火腿中蛋白质检测方案(定氮仪)

APPLICATION NOTEF&F-D-006-2014/A1 N/PROTEIN DETERMINATION IN CURED MEATSDUMAS COMBUSTION METHOD N/Protein Determination in Cured Meatsaccording to the Dumas combustion method Reference： AOAC 992.15 Crude Protein in Meat and Meat Products Tested with VELP Scientifica NDA 701 Dumas Nitrogen Analyzer (Code F30800070) Introduction Mortadella is a large Italian sausage or cold cut made of finely hashed or ground， heat-cured pork sausage， which incorporates at least 15% small cubes of pork fat (principally the hard fat from the neck of the pig). Mortadella is flavoured with spices， including whole or ground black pepper， myrtle berries， and pistachios and is a stapleproduct of Bologna. Salame is an Italian word defining crude or cooked meat obtained after a long period of seasoning， with the addition ofseveral different kind of ingredients as salt， garlic， wine， herbs in a spice mix. The variety of cured meat types is huge， depending on the meat origin， the grinding way， the ingredients and method ofcure. Salame can have different textures， tastes and flavors； it can be hot or smoked. For this reason， almost every Italian town has a local salame with a typical name. Protein Determination in Cured Meats The Dumas method starts with a combustion furnace (CF) to burn thesample， obtaining elemental compounds. Water is removed by a first physical trap (WT1 -DriStepTM)， placed afterthe combustion， and a second chemical one (WT2). Between the two， theelemental substances passed through a reduction furnace (RF). The auto-regenerative CO2 adsorbers (CO2) let pass only the elementalnitrogen that is detected by the LoGas TM innovative Thermal ConductivityDetector (TCD) with no requirement for a reference gas. The NDA 701 is controlled via PC through the intuitive DUMASoftTM. NDA 701 Preliminary Operations (daily) Follow the operating manual to start the NDA 701 and check that the following parameters are set： Temperature Combustion reactor(Code A00000158)： 1030°C Temperature Reduction reactor (Code A00000226)： 650°C Flow rate MFC1 He： 190 ml/min Flow rate MFC2 He： 200 ml/min Condition the system by testing 2 EDTA standard (Code A00000149) and 3 to 5 empty tin foils (Code A00000153) asCheck up. Verify the calibration curve with one or more tests as Standard by testing the same standard used for thecurve creation. Sample Preparation Weigh around 200 mg of the cured meat in a tin foil directly on the balance. Close the tin foil， obtaining a capsule. Load the capsule into the autosampler. Analysis Procedure Fill the following fields in the database： Sample name， Weight， Method， Sample type， Calibration number The “MEAT AND DERIVED PRODUCTS”method shows the following parameters： Protein factor： 6.25 O2 flow rate： 400 ml/min O2 factor： 1.4 ml/mg Press to start the analysis. Analysis time： from 3 minutes for one run. Typical Results on Cured Meats The obtained results are in accordance with the expected value. Results have been obtained with the followingcalibration curve： in a range of 0 - 12 mg N with 5 measurements of EDTA standard (N%=9.57) (Code A00000149).The data obtained are included in the tolerance admitted by the EDTA certificate. This is “protein”on a total nitrogen basis. Sample Sample quantity (mg) Nitrogen % Protein % Italian“Mortadella” 197.80 2.310 14.437 206.50 2.283 14.271 207.00 2.295 14.343 203.10 2.293 14，331 201.70 2.305 14.406 Average±SD% 2.297±0.011 14.358±0.065 RSD%* 0.461 0.455 Italian“Golfetta” 205.00 4.001 25.006 199.30 4.046 25.287 211.90 4.056 25.350 199.80 4.029 25.183 197.80 4.056 25.350 Average± SD% 4.038±0.023 25.235±0.145 RSD%* 0.576 0.575 Italian Pepper Salami 204.90 5.099 31.866 205.60 5.197 32.478 200.60 5.057 31.605 215.30 4.953 30.957 198.20 5.119 31.993 Average ±SD% 4.038±0.023 31.780±0.559 RSD%* 0.576 1.758 Expected Protein Value： Mortadella P%=14.0； Golfetta P%=25.0； for Salami P%=31.0 Protein Factor：6.25 * RSD% =(Standard Deviation*100)/ Average Conclusion In order to compare samples with varying nitrogen contents， three different types of cured meats were tested. The results are extremely reliable and reproducible， as demonstrated by the RSD， since the goal is to obtain <2.0%relative standard deviation， as requested by official methods. The results confirmed the no-matrix effect of nitrogen determination and the complete combustion of all three types ofcured meats' samples. NDA is the innovative solution for nitrogen/protein determination， according to the Dumas combustion method offeringaccurate and precise results. Copyright @ VELP Scientifica. All rights reserved.No part of this publication may be reproduced or transmitted in any form or for any purpose without the express permission of VELP.VELP Scientifica， ItalyTel：+ Fax： +ww.velp.com 杜马斯燃烧法测定火腿中的蛋白质含量。