Biochemistry Seminar

2. ➢INTRODUCTION
• VEGETABLE OILS & FATS (VOFS) HAVE A MAJOR CONTRIBUTION IN OUR
DIET AS COOKING SUPPLEMENT.
• SOME VOFS HAVE VERY HIGH ECONOMIC IMPORTANCE, TEMPTING
DEFRAUDERS TO ADULTERATE THEM WITH LESS EXPENSIVE OILS AND FATS TO
GET SOME ADDITIONAL PROFIT.
• THIS PRACTICE OF ADULTERATION DECLINED THE QUALITY OF VOFS
CROPPING A MATTER OF CONCERN, TO ENSURE A PROPER STANDARD OF
HYGIENE & TESTING OF THE PRODUCT.

3. ➢ANALYTICAL PARAMETERS FOR
FATS & OILS
•
ACIDITY FROM HYDROLYSIS
•
PHYSICAL & CHEMICAL CONSTANTS.
• PHYSICAL CONSTANTS INCLUDE:
❖ VISCOSITY (SPECIFIC GRAVITY)
❖ REFRACTIVE INDEX
❖ SOLIDIFICATION POINT

4. • KREIS’ TEST (RANCIDITY INDEX)
• IODINE VALUE
• SAPONIFICATION VALUE
• REICHERT – MEISSL VALUE
• POLENSKI VALUE
• ACID VALUE

5. Defined as the
weight of Iodine
absorbed by
100 parts by
weight of
sample fat/oil.
Iodine no. is directly
proportional to the
content of unsaturated
fatty acids.
Lower the iodine
number, lesser the
degree of saturation.
Susceptibility to
Rancidity increases for
the fat/oil having higher
iodine values.
Definition
Significance

6. Definition
•Defined as the no. of milligrams of potassium
hydroxide (KOH) required to neutralize the fatty
acids resulting from complete hydrolysis of 1g
of the sample oil/fatty acid present in the oil.
•Usually applied for Butterfat, Coconut oil, etc.
Significance
•It is a measure of the average
molecular size of constituent fatty
acids in given sample.
•Higher the saponification value,
shorter the chain of fatty acids.

7. • DUE TO RANCIDITY, EPIHYDRIN ALDEHYDE
OR MALONALDEHYDE ARE INCREASED
WHICH ARE DETECTED USING
PHLOROGLUCINOL WHICH PRODUCES RED
COLOUR WITH OXIDISED FAT.
• IT IS DEFINED AS NO. OF MILLIGRAMS OF KOH
REQUIRED TO COMBINE WITH FATTY ACIDS
WHICH ARE PRESENT IN GLYCERIDE FORM IN 1G
SAMPLE.

8. Fats and oils are composed of molecules known as triglycerides, which
are esters composed of three fatty acid units linked to glycerol. An
increase in the percentage of shorter-chain fatty acids and/or
unsaturated fatty acids lowers the melting point of a fat or oil. The
hydrolysis of fats and oils in the presence of a base makes soap and is
known as saponification. Double bonds present in unsaturated
triglycerides can be hydrogenated to convert oils (liquid) into
margarine (solid). The oxidation of fatty acids can form compounds
with disagreeable odors. This oxidation can be minimized by the
addition of antioxidants.