Got Milk?

The dairy industry today is one of the largest industries in the world.  The milk industry produces $21 billion a year.  Milk can then be transformed into a variety of different products that range from ice-cream to cottage cheese and everything in between.  Milk is also made up of mostly water.  However, there is also fat, proteins, lactose and other minerals floating around as well.  Both the readings and the class discussion touched upon the two proteins that make up milk, casein and whey.

Nowadays, many cows are constantly pumped with different antibiotics for various reasons.  The most common is rbST or recombinant bovine somatropin.  Some people see this as controversial, thus the FDA conducted a study and concluded that there is no difference in milk from rbST treated cows vs. non-treated cows.  Now, who am I to say which one is healthier or tastes better?  That is up for your interpretation!

It is important to note the two types of ways that the FDA ensures that the milk is safe for the public.  The first is pasteurization.  Simply put, it is heating the milk until all the dangerous alive stuff is now dead and not dangerous.  Adding a little bit more complexity entails the preservation of milk by killing pathogenic microbes by inactivating certain milk enzymes.  The second major way is through homogenization.  This is just the funneling of milk through smaller nozzles to break apart the fat globules that are in the milk.  This aides the process of keeping the milk the proper consistency.  Simply put, it makes sure the fat within the milk is evenly distributed.

Moreover, we talked about all the amino acids and the different intra-molecular forces that keep proteins from denaturing under normal circumstances.  The three main ones that we touched upon in class were; Hydrogen bonding, “pie-stacking”, and disulfide bonds.  Disulfide bonds are by far the strongest bonds.  They are commonly seen in bread.  Another fun fact about amino acids is that proline, which is categorized as a small amino acid, is very rigid due to its ring.  Thus, it cannot be involved in any alpha-helices and is most commonly found in gelatin.

img_0049Now for the fun stuff!  The heating of milk! I know it doesn’t sound like the most excited thing but don’t worry well get there.  Heating milk is how someone makes cottage cheese.  Cheese curds!  The heating separates the whey protein and curds.  The picture on the left shows the result for this reaction.  Now obviously the first part of this is to pour milk into a pot and turn the heat on.  Simple, right?  Then you just wait ad drain at the end and you have cheese curds and whey! All my life I always thought that whey was a solid  A lot of protein supplements advertise “Pure Whey Protein” and when you get the protein its solid.  So, without asking questions I just assumed that it was solid.  Sadly, I was mistaken.  Don’t believe everything you see on the internet! Except for this blog! 100% facts.

Another misconception I had was that the only way to make butter was to churn it.  Again, sadly mistaken.  We made butter in a mason jar.  Yes, you read that correctly.  Agitating the butter in the mason jar allows the fat globules to coagulate and form a solid.  That solid is butter.  Emulsifiers hold the fat globules together.  They have a hydrophilic end and a hydrophobic end.  The hydrophilic ends are water soluble while the hydrophobic ends are fat soluble.  Using the same chemistry, we also made butter in a kitchen aid!  Now this was not as much as a workout as making butter with a major jar but ended up producing the same product.

 

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The last and final experiment that we did was heating butter!  The butter was introduced to the heat and was stirred continuously for about 10-15 minuets.  The butter turned from solid to liquid and then back to solid!  The water in the butter evaporated and we were left with the butterfat, milk solids and lactose. Now, when we continued to heat up the now butterfat, milk solids and lactose the sugar begins to turn color and brown.  Similar to the caramelization’s that we did last week that Jack told you all about.  Besides making butter in a mason jar, which really shook me up, I thought this was the coolest reaction of the day.  I especially liked how it brought us back to the last class because it doesn’t matter how food starts, once you break it back down to one of the basic 4 food groups, everything remains constant.  Finally, to end the day, the class got to enjoy a variety of different cheeses that all had something special about them.  By the way, did you know that cheddar cheese came from the town of Cheddar, England?  That’s our fun fact of the day.  Thanks for tuning in to our class blog and be sure to stop by again next week to learn more about meats!

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