This standard specifies the qualitative determination method of urease in vegetable protein beverages. This standard is applicable to the qualitative determination of urease in vegetable protein beverages. GB/T 5009.183-2003 Qualitative determination of urease in vegetable protein beverages GB/T5009.183-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.183—2003
Partially replaces GB16322-1996
Qualitative analysis of urease in vegetable protein drinkingIssued on 2003-08-11
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implemented on 2004-01-01
GB/T5009.183—2003
This standard replaces Appendix A "Qualitative determination method of urease" in GB16322—1996 "Hygienic Standard for Vegetable Protein Drinks". This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard was drafted by Liaoning Provincial Food Hygiene Supervision and Inspection Institute, Beijing Municipal Food Hygiene Supervision and Inspection Institute and Tianjin Municipal Food Hygiene Supervision and Inspection Institute.
Main drafters of this standard ：Wang Xutai, Xu Jikang, Yang Yuzhi, Xu Liufa, Lu Shouzheng. 476
1 Scope
Qualitative determination of urease in plant protein beverages This standard specifies the qualitative determination method of urease in plant protein beverages. This standard is applicable to the qualitative determination of urease in plant protein beverages. 2 Principle
GB/T5009.183—2003bzxZ.net
Urease catalyzes urea at appropriate pH and temperature to convert it into ammonium carbonate. Ammonium carbonate forms ammonium hydroxide under alkaline conditions, and then reacts with potassium mercuric iodide complex salt in Nessler's reagent to form ammonium iodide. If the activity of urease in the sample disappears, the above reaction will not occur. NH.CONH:+2H,O Pulsatyl alcohol (NH.),CO,
(NH),CO,+2NaOHNaCO,+NH,OH
2K[HgJ+3KOH+NH,+NH,Hg?O1+7KI+2H,0 (yellow-brown precipitate)
3 Reagents
3.11% urea solution.
3.210% sodium tungstate solution.
3.32% potassium sodium tartrate solution.
3.45% sulfuric acid.
3.5 Neutral buffer solution: Take 611mL of 0.067mol/L disodium hydrogen phosphate solution, add 389mL of 0.067mol/L potassium dihydrogen phosphate solution and mix well.
3.5.1 0.067mol/L disodium hydrogen phosphate solution: weigh 9.47g of anhydrous disodium hydrogen phosphate and dissolve it in 1000mL of water. 3.5.2 0.067mol/L potassium dihydrogen phosphate solution: weigh 9.07g of potassium dihydrogen phosphate and dissolve it in 1000mL of water. 3.6 Nessler's reagent: weigh 55g of red mercuric iodide (Hgl2) and 41.25g of potassium iodide and dissolve them in 250mL of water. After dissolution, pour them into a 1000mL volumetric flask. Then weigh 144g of sodium hydroxide and dissolve it in 500mL of water. After dissolution and cooling, slowly pour it into a 1000mL volumetric flask, add water to the scale, shake it and pour it into the reagent bottle. After it is still, use the supernatant. 4 Analysis steps
4.1 Take two 10mL colorimetric tubes A and B, add 0.1g sample to each, then add 1mL water to each, shake for half a minute (about 100 times), and then add 1mL neutral buffer to each.
4.2 Add 1mL urea solution to tube A (sample tube) in the upper two tubes, and then add 1mL water to tube B (blank control tube). Shake tubes A and B well and place them in a 40℃ water bath for 20min. 4.3 After taking out the two tubes from the water bath, add 4mL water to each, shake well, then add 1mL 10% sodium tungstate solution, shake well, then add 1mL 5% sulfuric acid, shake well, filter and set aside.
4.4 Take 2mL of the above filtrate and add them to 25mL Senna colorimetric tubes (matching tubes) respectively, and then follow the steps below. 4.4.1 Add 15mL water to each and then add 1mL 2% potassium sodium tartrate. 4.4.2 Add 2mL of Nessler's reagent to each tube and then add water to the 25mL mark. 4.5 Shake well and observe the results (see Table 1).
CB/T5009.183—2003
Qualitative analysis of adenosine
Strong positive
Second strong positive
Weak positive
Symbol
Display
Brick red mixed oil or disinfectant
Orange red clarified liquid
Dark golden yellow or yellow clarified liquid
Light yellow or slightly yellow clarified liquid
The sample tube is the same color as the blank control tube or lighter
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