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2015/04/25

Test Protein in Food Ingredients


Protein is a polymer compound with a monomer in the form of amino acids. Presence of protein in a food ingredient can be known through some of the following tests:
  • Test biuret, to test the peptide bond, is characterized by the occurrence of a change in pink to purple.
  • Test Xantoproteat, for the presence of benzene in the protein core, marked with a yellow or orange.
  • Test Millon, to test for the presence of amino acids in a protein with a phenyl group, marked with a red ring.
  • Test sulfur, to test for the presence of sulfur in proteins. Reagents used are lead (II) nitrate or lead (II) acetate. Positive test if the precipitation of a black from Pbs.
The test foods containing carbohydrates and some reaction on carbohydrate similar to the test protein in food ingredients.
Protein has several types that are based on chemical composition, shape, and function.
1. Based on the chemical composition
Sample class
Example
Glikoprotein
Blood Globulin
Lipoprotein
Blood Lipoprotein
Hemoprotein
Hemoglobin
Fosfoprotein
Casein milk
Metaloprotein
Alkoholdehidrogenasi

2. Based on the form
Sample class
Example
fibers
Tripsin, keratin
Solid round
Protein transport, enzim

3. Based on the function
Sample class
Example
Protein transport
Hemoglobin
Protein structure
collagen in bones
Protein antibody
Immunoglobulin in vertebrates
Enzymes
trypsin, amylase
Protein nutrient
Casein Protein nutrients in milk, ovalbumin in egg
Regulatory Protein
Myosin, actin
Protein pengatur
Hormone

4. Based on the chemical composition
  • Protein simple

If simple hydrolyzed proteins, will only produce amino acids. An example is the protein albumin and globulin.
  • Protein combined

If the fusion protein is hydrolyzed, will produce amino acids and other compounds. Examples are as follows:
  • Glycoprotein, protein and carbohydrates
  • nucleoprotein, containing proteins and nucleic acids
  • Lipoprotein, protein and lipid
  • Kromoprotein, protein and dye material (hemoglobin and Hemocyanin).

Protein plays an important role for the human body, among others as follows:
  1. As a biocatalyst in the process of metabolism
  2. Food reserve
  3. Muscle Activator
  4. The carrier of oxygen to the cells
  5. As builder substance
  6. Maintain the balance of body fluids PH
  7. Network masks and protective to pathogenic microorganisms.