A) Research background (Introduction and problem statement) Proteins are crucial for us living things. Proteins are important constituents of foods. From the point of chemistry, they are known as polymers of amino acids. There are twenty different types of proteins that occur naturally in proteins. Nonetheless, they are the major sources of energy for living beings. It is also the proteins that determine the food texture. So, the isolated proteins are often used to provide desirable texture to certain foods. Normally, they are used as foaming agents, emulsifiers, gelling agents, and thickeners. Many food proteins are also enzymes which are able to enhance the rate of some biochemical reactions. These reactions are crucial for they have either good or bad effects on properties of foods. That’s why knowing the total concentration, type or functional properties of food are important. (People.umass.edu, 2018) In order to determine protein in food, scientists have created many methods through the history. First, looking at the Kjeldahl method which is based on determining how much nitrogen content is in food since protein contents of food are mostly determined by the basis of total nitrogen content. This method is applied to know nitrogen content and then multiplied by 6.25(100/16) to get protein content assuming average nitrogen content in protein is about 16 percent. Although this method is used for many applications, it still uses an average value and each protein has different conversion factor depending on the amino-acid composition. (Ijstr.org, 2018) Another method is called enhanced Dumas method. This method is based on the first method described by the scientist called Dumas. This method is known for its rapidness in determining protein concentration of food samples. This method came into rivalry with Kjeldahl method since this one is also efficient. (People.umass.edu, 2018) Next great method is called Biuret method. This biuret reagent (Cu (II) ion in presence of peptides in alkaline solution forms violet coordination complexes) is quite useful since it contains all chemicals required to carry out the analysis and can be bought commercially. This can be used to determine protein concentration because peptide bonds occur at the same frequency per amino acid in peptide. The reagent is mixed with protein solution and wait for absorption at 540 nm of it is directly proportional to the protein concentration according to Beer-Lambert Law. The great advantage of this method is that there is no interference from materials at lower wavelengths. (People.umass.edu, 2018)Problem statements:Which method should be used to determine plant protein concentration better in vegetable sample?Which method is the most easy and convenient to use and has more advantages?Objectives:1) To determine the method with better accuracy to find the protein concentration in vegetable sample2) To determine the most advantageous method to find plant protein concentration