Le intermission,
Before we delves more into the realm of fat and lipid, there are certain terms that you should know. People in the food industry used this term very much. Even those whom had worked as a frier in a fast food restaurant can recognized these term. (KFC worker should recognize some of these term)
Note that, all of these term are related to the type of fatty acids present in the Triglycerides (TAG), their location (middle? end? remember, TAG is consist of 3 fatty acid), chain length of the fatty acid and many more(I wrote the only one I've touched in previous post, there many more characteristic that affect all of these term) So, enough chat and let's get started shall we?
MELTING POINT
Fat and oil had melting point? Well, in this case, only fats are involve; saturated fats are solid in room temperature, like butter and margarine. It usually covers a wide range of temperature and the point where the fat melts. Let's take an example, suppose there are 2 butter; brand A & B. A melts at 30'C but B at 40'C, the different in melting point still exist even they are the same thing. The reason is because both butter have different composition of TAG. Among the fatty acids, the melting point increases with chain length. So, if the the type of TAG consists of 3 Arachidic acid (C20), and the other TAG consist of 3 Palmitic acid (C16); the butter with 3 Arachidic acid will have higher melting point.
SPECIFIC HEAT
if you study science, I'm sure you're know this. It is defined as the quantity of heat (yes, heat can be measured, Let's just say, it is measured in terms of Joules, where the energy is almost equivalent to the watt in electricity appliance, (joule=organic, watt=inorganic) If you want to know how, I suggest you've study thermodynamics in physics) required for a 1'C to increase in a unit weight of fat. In layman term; the energy needed to increase heat by 1'C. for most fatty acid, the specific heat depend on the unsaturation of it chain. The more unsaturated the fat/oil, the higher the specific heat . So in this case, the specific acid of oil is higher than fat. To make it sound simple, it easier to fry a butter than to heat an cooking oil.
SMOKE POINT
it is the temperature point where the fat/oil started to produce smoke ( just like it's name). Well you can see this if you continuously use the same cooking oil.Let say, you use the same oil to fried 70 chicken. However, after certain time, the oil started to produce smoked. if you could find a thermometer (I'm just kidding, you can't use thermometer, the mercury will instantly fly of the roof; It's very hot) the temperature recorded is the smoke point. In other meaning, you should change the oil. The oil which had reached smoke point is hazardrous. This because certain change had occur in the composition of oil, where there is bound that certain Acrylamide (A carcinogenic (cancer inducing) substance) had formed. If you want cancer in several years, by all mean, continue the cooking. :)
FLASH POINT
It is the temperature where the fat/oil can ignited a fire. Well, yes, oil can ignite fire IF YOU PUT A FIRE IN IT! as in this case, by HEATING (not put fire on it) to certain temperature, the oil can start a fire by itself. So if you want to produce Acrylamide, better watch out for Flash point, or all your work are in vain :)
CLOUD POINT
It is the temperature at which the fat/oil (mostly oil) turn cloudy. The cloudy in this case meant the start of crystallization of liquid fat/oil. In Malaysia, once done cooking, just leave the pan as it is. by 1 day, I believe the oil should have solidified and had a cloudy colour on it. Well, for those living in a cool climate, I dunno. But I guess you see these more than we (those who live in a tropical climate ) do.
POLYMORPHISM
It is defined as the existence of a substance in 2 or more form. The differences between form arise due to many form of molecular packing in a crystal structure. Like I said in the previous post (or have I?), the fat/oil does not only consist of 1 type of TAG. It consists of several TAG which have different type of fatty acid attached to them. To make matter worse, A TAG with same type of fatty acid attached but different arrangement DOES NOT COUNT AS THE SAME TAG. So, what use is polymorphism anyway? well, in analyzing a fat/oil, the reading could give many melting point (If you use Differential Scanning Calorimetry (DSC) you understand this) The many melting point is due to these TAG will did turn crystal (solidify) but each structure is not the same as the other. Thus, these crystal will had their own melting point and when analyze it give the number of melting point correspond to the number of tag it had. Just like that. :)So, these are the term you should know. there are actually more term, there are even that I didn't know. However, the answer is the same, if you want to know more, please look it on the web. :)
This is for now, see you in chapter 2. :)
I'ts getting harder to post in blog nowadays, however I insist on continuing it. Please check the blog on weekends, as I will most probably post at these time. Thank you for reading and please subscribe!
Adieu.
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