Associate Professor

Deptt. of Dairy Sc. & Tech. (Formerly A.H & Dairying)

R.K. (P.G.) College

 Shamli, U.P. India 

Overrun % In Butter

In butter industry milk or cream is generally purchased an the basis of its fat Content. Besides Butterfat, Commercially finished butter contains non-faatty Constituents such as moisture, curd and in many cases salt. The amount butter  therefore always exceeds the amount of fat used.

The difference between the amount of butter made and, the amount of fat churned is known as overrun and it is usually expressed as a percentage.

Importance – (1) An economic aspect it is source profit.

(2) A technical aspect it checks the efficiency of butter Industry operation.

Low over run shows that there is unnecessary loss of fat during the manufacture or contain more fat percentage than is prescribed by the legal standard. In these cases, the butter industry will incur heavy loss. High over rum indicates that butter may contain less butter fat than is required standard. or the different tests were over read.

According to FSSR (2011) Butter should contain minimum of 80% fat so maximum limit overrun possible in butter  is 25%.

The effective or accurate Control of overrun depends on

1. Accurate recording & weights and tests.

2. Controlled fat losses at every stage of  process.

3. Controlled Composition of butter.

Types - There are various types of overrun which include.

1. Theoretical (Pencil)- According to FSSR-2011 butter should contain a minimum of 80% fat  so maximum obtainable overrun in butter is 25%.

2. Compositional - It is based on the composition of butter and varies according to the fat percentage in butter

3. Factory- It is calculated on the basis of total butter recorded as butter packed for sale and total fat recorded as received.

4. Churn- In this type calculation for a particular type of churn.

Factors Influencing Over Run In Butter

The Following factors which affect the overrun.

1. In accuracy is weighing and fat testing of a sample of a milk, cream or butter.

2. Fat losses in skim milk and butter milk.

3. Mechanical fat losses.

4. Unavoidable fluctuation in the fat content & butter.

5. Weight allowance in butter packages.

6. Handling losses.

Overrun in butter is estimated by the following formula:

                  % Overrun = (B – F)/F X 100

Where,

B =Kgs of butter manufactured

F= kgs of fat churned

Yield Of Butter 

This is Calculated by the following formula

Y = F X (100+ % overrun/100

where,

Y = yield of butter

F = Fat Content of cream (Kgs)

Remark – Under Indian condition , assuming  percentage of overrun to be 20 then yield = fat content of  cream X 1.20.

Problem 1 - 1200 kgs of cream containing 40% fat was churned  into butter of 576 Kgs of butter was manufactured then calculate the overrun % in butter.

Solution

% overrun = Kgs butter manufactured – Kgs of  fat churned

                                          Kgs of fat churned         X 100

Amount of batter manufactured= 576 Kgs

Kgs of fat Churned = 40/100 X 1200 = 480 Kgs

% overrun= (576 - 480)/480 X100

96/480 X100 = 20%

Result- over run %. In butter = 20%

Problem 2  - 2000 kgs of cream containing 45% fat  is Converted into 80 % fat butter Calculate the amount of butter manufactured  and overrun %. If no loss fat during chaining process.

Solution

Amount of total fat in cream  =  45/100x2000 =900kgs

From 80 Kgs of fat, amount of butter Prepared =100 Kgs

From 900 kgs & fat, amount of butter prepared =100/80 X 900= 125 Kgs

% overrun = Kgs of butter  manufactured-Kgs of fat churned            X 100

                                                      Kgs of fat churned

            %over run = 1125 -900 / 900  X 100

                             =225/900 X 100 = 25

Result- Amount of butter manufactured =1125 kgs

overrun in butter = 25%

Problem 3

1500 Kgs cream testing 40%. fat is converted into butter.  If no loss of fat during churning  process, then calculate the amount of butter manufactured from this cream. The over run % to be taken as 20%

 

Solution  -  Amount of total fat in cream = 40/100 X 1500 = 600 Kgs

Suppose the amount of butter manufactured = xKg

%Overrun = Kgs of butter  manufactured - kgs of fat churned kgs    X 100

                          Kgs of fat churned  

 

20/1        = x-600/600 X100

(x-600) X 100= 20X600

x-600   = 20X600/100

x-600 = 120

x = 600+120 = 720Kgs

Result

Amount of  butter manufactured = 720 Kgs.

Problem- 4

3000kgs of cream containing 40% fat is converted into butter Containing of  80%. fat. If  the fat loss during churning is 10% Calculate the amount of butter prepared from the cream. The overrun in butter to be taken as 20%

Solution

Amount of total fat in Cream = 40/100 X 3000 = 1200 Kgs

Loss of fat during churned = 10/100 X 1200 = 120  Kgs

Amount of fat churned for butter Manufacturing = 1200-120= 1080Kgs

 

% overrun =  Kgs of butter manufactured – Kgs of  fat churned  X 100

                                           Kgs of fat churned

 

suppose the amount of butter manufactured = xKg

overrun in butter = 20 %

20/1 =  x – 1080/ 1080 X 100

20/1 = 100x-1080,00/ 1080

100x – 1080,00 = 20×1080

100x = 108000+21600

100x= 129600

x = 129600/100 =1296 kgs

Result-  Amount of butter prepared - 1296 kgs

Problem 5-  1000kgs of butter milk Containing 0.8 % fat is obtained from churning process. On the basic 18% overrun how many more kgs of butter could have been manufactured had the butter milk Containing only 0.2% fat.

Solution – Amount total fat in buttermilk containing  0.8%.  fat =0.8/100 X 1000 = 8 Kg

Amount of  total fat in  butter milk contain 0.2%fat = 0.2/100X1000=2Kg

Amount of extra fat churned = 8 - 2 = 6Kg

Overrun = kgs of butter manufactured - kgs of extra fat churned    X 100

                                      Kgs of extra fat churned

Suppose – The amount of extra kg of butter manufactured = x Kg

18 = x-6.0/ 6 X100

18/1 = (100x - 600)/6

100x - 600 =18x6

100x = 600+108

x = 108/100 = 7.08 Kg.

Result- Amount of extra Butter manufactured = 7.08 kgs.

Problem-6-  A butter sample contemning 16% water, 2.2% salt and 0.8% curd and manufactured from 110 kgs of fat with 2% churnning loss. Calculate the amount of butter manufactured and overrun  in butter sample.

Solution - Loss of fat during churning = 2/100X110 = 2.2Kgs

Amount of fat churned = 110 - 2.2 = 107.80Kgs

(Fat used for butter manufacture)

Fat % in butter = 100-(loss of fat during churning % + water % +salt% + curd)

Fat % in butter = 100-(2.2 +16.0+2.2+0.8)

Yield of butter = 100-21.2 = 78.8%

From 78.8Kg of  fat, the amount of butter manufactured = 100 kgs

From 107.8 kgs of fat, the amount of butter manufacture – 100/78.8 X 1.7.8 = 136.8 kgs

Yield of butter =        100 X Fat used for butter manufacturing                           

 Fat % in butter                                                                                                             

Yield of butter  = (100 X107.8)/78.8 = 10780/78.8 = 136.8 Kg.

% Overrun =          Kgs of Butter manufactured – Kgs of fat  churned   X 100

                                                     Kgs fat churned

% Overrun =           136.80 – 107.80/107.80 X 100

% Overrun =           2900/107.8 = 26.90

OR

Yield of butter = Fat in cream (Kgs) x (100 + OR%).

where  OR = Over run

Yield of butter = 107.80 x (100 +26.9)/100 = 136.80 Kg

Result -

1.  Amount of butter manufactured = 136.80 Kg

2. Overrun % in butter= 26.90

(B)  Estimation of Churning Losses

Problem 1- 850 kgs of butter containing 80% fat were produced them 2000kgs of cream with 3.5% fat. what & the percentage of  fat losses during churning.

Solution -  Weight of fat in cream- 35/100 X 2000 = 700Kgs

weight of fat in butter = 80/100 X850 = 680 Kgs

Losses of fat during churning process 700-680=20Kgs

hence percentage of fat loss  = 100/700 X 20 = 2.857

Result -  Fat losses during churning process is 2.857%

Adjusting of salt, content of butter.

Problem-2 900 Kgs of butter made with 80% fat. If butter containing 2% salt estimate the amount of salt required. If there is no loss of salt during butter working process.

Solution
A mount of salt per 100Kg of fat = % salt in butter/% of fat in butter X 100

                                                          =2/80 X100 = 2.5 Kg

Amount of fat in butter = 80/100 X 900 =720 Kg

Amount of salt needed = Amount of salt per 100 Kg fat /100  X  Amount of fat in butter

                                                                 =2.5 X720 /100  = 18 Kg

Result - Amount of salt added = 18 Kg

Adjusting the moisture content in butter.

Problem 3 – Churn contained 1150 Kg, cream containing 40 % fat, salted butter in churns indicate a moisture percentage of 15.5. The weight of butter milk is 650 Kg and tested 0.1% fat estimate the amount of water to be added to get 16% moisture in butter.

Solution – Weight of fat in Churn = 40/100 X 1150 = 460 Kg

Weight of fat in butter milk  = 0.1/100 X 650  = 0.65Kg

Fat in butter =460-0.65 =459.35

Weight of butter (Expected)  =  100 /100 - (Moisture % + MSNF % + Salt % ) X Fat in churns in kgs

Where,

                MSNF = Milk Solid – not fat

Assuming % M.S.N.F  &  2% Salt in butter

Wight of butter = 100 / 100-(16+1+2) X 459.35

                                      = 100 /81 X  459.35  = 567 .09

Required water = 16-15.5 /100 X 567.09

                                       = 0.5 X567.09/ 100 = 2.83 Kg.

Result – 2.83 Kg of water  will be required.

Reference

1.      Hunzikar, O.F (1940) The butter Industry 3^rd Edition.

2.     Jauhar (1989) Market Milk & Milk Products, Single Book Depot Baraut 1^st Edition.

3.     I CAR (1964) Milk products of India.

4.     Ahmed Tufail (1990). Dairy Plant Engineering & Management Kitab Mahal, Allahabad.

5.     Achya, K. and Rangapa, K.S. (1984) - The chemistry and manufacture of Indian Dairy product  2^nd Edition.

6.      Aneja, R.P., Mathur, B.N., Chandan, R.C and Benerjee AK (2002) Technology of Indian Milk Product. A Dairy India Publication, Delhi.

7.     Hari suresh - (1998) Dairy Science & Dairy Mgt. & Tech. Saroj Prakashan 647 katra Allahabad 1^st  editions.