Method for determining nitrogen content of meat using automatic nitrogen determination instrument

The quality of meat food quality directly affects people's health. The degree of freshness of the meat is generally determined by measuring the level of volatile base nitrogen in the meat. Volatile base nitrogen is the product of the decomposition of proteins due to the infection and reproduction of meat by external microorganisms and the deamination and separation of proteins in meat caused by enzymes secreted by microorganisms. The determination of volatile base nitrogen is usually carried out using semi-micro determination of nitrogen, which is cumbersome and time consuming. The automatic nitrogen analyzer has the advantages of simple operation, rapid time saving and accurate and reliable results. Effectively improve work efficiency. In this paper, the determination of volatile base nitrogen in meat with automatic determination of nitrogen is demonstrated. Satisfactory results have been obtained and it is considered that the method is worthy of promotion and application.
1 Experimental section
1.1 Instruments and Reagents
1.1.1 2400 Kjeldahl (Swedish Forster Corporation), AEL-200 electronic analytical balance (precision 0. 0001 g) o
1.1.2 Magnesium oxide suspension (lOg/L); Weigh lOg of magnesium oxide, add 1000m1 of water, and shake to a suspension.
1.1.3 20 g/L boric acid absorption solution, 0. Olmol/L hydrochloric acid standard solution, lg/L calsylate green ethanol solution, and 2 g/L methylene blue ethanol solution.
1.1.4 Instrument conditions: The analysis program is Kjeldahl 1. Set the sample solution to 30, distilled water to 50m1, alkali solution to 60m1, and stir in about ten modes.
1.2 Sample processing After removing the fat, bone and bond from the sample, weigh about 20. 0g into a conical flask, add 100m1 of water, shaking from time to time, immersed for 30min and filtered for later use.
1.3 Measurement
1.3.1 Principle of measurement The principle of automatic nitrogen determination method is the same as that of semi-micro determination method. Volatile base nitrogen refers to animal foods. Due to the action of enzymes and bacteria, protein decomposition occurs during the process of corruption. Basic nitrogenous substances such as ammonia and amines. These substances are volatile, and after evaporating in an alkaline solution, the results are calculated by titration with standard acids.
1.3.2 Measurement process Absorb 20. Oml sample filtrate is added to the digestive tube 20m1 magnesium oxide suspension was directly placed in the automatic determination of nitrogen distillation apparatus II, while doing a blank test. The entire measurement process, distillation, titration, digital processing and results printing are all automatically performed.
1.3.3 results can be directly selected mg%, g% or mg/kga
2 Results and Discussion
2.1 The spike recovery test to take 8 different types of samples, respectively, in the determination of adding a certain amount of sulfuric acid hinge, the recovery test was spiked, the determination of the recovery rate of the spike were 97.8% to 100. 1%, The average recovery rate was 99.1%, which met the requirements of the analysis.
2.2 Precision of the method Take 8 samples of different types and perform parallel determinations for 6 times. The results are shown in Table 1. After statistical analysis, the coefficient of variation was between 0.02% and 1.50%.

2.3 Comparison of different methods For different kinds of meat samples, the semi-micro nitrogen determination method and the automatic nitrogen determination instrument were used to determine the site of the nitrogen-occurring base nitrogen. The results were basically the same. After the paired test, P> 0.05. There was no significant difference in the results of the two methods, which met the requirements of the method.
Determination of volatile base nitrogen in meat products using an automatic nitrogen determination method. The method of operation is simple, the analysis speed is fast, safe and reliable, saving time and effort. It takes only 6 minutes to measure a sample and the result can be read directly. It is suitable for the determination of large quantities of samples. The method has high precision and accuracy. It has certain practicality and reliability for the determination of volatile base nitrogen in meat products and is worthy of promotion.

Related equipment: Distiller

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