Lab: Isolation Of Casein
Leah Romero
04/18/2018
Lab 9 Conclusion
Chem. 102L For lab 9, isolation of casein, the main purpose was to take the milk sample that was provided in the lab and through the addition of acid, be able to find the pH of the milk at the isoelectric point of casein. Isoelectric point is the pH at which a particular molecule carries no net electrical charge. The main points of the lab or the outcomes we were looking for were to be able to look at the properties of proteins in casein and be able to identify them properly. Another main point was to be able to explain and use the principles of protein isolation that is learned in this lab. The mass of the Casein will be measured and the amount of it in the milk sample provided will be calculated out. …show more content…
The results of the milk provided in the lab and the milk at my house showed a slight difference in results. For the milk sample that was given in the lab, the mass of beaker was 1.82g. The mass of the beaker plus the milk was 10.5g, which this makes the mass of the milk 8.33g. The pH of milk pre-acid was 8. The pH of milk post-acid was 3. The mass of the filer paper was 1.20g. The mass of the filter paper plus casein was 6.32g, which means the mass of the casein was 5.12g. The percentage of casein in the milk was calculated out by the equation mass of casein/ mass of milk sample × 100. The percentage that was calculated out 61%. For the optional milk sample, the milk that was used was whole milk, meadow gold. The mass of the beaker was 1.81g. The mass of the beaker plus the milk was 10.42g. The mass of the milk was 8.61g. The pH of milk pre-acid was 7. The pH of milk post-acid was 2. The mass of the filer paper was …show more content…
Milk is one of the main sources of our protein. Casein is the most prevalent protein in mammalian milks according to the background information found in this lab. In a cow’s milk, 80% of it is casein and the other 20% is whey. Whey is what makes the milk watery, it’s the remaining substance after the curds have formed. Casein is milks base and it is soluble in water, but very poorly. Since it is poorly soluble in water, this could cause the dry milk to not have as much protein present when being mixed with water. This could be why when comparing the two milks, the liquid milk had more protein present. If you ever look at milk that has been sitting in the fridge and some was left on the wall of the jug and there is little white pieces that is casein. The protein formed micelles in the lab due to it being negatively attracted to water. When seeing these little bubbles, I quit adding the acid (vinegar) and took the pH level. In this lab the chemical property that was used was the change the pH of the milk for both of the milks. Acetic acid (vinegar) was used to reach the isoelectric point. The chemical property that played a huge role in this was the acid changed the pH can disrupted the
04/18/2018
Lab 9 Conclusion
Chem. 102L For lab 9, isolation of casein, the main purpose was to take the milk sample that was provided in the lab and through the addition of acid, be able to find the pH of the milk at the isoelectric point of casein. Isoelectric point is the pH at which a particular molecule carries no net electrical charge. The main points of the lab or the outcomes we were looking for were to be able to look at the properties of proteins in casein and be able to identify them properly. Another main point was to be able to explain and use the principles of protein isolation that is learned in this lab. The mass of the Casein will be measured and the amount of it in the milk sample provided will be calculated out. …show more content…
The results of the milk provided in the lab and the milk at my house showed a slight difference in results. For the milk sample that was given in the lab, the mass of beaker was 1.82g. The mass of the beaker plus the milk was 10.5g, which this makes the mass of the milk 8.33g. The pH of milk pre-acid was 8. The pH of milk post-acid was 3. The mass of the filer paper was 1.20g. The mass of the filter paper plus casein was 6.32g, which means the mass of the casein was 5.12g. The percentage of casein in the milk was calculated out by the equation mass of casein/ mass of milk sample × 100. The percentage that was calculated out 61%. For the optional milk sample, the milk that was used was whole milk, meadow gold. The mass of the beaker was 1.81g. The mass of the beaker plus the milk was 10.42g. The mass of the milk was 8.61g. The pH of milk pre-acid was 7. The pH of milk post-acid was 2. The mass of the filer paper was …show more content…
Milk is one of the main sources of our protein. Casein is the most prevalent protein in mammalian milks according to the background information found in this lab. In a cow’s milk, 80% of it is casein and the other 20% is whey. Whey is what makes the milk watery, it’s the remaining substance after the curds have formed. Casein is milks base and it is soluble in water, but very poorly. Since it is poorly soluble in water, this could cause the dry milk to not have as much protein present when being mixed with water. This could be why when comparing the two milks, the liquid milk had more protein present. If you ever look at milk that has been sitting in the fridge and some was left on the wall of the jug and there is little white pieces that is casein. The protein formed micelles in the lab due to it being negatively attracted to water. When seeing these little bubbles, I quit adding the acid (vinegar) and took the pH level. In this lab the chemical property that was used was the change the pH of the milk for both of the milks. Acetic acid (vinegar) was used to reach the isoelectric point. The chemical property that played a huge role in this was the acid changed the pH can disrupted the