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CN-122016432-A - Preparation method of volatile basic nitrogen standard substance in food

CN122016432ACN 122016432 ACN122016432 ACN 122016432ACN-122016432-A

Abstract

The invention discloses a preparation method of a volatile basic nitrogen standard substance in food, which comprises the following steps of (1) cutting fresh livestock meat, poultry meat or/and fish meat to remove tendons, bones, skin and fat, crushing pure meat to obtain meat paste, (2) weighing a certain amount of meat paste, adding a calculated amount of ammonium sulfate aqueous solution into the meat paste, continuously crushing and stirring the mixture until the mixture is uniform, (3) freeze-drying the meat paste after the uniform mixing to obtain meat powder blocks, (4) crushing the meat powder blocks, collecting the freeze-dried powder, sieving the freeze-dried powder by using a 60-mesh sieve, detecting the water content of the sieved freeze-dried powder, wherein the water content is less than 5 percent, and (6) subpackaging and sealing the freeze-dried powder into independent packaging units through uniformity inspection to obtain the volatile basic nitrogen standard substance. The standard substance has the advantages of uniform content of volatile basic nitrogen, good short-term and long-term stability and accurate content.

Inventors

  • Yang Diemei
  • LI QINGQING
  • XUE FENG

Assignees

  • 上海市质量监督检验技术研究院有限公司

Dates

Publication Date
20260512
Application Date
20260224

Claims (8)

  1. 1. The preparation method of the volatile basic nitrogen standard substance in the food is characterized by comprising the following steps of: (1) Cutting fresh livestock meat, fowl meat or/and fish meat to remove tendons, bones, skin and fat, and pulverizing pure meat to obtain meat paste; (2) Weighing a certain amount of meat paste, adding a calculated amount of ammonium sulfate aqueous solution into the meat paste, mixing, and continuously crushing and stirring until the meat paste is uniform; (3) Freeze-drying the meat paste after being added with the label and uniformly mixed to obtain meat powder blocks; (4) Pulverizing meat powder, collecting lyophilized powder, and sieving with 60 mesh sieve; (5) Detecting the moisture content of the screened freeze-dried powder, wherein the moisture content is less than 5%; (6) And subpackaging and sealing the freeze-dried powder into independent packaging units, and obtaining the volatile basic nitrogen standard substance through uniformity inspection.
  2. 2. The method for preparing a standard substance of volatile basic nitrogen in food according to claim 1, wherein the uniformity test is performed according to JJF 1343-2022 requirements of standard substance determination and uniformity, stability evaluation, when the total unit number N >500, the unit number is extracted > =15.
  3. 3. The method for preparing the volatile basic nitrogen standard substance in food according to claim 1, wherein the livestock meat is one of pork, beef or mutton, the livestock meat is chicken or duck, and the fish meat is cod meat or tilapia meat.
  4. 4. The method for preparing the volatile basic nitrogen standard substance in the food according to claim 1, wherein the volatile basic nitrogen standard substance in the food is one of freeze-dried powder prepared from pork, beef, mutton, chicken, duck or fish.
  5. 5. The method for preparing a standard substance of volatile basic nitrogen in food according to claim 1, wherein the concentration of the aqueous solution of ammonium sulfate is set according to the content of the volatile basic nitrogen, and the concentration of the aqueous solution of ammonium sulfate is calculated by inverting according to the material balance rule according to how much nitrogen is prepared.
  6. 6. The method for preparing a volatile basic nitrogen standard substance in food according to claim 1, wherein the concentration of the ammonium sulfate aqueous solution is 0.920-23.3 g/L.
  7. 7. The method for preparing the volatile basic nitrogen standard substance in food according to claim 1, wherein the freezing temperature of the vacuum freeze dryer is-35 to-65 ℃, the pre-pumping vacuum degree is 0.1 to 0.5mbar, the first stage of the primary freeze drying is set to be 0.4 to 1.0mbar, the second stage is set to be 0.4 to 1.0mbar, and the total freeze drying time is 24 to 36 hours.
  8. 8. The method for preparing a volatile basic nitrogen standard substance in food according to claim 1, wherein the rotational speed of the high-speed pulverizer in the step (4) is 25000-32000 r/min.

Description

Preparation method of volatile basic nitrogen standard substance in food Technical Field The invention belongs to the field of detection of volatile basic nitrogen in food, and particularly relates to a preparation method of a volatile basic nitrogen standard substance in food. Background The volatile basic nitrogen (Total Volatile Basic Nitrogen, TVB-N for short) refers to alkaline nitrogen-containing substances such as ammonia and amines generated by decomposing proteins in the process of spoilage of animal foods due to the action of enzymes and bacteria. Such substances are volatile, and the higher the content, the more amino acids are destroyed, in particular methionine and tyrosine, and thus the nutritional value is greatly affected. Volatile basic nitrogen is an important physicochemical index for evaluating the freshness of foods using meat and fish as main raw materials. The volatile basic nitrogen has a clear correspondence with the spoilage of animal foods, and is an important index of food safety inspection standards, especially for meats and fish. The national food safety standard fresh (frozen) livestock and poultry products (GB 2707-2016) specifies that the maximum limit value of volatile basic nitrogen in fresh (frozen) livestock and poultry products is 15mg/100g. The national food safety standard fresh and frozen animal aquatic products (GB 2733-2015) prescribes that the maximum limiting value of volatile basic nitrogen in sea water fish and shrimp is 30mg/100g, the maximum limiting value in sea crab is 25mg/100g, the maximum limiting value in fresh water fish and shrimp is 20mg/100g, and the maximum limiting value in frozen shellfish is 15mg/100g. In food safety national standard animal aquatic products (GB 10136-2015), the maximum limit value of volatile basic nitrogen in salted raw food animal aquatic products is 25mg/100g, and the maximum limit value in prefabricated animal aquatic products (without dry products and salted products) is 30mg/100g. Volatile basic nitrogen is the most important physicochemical index of food freshness, and is also a conventional inspection project of national supervision spot check. The volatile basic nitrogen has a clear correspondence with the spoilage of animal foods, and is an important index of food sanitation inspection standards. At present, most of detection of volatile basic nitrogen in meat uses a traditional chemical detection method or a high performance liquid chromatography method, and the 'GB 5009.228-2016 determination of volatile basic nitrogen in food' prescribes that the determination methods of volatile basic nitrogen include a semi-trace nitrogen determination method, a trace diffusion method and an automatic Kjeldahl nitrogen determination method. Patent documents CN114264630A and CN103712948A disclose a method for establishing a database for rapidly detecting mutton volatile basic nitrogen based on near infrared, which comprises the steps of collecting a plurality of fresh mutton samples, dividing the fresh mutton samples into a modeling set and a testing set, collecting near infrared spectrums of each sample, determining the content of the volatile basic nitrogen in each sample according to a chemical detection method specified by national standards, establishing a corresponding relation between the near infrared spectrums of any sample and the content of the volatile basic nitrogen, establishing a prediction model of the content of the volatile basic nitrogen of the sample by utilizing the corresponding relation between the near infrared spectrums of each sample in the modeling set and the content of the volatile basic nitrogen, correcting the accuracy of the prediction model by utilizing the corresponding relation between the near infrared spectrums of each sample in the testing set and the content of the volatile basic nitrogen, obtaining a corrected prediction model, and storing the corresponding relation between the near infrared spectrums of the samples and the content of the volatile basic nitrogen in the corrected prediction model into the database. A standard substance is a substance or material that has been determined to have one or more sufficiently uniform characteristic values, and as a "gauge" in the analytical measurement industry, plays an indispensable role in the fields of calibrating measuring instruments and devices, evaluating measurement analytical methods, measuring the characteristic values of substances or materials, and assessing the operational skill level of an analyst, and quality control of a product during production, etc. The standard substance is used as a chemical weight in relative measurement, and has very important verification and guarantee functions on the accuracy of detection results. The method is a support for high-efficiency and accurate detection technology behind research on the nutrition components and safety of livestock meat, poultry meat and fish meat. The development and application