Analysis Of Protein
Analysis of Protein1
ProteinCodex Guidelines on Nutrition LabellingProtein Total Kjeldahl Nitrogen x CFCF 6.25 for mixed food2
Conversion factorsConversion factor can vary from 5.18(almonds) to 6.38 (milk and dairyproducts)Where to find the conversion factors?Codex standardsIf not available in codex standards,Æ others, e.g. AOAC, GB, FAO publication3
How to get Codex x en.jsp4
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Codex standard (example)CODEX STANDARD FOR DURUM WHEAT SEMOLINA AND DURUM WHEATFLOUR6
AOAC official methodsTotal Kjeldahl NitrogenMethodMatrixConversion factor920.53Beer6.25945.23*Brewing sugars and ns5.7 for wheat and its products, 5.18 for almonds, 5.46 forpeanuts and brazil nuts, 5.30 for tree nuts and coconut, 6.38for dairy e-cream and frozen desserts6.38920.152Fruit products6.25981.10Meat6.25950.48Nuts and nuts products* procedure similar to 920.53** procedure similar to 920.87*** procedure similar to 991.205.18 for almonds, 5.46 for peanuts and brazil nuts, 5.30 forother tree nuts and coconut7
National Standard of P.R.C.(國家標準)GB/T 5009.5-2003 �數 (conversion factor):一般食物為6.25; 乳制品為6.38; 麵粉為5.70;玉米,高梁為6.24; 花生為5.46; 米為5.95;大豆及其制品為5.71; 為5.83; 芝麻,向日葵為5.308
FAO publicationFAO Food and Nutrition Paper 14/7FoodFactorCerealsFoodFactorPulses, nuts and seedsWheat whole meal or flour5.83Groundnuts5.46Wheat flour (low or medium extraction)5.70Soya bean (all products)5.71Macaroni, spaghetti, wheat pastes5.70Almonds5.18Wheat bran6.31Brazil nuts5.46Rice (all products)5.95Coconut5.30Rye (all products)5.83Chestnuts5.30Barley (all products)5.83Seeds (sesame, safflower, sunflower)5.30Oats (all products)5.83Other seeds5.30Other Foods6.25Milk and Dairy ProductsMilk (all-fresh or dry)6.38Cheese (all)6.38Butter (and margarines)6.389
Flow Chart forTotal Kjeldahl 10
SampleSample size Definition of “0” 0.5 g/100ge.g. if sample contains 0.5% protein andthe conversion factor 6.25, 1 g samplecontains (1 x 0.5%)/6.25 0.0008 g of N( 0.06 mMole) (0.6 ml x 0.1M HCl)11
Digestion (1)Reagents:i) conc. H2SO4ii) Na2SO4 or K2SO4iii) catalyst (e.g. CuSO4.5H2O, TiO2)12
Digestion (2)ratio of H2SO4 : Na2SO4 or K2SO42.5:1 (initial) Î 1:1 (final)proportion of acid to salt affecttemperature¾ Too much acid Î incomplete digestion¾ Too little acid Î loss N13
Digestion (3)ConditionsTemperature: 420 CTime: 2 hrAppearance of final solution: clearsolution14
Digestion (4)15
Distillation and Titration (1)DistillationAdd NaOH Æ strongly alkalineDistill NH3 into 1) standardized HCl or 2) boricacidTitration1) with NaOH2) with HCl16
Distillation and Titration (2)17
AOAC official methodsCombustionMethodMatrix992.15Meat and meat products992.23Cereal grains and oilseeds997.09Beer and brewing grains18
Flow Chart for HomogenousHomogenousSampleSamplei)i) Furnace,Furnace,temptemp 950950 C Cii)ii) ectionsystemsystemReadReadresult,result,%N%N19
Instrument requirementSample size : 200 mgWorking rangee.g. 0.5% to 60% protein 0.08% to10% N20
Combustion Instrument21
Available proficiency testFAPASAOACLGC22
CRMNISTBCRLGC/ERM23
Thank You24
AOAC official methods Combustion 997.09 Beer and brewing grains 992.23 Cereal grains and oilseeds 992.15 Meat and meat products Method Matrix. 19 Flow Chart for Combustion Homogenous Sample Homogenous Sample Combustion instrument i) Furnace, temp 950 C ii) Isolation system
protein:ligand, K eq [protein:ligand] [protein][ligand] (1) can be restated as, K eq 1 [ligand] p 1 p 0 (2) where p 0 is the fraction of free protein and p 1, the fraction of protein binding the ligand. Assuming low protein concentration, one can imagine an isolated protein in a solution of Nindistinguishable ligands. Under these premises .
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of protein assay for research applications. Protein assays based on these methods are divided into two categories: dye binding protein assays and protein a ssays based on alkaline copper. The dye binding protein assay s are based on the binding of protein molecules to Coomassie dye under acidic conditions.
biological significance of protein complexation with RNA has been well recognized, the specific mecha-nism of protein–RNA interaction is not fully understood [10]. Measurement of sequence–specific DNA– protein and RNA–protein interactions is a key experimental procedure in molecular biology of gene regulation.
protein-protein interaction data and the protein sequences. In particular, our method as-sumes no knowledge of the 3D protein structure, or of the sites at which binding occurs. Our approach is based on the assumption that interaction sites can be described using a limited repertoire of conserved sequence motifs [11].
x Determine protein concentrations using the Biuret Protein Assay. BACKGROUND The determination of protein concentration is an essential technique in all aspects of protein studies and proteomics. This lab activity is designed to teach students the principl es behind a common protein es
Furthermore, high protein diets may also be more likely to help keep the weight from coming back, improving weight maintenance, due to better compliance and increased satiety.3,4 Because high-protein diets gain intermittent popularity, it is likely that some patients and clients will seek guidance from RDs when considering whether to try a high .File Size: 379KBPage Count: 12Explore furtherNine Ways to Limit Fat Intake Healthy Eating SF Gatehealthyeating.sfgate.comHigh Protein Diet Plan for Weight Loss Protein Food Listwww.dietdoc.comHow to reduce your carbohydrate intake to lose body fatsteptohealth.comNutrition Management Guidelines – Ketogenic Diet Page 1 of 3www.kdheks.gov6.4: Protein Recommendations - Medicine LibreTextsmed.libretexts.orgRecommended to you b
Diets containing 20 % or more of their total energy as protein have been labeled “high protein diets” and those containing 30% or more energy as protein have been dubbed “very high protein diets” (18). Accordingly, a “high protein diet” for the aver
