Determination of Protein

Protein Detection Methods in Foods

There is protein in all foodstuffs of animal and plant origin. Compounds that contain nitrogen in food are known as protein. Protein determination in foods is based on determining the amount of nitrogen. The amount of protein determined by the amount of nitrogen is called the "crude protein amount".

Proteins are compounds with large molecules formed by the combination of amino acids, the building blocks. With 22 amino acid types, there are countless protein types in nature.

The reasons for determining the amount of protein in foods:

- Determining the conformity of food to current quality standards
- Determining the nutritional value of food
- Detecting the general composition of food
- Determining the price of the food offered for sale
- Determining the processing technique to be applied to food

Different methods are used to determine total protein in foods.

1. Biuret method
2. Lowry method
3. Pyrochemiluminescent method
4. Xantoproteic acid reaction method
5. Millon reaction method
6. Paint binding method
7. Bicinshoninic acid method
8. Ninhydrin method

The Methods Considering the Total Nitrogen Found in Proteins

1. Kjedahl Method
2. Dumas Method
3. Meulen Method

Among the methods mentioned above, the most used method is the ones in which the amount of nitrogen is taken into account.

99% of the total amount of nitrogen in foods originates from proteins. For this reason, it is primarily based on the determination of the amount of nitrogen and the determination of the amount of protein by multiplying this value with a factor determined for foodstuffs.

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