Extraction And Determination Of Crude Fat From Plant And An - PowerPoint Presentation

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Extraction And Determination Of Crude Fat From Plant And Animal Tissues

Ms. Nadia AmaraSlide2

Introduction of Crude

Fat :

Determination

of Crude Fat is the term used to refer to the crude mixture of fat material present in a

sample.

Crude

fat is the traditional measure of fat in food products

.

Fat is important to all aspects of meat production and processing.

Lipids/fats

are relatively non-polar molecules, they can be pulled out of a sample using relatively non-polar solvents.

(With

a non-polar solvent, only non-polar molecules in the sample dissolve while polar ones do

not ).

The

lipid materials may include triglycerides, diglycerides, monoglycerides, phospholipids, steroids, free fatty acids, fat soluble vitamins, carotene pigments, chlorophylls,

etc.

Crude

fat content is determined by extracting the fat from the sample using a solvent, then determining the weight of the fat recovered

.Slide3

The common approach for total crude fat determination is based on the solubility of lipids in non-polar organic solvents such as hexanes, petroleum ether, or other

non-polar

solvent .

In this lab we will determine the crude fat extracted by petroleum ether solvent .

This method is applicable to extractions of oilseeds, meats, feeds, and foods

.

Calculation :

Crude Fat % ( % of Dry matter) = (weight of crude fat + weight of extraction flask )-(weight of extraction flask) / weight of sample *100Slide4

Principle of Soxhlet extraction

:

Soxhlet

extraction is a continuous solid / liquid extraction

.

A

solid which contains the material to be extracted is placed in what is called a thimble

.

A thimble is made out of a material which will contain the solid but allow liquids to pass

through. A

lot like filter paper.

The

thimble containing the material is placed in the Soxhlet

extractor.

An

organic solvent is then heated

.

As it boils its vapors rise up and are condensed by a

condenser. The

condensed solvent then fills up the

thimble, and after

it fills with enough solvent it automatically siphons back down into the container of organic solvent. Slide5

This process takes place over and over again until all the material to be extracted from the solid in the thimble is now extracted into the organic solvent.

This

cycle may be allowed to repeat many times, over hours or

days.

The

advantage of this system is that instead of many portions of warm solvent being passed through the sample, just one batch of solvent is

recycled.

After

extraction the solvent is removed, typically by means of a rotary evaporator, yielding the extracted compound. The non-soluble portion of the extracted solid remains in the thimble, and is usually discard.Slide6

1:

 Stirrer bar/anti-bumping granules

2:

Still pot (extraction pot)

-

still pot should not be overfilled and the volume of solvent in the still pot should be 3 to 4 times the volume of the soxhlet chamber.3: Distillation path4: Soxhlet Thimble5: Extraction solid (residue solid)6: Syphon arm inlet7: Syphon arm outlet8: Reduction adapter9: Condenser10: Cooling water in11: Cooling water outSlide7
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Advantages :

Inexpensive equipment

usage.

Filtration Not

required.

Continuous contact with the

solvent.Possibility of extracting more sample mass than the other methods available.Wide industrial application and efficient.Disadvantages :

Relatively slow extraction(24-48

hrs.).

Large amount of solvent is needed (350-500ml

).

Some solvents create environmental problems such as

toxicity.Slide9

Equipments & Reagents :

Analytical

balance

.

Soxhlet extraction unit comprising: ( Round bottom flask, Soxhlet extractor and condenser ,Heat source, either electric heating mantle, or steam bath ).Electrical drying oven to be operated at 70 C .Petroleum Ether(boiling point: 40-60ºC).

Method :

Weigh

6 g

of the

food

sample into extraction thimble. 

Place the thimble inside the Soxhlet Apparatus.

Connect a dry pre-weighted solvent flask beneath the apparatus

.

add 90 ml of

Petroleum

Ether and

connect the condenser

.

Turn on the heater and extract for 12 hrs.

After

completing the extraction, remove the

thimble.

Complete

the removal of ether on a boiling

bath or hot plate under the hood .

Dry

flask at

70ºC

for 30

mins

.

Cool

to room temperature and weigh the extraction flask .