Processing of butter - How it is made?

Butter- 

Fat separated from the cream 

1. Butter may be defined as a fat concentrate which is obtained by churning cream gathering the cat into a compact mass and then working on it.
2. According to PFA rule, there are certain specification for butter, 

• It should be free of animal fat, wax, mineral oil and vegetable oil. 
• There should be no preservative except salt (NaCl).
• Should not contain less than 80% fat.
• Not more than 1.5% curd. 
• Also NaCl not be used more than 3%.
• Diacetyl may be added but not more than 4 ppm, which gives the typical flavour. 
• In butter, some of the alkalines are added - Calcium Hydroxide, Sodium Bicarbonate.  

Various kind of butter -

1. Pasteurize cream butter
2. Ripened cream butter
3. Unripened cream butter
4. Salted butter
5. Unsalted butter
6. Sweet cream butter
7. Sour cream butter
8. Fresh butter
9. Cold storage butter
10. Dairy butter
11. Creamy butter

The standard composition of butter 

Butterfat - 80.2%

Moisture - 16.3%

Salt - 2.5%

Curd - 1% 

Fat-soluble vitamins - Vit- A, D & K

Method of Manufacturing 

Important points- 

1. Grading of cream based on the quality of cream- 

• 1-grade cream is sweet cream and slightly sour.
• 2-grade cream is sour and coagulated. 
• 3-grade cream is rejected, quite fermented.

    2. Testing - cream is tested for fat, SNF and acidity. 

    3. Preheating - to increase the efficiency of the operation. 

    4. Ripening - Addition of starter culture for fermentation, to enhance the flavour and lesser fat loss in the serum. It is ripened by the starter culture that is streptococcus lactis and Streptococcus cremoris. Some more microorganisms are known as aroma producer- 

• Streptococcus diacetylactis
• Leuconostoc citrovorum
• Leuconostoc dextranium

1. These microorganisms produce diacetyl which gives the typical aroma.
2. Inoculated at 21°C for 15-16 hours.
3. Acetic acid or propionic acid also gives some flavour.
4. Set range for standard diacetyl content is 0.2 to 0.6 ppm gives a mild flavour to butter.
5. More than 2.55 ppm and 4 ppm rise in butter could be rejected. 
6. Mother substance from which diacetyl is produced are acetyl, methyl and sometimes citric acid is added before fermentation.  

Churning - 

Separation of fat from cream. Agitation of cream at a suitable temperature until the fat globule adheres to forming a larger and larger masses until the complete separation of fat and serum occur.

• Cream in a form of emulsion - stable in nature
• fat - skim milk emulsion 
• churning breaking out the stability of fat and milk 

Force for making stable

Surface Tension - 

- Cream and fat globule retain their individuality

- Prevent butter formation 

Phenomena of adsorption - 

- Fat globule in milk or cream, they are in a layer which is phospholipid layer. 

- This membrane resists de - emulsification 

- Adsorb at the surface of fat globule

- They make the charge stabilize. 

Electric Charge - 

- Fat globules are negatively charged. 

- result all of them repel each other.

Viscosity - 

- higher the viscosity more stable is an emulsion 

- Resist Churning 

During the churning, the temperature is above the melting point of the fat 31-38°C. Agitation results in the subdivision of fat and serum.

Churning operation - 

1. It starts with the preparing of churning by cleaning, sanitization and deals with all the types of pre-treatment.
2. Filling cream into the churn, slightly above the capacity. 
3. Addition of butter colour- carotene and annatto, 250 ml of colour is added to 100 kg of butter. 
4. Operation of churning - 

• Initial rotation (5-10 times)
• liberate any gas present in the cream. 
• the rise in temperature of 1-3 °C of the cream
• Foaming
• addition of water to lower the temperature
• after the foaming, breaking stage occurs when the cream breaks away, the formation of butter grains of pea-size.
• Churning is stooped and fat is collected
• washing of butter - to remove every adhering particle of serum or buttermilk.

The procedure of washing - 

Buttermilk is drained, then water is added to butter which has the temperature 1-2 °C lower than churned butter, the amount is equal to the amount of buttermilk separated from fat. Then churned is again switched on after few rotations then water is drained out. Washing is followed by salting and working (kneading of butter)

Reason for adding salt - 

• To improve the keeping quality 
• to enhance the taste 
• to increase the overrun 
• Salt must not be exceeded to 2-2.5%, maximum 3%. 

The objective of kneading or working - 

1. To complete dissolve, uniformly distribution and properly incorporate the salt. 
   To expel the buttermilk and to control the moisture content of the butter.
2. To bring the butter raise together into the compact mass, convenient to handling and packaging.

Packaging of butter - 

Packaging material for butter should have excellent barrier properties such as

· It should be moisture-proof

· It should be greaseproof

· It should be impervious to light

· It should have good strength (to prevent tampering during transportation etc.).

Some of the packaging materials used for butter packaging are

i) Parchment paper – also known as butter paper.

ii) wax-coated paper

iii) cellophane

iv) cardboard boxes and teak wood drums lined with food-grade plastic

v) Aluminium foil laminates

vi) Lacquered tin cans (it is costly but is advantageous in tropical countries and prevents de-shaping during storage and transportation.)

Techniques of packaging

1. Manual moulding and wrapping

2. Mechanical moulding and hand wrapping

3. Fully automatic units which mechanically moulds, patts and wraps. It reduces labour cost, handling losses and is suitable for large scale operation. The machine can be reset for different size viz. 10, 15, 100, 250 and 500g. Some of the well-known brands of fully automatic butter packaging machines are Kustner, Benhill (both are German) and SIG (Swiss). In these machines, after wrapping, the pat goes to carton machine for packing in card boxes and transferred to cold storages (5°C) for 24-48 h and then shifted to low-temperature storage (-23 to -29°C).

Storage of Butter

For the sake of consistency and appearance, butter should be placed in cold store as soon as possible after wrapping and should be chilled to 4°C for 24 to 48 h. Unless this is done, fat crystallization is very gradual and the butter retains its freshly churned consistency and appearance for several days. However, once it has been sufficiently chilled, a subsequent rise in temperature will not make it as soft as it would have been at the same temperature prior to its chilling. The initial freshly churned, somewhat ointment like consistency is transformed to that typical for butter. This change is known as the setting of butter. The butter cannot be considered finished until it has been chilled or set. A low storage temperature also improves its keeping quality and reduces the risk of the package being deformed.

As butter is essentially a perishable product it should not be stored longer than necessary. However, when production exceeds demand and also quite often to level out the fluctuation between high flush season production and low summer production, storage of butter becomes unavoidable. For a short period, butter can be stored at about 4°C but if longer storage is involved it must be deep-frozen at -23°C and only best quality butter should be selected for deep freezing. Since the solubility of salt is low (35.7% at 0°C), some salt crystallization may occur during storage but the crystals re-dissolve on thawing.