food principles Flashcards
Aeration
- air is introduced into a mixture or batter.
- can affect the overall texture, flavour or result of the item prepared.
Chemical raising agent
- baking powder, containing two active ingredients: bicarbonate soda and Cream of tatar.
- The reaction occurs when the raising agent is in contact with a liquid, in which the alkali and acid react together to form new molecules of carbon dioxide.
biological raising agent
- dependent on the environment e.g warmth, carbohydrates, moisture.
- When these requirements are met, it goes through a process called fermentation (when the yeast converts sugars to alcohol and carbon dioxide.
Caramelisation
- Carbohydrates (sugars found in starches, fruits and vegetables), shift in temperature and change in flavour when put under high temperatures for a duration of time.
- caused by a substance called pyrolysis (a large category of reactions when substances undergo a range of high temperatures).
- meats experience caramelisation as well, also due to pyrolysis though in this scenario pyrolysis reacts with amino acids present in proteins (maillard reaction).
- In carbohydrates pyrolysis reacts with sugars.
Dextrinisation
- the browning of starches when subjected to dry heat in which they are broken down (chemical reaction) into sugars (dextrin).
- classified as a non-enzymic and chemical change.
- Dextrins are characterised by distinct taste, consistency and brown colour, commonly found in the toasting of breads, baked goods, sauces and other foods alike.
The degree of dextrinization is determined by:
- temperature
- Duration of time the food is heated for
- Type of starch in product
- Addition of other ingredients
- Action of certain enzymes
Gluten
- Common breads such as wheat, rye and barley contain a mixture of proteins: glutenin and gliadin.
- flour is produced when the two proteins combine to form gluten when in contact with water. The more the dough is mixed the more glutinous the dough will become, ultimately changing the texture of the dough (elasticity and stretchiness).
- The gluten would form due to the kneading of the dough, during the kneading process, gluten strands strengthen and increase in length, nevertheless when too much gluten is formed the elasticity will decrease and cause the dough to become chewy and tough.
- Fats can prevent gluten development by forming a coating around proteins.
Lamination
- repeatedly rolling, folding dough to create thin layers of butter, ultimately giving many pastries such as croissants its signature texture.
- used to strengthen dough through agitation of gluten strands.
Air
require the dough to be punctured before placed in the oven, this is to ensure the pastry does not puff up too much due to the build up of steam and become thick.
Steam
created layers of alternating fats and dough results in a production of steam during baking,
ultimately be released in the form of water vapour causing the pastry to rise. Through the cooling process the pastry will then set.
Water vapour
the dispersion of water in a gaseous form in the atmosphere: assists in the creation of steam, contributing to the signature flaky, light texture of many pastries.
Layers
- The layers are alternating fat and dough.
- Through the baking process water boils off steam from the gluten in the dough and goes into the fat layers creating large bubbles of dough.
Mechanical raising agent
- The most common raising agent would be baking powder, however steam is the only leavening agent that works well in puff pastry.
- Steam is produced by the many layers of butter.
Folding
Is a technique almost identical to lamination, as mentioned before it is the repeated folding of pastry dough to create multiple alternating layers of fat and dough.
Rolling
Rolling in puff pastry should be carefully completed as to not fully incorporate the fats in the dough through heat and pressure, in other words overworking the dough.
the use of rolling ultimately ensures equal thickness
