Edible Oils

Question 1

Oils and fat consist mainly of…?

Answer 1

Triacylglycerols

Question 2

Edible oils are derived from plants and animals such as…?

Answer 2

Crushed seeds - high in unsaturated fatty acids
Animal fat - high in saturated fatty acids
Fish oil - high in long chain polyunsaturated fatty acids

Question 3

Why is rapeseed not edible?

Answer 3

Because it contains a harmful acid called Eruic acid

Canola oil has this acid too but only 2% so is ok to eat

Question 4

Oil extraction process

Answer 4

1. Oilseeds are first stored for at least a month after harvest to allow enzymes to break down chlorophyll contaminants. They must be kept dry and cool bc seed respiration can produce moisture which results in mould growth.
2. Seeds are cleaned and stems tossed out.
3. Seeds are dehulled/cracked and cooked before oil is extracted (up to 95% oil recovery)
4. Extraction is done by mechanical crushing (screw press)or solvent extraction (hexane)

Question 5

Purpose of Edible oil refining

Answer 5

Purpose - to remove impurities such as free fatty acids which promote oxidation (oxidative rancidity) and off flavours

Question 6

Edible oil Chemical Refining process

Answer 6

Crude oil in
De gumming by water extraction and acid treatment
Neutralization
Water washing and centrifuge
Drying
Winterization
Bleaching
Deodorization