Food science Flashcards
What is shallow frying?
A pan with a moderate amount of fat or oil is heated to a high temperature
What is stir frying?
A fast method of cooking food at a high temperature with a small amount of oil
What are examples of shallow frying?
Cuts if the meat like bacon, sausages, vegetables, fish, steak
What is the nutritinal effect of Shallow frying?
Can be a quick method of cooking, helping to retain vitamins and minerals. May increase the fat content of the meal
Whats the effect of Shallow frying?
Browns the food and gives it a crispy texture
What are examples of stir frying?
Meat, poultry, shelfish, vegetables, noodles
What are the nutritinal effects of stir frying?
Vitamins, minerals and antioxidant values are retained
What’s the effect of stir frying?
Fresh and visually appealing as the colour and texture of the food is retained
What is coagulation?
Coagulation is a change of structure of the protein. The denatured and protein molecues join and change the texture and apperance of the protein food
What is denaturation?
the unfolding or breaking up of a protein, modifying its standard three-dimensional structure
(to change by chemical or physical means breaking the chemical bons)
Can be denatured by heat, mechanical action, or using acid in marinating
What are the effects of heat on protein?
Eggs - When an egg is heated, the whites change colour and becomes solid
Meat - As the meat is heated, it changes colour and the fibres lose water and shrink, if cooked for too long it becomes chewy.
What does heat and acid do to the proteins?
It changes shape and structure of the protein permanemtly
Example - Egg whites, turns into a foam when whisked
What does an acid do?
It denatures protein and help tenderise meat. Adding immersing foods in citrus juice , vinegar, wine, beer or yoghurt with other seasonings also adds flavour and keeps it moist
Example - Turning milk into cheese
What is gluten?
Gluten is a structual protein, it is developed by kneading, which strengthens and lengthens the gluten strands, the dough becomes strechy and elastic meaning it can change shape
Hard wheat has a high protein content, good quality gluten makes strong flour, soft wheat has a lower gluten content and is used to produce plain and self-rasising flour.
What is agitation?
It is when you mix it or stir it, knead
What is an example of agitation or mechanical action on protein?
An example is whiksing and egg, the protein stretches as the molecues unfold and form a mesh to trap bubbles of air, this eventually forms a foam
What is a foam formation?
Foams are formed when gases (mainly air) are trapped inside a liquid, for example whisking an egg - the more its whilsked the stiffer it gets and will stand in soft peaks
What is Gelatinisation?
Geletinsation is where chemical reaction where starch thickens in presence of moisture and heat
Examples - potatoes, rice, pearl barley, pasta, and some sauces
What is a amylose and amylopectin?
Two types of starch molecues densely packed together
What is caramelisation?
Caramelisation occurs when carbohydrates such as sugar are heated, at high temperatures water evaporates and sugar begins to break down and turn brown
Different sugars caremelise at different temperatures, for example when sucrose is heated it melts down into glucose and fructose and begins to caremlise at 160*C
What is dextrinisation?
It is the structual modification of starch that usually occurs in the presences of dry heat, when heated starches break down into sugars called dextrin. Dextrin is brown which results in food turning golden brown when baked. It also changes the taste and smell of food
Example- Toast
What is plasticity?
Plasticity is the ability to be spread and shaped
What is shortening?
Shortening is a fat, solid at room temperature, which can be used to give foods a crumbly and crisp texture like pastry (the rub in method)
In shortening when the fat coats the particles of flour creating a barrier and limiting the gluten molecues from developing. When water is added the gluten strands can only form short lengths.
What is aeration?
Aeration is the process of trapping tiny pockets of air into a mixture giving a well risen and light texture to bake goods liike cakes.
What is creaming?
When fat and sugar are beaten together to make a smooth creamy texture
What is emulsification?
It is the process of dispersing two or more immisible liquids together to form a semi stable mixture. An emulsion happens when small droplets of one solution are dispersed throughout another
Examples - Egg yolks, mustard, soy and guar gum are natural emulsifiers
What is an immisible liquid?
A liquid that cannot be mixed with another liquid without not spearting
Example - oil and water
What are hydrophilic and hydrophobic?
Hydrophilic is the part that is attratced to water
Hydrophobic is the part that isnt attracted to water
what is a raising agent
Raising agents include anything that causes rising within foods, and are usually used in baked goods
examples: bicarbonate of soda, baking powder and self-raising flour
Can you explain the difference between mechanical aeration and chemical aeration in food preparation?
mechanical: air is added by sieving the flour, creaming the fat and sugar, beating in the egg
chemical: aeration by baking powder and baking soda
What is the purpose of chilling
helps stop harmful bacteria from growing
How do physical changes, like the expansion of steam, contribute to the texture of certain baked goods?
The moist steam reinvigorates the yeast in the dough. Steam gives bread dough time to expand: the added moisture keeps the dough from drying out before it has time to rise.
what is Pasteurisation
a process of heat processing a liquid or a food to kill pathogenic bacteria to make the food safe to eat and to preserve longer
examples: milk,
what is Ultra heat treatment
UHT
a food processing technology that sterilizes liquid food, most commonly milk, by heating it above 135 °C over a very short time period
what does sterilized mean
Put into special bottles and heated to 110°C for 30 seconds, Can be stored unopened for several months
what is Homogenisation
a process by which the fat droplets from milk are emulsified and the cream does not separate
