Curds Lab
Title: What is the effect of acidic substances on the mass of curd formation?
Purpose
The purpose was to determine if lemon juice or if vinegar produced more curds.
Background Information Curds were formed by a change in pH or by a change in temperature of the milk. Milk has a pH of 6.6 approximately, and at this pH the proteins were able to repulse each other, creating a negative charge. One of the proteins in milk is called casein, which when an acid of a lower pH than 6.6 was added, it will start to clump up causing curds to form and lactic acid to remain. In this reaction, the milk was serving as a base while the lemon juice or the vinegar was the acid by “the positive hydrogen atoms get attracted to the negative micelles, making them neutral” (Dr. Swain at Northwestern University). In making the proteins neutral, they no longer repulse one another, and they attract and start to clump up into curds.
Another way for curds to form was through the increase of temperature or kinetic energy. Curds were formed when the kinetic energy was increased because the milk goes through a process of denaturation, which “involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule” (Encyclopedia …show more content…
With the information and data that was collected, the hypothesis was supported that if lemon juice was added then the mass of the curds will be greater. Lemon juice with a pH of 2 had a higher concentration of hydrogen ions than vinegar with a pH of 2.4; therefore, there was more positive hydrogen ions in the lemon juice to be donated to the negative proteins in the milk making more and heavier curds than the vinegar. In trials one, two, three and in the average of each independent variable, the lemon juice had the greatest mass. Lemon juice was shown to have given more mass to the curds, supporting the
Purpose
The purpose was to determine if lemon juice or if vinegar produced more curds.
Background Information Curds were formed by a change in pH or by a change in temperature of the milk. Milk has a pH of 6.6 approximately, and at this pH the proteins were able to repulse each other, creating a negative charge. One of the proteins in milk is called casein, which when an acid of a lower pH than 6.6 was added, it will start to clump up causing curds to form and lactic acid to remain. In this reaction, the milk was serving as a base while the lemon juice or the vinegar was the acid by “the positive hydrogen atoms get attracted to the negative micelles, making them neutral” (Dr. Swain at Northwestern University). In making the proteins neutral, they no longer repulse one another, and they attract and start to clump up into curds.
Another way for curds to form was through the increase of temperature or kinetic energy. Curds were formed when the kinetic energy was increased because the milk goes through a process of denaturation, which “involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule” (Encyclopedia …show more content…
With the information and data that was collected, the hypothesis was supported that if lemon juice was added then the mass of the curds will be greater. Lemon juice with a pH of 2 had a higher concentration of hydrogen ions than vinegar with a pH of 2.4; therefore, there was more positive hydrogen ions in the lemon juice to be donated to the negative proteins in the milk making more and heavier curds than the vinegar. In trials one, two, three and in the average of each independent variable, the lemon juice had the greatest mass. Lemon juice was shown to have given more mass to the curds, supporting the