The document summarizes a laboratory experiment where students extracted and quantified proteins from different types of milk. Students prepared milk samples using a dilution and phosphate buffered saline, added dye reagent and incubated the samples to develop color. They then used a spectrophotometer to measure absorbance and plotted a standard curve to calculate the protein concentration in their milk samples. The goal was to learn a new technique for quantifying proteins found in common foods.

1. University of Puerto Rico<br />Cayey Campus<br />Jessica Díaz Rivera<br />RISE Program<br />Cayey Campus<br />Paragraph 11: Got Protein<br /> In this laboratory we learned how to extract, quantify and purify proteins. Our objective was to calculate the quantity of proteins in a milk solution. Every pairs had two different types of milk. I had fat free powder milk and soy milk from which to extract the proteins. We had to prepare a dilution of the milk samples using 1X PBS. We labeled the cuvettes as follows: one blank, seven samples and two milks samples, each of them with different standards. After we put the dye reagent in each cuvette, we also added the 1X PBS and the standard solution. We had to cover each cuvette 3X to mix it with parafilm. Next, we incubated all the samples at room temperature for a period of 60 minutes. We then visually we compared the color of the unknown samples against the standards of the known concentrations. At the end, we read the samples in the spectrophotometer to calculate the absorbance. After the absorbance of the seven standards-were obtained, we had to create a standard curve by plotting the A595 values of the known standards on the y-axis versus the concentration in mg/ml on the x-axis. We did not use the standard number one because the preparation of the standard in the spectrophotometer gave us a negative value. At the end, we could compare the protein concentration of the standard curve and milk labels of the samples to see the quantity of protein. To conclude we learned a new technique to extract protein from common foods. <br />