Milk Lab

 What's this "milk" lab all about?

Well we are glad you asked, the purpose of the milk lab was to determine the percentage of protein in Prairie Farms non-fat milk. Once this percentage was determined, it was compared to the percentage found on the Prairie Farms milk carton.  The lab dealt with the denaturing of proteins due to the dramatic change in the pH level of milk.

Day 1.. The Cooler than Absolute Zero crew takes on the "super sexy" milk lab.

First, as all.. Super responsible, A.P students; we read through the procedure at home before the lab.

Next, we began to go through the lab procedures which were written on our worksheet; along with writing in our collected data in the table provided. 

In these pictures, we are massing out the milk and adding in acetic acid to denature the milk, resulting in curds forming.

Fun fact #1: Milk curdles when acid is introduced into the milk which causes the milk to drop in pH levels and that puts the milk into a state of denaturalization. Thus causing proteins to lump together.

After, we let the milk sit for 5 minutes.. (Tick.. Tock.. Tick.. Tock) & then filtered it through.

(Of course, we did this part twice because our filter paper broke the first time.. And just our luck!)

ALERT! ALERT! ALERT! RANDOM TANGENT ON THE WAY! ALERT! ALERT!

 During this 5 minute wait... Our super awesome, A.P Biology teacher was giving a speech; we decided to photograph this for memory. (We are still waiting on that autograph, Filipek!)

Next, after.. That nerdy distraction; we added Biuret Reagent to distilled water and our failed-filtered milk... (In normal people words, it basically tests the protein presents in a substance).

When a protein is present, it turns a purplish, blue color! As seen above :) (In this case, protein is present in the milk!)

Fun Fact #2: Yogurt is made by fermenting bacteria in milk, allowing the bacteria to churn out lactic acid which helps give yogurt its creamy texture. If you heated fresh milk and left it at 100 degrees Fahrenheit for a few hours, it would turn into yogurt.


Day 2..... Continuation of the "super sexy" milk lab.

After the grueling first day.. We simply massed the filtered paper and calculated all of our data! 

Fun Fact #3: Casein is a phosphoprotein commonly found in mammalian milk. It plays a major role in cheese, is a binder for the end of safety matches, and is responsible for giving us so many important Nutrients.

                                                           Data

Da

Here is the data we collected during our milk lab. As you can see, we had to find the mass of the filter paper, both the filter paper and dry protein, and the dry protein alone. As you can see in the picture above, our group found two sets of numbers. This is because we had a mishap and tore our first filter paper, which destroyed the hole filtering process. To clear an confusion, our data chart has a mass of our first filter paper which is labeled under the column "reg", and the mass for our second filter are under the "coffee" column.  To make our data a bit more accurate, we decide to add up both masses and put it under the column titled, "total". With our results, we recorded less protein in the milk than what we said to be on the carton. Our percent error was -70.31% due to a couple different factors. The first time we tried filtering the milk, we punched a hole through the filter, letting most of both; the liquid milk and solid protein through. We left this filter aside to dry and record the mass of protein. What we did, was take all of what went through the first filter and put it through a second one. This time we used a coffee filter (look at us, stepping up our game. Come at us, bro.. #sorrynotsorry). Using test tube tongs, we squeezed what was in the filter as a way to quicken how much liquid was filtered at one time. This was successful for a decent amount of time until the filter paper gave out once more, and broke. (Just our luck..) This time, less of the milk spilled out of the paper. We did the same thing that we did the first filter, and massed it. Altogether, we massed .74grams of protein, a significant difference in the amount shown on the carton. This was due to the filter paper breaking, and therefore; our results are not valid. 

Conclusion

So, at the end of all this.. We, as a team, concluded that the carton containing milk had more proteins than the milk we made. Our team's milk contained only 4.75% of protein, which is equal to .74grams. The Priaire Farms milk contained 16% of protein which is a huge difference compared to our results. We do have a wicked, totally awesome.. super nerdy explanation for this! We accidentally poked a huge hole in the filter paper. (Ivan's fault; yes I am throwing you under the bus.. JK, we love you tie-guy) This definitely created some, tiny error in our experiment. This incident is most likely going to cause our collected data to be inaccurate, but hey; we tried our best!

Works cited

<"Casein." Wikipedia. Wikimedia Foundation, 22 Sept. 2014. Web. 22 Sept. 2014.
http://en.wikipedia.org/wiki/Casein>

<"A Quick Guide to Yogurt Preparation and Variations." About. N.p., n.d. Web. 22 Sept. 2014."
http://homecooking.about.com/od/cookingfaqs/f/faqyogurt.htm>

<"Why Does Milk Curdle -- and When Is It a Good Thing?" About. N.p., n.d. Web. 22 Sept. 2014.

foodreference.about.com/od/dairy/a/why-does-milk-curdle.htm>