Analysis of fats and fixed oils

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Chapter 12
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1

Greek word for fat

Lipos

2

fats is composed of what elements

Carbon, Hydrogen. Oxygen

3

Universal liquid solvent

Chloroform and methanol

4

What causes the free acids in oils, fats and waxes?

It is due chiefly to the hydrolysis of esters composing then(rancidity)

5

Types of fats

Unsaturated fats and saturated fats

6

What is unsaturated fats?

It is found in plant foods and fish

7

It is a type of unsaturated fats that is found in most vegetable oils

Polysaturated

8

It s a type of unsaturated fats that is found in avocadoes, olive, peanut and canola oil

Monosaturated

9

It is a type of unsaturated fats found in oily fish like tuna and salmon

Omega-3-fatty acids

10

This type of fats is found in meat and other animal products

SAturated

11

The physical methods in analysis of fats and fixed oils

Specific gravity

Melting point

Solidification temperature of fatty acids

12

Chemical methods of analysis of fats and fixed oils

Acid value, saponification value, ester value, iodine value, hydroxyl value and acetyl value

13

What is acid value?

It is the number of mg of KOH used to neutralize the free acids of 1 g of sample(fats, wax, resin, balsam or similar organic substances)

14

Formula for acid value

card image

A.V= VxNxMW / Weight of sample

15

It is the natural process of decomposition of fats or oils by either hydrolysis or oxidation or both, process of degradation converts fatty acids of oils into free acids

Rancidity

16

Types of rancidity

Oxidative rancidity

Hydrolytic rancidity

Microbial rancidity

17

Also known as the hydrolysis or enzymatic oxidation

End product is the formation of aldehyde, epoxide and peroxide

Hydrolytic rancidity

18

Also known as auto-oxidation

it is due to the auto-oxidation of PUFA present in triacylglygerols byt he atmospheric 02 on free radicals. oxyen is absorbed from the environment

Oxidative rancidity

19

Refers to a water-dependent process in which microorganisms, such as bacteria or molds, use their enzymes such as lipases to break down fat. Pasteurization and/or addition of antioxidant ingredients such as vitamin E, can reduce this process by destroying or inhibiting microorganisms.

Microbial rancidity

20

It is the process of converting fats into soaps

It is the number of mg of KOH used to neutralize free acids containing 1 g of sample and saponify esters containing 1 g of the sample

Saponification, saponification value

21

These are substances present in oils that are not saponifiable by alkali hydroxides and are extracted by ordinary fat solvents

Unsaponifiable matter

22

Unsaponifiable matter found in animals oils anf fats

Cholesterol

23

Unsaponifiable matter found in vegetable oils and fats

Phylosterol

24

Saponification value formula

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S.V= (V1-V) x N HCl x MW / Weight of the sample

25

The number of mg of KOH used to saponify ester in 1g of the sample

Ester value

26

Ester Value formula

E.V= S.V- A.V

27

The number of g of iodine absorbed by the 100 g of fats/sample

Iodine Value

28

Methods of determining iodine value

Hanus Method(1)

Wijs Method(2)

29

Test Solution is Iodochloride TS or ICl

Wijs method

30

Test Solution is Iodobromide TS or IBr

Hanus method

31

Classification of oils

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Drying oils- >120 (Linseed oil, cod liver oil)

Semi-drying oils - 100-120 (cottonseed and sesame oils)

Non-drying oils- <100(olive and almond oil)

32

the number of mg of KOH use to neutralize 1g of acetylated fatty acids

Acetyl value

33

The number of mg of KOH equivalent to the hydroxyl content of 0.1g of the substance

Hydroxyl value(number)

34

Hydroxyl formula

[(MrxN)/W] x {B+[(WxA)/C]/-T}

35

True or false

Lipids is soluble in organic solvents

True

36

True or false

All fats and oils are mixture of PUFA and MUFA

False, all fats and oils are mixture of saturated and unsaturated fats

37

Acid Value <112 = acid content was low and that it was inferior quality

True

38

Acid Value>168= adulterated with some substances having high acid value

True

39

Both the Hanus and Wijs method used this indicator

Starch