Simple Lipids Flashcards

1
Q

Why are simple lipids called as neutral lipids

A

They are called neutral because they are uncharged due to absence of ionisable groups

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2
Q

Why are simple lipids called as Triglycerides

A

They are esters of glycerol with various fatty acids. Since the 3 hydroxyl groups of glycerol are esterified , the neutral fats are called as Triglycerides

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3
Q

What are all the types triglycerides ( Fats and oils)

A

1)Simple Triglycerides
2) Mixed triglycerides

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4
Q

What are simple Triglycerides

A

If the three fatty acids connected to glycerol are of the same type it is called as simple Triglycerides
e.g, Tripalmitin

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5
Q

What are mixed Triglycerides

A

If the three fatty acids connected to glycerol are of different types it is called mixed Triglycerides
e.g, stearo- diolein and palmiti-oleo-steaein

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6
Q

What is the difference between fats and oils

A

Oils are liquid in room temperature whereas fats are solids in room temperature

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7
Q

What are all the physical properties of fats and oils

A

1) Freshly prepared fats and oils are colorless, odourless and tasteless. Any colour or taste is due to association with foreign substance
2) Fats have specific gravity less than 1 and therefore, they float on water
3) Fats are insoluble in water but soluble in organic solvents
4) Melting points of fats are usually low

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8
Q

What are all the chemical properties of fats and oils

A

1) Hydrolysis
2) Saponification
3) Halogenation
4) Hydrogenation or hardening of oils
5) Oxidation (Rancidity)

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9
Q

What is hydrolysis of fats and oils

A

They are hydrolyzed ( Broken down in the presence of water) into fatty acids and glycerol by the action of steam, acid, alkali or enzymes ( lipase of pancreas) . Glycerol and fatty acids are produced at the end

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10
Q

What is Saponification of fats and oils

A

Alkaline hydrolysis produces glycerol and salts of fatty acids ( Soaps )

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11
Q

What is Halogenation of fats and oils

A

Neutral fats containing unsaturated fatty acids have the ability of adding halogens at the double bond

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12
Q

What is hydrogenation or hardening of oils

A

It is a type of addition reaction in which hydrogen is added into the double bond of unsaturated fatty acids
It is done unde high pressure of hydrogen and is catalysed by finely divided nickel

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13
Q

What is oxidation ( Rancidity )

A

It is a toxic reaction of Triglycerides which leads to unpleasant odour or taste of oils and fats developing after oxidation by oxygen of air

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14
Q

What is Rancidity

A

It is a physio-chemical change of fats that leads to development of bad odour or taste or abnormal colour after ageing in the exposure to oxygen and moisture

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15
Q

What are the types of Rancidity

A

1) Hydrolytic Rancidity
2) Oxidative Rancidity
3) Ketonic Rancidity

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16
Q

What is Hydrolytic Rancidity

A

It results from the slight hydrolysis of the fat by lipase from bacterial contamination leading to the liberation of free fatty acid and glycerol at hig temperatures and moisture

17
Q

What is oxidative Rancidity

A

It is oxidation of fat or oil by exposure to air, oxygen, light or heat producing peroxide derivatives which on decomposition gives substance like peroxide, aldehyde and ketone which have bad odour and toxic

18
Q

What is Ketonic Rancidity

A

It is due to contamination with certain fungi such as aspergillus Niger on fats such as coconut oil. Ketones, fatty aldehydes and fatty alcohols are formed

19
Q

What accelerates Ketonic Rancidity

A

Moisture accelerates Ketonic Rancidity

20
Q

What is iodine number or value

A

It is the number of grams of iodine absorbed by 100 grams of fat or oils

21
Q

What is the use of iodine number

A

It is the measure for the degree of unsaturation if the fat as a natural property for it

22
Q

What is Saponification number

A

It is the number of milligrams of KOH required to completely saponify one gram of fat

23
Q

What is the use of Saponification number

A

Since each carboxyl group of a fatty acid reacts with one mole of KOH during Saponification, therefore the amount of alkali needed to saponify certain weight of fat depends upon the number of fatty acids present per weight. Thus fats with short chain acids will have higher Saponification number than long chain fatty acids

24
Q

What is acids number

A

It is the number of milligrams of KOH required to neutralize the free fatty acids present in one gram of fat

25
Q

What is the use of acid number

A

It is used for detection of Hydrolytic Rancidity as it measures the amount of fatty acids present

26
Q

What is Reichert- Meissl number

A

It is the number if millilitres of 0.1N KOH required to neutralize the water soluble fatty acids distilled from 5 grams of fat

27
Q

What is the use of Reichert-Meissl number

A

This studies the natural composition of the day and is used for detection of fat adulteration

28
Q

What is acetyl number

A

It is number of milligrams of KOH required to neutralize the acetic acid liberated from hydrolysis of 1 gram of acetylated fat

29
Q

What is the use of acetyl number

A

It is used for studying the natural property of the fat and to detect adulteration and Rancidity