Protein detection method for staged accurate temperature control milk-containing product

Abstract

The invention discloses a protein detection method for a staged accurate temperature control milk-containing product. The protein detection method comprises the steps of (1) weighing a sample; (2) carrying out a digestion reaction in a digestion furnace to prepare a digestion liquid; and (3) detecting the protein content in the digestion fluid by using an automatic Kjeldahl apparatus. The method has the advantages that by precisely controlling the heating rate in stages, on one hand, foam formation can be avoided, so that the detection result is more accurate, on the other hand, the release speed of the concentrated sulfuric acid is reduced, the product carbonization is more complete, the detection accuracy is further improved, meanwhile, sufficient time is provided for thoroughly dilutingthe concentrated sulfuric acid, and the environmental pollution risk is reduced; according to the invention, the staged heating temperature is set, so that the fat can be completely released, the product end point digestion color can be rapidly achieved, the digestion end point can be completely achieved with the detection method provided by the invention after the simultaneous use for 2 h, and the digestion end point can be achieved only by continuously prolonging different digestion time according to various characteristics of the actual product in the existing standard detection method; the detection result is more accurate, the detection efficiency is high, and safety and environmental protection are achieved.

Description

Technical field: [0001] The invention relates to a method for detecting protein, in particular to a method for detecting protein containing dairy products with precise temperature control in stages. Background technique: [0002] The protein is detected according to the national standard GB5009.6, wherein the automatic Kjeldahl method is as follows: Weigh a well-mixed solid sample of 0.2g-2g, a semi-solid sample of 2g-5g or a liquid sample of 10g-25g ( About 30mg-40mg nitrogen), accurate to 0.001g, into the digestion tube, then add 0.4g copper sulfate, 6g potassium sulfate and 20mL sulfuric acid in the digestion furnace for digestion. When the temperature of the digestion furnace reaches 420°C, continue to digest for 1 hour. At this time, the liquid in the digestion tube is green and transparent. Take it out and cool it, add 50mL of water, and add sodium hydroxide solution, hydrochloric acid or Sulfuric acid standard solution and boric acid solution containing mixed indicat...

AI Technical Summary

Problems solved by technology

The automatic Kjeldahl method recorded in the national standard GB5009.6 does not clearly specify the time and rate of heating to above 420°C. In the actual process, the general product can be instantaneously raised to above 420°C to start constant temperature, and the digested sample turns green. It is transparent, but the product containing fat does not control the heating time and rate when it rises above 420°C, and there are the following problems: 1. The product has gas bubbles attached to the surface of the digestive tube, which affects the test results; 2. The concentrated sulfuric acid evaporates excessively , affecting the environment and test results; 3. The standard does not clearly state how much temperature is above 420°C. Due to the ingredients of the product, some products are kept at 420-450°C for 1 hour. The product color does not reach the end color, and it needs to last longer It takes time to reach the final color of product digestion, and the color does not meet the standard, which affects the test results; 4. In the standard, the liquid in the digestion tube is cooled to room temperature before adding water, distillation, and titration detection. The waiting time is long, and the distillation equipment is consumed for heating. Power, increase power consumption, waste energy

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