Processing of fats and oils Flashcards
What is the first in processing oilseeds
crushing and heat treatment
What is the purpose of the heat treatment in the oil processing
inactivate the lipase and the lipooxygenase
Lipoxygenase catalyzes the ____ of polyunsaturated fatty while Lipase (an enzyme present in every living system) catalyzes ____
direct oxidation lipolysis
What is the configuration system needed by the enzymes ?
pentadiene system
What are the three ways in which oil can be obtained from plant sources?
- hydraulic pressing 2. expelling 3. Solvent extraction
What is hydraulic pressing?
Simply involves the use of a screw press to apply pressure and crush the seed to force the oil out from the crush
What is expelling?
Mechanical version of hydraulic pressing - continuous process
how is used the meal from the expelling?
feed livestock, solvent extraction or health food.
What is solvent extraction?
Organic solvent (usually hexane) is used to extract the residual oil from the oilseed cake produced by the expelling operation
What is rendering?
heat processing done to animal fat. Lipid melts and is released from the tissues
Hydraulic pressing is used for extracting oil because : A. It is a very efficient method B. It is a fast method C. Of the good quality of the oil produced D. All of them E. None of them
E
Why is the oil dark after the first steps of oil extraction?
The dark color is due to lipid- soluble pigments such as carotenoids and chlorophyll and pheophytin (produced by loss of Mg2+ ion from chlorophyll)
What are the 4 steps of subsequent processing operations?
Step 1 - Settling and Deguming Step 2 - Refining Step 3 - Bleaching Step 4 - Deodorization
What is settling and deguming?
Settling and degumming refers to simply vigorously mixing the oil with water and allowing it to stand in a conical tank for some time and then separate the aqueous and organic phase (non-polar)
After extraction, the oil is: A. Light yellow liquid that can be consumed immediately B. Dark smelly liquid that needs further processing C. Dark liquid that can be consumed but consumers prefer it to be light colored
B
What is refining?
Refining refers to removal of free fatty acids from oil Involves the treatment of the oil with dilute alkali, so as to convert the fatty acids into soap (salt of a fatty acid):
What is bleaching?
the bleaching operation is designed to remove the colored material from the oil (carotenoids, chlorophyll, and pheophytin) using dry bentonite clay because the composite are more polar than TG
What is deodorization?
steam stripping, which involves spraying the oil into an evacuated chamber containing superheated steam flowing steam stripping, which involves spraying the oil into an evacuated chamber containing superheated steam flowing so the volatiles are carried away
What is removed from these steps : Step 1 - Settling and Deguming Step 2 - Refining Step 3 - Bleaching Step 4 - Deodorization
1- removal of phopholipids 2- removal of FFA, proteins and carbohydrates 3- removal of colored material and metal ions 4- removal of volatile compounds
The process that removes volatile compounds that give the oil off‐flavors not acceptable to most consumers is called:
deodorization
What is winterization?
colder temperature to separate the saturated TG from the unsaturated. The saturated will precipitate
What is hydrogenation?
process used to change the physical and chemical properties of fats and oils by reducing their overall degree of unsaturation.
T or F : during hydrogenation there is positional and geometric isomerization
t
when pressure increase the trans fatty acid % ____
decrease
