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FDSC251 > Processing of fats and oils > Flashcards

Processing of fats and oils Flashcards

1
Q

What is the first in processing oilseeds

A

crushing and heat treatment

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2
Q

What is the purpose of the heat treatment in the oil processing

A

inactivate the lipase and the lipooxygenase

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3
Q

Lipoxygenase catalyzes the ____ of polyunsaturated fatty while Lipase (an enzyme present in every living system) catalyzes ____

A

direct oxidation lipolysis

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4
Q

What is the configuration system needed by the enzymes ?

A

pentadiene system

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5
Q

What are the three ways in which oil can be obtained from plant sources?

A
  1. hydraulic pressing 2. expelling 3. Solvent extraction
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6
Q

What is hydraulic pressing?

A

Simply involves the use of a screw press to apply pressure and crush the seed to force the oil out from the crush

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7
Q

What is expelling?

A

 Mechanical version of hydraulic pressing - continuous process

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8
Q

how is used the meal from the expelling?

A

feed livestock, solvent extraction or health food.

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9
Q

What is solvent extraction?

A

Organic solvent (usually hexane) is used to extract the residual oil from the oilseed cake produced by the expelling operation

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10
Q

What is rendering?

A

heat processing done to animal fat. Lipid melts and is released from the tissues

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11
Q

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

A

E

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12
Q

Why is the oil dark after the first steps of oil extraction?

A

The dark color is due to lipid- soluble pigments such as carotenoids and chlorophyll and pheophytin (produced by loss of Mg2+ ion from chlorophyll)

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13
Q

What are the 4 steps of subsequent processing operations?

A

Step 1 - Settling and Deguming Step 2 - Refining Step 3 - Bleaching Step 4 - Deodorization

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14
Q

What is settling and deguming?

A

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)

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15
Q

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

A

B

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16
Q

What is refining?

A

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):

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17
Q

What is bleaching?

A

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

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18
Q

What is deodorization?

A

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

19
Q

What is removed from these steps : Step 1 - Settling and Deguming Step 2 - Refining Step 3 - Bleaching Step 4 - Deodorization

A

1- removal of phopholipids 2- removal of FFA, proteins and carbohydrates 3- removal of colored material and metal ions 4- removal of volatile compounds

20
Q

The process that removes volatile compounds that give the oil off‐flavors not acceptable to most consumers is called:

A

deodorization

21
Q

What is winterization?

A

colder temperature to separate the saturated TG from the unsaturated. The saturated will precipitate

22
Q

What is hydrogenation?

A

process used to change the physical and chemical properties of fats and oils by reducing their overall degree of unsaturation.

23
Q

T or F : during hydrogenation there is positional and geometric isomerization

A

t

24
Q

when pressure increase the trans fatty acid % ____

A

decrease

25
Q

when pressure increase the trans fatty acid % ____

A

decrease

26
Q

When temperature increase, the trans fatty acid % _____

A

increase

27
Q

When temperature increase, the selectivity ratio _____

A

increase

28
Q

When temperature increase, the reaction rate _____

A

increase

29
Q

when pressure increase the selectivity ratio ____

A

decrease

30
Q

when pressure increase the rate ____

A

increase

31
Q

when the agitation increase, the selectivity ratio ___

A

decrease

32
Q

when the agitation increase, the selectivity reaction rate ___

A

increase

33
Q

when the catalyst increase, the selectivity ___

A

increase

34
Q

when the catalyst increase, the reaction rate ___

A

increase

35
Q

when the catalyst increase, the trans% ___

A

increase

36
Q

Enumerate the effects of an increase in temperature, pressure, agitation and catalyst concentration on selectivity ratio, trans content and reaction rate

A
37
Q

T or F : The extracted oil is mixed with water to eliminate unacceptable flavors

A

F

38
Q

The process that involves the treatment of the oil with dilute alkali to convert free FAs into soap to remove them from extracted oil is:

A

refining

39
Q

T or F : Increasing the pressure during the hydrogenation process will increase the trans fatty acid content in the end product.

A

F

40
Q

What is done to remove the hydrogenation catalyst from the oils?

A

Bleaching step with bentonite clay or charcoal.

41
Q

T or F : virgin oil hasn’t been refinied so there is only physical methods done to extract the oil

A

true.

42
Q

Whu wouldn’t original fish and soybean oil not be a good biodiesel?

A

Because of the high double bond content. These oils polymerise and you don’t want an oil that polymerise has a biofuel

43
Q

What are the 5 components that are in the oil before the additional processing steps?

A
  1. FFA content that needs to be removed from the oil because they produce off-flavors produced by the plant lipase
  2. Oxidative products produced by the lipooxygenase and oxygen, produce off flavor
  3. Flavor componntents that can give an oil a fishy/paint-like taste
  4. Free metal ions like the Mg from chlorophyll.
  5. Phospholipid that are naturally present in the oils
44
Q
A

FDSC251 (22 decks)

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