Cheese Lab

In this lab, we asked the question: what are the optimal conditions and curdling agents for making cheese? We found that warm and acidic conditions are optimal and chymosin is the best curdling agent. Chymosin, rennin, and buttermilk all curdled the milk in five minutes or less in a more acidic environment. Chymosin and rennin showed some signs of curdling in five minutes or less in the heat. Nothing curdled in a colder environment within the time we had. Chymosin was the only enzyme that curdled the milk within the time we had with a time of 20 minutes in a more basic environment. The warm and acidic conditions had the fastest times for all the different enzymes. Since chymosin curdled the milk in almost every condition except the cold, it was the optimal curdling agent. While rennin still curdled milk a little quicker in the pH control, we decided chymosin was better because it curdled the milk in more conditions.

While our hypothesis was supported by our data, there could have been errors due to timing and the control/heat. There could be errors due to timing because our instructions told us to check for curds every five minutes. However, the curds could have appeared after four or even three minutes. So while the data says that milk with chymosin, rennin, or buttermilk under acidic conditions curdled in exactly five minutes, the times could actually be quicker. Another was with the control because the temperature of everyone’s armpit could be different. Some people had jackets on and some did not. This could have an effect on the curdling time as well, because as we can see, warm conditions are better for the reactions to happen. Everyone has a slightly different body temperature, so the cooler people would have slower reactions, and the warmer people would have faster reactions. Due to these errors, in future experiments I would recommend two changes. One, check the curds every minute instead of every five minutes. This will reduce the margin of error. Two, put the mixtures in an environment with a similar temperature to the human body, but make all of them exactly the same temperature.

This lab was done to demonstrate how enzymes work at their best when they are in favorable pH and temperature conditions. From this lab I learned that enzymes work best in certain conditions and not very well in others, which helps me understand the concept of denaturation and activation energy. Based on my experience from this lab, I will be able to change the conditions if I want a reaction with an enzyme to occur faster.

Curdling Agent:	chymosin	rennin	buttermilk	milk (control)
Acid	5	5	5
Base	20
pH control	15	10
Cold
Hot	5	5
Temp control	10	10