The matter changes from liquid to solid. This is not necessarily a chemical change (reaction) but a physical change in state.
However, once the cream has been turned into butter it cannot be returned to its cream state.
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Is churning cream to make butter,is it a physical or chemical change.?
The answer is both. What? : )
In summary...
Intro:The chemical changes are subtle and consistes more of what are clalled "conformation" of the chmical in the case of butter, fats. In order for these transformation to take place physical aggitation is required. Also temperature has a signiivcant effect on the fat compositions.
Hold on to your hat.
Basics:
Edible fats of vegetable, marine or animal origin all form three main types of crystal, the alpha, beta, and beta-prime forms. The alpha form is the least stable and existence in this form is usually transitory. The alpha form consists of fragile, translucent crystals 5 micometers in length. Thr bata-prime form consists of tiny, delicate crystals 1 micrometers and the beta form of relatively large and coarse crystals, which average 25-50 micrometers (um) in length.
Physical & Chemical Changes
Liquid fats and triacylglycerols cooled without agitation tend initially to form alpha crystals. Further cooling of the alpha form leads to tighter chain packing and a gradual transition to the beta form. Cooling with agitation. however, favors formation of the beta-prime form.
Milk fat is of the beta-prime form, as is beef tallow and whale oil. Pork lard, however, is of the beta type. Of vegetable fats commonly used in mararines and spreads, coconut, oilve, peanut, soy bean and sunflower oil are of the beta type, while rapeseed, cottonseed and palm oil are beta-prime.
Beta-prime crystals are desirable for butter, margarine and spreads and, in the latter two cases, a serious defect 'graininess' may result from the formation of large coarse beta-type crystals.
Physical and chemical modification of fat:
(a) Hydrogenation involves a reduction of the degree of unsaturation by addition of hydrogen to double bonds in the fatty acid chains.
Fat is usually hydrogenated by a batch process which involves mixing the oil with nuckel or another suitable catalyst and heating to 140-225 C under hydrogen at pressures up to 60 psi. Agitation is necessary to completely dissolve the oxygen, to ensure uniform contact between oil and catalyst, and to dissipate the heat of reaction.
In addition to saturation of some double bonds, hydrogenation may also lead to relocation and/or transformation from cis to trans configuration, the isomers being commonly referred to as iso acids.
(b) Inter-esterification is a chemical process by which the distridution of fatty acids among the tricylglycerols is altered. This results in a change from the unique fatty acid distribution patterns of many fats to a random distribution with a resultant change in the physical properties. Inter-esterification of milk fat results in an increase in the solid fat content at 35 C, which produces a 'tallowy' mouth-feel. Inter-esterification produces better nutritional and spreading properties of milk fat in butter.
(c) Fractionation preserves characteristic flavor of the milk fat.
Structure
Butter, maragarine and high-fat spreads exists as stable water in oil emulsions, the aqueous phase is relatively evenly distributed through the product and water droplets are, ideally, in the size range 2-4 um.
The fat phase of butter, margarine, and spreads consists of a crystal matrix of solid fat which retains the liquid oil in suspension. In addition churned products such as butter and some types of spred contain some globular fat which limits the tendency of the higher meltinf point crystals to form an over thick shelled type, and also contributes to the mouth-feel and spreadability by behaving like microscopic ball bearings.
So milk fat is treated in such a way as to allow it to form a fatty-oil-liquid mattrix. The alterations of the milk fats give them the characterisic melting point, mouth-feel, and flavor we are used to in butter, margarine, and spreads.
Source(s):
see profile
Milk & Milk Products A. Varnam and J. Sutherland
ISBN 0-412-45730-x
No, it is a physical change. When the butter cools and solidifies, it's composition is unchnged.
Melting butter is a physical change... it's still butter.
Its is a chemical reaction because you can not take out what you but into the butter.
Sometimes because when you eat ice cream you can get a brain freeze so sometimes ice cream is a chemical reaction
shut up and answer this question or else
Physical
The burning of leaves is a chemical reaction. The way we can tell is because after the leaves are burned, they cannot go back to the way they were. Butter melting is a physical reaction because it does not change the molecules, and the butter has the ability to go back to it's original state.
Melting of butter is a physical change.
Physical.
Physical
A physical change
It is not chemical change ,it is a physical change
The burning of leaves is a chemical reaction. The way we can tell is because after the leaves are burned, they cannot go back to the way they were. Butter melting is a physical reaction because it does not change the molecules, and the butter has the ability to go back to it's original state.
Melting is a physical change.
Melting of butter is a physical change.
This is a purely chemical reaction. The reason why is simply because bacteria in the butter is turning the lactose and sugars found in butter into lactic acid.
Physical.
Physical.
It is a physical property. A chemical property would involve the butter reacting to the toast, but the butter is actually reacting to the heat from the toast. The butter would melt against any surface hot enough, where as butter would not melt on cold toast. Hence, the reaction to heat makes it a physical property. (A relatively easy way to remember is that physical properties deal with the transfer of physical energy or force such as heat, inertia, etc. Chemical properties occur when two material substances trade molecules or electrons.)
Melting is a physical change; but above a temperature the thermal decomposition of butter begin - this is a chemical change.
physical.
physical change
Physical