DETERMINATION OF PROTEINS BY THE KJELDAHL METHOD IN CEREALS OF THE MARKETS IN KORÇA CITY

Proteins are organic substances, macromolecules which mainly consist of the elements of carbon, hydrogen, oxygen, nitrogen, and rarely sulphide. Proteins are the main building blocks of cells. They not only give cells a structure, but are also molecular machines, where they transport materials, pump ions, catalyze chemical reactions and recognize signaling substances. The Kjeldahl Method is used to determine the protein content in cereals, a method invented since 1883, which consists of mineralizing the content of flour using Se and Cu2SO4 catalysts and burning the content with H2SO4cc for about 1 hour. After mineralization, it continues with distillation and finally with the titration of the distillate to determine the amount of acid needed to neutralize the distillate. This methodology is used to calculate the nitrogen content in cereals and then it is converted into protein content using conversion coefficients. In the study, samples of flour from different cereals of Korca city markets were taken for which the same analysis was performed and the final results are presented in the final table where buckwheat has the highest protein content of 17.59% and rye has the lowest content of 6.12%.