Cooking Oil:
| Origin | Satu rated |
Mono unsatu rated |
Poly unsatu rated |
Smo king temp. oC |
|
Almond |
8% |
66% |
26% |
221 |
|
Avocado |
12% |
74% |
14% |
271 |
|
Canola |
6% |
62% |
32% |
242 |
|
Coconut |
92% |
6% |
2% |
177 |
| Rice bran |
20% |
47% |
33% |
254 |
|
Corn |
13% |
25% |
62% |
236 |
|
Cottonseed |
24% |
26% |
50% |
216 |
|
Grape seed |
12% |
17% |
71% |
204 |
|
Hemp |
9% |
12% |
79% |
165 |
|
Mustard |
13% |
60% |
21% |
254 |
|
Olive (virgin) |
14% |
73% |
11% |
215 |
|
Olive (refined) |
14% |
73% |
11% |
225 |
|
Palm |
52% |
38% |
10% |
230 |
|
Peanut |
18% |
49% |
33% |
231 |
|
Safflower |
10% |
13% |
77% |
265 |
|
Sesame |
14% |
43% |
43% |
232 |
|
Soybean |
15% |
24% |
61% |
241 |
|
Sunflower |
11% |
20% |
69% |
246 |
Vegetable oil are lipid
materials derived from plants like soy beans. Vegetable oils are composed
of triglycerides and is extracted from oil seeds and cooking oils preferably
from olives, soybeans, rape- and sunflower seeds.
Extraction Today vegetable oil processing is preferably made by chemical extraction, using solvent extracts like hexane, which produces better yields at a lower cost than by mechanically expelling the oil.
Refining. The crude oil from expellers or solvent extraction plant contains impurities to be removed making the oil edible, palatable and stable against rancidity during storage. The impurities are:
Margarine
and Bakery Shortening. Fats with higher meleting point may be produced
from liquid oils
by hydrogenation or transesterification (Inter-Esterification). Lipase-catalyzed
transesterification has been used to obtain more natural products more
accepted by consumers.
Extraction Today vegetable oil processing is preferably made by chemical extraction, using solvent extracts like hexane, which produces better yields at a lower cost than by mechanically expelling the oil.
Refining. The crude oil from expellers or solvent extraction plant contains impurities to be removed making the oil edible, palatable and stable against rancidity during storage. The impurities are:
- Gums: The hydratable gums (phospholipids) are removed during "Degumming" - a treatment with phosphoric acid and centrifugal separation.
- Hydrolysis Products: Diglycerides and monoglycerides and free fatty acids are removed during "Neutralisation" - a treatment with caustic forming soap with the fatty acids, followed by centrifugal separation.
- Protein, Carbohydrates, Resins: These are also removed during "Neutralisation".
- Colour: Chlorophyll (green) carotene (red), anthophyll (yellow) and gossypol (orange) impart distinct colour to the oil and are removed during "Neutralisation" and "Bleaching" - treatment with active carbon and pressure filtration.
- Odour is present in small amounts but imparts strong objectionable odour to the oil. Odour is volatile constituents and is removed by "Deodorisation". The oil is heated and de-airated under high vacuum and steam injection. The deodorised oil is cooled and filtrated.
- Wax: In particular sunflower oil and rice bran oil contains appreciable amounts of waxes. Waxes are high melting esters of fatty alcohol of long chain fatty acids. Wax is removed by "Dewaxing" - chilling and filtration.
Margarine
and Bakery Shortening. Fats with higher meleting point may be produced
from liquid oils
by hydrogenation or transesterification (Inter-Esterification). Lipase-catalyzed
transesterification has been used to obtain more natural products more
accepted by consumers.