c the danger zone
- Food
- Moisture -
- pH - neutral conditions
- Oxygen
Pathogenic bacteria
Salmonella and Staphylococcus aureus
Food bourne illnesses
E.coli and Campylobacter
How to prevent cross-contamination
- Wash hands with anti-bacterial soap
- Never wash raw chicken
- Store food in the correct fridge position
- Cook meat, fish and eggs thoroughly
- Cover cuts with blue plasters
- Keep animals away from food
Ambient food
Can be stored at room temperature in a sealed container