Food Technology - Functions of ingredients

Food Technology - Functions of ingredients

1. STARCH

   • Obtained from cereals, root vegetables or fruit
   • used to thicken liquids
   • When cold, starch forms a gel- this is made using gelatinsation
     • 1. Starch particles do not dissolve in liquids, instead they form suspension
       • 2. Stirring or agitating the liquid keeps the starch particles suspended
         • 3. if it is not stirred the particles sink to the bottom and forms lumps
           • 4. When liquid reaches 60oc the starch begins to absorb liquid and swell
             • 5. At 80oc the particles break open and release starch- making the mixture thick and viscous. THIS IS GELATINISATION
               • 6. The process is completed when the mixture reaches 100oc. the thickened liquid now forms a gel which solidifies when cooling
   • Modified starches
     • Modified to: Thicken instantly, allow sauces to be reheated, thicken low calorie dressings

2. FATS AND OILS

   • sources
     • Animal
     • Vegetable
     • Fish
   • Types of fat
     • Solid at room temperature
     • liquid at room temperature
   • Functions
     • flavour
     • Moistness
     • Seals (preserves)
     • Shortens/changes texture
     • aerates
     • Extends shelf life

3. SUGAR

   • Functions
     • Add sweetness
     • preserve
     • lighten product
     • decorate
     • enhance flavour
   • Transformations
     • DEXTRINISATION
       • starch is converted into a simple sugar and can be caramelised.
     • CARAMELISATION
       • The simple sugar thickens and turns brown and adds flavour

4. EGGS

   • Functions
     • Aeration
       • Whisking egg whites, stretches protein and incorporates air.
         • A foam is created by smaller bubbles
           • This foam remains stable because heat generated by whisking coagulates it.
     • Emulsification
       • If water and oil are forcefully mixed this occurs
         • however it remains in suspension unless and emulsifier is used
     • Coagulation
       • Eggs set and eventually solidify
         • they can be used for: thickening, binding and coating
     • other uses
       • can be used to garnish
       • can be used to glaze
   • Raw and partially cooked eggs can contain samonella

5. MEAT

   • ANimal
   • Poultry
   • Offal
   • Cooking meat
     • Tenderising
       • Marinating
       • Mechanical
       • Artificial substances
       • Artificial substances
     • protein is destroyed and meat changes colour
     • Connective tissue changes into gelatine
     • Overcooked meat becomes indigestible
     • non enzymix browning occurs on meat because protein reacts with simple sugars
   • Issues affecting meat consumption
     • religious beliefs
     • ethical factors

6. FISH

   • Types
     • Oily fish
     • Shellfish
       • molluscs
       • crustaceans
     • white fish
       • round fish
       • flat fish
   • Preparation and preservation
     • care taken with storage as fish is a protein and has a high risk
     • prepared and frozen to remain in peak condition
     • Smoking and canning
     • flesh is always tender
     • Can be steamed or poached
   • Environmental issues
     • Fish supplies are running out
       • Boats have restrictions
       • money has been invested into fish farms