What is amino acid nitrogen? Very few people know

Amino acid nitrogen is a substance found in the seasoning soy sauce, and it is the main raw material of soy sauce. It can make the soy sauce taste more delicious. At the same time, the more amino acid nitrogen the soy sauce contains, the mellower the taste will be, and it is also very beneficial to the body to eat it.

1. What is “amino acid nitrogen”?

Amino acid nitrogen refers to the content of nitrogen in the form of amino acids. The minimum content of amino acid nitrogen in soy sauce shall not be less than 0.4g/100ml.

2. Based on the "amino acid nitrogen" content , what grades can soy sauce be classified into? How to identify the quality of soy sauce through the "amino acid nitrogen" index of soy sauce?

It can be divided into four grades: special grade, grade one, grade two and grade three, and the amino acid nitrogen content is ≥0.8, ≥0.7, ≥0.55 and ≥0.4g/100ml respectively. The higher the "amino acid nitrogen" index, the higher the amino acid content in the soy sauce and the better the umami taste.

3. What precautions should consumers take when buying soy sauce in daily life?

1. Must have QS certification mark;

2. Buy by grade: the higher the "amino acid nitrogen" content of the same brand, the better the umami taste;

3. Give priority to purchasing "pure brew". For example, there are words like “traditional craftsmanship”, “carefully brewed”, “pure brew”, “formulated”, etc.

4. Look at the ingredient list and find that the fewer food additives the better;

5. According to cooking needs: choose "dark soy sauce" for coloring, and "light soy sauce" for salad dressing;

6. Product standards are divided into "low-salt solid state" and "high-salt dilute state". Although they have nothing to do with the saltiness of soy sauce, the color of the former is darker than the latter, and the sauce aroma of the latter is relatively stronger than the former. Consumers can make their purchase based on the characteristics of these two.

Detection method =

According to the soy sauce hygiene standard GB 2717-2003, if the amino acid nitrogen in soy sauce is less than 0.40g/100ml, it means that the soy sauce is an unqualified product. There are mainly the following detection methods for amino acid nitrogen:

1. Formaldehyde titration

GB 18186-2000 "Brewed Soy Sauce" stipulates that when testing amino acid nitrogen in soy sauce, formaldehyde is used as a masking agent, that is, formaldehyde is used to mask the amino group in the amino acid, making the solution carboxyl acidic, and then titrated with sodium hydroxide standard solution under the indication of the acidity meter.

2. Colorimetry

Principle: In sodium acetate-acetic acid buffer at pH 4.8, amino acid nitrogen reacts with acetylacetone and formaldehyde to generate yellow 3,5-diacetyl-2,6-dimethyl-1,4-dihydropyridine amino acid derivatives. The absorbance is measured at a wavelength of 400nm and the quantification is compared with the standard [2].

3. Hantzsch reaction rapid assay

1. Scope of application

This method is suitable for the determination of amino acid nitrogen in condiments.

2. Principle

Based on the Hantzsch reaction principle, a mixed solution of acetylacetone and formaldehyde was used as an amino acid derivatization reagent to determine the

Method for determining amino acid nitrogen in condiments.