Butter Oil - Overview
Butter oil is light, yellow-colored and has a clean bland taste. It is a dairy product which is created by removing the water content and the nonfat milk solids contained in butter. It consists more or less of milk fat and it is the purest form of milk fat product. Although butter oil is a modern industrial product, it has ancient traditional roots in some cultures.
Butter fat in milk consist of various types of fat lipids, each fraction unique in nature and having a separate melting point. The main fraction consists of triglycerides of fatty acids. The melting point for milk fat is 37oC ; Butter oil starts to convert in solid form at temperatures of less than 17oC.
Butter oil is an excellent form of storage and transportation of butter fat because it occupies less space than butter, which was a traditional form of storage for butter fat. Butter oil is typically packed with an inert gas, Nitrogen (N2), and can be stored for several months, in this case storage temperature has to be maintained up to 25oC to increase its shelf life. Butter oil is convenient to use in liquid form because it is easy to mix with food recipes, formulas and other products and it is used for recombination of various dairy products, but are also used in chocolate and ice cream manufacturing industries.
Butter oil can be produced by two methods, in a continuous flow direct from cream or via butter. The quality of butter oil mainly depends on the quality of raw material and there should be no difference whichever method is chosen. If for any reason, the respective qualities of cream and butter should be considered not good enough; there are some means to recover the same by polishing (washing) the oil or neutralizing it before the final evaporation step passed. The way to perform either of those operations is discussed below under refining.
a. Butter oil from cream
Pasteurized or non-pasteurized cream of 35% to 40% fat content enters the plant via balance tank, flowing towards the plate heat exchanger to balance the temperature or pasteurization to the centrifuge for pre-concentration of the fat to about 75% (the temperature at pre-concentration and downstream to the plate heat exchanger for to maintain temperature up to 60°C ). The light phase is collected in a butter tank to await for further processing while the heavy phase, typically called butter milk, can be passed through a separator for recovery of fat which will then be mixed with incoming cream. The skim milk goes back to the plate heat exchanger to balance the temperature and thence to a storage tank.
After the intermediate storage tank the cream concentrate is fed to a homogeniser for phase inversion, after which it passes through the final concentrator. As the homogeniser operates at a lightly heavier capacity than the final concentrator, the surplus product not caught by the concetrator is recirculated to the buffer tank. Part of the mechanical energy used in the homogenization process is converted into heat to avoid disturbing the temperature cycle of the plant, this surplus heat is removed in the cooler.
Finally the oil, consisting of some 99.5% fat is preheated to 95-98°C in plate heat exchanger and routed into the vacuum chamber to obtain a moisture content not exceeding 0.1%, after which the oil is cooled to 35 to 40°C , the typical packing temperature.
b. Butter oil from butter
Butter oil is also produced from butter, especially butter that is not expected to be used within a reasonable period of time. It has been found by experience that there may be some difficulties in achieving a completely bright oil after the last concentration step when newly manufactured butter is starting material because the oil tends to be impaired by sight cloudiness. This phenomenon does not occur with the butter that has been stored for two weeks or more.
The image beside shows butter from boxes which have been stored for some period of time. The raw material may also be frozen butter stored at 25°C, After having been stripped of the boxes, the butter is melted by indirect steaming in equipment of various kinds. Before the final concentration starts, the temperature of melted butter should have reached 60°C.
After melting and heating the hot product is pumped to a holding tank where it may be held for a certain period of time, 20-30 min primary to ensure complete melting but also for protein to aggregate.
From the holding tank the product is pumped to the final concentrator, after which light phase, containing 99.5% fat, proceeds to a plate heat exchanger for heating to 90-95°C, thence to vacuum vessel and finally back to plate heat exchanger for cooling to packing temperature of 35 to 40°C.
The heavy phase can be pumped into tank for buttermilk or into a waste collection tank, depending on whether it is pure or contaminated with neutralizer.
The Uses of Butter Oil
Baking & Dairy Industry
Butter oil is mainly used in the dairy products industry due to its light yellow color, free from sour and bitter taste. Due to its good flavor, it is mixed with milk powder to produce liquid milk and other milk products. In baking industry , butter oil is applied to cracked surfaces to increase gloss and appearance. It is also used in the chocolate manufacturing industry due to its shelf life, aroma and flavor.
Pastry & Confectionery Industry
Butter oil is used to increase puff for pastries and pie shell. It is also used for aroma and flavor enhancement. In chocolate and candy industry it is used to control fat bloom. The main advantage of butter oil is, it melts easily, and it can be pumped and mixed with other food ingredients. The lipolyzed form of butter oil is used to produce a concentrated root of creamy and buttery flavor which is used in bakery, low-fat and low-calorie caramel food products. Powders of spray-dried butter oil is mixed with sugar or flour and used as a food component during baking, confectionery and ice cream production.
Food Product Substitutes
Butter oil is also used as a substitute in various food products. For example, in the high melting fractions it is used as cocoa butter substitutes or as a replacement for specialty baked goods such as bread pastry. Also, the low-melting fractions with a concentration of flavors, vitamins and pigments could be used for production of a soft butter, spreadable at refrigerator temperatures.
|Common Name||Butter Oil|
|Synonyms||Anhydrous milk fat|
|Appearance||Pale yellowish liquid|
|Free Fatty Acid||%||0.3 (max)|
|Peroxide Value||mg/kg||0.2 (max)|