Oils and fats Flashcards
How much lipid is in seeds or fruits?
20-50% by weight
What is oil?
The energy reserve for germination
What can the residue from oil seeds be used for?
Animal feed as it is high in protein
Why are seeds easily transported and stored?
Because they have a low moisture content and won’t go off
What are the 2 methods for oil extraction from soya beans?
Direct solvent extraction and mechanical extraction
How can omega 3, 6 and 9 be identified in fatty acids?
Depending on where the double bond is on the carbon chain
What is the structure of erucic acid?
22 carbons with one double bond (22:1) at the 9th carbon (omega 9)
What are triacylglycerol’s?
Fats consisting of 3 fatty acids (2 right, 1 left) and a glycerol backbone
What are phospholipids?
Cause foaming during cooking and draw water into oil leading to hydrolysis and TAG molecules
How are phospholipids removed?
A process called degumming where they are hydrated and oil and water are separated using centrifugation
What is lecithin?
A hydratable phosphate used in the food and pharma industries
Why are fats and oils processed?
- Shelf life
- Eating quality
- Appearance
- Safety
What are the processes for fats and oils?
- Rendering
- Wet screw pressing
- High pressure screw pressing
- Pre-pressing solvent extraction
- Direct solvent extraction
At what temperature does sterilization and digestion occur at in wet screw pressing?
Sterilization: 132°C
Digestion: 90°C
What is the process for soya bean extraction?
- Beans are tempered at 24°C for 7-10 days
- Cracking and dehulling reduces the impurities and increases protein
- Conditioning at 60-80°C for 30-60 mins weakens the cell wall, reduces viscosity, coagulates proteins and sterilises seeds
