Methods of Manufacture of Butter oil

The following methods are used for manufacture of butter oil.

•  Evaporation under vacuum.
•  Decantation of molten butter.
•  Centrifugal separation of butterfat followed by vacuum drying.
•  Direct from cream by de-emulsification and centrifugation.

First three methods make use of butter as raw material.

 

i. Evaporation of Butter under Vacuum

This is a batch process and carried out normally under vacuum. Molten butter is taken in a vacuum pan and boiled under vacuum until moisture is completely removed.SNF (residue) is subsequently removed by physical or mechanical methods. Neither the efficiency of the process nor product quality are satisfactory in this method.

 

ii. Decantation

It is like pre-stratification method of ghee making, i.e. butter is heated to about 80oC, left undisturbed for some time. This results in the formation of three layers,viz. top scum, middle fat and bottom serum. The top layer and bottom layers are discarded and middle fat layer is separated and used as Butter oil. Fat recovery is less, hence method is uneconomical, especially when employed on a large scale.

 

iii. Centrifugal Separation followed by Vacuum Drying

This is a continuous method and produces a product of high quality. Invariably butter oil is prepared by this method. Butter (unsalted) is dumped in the butter melter, which is a vertical jacketed stainless steel tank fitted with an agitator. Hard butter is cut into small pieces before heating.Then steam valve is opened and agitator is started. The temperature of water in tipping tank is adjusted to 77 – 79oC with the help of steam and hot water is allowed to pass through the oil separator. Subsequently molten butter is allowed to go to tipping tank and oil separator. The rate of flow is so adjusted that there is no overflowing. The melt is separated into oil and serum.

The oil flows into the float controlled balance tank and from there into the vacuum pan due to suction. Here it is heated at 56-63oC under a vacuum of 56-62 cm Hg.All the moisture is removed from all the oil at this stage. At the end of operation,the vacuum is released and butter oil allowed to flow by gravity into the receiving kettle for subsequent cooling, packaging and storage.

 

iv. Directly from Cream by De-emulsification and Centrifugal Separation

The process utilizes the principle of de-emulsification of cream used in various continuous butter making processes. De-emulsified fat may then be melted and clarified by centrifuging and vacuum heating.