Lipids

Question 0

What is the trans isomer of Oleic acid, and what does it do in the body, where is it found

Answer 0

Eladic acid, raises vldl, low HDl and up cetp. Majorly found in hydrogen veg oils

Question 1

Three kinds of lipids

Answer 1

Triacyl
Phospho
Sterols
Excluding butyrate, these are assumed to be 8+ carbons long

Question 2

What desaturated do humans have, and what do they make

Answer 2

9 654, Oleic acid is a desaturated form of steric acid, which comes from palmitic acid.

Question 3

Steps in gas crom analyzing lipids

Answer 3

Extraction, saponification, methylation, volatility

Question 4

What do phospholipids contain, and what is their function

3 kinds, where are they found

Answer 4

They contain po4, 2 tags on sn12, and a nitrogen containing group, when n is gone it is phosophtidic acid
They are emulsifiers. Lecithin is an example. Can have choline as a head group, found in eggs and soybeans, extrCted with hexane
Ethanol amine, cephlin . In Pufas and bilayers

Question 5

What are sterols, what do they make

Answer 5

Alcohol derivatives, d, bile, cholesterol

Question 6

Types of fat rancidity

Answer 6

Oxidative, lipolytic

Question 7

Oxidative rancidity- mechanism, products ( factors affecting ) auto oxidation

Answer 7

Heat, light, oxygen, ionization, loss of flavour and efas, toxic compounds, breaks fas from glycerol, intermediates formed = nasty odour , which condensates. Forms lipid hydroperoxides
Aldehydes provide Roma

Question 8

Lipolytic rancidity, brought Bout, where found, mechanism

Answer 8

More prone to oxidation then o2, hydrolysis by oxy, gen free fas , produces various aromas, lipase activity in fluid phases very active - more in homogenized milk since finely dispersed

Question 9

Hydrolysis of lipids generated by

Answer 9

Acid, bases , enzymes, thermal , gen short chain fas , lipase. Moisture in lipid

Question 10

Oxidative rancidity mechanism.

Answer 10

Form lipid hydroperoxides , breakdown lipid hp. I,p,t

Question 11

Initiation

Answer 11

Unsaturated lipids lose a hydrogen, forming a lipid radical, in the presence of an initiator, can also be incorporated into a ROOH, forms a hydroperoxide

Question 12

Propagation

Answer 12

The lipid radical reacts with oxygen to form a lipid peroxyl radical LOO
Will attack fatty acid double bonds to get a h, produces another one of itself

Question 13

TerminAtion

Answer 13

Can combine with another radical to terminate, or can run into an anti oxidant lool o2, or loo + ah – looh + a

Question 14

How to stop auto oxidation,

Answer 14

Avoid initiators, saturate or hydrogenated fat , add vitamin e

Question 15

Hydroperoxides function

Answer 15

Central mechanism of lipid breakdown, easily decompose to form hydroperoxide free radicals, breaks double bonds forms aldehydes , ketones carboxylic acids

Question 16

Environmental factors in lipid oxidation

Answer 16

Oxidation, temp, light, moisture, analysts, nit oxidants, moisture

Question 17

antioxidants

Answer 17

Slow rancidity, does not stop production of aldehydes and ketones rom hydroperoxides

Question 18

How do ntioxidants work

Answer 18

Retardation auto oxidation. Compete for oxy binding retardation free radicals inhibition of catalysts , stabilize hydroperoxides most importants is blocking of propagation.

Question 19

Blockage of propagation mechanism via anti ox

Answer 19

Ah acts as a hydrogen donor to loo or l, a does. A does not act as an initiatior itself enters a termination reaction. Can be regenerated if favourable

Question 20

What should food grade anti oxidants hAve. Also what is a contributor to lipid oxidation thru catalytic action

Answer 20

Should be fat soluble. Metallic ions, cu, iron.

Citric acid sequesters metals , enhance phenolic antiox activity

Question 21

Browning of fruits and veg when cut

Answer 21

EnzymTic action of phenolic compounds . Ascorbic acid prevents this , critic acid enhances the effectively of Ascorbic acid in preventing browning

Question 22

E numbers

Answer 22

300-399

Question 23

Synergism

Answer 23

The two nit oxidants together and greater then when used sepErately mixed free radical quenchers, mixed free rad and a metal cheating agent . A synergist may have more then one role , electron donor as well as Metal Che.ator

Question 24

Measuring lipid oxidation

Answer 24

Rate of oxy uptake , formation of per oxides, ydroperoxidsz , mall aldehydes conj dienes , free fatty acids

Question 25

Rte of oxygen uptKe tbars

Answer 25

Oxidized fat reacts with tba, forms tba acid, gives red coloured complex , correlates with degree of rancidity

Question 26

Types of fat in foods

Answer 26

Milk fat, Lauric acid ( coconut oil) , veg butter , Oleic linoleic, linolenic, animal fat Marine oils

Question 27

Milk fat

Answer 27

Palmitic Oleic , steRic, short chain , branched, odd numbered

Question 28

Lauric acid

Answer 28

Coconut oil. Babassu large number of saturated , low melting point

Question 29

Cocoa butter, narrow melting range, no tri saturated , large number of saturated

Answer 29

Above lol

Question 30

Lonoleic

Answer 30

Canola, olive, safflower, most abundant, less then 20 saturated

Question 31

Linolenic

Answer 31

Hemp, soy, whet germ

Question 32

Animal fats

Answer 32

C16, 18, some oleic and linoleic , mostly fully saturated tag , high mp. Small amounts of odd numbered

Question 33

Marine oils

Answer 33

Long chain Pufas up to 6 dbl bonds, a and d , less resistant to oxidTion usually have dha and EPA at sn2

Question 34

Plant tags

Answer 34

Seed oils have unsaturTed fatty acids at sn2 13 are sat

Question 35

Animal tags

Answer 35

Varies among animal/ where on animal , depot fat can be altered by changing dietary fat c16 at sn1, c14, sn2, short chain in milk is at sn3

Question 36

Pig fat

Answer 36

Unique | Sn1and 3 c18, sn2 c16

Question 37

Impurities in refining , steps in refining,

Answer 37

``` FFA, phospholipids, carbohydrates,proteins, water, pigments, fat oxidation products Settling degumming Neut using base Bleaching Deodorizing Hydrogenation ```

Question 38

Settling and degumming

Answer 38

Water, protein materials and cho, oil is heated and allowed to stand

Question 39

Neutralization

Answer 39

Uses NaOH, created rootstock or soapstock, removes phospholipids and colouring materials

Question 40

Bleaching

Answer 40

Removes residual soapstock , phospholipids and oxidation products , oil is then filtered with activated carbon,

Question 41

Deodorization

Answer 41

Steam distilization , used to remove volatile compounds , critic acid is often used to bind metals

Question 42

Hydrogenation

Answer 42

Adding h+ to double bonds aids in stability Liquid oil is converted to semi solid fat or plastic fats , shortening or margarine Improves oxidative stability , decrease in the number of unsat fas