Detection method for non-protein nitrogen-containing compound in feed protein raw material

Abstract

The invention provides a method for detecting non-protein nitrogen-containing compounds in a feed protein raw material. Compared with other aldehyde, ketone and carbohydrate, formaldehyde produced in the decomposition of an ureaformaldehyde polymer, which is one of the non-protein nitrogen-containing compounds (NPN), under the action of hot sulfuric acid, has the characteristic that formaldehyde can form a purplish red substance with chromotropic acid, and the characteristic can be utilized for verifying whether the raw material is adulterated. The method comprises the following steps: after degreasing and drying the protein raw material with petroleum ether, placing the sample under a stereo microscope; picking out and placing suspicious materials into a 50ml beaker with a pair of tweezers; adding 1ml of chromotropic acid into the beaker; heating the beaker with an electric stove until fume starts rising; and taking the beaker off from the electric stove, and adding 50ml of water into the beaker instantly. The fact that the liquid turns purplish red shows that a non-protein nitrogen (NPN)-containing compound, called unreaformaldehyde polymer, is present in the sample, so that whether the sample is adulterated can be verified accurately.

Description

Technical field: [0001] The invention relates to the field of detection of feed raw materials, in particular to a detection method capable of detecting the adulteration phenomenon of urea-formaldehyde polymer, one of non-protein nitrogenous compounds (NPN), in feed protein raw materials. Background technique: [0002] The detection method of protein content in feed GB6432-1994 is obtained by multiplying the content of nitrogen element by Kjeldahl method and multiplying it by a coefficient (6.25). There is a big defect in this sample detection method, that is, all nitrogen-containing compounds in the sample are identified as proteins. This has left a technical loophole for unscrupulous businessmen, who often add some cheap nitrogen-containing compounds (such as urea, urea-formaldehyde polymers, melamine, etc.) to protein raw materials to make huge profits and harm animals. growth, affect the quality of livestock products, and cause food safety risks. [0003] Advantages of ...

AI Technical Summary

Problems solved by technology

This has left a technical loophole for unscrupulous businessmen, who often add some cheap nitrogen-containing compounds (such as urea, urea-formaldehyde polymers, melamine, etc.) to protein raw materials to make huge profits and harm animals. growth, affect the quality of livestock products, and pose a food safety risk