information and chemistry of ghee

1. At present, about 28% of the total milk production is utilized for the
manufacture of about one million ton of ghee per annum
INTRODUCTION
Ghee is a very popular product since from ancient time and have greater
demand during festival and other ceremonial functions
Best ways to salvage substandard and returned market milk at
commercial dairy level is separation of fat from these and convert this fat
to ghee.
Ghee has a market demand of around one million ton per annum in
India

2.  DEFINITION:-
According to FSSR-2011, ghee means the pure heat
clarified fat derived solely from milk or curd or from desi (cooking)
butter or from cream to which no coloring matter or preservative has
been added
 PRODUCT DESCRIPTION AND CHEMICAL COMPOSITION OF GHEE
Ghee could be in liquid, semisolid and some time in solid state based on
the storage temperature
Ghee made from buffalo milk is whitish with greenish tinge and that of
cow milk is golden yellow colour. It is usually prepared form cow milk,
buffalo milk or mixed milk.

3. Ghee is a complex lipid of glycerides (majorly triglycerides), free fatty
acids, phospholipids, sterols, sterol esters, fat soluble vitamins,
carbonyls, hydrocarbons, carotenoids, (only in ghee derived from cow
milk). Its detailed chemical composition is given below.
Constituents Cow milk ghee Buffalo milk ghee
Fat (%) 99 – 99.5 99 – 99.5
Moisture (%) <0.5 <0.5
Carotene(mg/g) 3.2-7.4 ..
Vitamin A(IU/g) 19-34 17-38
Cholesterol (mg/100g) 302 – 362 209 – 312
Tocopherol(mg/g) 26 – 48 18 – 31
Free fatty acid (%) 2.8 2.8

4. Milk fat contains at least 500 fatty acids and fatty acid derivatives with 4
to 20 or more carbon atoms in their chain. The fatty acid may saturated
or unsaturated and usually contains an even number of carbon atoms.
Fatty Acid (%) Cow milk ghee Buffalo milk ghee
Butyric 4.4 3.2
Caproic 1.5 2.1
Capric 1.3 2.6
Lauric 1.8 2.8
Myristic 10.8 11.9
Palmitic 33.1 30.6
Stearic 12 10.1
Oleic 27.2 27.4
Linoleic 1.5 1.5
Linolenic 0.5 0.6

5.  METHODS OF PREPARATION
The principle involved in ghee preparation include -
1) concentration of milk fat in the form of cream or butter.
2) Heat clarification of fat rich milk portion and thus reducing the
amount of water to less than 0.5%.
3) Removal of the curd content in the form of ghee residue.
There are five methods of ghee making -
1. Desi or Indigenous Method
2. Direct Cream Method
3. Creamery Butter Method
4. Prestratification Method
5. Continuous Method

6.  PRE-STRATIFICATION METHOD
Butter is produced from aged cream of 38 to 40% fat using then batch
churn. Butter is then melt at 80°C. This molten butter is kept
undisturbed in a ghee kettle or boiler at a temperature of 80-85°C for 30
min
- Product stratifies into 3 distinct layers
1. Denatured protein particles (curd particles) and impurities are
collected on top layer
2. Middle layer consists of clear fat
3. bottom layer consists of buttermilk serum carrying 80% of
moisture and 70% of solids-not-fat contained in butter.

7. The bottom layer is then carefully removed without disturbing the both
top and middle layers.
Middle layer, largely consists of fat is heated to 114±20°C along with
top layer of floating curd particles and denatured protein.
 Advantages of pre-stratification method -:-
1. Removal of buttermilk (bottom layer) eliminates prolonged heating
for evaporation of the moisture
2. Formation of significantly low quantity ghee residue
3. Low quantity of ghee absorbed into ghee residue so less fat loss
along with ghee residue
4. Production of ghee with lower FFA and acidity

8.  GRANULATION :-
Granulation is important criterion of quality; higher
temperature of clarification gives better grain size due to high
phospholipids content
• Phenomenon -
Completely melted ghee on cooling to prevailing Indian temperatures,
can assume the form of large, coarse grains suspended discretely or in
clusters in a liquid phase
The process of crystallization is initiated with the formation suitable
nuclei.
Stirring or agitation and seeding (at the rate of 1 – 3%) encourage the
nucleus formation.
For better granulation, ghee should be slowly cooled to 28°C in 2-3
hours time and agitation is required during granulation to form smaller
granules.

9.  Causes of granulation -
content of glycerides of higher melting saturated
fatty acids, especially palmitic & stearic. Thus buffalo milk ghee show
predominant granulation than cow milk ghee.
 Factors influencing yield -
1. Method of production
2. The fat content of the raw material used
3. Quality of milk or cream
4. Fat recovery from ghee residue
 Quality of ghee made from substandard milk -
Parameter Fresh milk ghee High acid milk
ghee
Liquid portion Less More
Colour units High Less

10.  FLAVOUR FORMATION IN GHEE
Free fatty acids, carbonyls and lactones are the major groups of
compounds contributing to ghee flavour
• Carbonyls :-
The quantity of carbonyls is directly proportional to the
temperature of clarification.
‘Head space‘ and ‘volatile‘ carbonyl content of fresh desi cow ghee is
higher that of buffalo ghee
whereas total carbonyl content of fresh desi buffalo ghee is higher than
that of cow ghee.
Carbonyl content found to increase during storage.

11. • Lactones :- The lactone level in buffalo ghee has found to be higher
than that in cow ghee.
It was the highest in direct cream (DC) ghee, followed by creamery
butter (CB) and lowest in desi ghee.
The lactose level in butter (12 ppm) increased 1.9, 2.4, 2.8 and 3.0 fold
on clarifying at 110°C, 120°C, 140°C and 180°C respectively
Clarification butter at 100-120°C doubles the lactones level from butter.
The lactone level in ghee showed a significant rise on storage
Components Cow ghee Buffalo ghee
Total carbonyls ( m/g) 7.2 8.64
Volatile Carbonyls
( m/g)
0.33 ..
Head-Space Carbonyls
(gas stripped) m/g)
0.035 0.027

12. • Formation of flavour components are due to
(i) Heat interaction between the native carbohydrates and protein
system of cream
(ii) Due to heat effect on the unfermented residue as well on
fermented metabolic products formed by ripening process.
 Texture of ghee
When ghee is stored at room temperature, it crystallizes into three
distinct fractions or layers, 1. Oily
2. granular semi-solid at the bottom
3. hard flakes portion floating on the surface
Layer formation in ghee could be prevented by storing it at 20°C or below
immediately after preparation.

13.  Market Quality of Ghee
Consumer judge the quality of ghee base on its inherence flavour, colour
and appearance
Ghee should have characteristic pleasant, nulty, slightly cooked rich
aroma.
 chemical and other physical preventers are evaluated to judge the quality
of ghee and also to prevent adulteration of ghee
(i) Refractive Index
Ratio of the velocity of light in vacuum to the velocity of
light in the sample medium
• In case of milk fat reading is normally made at 40°C using Abbe
refractometer and its values range from 1.4157 to 1.4566.
• This value is low in comparison to the other fats and oils.

14. • Refractive Index could be used as indicator of adulteration
II. Iodine Number
• It is defined as number of grams of iodine absorbed by 100 g of fat under
specified conditions.
• Thus constant is a measure of the unsaturated linkages present in a fat
• The iodine number for milk fat falls within the range of 26 to 35
• This is estimated using Wig‘s method.
III. Reichert-Meissl Number
•This is defined as number of ml of n/10 Sodium hydroxide required to
neutralize the steam volatile water soluble fatty acids distilled from 5 g of
ghee under precise conditions specified in the method.

15. • It is primarily measure of butyric acid and caproic acid. The value for
milk fat ranges between 17 to 35
IV. Polenske Number
It is defined as number of ml of N/10 Sodium
hydroxide required to neutralize the steam volatile water insoluble
fatty acids distilled from 5 g of fat under precise conditions specified in
the method
• It ranges from 12 to 24 for milk fat
V. Saponification Number
• It is defined as the number of milligrams of potassium required to saponify
one gram of fat
• The value ranges from 210 to 233 and more often falls in the range of
225 to 230.

16. VI. Melting Point
• Melting point for milk fat ranges from 30°C to 41°C
 FACTORS AFFECTING THE MARKET QUALITY OF GHEE
(i) Raw-materials (Milk, Dahi, Cream, Butter) used for ghee making
(ii) Method of preparation and temperature of clarification
(iii) Type of feed
(iv) Season
In winter and monsoon, the granulation is more due to
changes in the fatty acid profile. Winter ghee showed higher acidity,
melting point and grain size where as in summer the saponification
value was found to be higher.

17.  GRADING OF GHEE
• The quality of ghee can be judged by physical and chemical analysis
•The Agricultural Produce (Grading & Marking) Act, 1936 empowers
the Central Government to fix quality standards, known as ‘AGMARK‘
standards
•The word 'AGMARK' is a derivative of "Agricultural Marketing".
 Objectives of AGMARK
i. To assure the consumer a producer of pre-tested quality and purity
ii. To enable manufacturers of high grade product to obtain better returns
iii. To develop an orderly marketing of the commodities

18. Grade Letter and Circular
border colour
Special Red
General Green
Standard Chocolate
 AGMARK grades of ghee
1. Special Grade 2. General Grade 3.Standard Grade

19.  AGMARK standards of ghee
Parameters Special Grade General Grade Standard Grade
Baudouin Test Negative Negative Negative
Butyro-
refractomer
reading at 40°C
40.0– 43.0 40.0– 43.0 40.0– 43.0
Reichert Meissl
value
Not less than 28.0 Not less than28.0 Not less than28.0
Polenske value 1.0 – 2.0 1.0 – 2.0 1.0 – 2.0
Moisture content Not more than
0.3%
Not more than
0.3%
Not more than
0.3%
Percentage of
Free Fatty
Acid (as oleic
acid)
Not more than 1.4 Not more than
2.5
Not more than
3.0

20.  DEFECTS IN GHEE
1. Flavor Defects - Smoky, Overcooked or bunt, Undercooked, Rancid,
Oxidized/oily/metallic,
2. Texture Defects - Greasy
3. Appearance Defects - Burnt colour, Higher Sediment
 ADULTERANTS IN GHEE
1. Vanaspati (Hydrogenated vegetable oil). Because of close resemblance
in its texture most commonly used this as adulterant to ghee.
2. Refined (de-odourized) vegetable oil
3. Animal body fat