Analytical Methods to Measure the Constants of Fats and Oils

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ANALYTICAL ANALY TICAL METHODS TO MEASURE THE CONSTA CON STANTS NTS OF FATS FATS AND OILS [1] Acid value (Acid Numbe! +he acid ,alue - AV) is the is the number that epresses in milligrams the uantit& o" potassium h&droide reuired to neutrali1e the "ree acids present in ( g o" the substance. +he acid ,alue ma& be o,erestimat o,erestimated ed i" other acid components are present in the s&stem s&stem e.g. amino acids or  acid phosphates. +he acid ,alue is o"ten a good measure o" the brea% down o" the triac&lgl&crols into "ree "att& acids which has an ad,erse e""ect on the ualit& o" man& lipids.

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2cid ,alue is the measure o" h&drol&tic rancidit&. n general it gi,es an indication ab out edibilit& o" the lipid. ' dible oil contain  (6 ' Pharmaceutical oil must not ha,e an& acidit&. acidit&.

AV =

ml of KOH x N x 56 Weight eigh t of o f Sam Sa mple

= mg of KOH 7 = 7ormalit& o" 9

6 Free Fatt& 2cid -FF2; = 2<  0.503

Ma%eial • Fat or 9il • 2bsolute ethanol alcohol •   Phenolphthalein • 0.( 7 9 &'cedue

(. Place 5.0 5.0 g o" "at "at or oil oil in a dried dried conical conical "las%. "las%. ). 2dd )5 ml ml o" absolute absolute ethanol alcohol alcohol and add - )'3; drops o" phenolphthalein 3. ea eatt with with sha sha%in %ing g in water bath -56; "or (0 mi minut nutes es th then en cool +i +itra trate te the sol soluti ution on against 0.( 7 9 until pin% color appears -end point;. 4. ecord &our obser obser,atio ,ations. ns. 5. >alculate the acid ,alue -2< -2

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Aaponi"ication oconut oil >otton seed oil Ao&bean oil lard Cutter "at and ,egetable "ats

Aaponi"ication =>' H Cr ecess → '>'>Cr' H Cr remaining +he amount o" Cr that has reacted is determined b& measuring the amount o" Cr remaining a"ter the reaction has gone to completion -Cr reacted  =Cr ecess  ' Cr remaining;. +he amount o" Cr 

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>oconut oil

8 ' (0

Cutter

)5 ' 40

Cee" tallow

30 ' 45

Palm oil

3# ' 54

Lard

45 ' #0

9li,e oil

#5 ' !5

Peanut oil

85 ' (00

>ottonseed oil

(00 ' ((#

>orn oil

((5 ' (30

Fish oils

()0 ' (80

Ao&bean oil

()5 ' (40

Aa""lower oil

(30 ' (40

Aun"lower oil

(30 ' (45

Linseed oil

(#0 ' )05

Baterial • 9il or "at • anus solution - itIs prepared b& dissol,ing (8.) g o" iodine in (L o" glacial acetic acid and then add 3 ml o" bromine water "or increasing the halogen content. • (56 potassium iodide solution • (6 starch solution • 0.( 7 Aodium thiosul"ate solution. Procedure (. Eeigh approimatel& 0.)5 g o" the "at or oil into a )50 mL conical "las%.

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7 o" 7a)A)93

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  0.()#g/me

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