This document discusses various tests used to analyze fats and oils, including acid value, saponification value, iodine value, acetyl value, and Reichert-Meissl value. It provides definitions of each test and describes the procedures for determining the values. The acid value measures free fatty acids, saponification value measures ester content, iodine value measures degree of unsaturation, and acetyl value and Reichert-Meissl value provide other measures of purity and composition. Understanding these values is important for evaluating the properties and quality of different fats and oils.

1. FATS AND OILS
BY S LAXMAN

2. ANALYSIS OF FATS AND OILS
They are important components of various medicines , lubricants
and other items.
Daily we consume fats and oils in one or other form.
The value of particular fat or oil depends on its composition and
purity
Purity and composition in turn depends on the degree of
saturation , acidity on hydrolysis and molecular weight.

3. SOME COMMON TESTS
• ACID VALUE
• SAPONIFICATION VALUE
• IODINE VALUE
• ACETYL VALUE
• REICHERT-MEISSL VALUE

4. ACID VALUE
• DEFINED AS THE NUMBER OF MILLIGRAMS OF KOH REQUIRED TO NEUTRALISE 1
GRAM OF FATS OR OILS
• IT INDICATES THE AMOUNT OF FREE FATTY ACIDS PRESENT IN AN OIL OR FAT
• THE ACID VALUE IS THE MEASURE THE BREAK DOWN OF THE TRIGLYCERALS
INTO FREE FATTY ACID WHICH HAS AN ADVERSE AND UNDESIRABLE EFFECT

5. PROCEDURE
• WEIGHT ACCURATELY A QUANTITY OF FAT OR OIL IN A CONICAL FLASK .
• THEN ADD 50ML OF ETHANAL-ETHER SOLUTION, SHAKE IT WELL.
• TITRATE THE SOLUTION WITH POTASSIUM HYDROXIDE USING PHENAPTHALEIN
AS INDICATOR, UNTIL PINK COLOR IS OBTAINED
𝐴𝐶𝐼𝐷 𝑉𝐴𝐿𝑈𝐸 =
𝑉𝐾𝑂𝐻 × 5.61
𝑊
• 𝑉𝐾𝑂𝐻 VOLUME OF KOH USED
• W IS WEIGHT OF FAT OR OIL

6. SAPONIFICATION VALUE
• DEFINED AS THE NUMBER OF MILLIGRAMS OF KOH REQUIRED REQUIRED TO
COMPLETELY SAPONIFY 1GRAM OF FAT OR OIL
• PRINCIPLE IT IS DETERMINED BY REFLUXING A KNOWN QUANTITY OF THE
SAMPLE WITH AN EXCESS OF 0.5 N ALCHOLIC KOH FOR 30 MINUTES AND
TITRATE UNUSED ALKALI WITH 0.5 N HCL

7. PROCEDURE
• TAKE 2 GMS OF IN A CONICAL FLASK WITH REFLUX CONDENSER.
• ADD 25 ML OF 0.5 ETHANOLIC KOH AND SMALL AMOUNT OF PUMIC POWDER
AND BOIL UNDER REFLUX ON A WATER BATH FOR 30 MINUTES ADD 1ML OF
PHENOL PHTHALEIN SOLUTION TITRATE 0.5N HCL
• 𝑆𝐴𝑃𝑂𝑁𝐼𝐹𝐼𝐶𝐴𝑇𝐼𝑂𝑁 𝑉𝐴𝐿𝑈𝐸 =
28.05(𝐵−𝐴)
𝑊
B= ML OF HCL USED FOR BLANK TITRATE
A= ML OF 0.5 HCL USED FOR TITRATION
W= WEIGHT OF SAMPLE

8. IODINE VALUE
• IT IS DEFINED AS THE NUMBER OF GRAMS OF IODINE TAKEN UP BY 100 GMS OF
FAT OR OIL
• PRINCIPLE IT IS DETERMINED BY TREATING BY GIVEN SAMPLE OF FAT OR OIL
WITH IODINE MONOCHLORIDE OR IODINE IN ETHANOL IN PRESENCE OF
MERCURIC CHLORIDE. UNREACTED IODINE IS THEN CALCULATED

9. PROCEDURE
• IT IS CALCULATED BY TWO METHODS
• HUBL’S METHOD FAT OR OIL SAMPLE US DISSOLVED IN CARBON TETRA
CHLORIDE AND IS TREATED WITH STANDARD SOLUTION OF ETHANOLIC IODINE
IN PRESENCE OF MERCURIC CHLORIDE UNUSED IODINE THEN CALCULATED WITH
TITRATION BY STANDARD SODIUM THIOSULPHATE SOLUTION
• WIJ’S METHOD IT USES IODINE MONOCHLORIDE IN ACIDIC ACID IN PLACE OF
IODINE
• IODINE CHLORIDE READILY COMBINES WITH DOUBLE BONDS PRESENT IN FAT OR
OIL. THE UNREACTED IODINE IS THEN CALCULATED WITH POTASSIUM IODIDE
AND TITRATION WITH STANDARD SODIUM THIOSULPHATE USING STARCH AS
INDICATOR

10. FORMULAE
𝑖𝑜𝑑𝑖𝑛𝑒 𝑣𝑎𝑙𝑢𝑒 =
(𝑎 − 𝑏) × 1.27
𝑊
a = reading for blank titration
b = reading for actual titration
W = weight of fat or oil taken

11. ACETYL VALUE
• IT IS DEFINED AS THE NUMBER OF MILLIGRAMS OF POTASSIUM HYDROXIDE TO
NUETRALISE THE ACETIC ACID PRODUCED BY THE SAPONIFICATION OF 1 GRAM
OF COMPLETELY ACETYLATED FAT OR OIL

12. PROCEDURE
• TO GIVEN SAMPLE ADD 5ML OF ACITIC UNHYDRIDE PYRIDINE MIXTURE (1:7) , ADD 1
ML OF WATER.
• PUT ON A WATER BATH FOR ABOUT 30MINUTES THEN COOL IT
• TITRATE WITH 0.5 NORMAL KOH USING PHENAPTHALEIN INDICATOR
𝐴𝐶𝐸𝑇𝑌𝐿 𝑉𝐴𝐿𝑈𝐸 =
𝐸×4.3
𝐴
A= WT OF SAMPLE ACETYLATED
E= ACIDITY EQUIVALENT

13. REICHERT-MEISSL VALUE(RM VALUE)
• IT IS DEFINED AS THE NUMBER OF ML OF 0.1 NORMAL KOH REQUIRED TO
NUETRALISE WATER SOLUABLE STEAM
• IT IS INDICATOR OF HOW MUCH VOLATILE FATTY ACID CAN BE EXTRACTED
FROM FAT THROUGH SAPONIFICATION. IT IS A MEASURE OF VOLATILE ACID IN A
GIVEN FAT OR OIL.
• PRINCIPLE FOR THE DETERMINATION OF RM VALUE KNOWN SAMPLE IS
COMPLETELY SAPONIFIED WITH ALKALINE. SOLUTION IS ACIDIFIED WITH H2SO4
AND THEN STEAM DISTILLED VOLATILE ACID I THEN TITRATED WITH 0.1
NORMAL KOH SOLUTION

14. PROCEDURE
• TO THE 10 GRAM OF SAMPLE ADD AN EXCESS OF 0.1 NORMAL NaOH SOLUTION IN
ORDER TO COMPLETELY SAPONIFY THE FAT. THE SOLUTION IS ACIDIFIED WITH
DILUTE H2SO4 AND IS UNDERGONE STEAM DISTILLATION. THE DISTILLATE
CONTAINING THE VOLATILE ACID IS THEN TITITRATED WITH 0.1 NORMAL KOH
SOLUTION USING PHENAPTHALEIN AS INDICATOR
𝑅𝑀 𝑉𝐴𝐿𝑈𝐸 = 1.10(𝑇1 − 𝑇2)
• 𝑇1 𝐼𝑠 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 0.1𝑛 𝑘𝑜ℎ 𝑢𝑠𝑒𝑑 𝑓𝑜𝑟 𝑡𝑖𝑡𝑟𝑎𝑡𝑖𝑜𝑛
• 𝑇2 is volume of 0.1 n koh used for blank titration
SIGNIFICANCE OF RM VALUE R.M VALUE USED FOR TESTING THE PURITY OF BUTTER
AND DESI GHEE WHICH MAY CONTAIN HIGH AMOUNT OF GLYCERIDES OF BUTYRIC
ACID AND OTHER STEAM VOLATILE FATTY ACID RESIDUES.