Leatham, Dallin (Weber State University)
Faculty Advisor: Domek, Matthew (Weber State University, Microbiology); Oberg, Craig (Weber State University, Microbiology); Culumber, Michelle (Weber State University, Microbiology); Walker, Edward (Weber State University, Biochemistry)
Gouda cheese is known for its buttery flavor which is produced by the compound 2,3-butanedione or more commonly known as diacetyl. To measure the concentration of diacetyl in cheese a colorimetric test for vicinal diketones is used, known as the Voges and Proskauer (VP) method. This method involves using 5.0% a-naphthol and 0.4% creatine-KOH to develop a pink to red color. In the VP method the concentration of diacetyl is directly related to the absorbance. When this method was performed using known concentrations of Diacetyl in dH2O, a linear relationship was found to have a R2 value of .9571 confirming that the VP method is a viable method of testing for diacetyl concentration. It was proposed that by using a GC-MS to measure these concentrations a simpler test could be performed with similar or improved accuracy. Extracting of the diacetyl from Gouda cheese was done using a stomacher and a mixture of 50:50 acetone:dH2O. Before the concentration of cheese was measured dilutions of diacetyl concentrations were run in a 50:50 acetone:dH2O mixture at 0.1 uL/mL, 1 uL/mL, and 10 uL/mL. The concentrations of diacetyl that gouda cheese commonly contains are from 0.01 uL/mL to 0.1 uL/mL. It was found that the concentration of .1 uL/mL of diacetyl could not be distinguished from the background interference of the instrument. Currently it seems that using a GC-MS to determine diacetyl concentrations in gouda cheese might not be a practical method. Further research and a better understanding of the equipment could improve this method in order to obtain readable results.