The importance of protein content determination

Proteins are nitrogenous compounds that play an important role in animals and plants. The appearance of each cell is accompanied by recombination of proteins. However, different substances have different protein contents. For example, the protein content of plant tissues is lower than that of animal tissues. Muscular and visceral pro content in animals is much more. 20.1% of beef and 26.2% of milk powder. The level of protein content can also reflect the nutritional value of the substance. Therefore, in the food testing industry, it is often necessary to determine the amount of protein in a substance.

The protein is measured by measuring the amount of nitrogen in the substance. The amount of Pro is generally calculated by multiplying the total nitrogen by an appropriate protein conversion factor. This coefficient is determined by the nitrogen content of pro in the material. Pro's nitrogen content is generally 15-17.6%. For a 16% conversion factor = 6.25 (eggs, green beans, meat, corn, etc.).

The Kjeldahl method is the most common method for determining the protein content. The principle is that the protein is heated and digested with sulfuric acid and a catalyst to decompose the protein. The decomposed ammonia and sulfuric acid produce ammonium sulfate, which is then basified and distilled to separate the ammonia. After absorbing with boric acid, titrate with standard sulfuric acid or hydrochloric acid and multiply the conversion factor by the amount of acid consumed. That is protein content. The protein analyzer produced by Top Instruments uses the Kjeldahl principle. It mainly includes four steps, digestion - distillation - absorption and titration.