November 19th, 2024 By: Dr. Allison Henry
The Lab
For my first job shadow, I was able to attend one of Dr. Allsion Henry’s food science labs. This lab was centered around the concept of extracting milk protein. The objective of this lab was to demonstrate the precipitation of protein from milk with the introduction of acid. For this they used vinegar. They also wanted to test the effectiveness of casein as a bonding agent to make a casein glue.
The students first had to extract the casein from the milk. They heated the milk using a Bunsen burner and then added one teaspoon of vinegar. Immediately after the addition of the vinegar, they had to continuously stir it for two minutes. This allowed for the casein to develop into a curd-like substance. The remaining liquid in thier beaker was the whey protein. They then strained the curds using a cheesecloth. Once strained, they add ammonia as an irritant to almost liquify the curds. The leftover substance was what they used as an adhesive in the next step of the lab.
Once they had created their adhesive, they were tasked with building a structure out of wooden popsicle sticks. These structures would then be judged by an unbiased judge and the winner would receive five bonus points on thier previous test. Throughout the lab, I noticed that some groups were having issues with the structural aspects of thier buildings. The adhesive was not as strong as regular glue and took an extensive amount of time to dry. Therefore, some projects crumbled under thier own weight. However, at the conclusion of this lab, there were some outstanding products. My favorite building was the one designed by two biochemical majors, they built a rural scene. Depicting two windmills and some cows. I thought that this was very creative and the little cows were adorable!
What I Learned
During this lab, I learned that standard milk is composed of two main proteins; casein and whey protein. Casein is considered relatively digestible when compared to other ingested food proteins, this makes it imperative to human food. Casein is negatively charged when it is in its natural state. This negative charge permits the casein to disperse within the milk. Therefore, when you add acid to it, such as vinegar, the H+ neutralizes the negatively charged casein. So when they acidified the milk, the pH was allowed to reach 4.6, which brought the casein to its isoelectric point. This allowed for the casein to precipitate as curds. This acid casein is the basis of the manufacturing of cottage cheese and cream cheese. It can also be used in the chemical industry; in the production of adhesion products, textiles, and cosmetics; and as a binding agent in food products.
What I Enjoyed
This lab taught me about the components of milk and the development of many differing dairy products. I thought it was very interesting to see how milk can be turned into a glue-like substance. I thoroughly enjoyed being able to sit in on a college lecture, it was very educational! I cannot wait to be a part of these labs soon. It was such a dream and a delight to spend my afternoon with Dr. Henry and her class! I cannot wait to go back.
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