Determination of Crude Protein Content (Part-1)_A Complete Procedure (AOAC 2001.11)
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- čas přidán 27. 07. 2024
- Determination of crude protein content is a common proximate analysis. This parameter is very important for the analysis of food and feed sample. This video represents the detailed procedure of protein analysis by the Kjeldahl’s Method.
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It's truth that CZcams have less video like this. I am assistant professor and some time professor also need this type of video for students to make them understand. I highly appreciate this one and will also show to students. Thanks for this.. and add many more like this 😊
It means a lot to me. Thank you so much for the appreciation. Please share my videos in Your circle/site.
I get a lot of knowledge from youtube MicroChem's Experiments. Very clear and in accordance with apllicable work procedures. Thank you very much.🙏
Thank you so much for this, I was asked to do this analysis at work and this video was really helpful. Thank you so much
Thanks
Thanks a lot...for making practical videos...its most most important for clarification of concepts
Rajesh Tayade, Thank you very much for your comment. Be with us.
Thank you so much. Very useful for me.
Make more practical videos like this.
Mention the parameter
😍👌Really appreciated one..So simplistic, but perfect👍..I always choose your videos as prime for my doubts..☺️also sub teacher also preferred it than other..and what might be the reason 😁.. Keep going 🤗
Thank you so much 😀
Outstanding production ❤️❤️
Thank you Afroza ! Cheers!
Thank you, for this detailed video
Welcome to the channel. Stay with us for more
Really helpful video thanks again.
You are most welcome
The details of methods very nicely described.
Thank you so much.
Very helpful and detailed video. Really very good
Glad it was helpful!
Please how did you get the wheat factor? I’m working with starch, how can I get the factor to enable me do the calculations
Thanks alot for better understanding 😇May Allah bless you always
Thank you so much
Excellent in a word !!!!!
Thanks
I would like to thank you for the clear and precise explanation. Could you please tell which book edition you took from this procedure (AOAC 2001.11).
can you use dehydrated mealworm (in the form of powder) as the homogenized sample to determen the proteine content
Merci beaucoup de m'avoir aider merci et 1000 Merci
Can you help me calculate protein levels from the following data, I use the back titration method example: titration blank (NaOH: 0.1016 N) = 24.88 ml titration sample (NaOH :0.1016 N) = 22.17 ml sample weight = 0.1548 gr
Which method is used for extracting soybean seed protein...please give any reference for thesis..?
Which type of heating element is best... Wire Mesh type or Hot Plate type? & Why? U r using hot plate type
Please tell about the formation of methyl red indicator used in the titration process ?
How methyl red indicator is prepared ?
Thanks alot Sir
Really great work.
Thanks
Thanks. It is useful lesson.
Abdisamad Hassan, you are most welcome. Many more videos are waiting to be uploaded. Thanks for being with us.
good presentation and i like the classical here
Thank you. Stay with us
Tysm😊❤
Informative content👌👌👌
Thank you so much
Please i need procedure for true protein analysis in feed and calcium and phosphorus in feed
highly appreciated .add one.more on full atomatic protein analyser
Noted. We will upload soon
Is this same for fish feeds too I mean the procedure ?
This video is really helpful...but how we will get different factors of sample please tell...i mean how do you get to know the wheat grains factor is 5.70....how to calculate this factor of any raw material please explain
Thanks it is very helpful
Thank you too
highly apprecible ,many thanks
kindly requested for making videous on calcium and phosphorus analysis using spectophotometer
Will try
Thank you so much
You're most welcome
What is the name of the Catalyst you mixed with the concentrated H2SO4? Thank you very much !!!
More about catalyst in this video: czcams.com/video/ApdUDq9EhLE/video.html
You should add the sample in the distillation vessel first and then add NaOH-solution. In the procedure shown on the video sample will react with NaOH-solution in open and it leads loss of nitrogen in form of ammonia. Also the receiving part should be under the liquid level.
Thank you for your findings.
In AOAC, it is not said to keep the receiving part under the liquid level. And in this way, shown in this video, we get the expected results. This is because the loss of nitrogen is negligible. Anyways thanks for your suggestion.
@@MicroChemsExperiments It is obvious in this case that it has to be under liquid level. Also Kjelldahl method is pretty old and it has always been that way and finally it is stated in the AOAC 2001.11 in part "Distillation" "Place graduated 500 ml Erlenmeyer titration flask containing 30 ml H3BO3 solution with indicator on receiving platform, and immerse tube from condenser below surface of H3BO3 solution."
@@BadPete81 Okay. Thank you for your information.
It is very important to keep the recieving funnel under the solution as nitrogen can escape!
Thank you for a wonderful explanation of protein estimation, it will help me a lot . Thanks man 👍👍
You are most welcome. Stay with us.
Can we use this testing method to analyze protein sample in whey protein products that are on market?
Obviously, you can apply this method for testing Whey Protein
CZcams had lack of this kind of videos. Thnaks for sharing. Hope you will upload every analysis. Any link for the AOAC methods?
Iftekhar Kabir, Thank you so much for being with us. Lots of videos are yet to upload. AOAC methods are not publicly available in internet. We have AOAC official book which was purchased from AOAC officials.
@@MicroChemsExperiments please, could you sent me this Book or AOAC mehtod in pdf, I need these methode for m'y studies, thanks you.
@@taharhanafi7928❤a
In the calculation equation V1 is the volume of unused boric acid but we need the actual volume of used boric acid, so here you have use 30- V1 instead of V1
Please clear the doubt as soon as possible
outstanding
@Livestock Pdoduction, Thank you so much. Be with us.
how is the sample prep for liquid samples? do we weigh it in g also?
Liquid sample should be weighted in gram. So take 2g liquid sample for testing.
Sir I have a doubt while titrating can we add mixed indicator in place of methyl red?
Mixed indicator combines both methyl red and bromocresol green
I don't know any reference method of using mix indicators. I'm not sure about that
do AOAC 2001 and AOAC 2005 are the same? in procedure and equipment etc
Yes. Same procedure and equipment
could you please explain from where did 10 come from in the equation for nitrogen
This calculation is derived from AOAC official method. So they used Kjehldahl's method and provided equation for calculation based on the difference steps of this method. So, please study about Kjehldahl's method to get proper explanation. Thank you.
Please further explain me the presence of number ten (10) in the divisor of the "Nitrogen percentage formula"??
Later
how will I know the acid factor (f1)?
RM G, the acid factor (f1) in the equation of protein determination is given by the method AOAC 2001.11. So, find the acid value in AOAC 2001.11.
For plant samples, should it also be homogenised???
Your sample should be ground before the analysis.
Very detailed video! One quick question, can I know if I can use this method for liquid sample? How the method will be when I want to measure the weight as my sample is liquid?
Yes. This method is applicable for liquid sample also. You can take 2g of liquid sample in a glass beaker first. Then transfer the weighted liquid sample from breaker to digestion flask quantatively washing with 20 ml sulfuric acid and add catalyst & heat the digestion flask to digest your sample in presence of acid and catalyst.
@@MicroChemsExperiments Thank you for the explanation!
@@amninazifa5244 you are welcome
why you turn off the distillation is obtained 100 ml of distillate? Could we done to finish the distillation?
Do not wait to finish the distillation. It will cause to crack on the flask
what will be the acid factor of h2so4?
thank you
Not sure actually. Please use HCl
Sir sample or catalyst ke baad h2so4 he kyo daalte hai
may i know the sample used ?. And if i prepare my chemical , how long to keep them before using for analysis ?
Wheat flour sample. You can store prepared chemicals for 6 months.
Nice video, but subtitles made my day - "Open the vulve to drain....Now close the vulve"😂
Thanks anyways
Hello sir what other alternative technique can we apply for the determination of crude protein ????
There are some automated protein analyzers. You can use those equipment
Please howmuch weight can take from fresh or wet plant sample
You should take 4g
Do you prepare the same method for blank but just skip the sample into balance?
Yes, exactly
Very nice explanation, kinley share the AOAC document with us
Sorry we don't share any document
How can we determine the value of protein in raw vegetable?? Is it necessary to make powder form of vegetable??or we can use 2 gm of raw vegetable....
Just use 2g raw sample
Can this be used for knowing protein content of bacteria grown in broth culture?
Not sure. You can try
can we use this method for rice which are available in market
Yes
Why not use FeSo4 replace serenium Dioxide...which catalyst weight after 2 gm sample
I`d prefer titanium oxide
Can we use this method for fish muscles protein analysis ?
Yes
Can I get protien percent in soymilk. If after calculation result saying protien percent is 3.4 than we can say it 3.4 gm in 100 gm of soymilk or not.
Yes
Is this method will same for insect protein determination ??????
Yes
At 12:24 why are you adding more distilled water?
To facilitate proper distillation in a large volume of solution
It was a very useful video. Can you elaborate more on how to run blank digestion and distillation? Thank you in advance.
Conduct the blank digestion and distillation as same as sample. Just dont add sample in the flask during digestion.
Thanks for being with us
@@MicroChemsExperiments Thank you for the quick reply. We are trying to implement the Kjeldahl's method exactly as explained in the video. However, during titration using methyl red indicator, the color shift appears to be very gradual and some times its very difficult to distinguish the color shift from yellow to orange. This might lead to mistakes in end point determination. Any suggestions to improvise?
@@guruprasadk3848 Endpoint should be counted just at the point in which drop of 0.1N HCl the color turned into orange. Do the titration slowly and carefully against white background. Do saveral trial and try to do accurately. Your skill will develop with time.
Another sugestion is determine the protein of known sample (eg: Pasteurized milk has a protein value of 3.5 to 3.7) in several trials and match the known protein value in diferent titration values of conducted trials. In this way you will be a skilled analyst.
@@MicroChemsExperiments Thanks a lot for your suggestions... will contact you through your facebook page incase of further queries... keep up the good work... cheers!!!
@@guruprasadk3848 Thanks for being with us.
How can I find the text version of this?
The link of Part 2 of this method is here: czcams.com/video/ApdUDq9EhLE/video.html
Ok so quick question does the flask have to be a kjeldahl flask or can I use a volumetric flask if the first is unavailable? Also can I digest it on a soxhlet?
You can't digest on Soxhlet because the fume of H2SO4 will spread-out all over the lab and Env. There is no fume receiving system in Soxhlet.
@@MicroChemsExperiments Oh ok thank you for clearing that up
@@kadelin3318 You are most welcome.
Sir, how to prepare 2% boric acid indicator ?
Reagent preparation for protein analysis is given in this video: czcams.com/video/ApdUDq9EhLE/video.html
In calculation for %nitrogen why we multiply 10 by weight of sample in denominator
It is a simplified formula. 1000 was multiplied with the sample weight to convert the weight in mg from g. But after simplification, 1000 became 10
thank you so much
You are most welcome
@@MicroChemsExperiments ☺
So why did you use 0.1 as the Normality of HCl in your calculation and not the exact 0.0975 N from part 2? That you worked when you titrated HCl against NaOH using phenolphthalein ad your indicator?
Very smart...
You are right. But I did not used the exact chemicals prepared in part 2 for protein titration. Rather I used 0.1N HCl and thats why I calculate protein using 0.1N.
Part-2 video is prepared in different time, just to show you about the preparation.
@@MicroChemsExperiments Got it!.
What about if we use 0.5N sulfuric acid as the titration?
7.003*volume of H2S04 in ml * Nf*100 / weight of sample = % nitrogen
You can use. But in the calculation, count 2 as acid factor
can you please tell what is acid factor?
Each acid have a factor when it is used in a titration. For more, take help from Google
Is this method applicable for dehydrated fruits?
Applicable
Another one question..if I need to prepare catalyst on my own, how much will be the potassium sulphate+copper sulphate+selenium dioxide that I need to use to make the catalyst?
Every details of the reagent preparation is given in this video: czcams.com/video/ApdUDq9EhLE/video.html
@@MicroChemsExperiments thank you!
@@amninazifa5244 You are welcome
Can you make some videos on sugar lab chemist working and all test like determine Rs reading and it's benefits and losses
Noted
the AOA method uses the molarity of HCL in the calculation, why did you use normality?
thank you
For hydrochloric acid the normality and molarity is the same (equal). So, no matter what I wrote. You can write molarity.
@@MicroChemsExperiments okay thank you
RB oil me gums and wax kaise chek kre eska vdo banaye sir
Noted
Very Nice
Thank you
From where did you drive the %N determination formula and why didn't you run the blank
Though the formula in AOAC 2001.11 method is different from yours and they also subtracted the concordant reading of the Vs fron the Vb
Hadiqa Iqbal, Thank you for your questions and observations.
First of all, we used %N determination formula from AOAC 2001.11 method which is modified in two places:
1. we didn't use burette reading of blank (Vb) because we didn't conduct any blank digestion in this experiment.
2. We used additionally Acid Factor (F1) which is not mentioned in AOAC book but used by the FAO method of ''Quality assurance for animal feed analysis laboratories, Page-90''.
***We didn't go for the blank digestion to simplify this method and we conducted several studies in our lab and found that there is no significant different in the protein result when we don't run blank digestion.
***Acid factor is only necessary when you want to titrate with any other acid rather than HCl.
So, If you want, conduct a blank digestion along with sample (as it gives more accurate protein result) and substract Blank Burette reading from the Sample burette reading. You can also ignore the acid factor if you always use HCl in the titration.
Thank you.
As far as i have studied if we are placing normality value of acid we don't add acid factor in calculations. As far as acid factor is concerned it always gets include into the calculations when we note molarity instead of normality
Is that so ?
Can you share the method of fao with me plss
@@hadiqaiqbal795 As the acid factor is 1, so you can remove it from the calculation thus creating no differences in results.
But if you use other acids like H2SO4, then you need to add acid factor in the calculation. In case of HCl, no need to use and Factor for Acid.
@@hadiqaiqbal795 Knock in our facebook page for FAO method.
Mam please make video of non Protein nitrogen procedure and calculation.
Noted
Can anyone tell me how to clean these kjeldahl's flask?
Soake in 10% HCl overnight. Clean with soap solution next day
It is really helpful but i am unable to get results while testing for DOC . At time of digestion colour is not changing to green …. The sample gets totally black and after 2 hours or more than that unbale to get results… please suggest sir
Which sample are you testing?
De oiled rice bran
Can you please tell me the name of the method or how can I cite it.
Also can I know the method can be used in soil. What will be factor for soil
You can use the AOAC method number in the title in your reference to cite. This method is not applicable for soil sample.
@@MicroChemsExperiments can you recommend me a method applicable to soil
@@nitikanarang6553 Ok we will let you know later.
Why did you add concentrated H2SO4 solution in the Kjeldahl flask so close the balance machine? It isn't a good procedure.
Mauro Korn, thank you for your observation. I should use fume hood during handling H2SO4. We actually did it intentionally to shorten our video time, focusing only on the procedure. But normally in our lab we use fume hood.
@@MicroChemsExperiments , Today I will suggest and comment this video with my students. Considering the covid-19 pandemia, it is the best option to explain and to discuss practical procedures with our students. Thanks!
@Mauro Korn
Thank you Sir for choosing my videos. We are very much happy to be a part of your Practical Classes for your students. Be with us.
I want to know what samples did u used? Thank you!
Ainen Lagroma, Thanks for your comment.
We used low protein feed (raw materials) sample to test for protein determination, in this video.
@@MicroChemsExperiments thank you so much for responding! Does this method can also applied in liquid samples? Can't seem to find any information using a liquid sample.
@@ainenlagroma3644 Yes. You can apply this method for testing a liquid sample for Protein determination. Take 2g liquid sample (Ex: Milk) in the digestion flask and carry out the experiment in the same way as shown in this video.
Is the same procedure applied to find out the protein of raw vegetables
Yes. Same method
@@erikalee9357 Yes you can test coffee beans also
why are we titrating acid with acid?
also, I didn't understand the dilution factor. would you be kind enough to explain it in detail
thank you
the dilution factor is of the solution in receiving flask that contains boric acid?
This calculation is derived from AOAC official method. So they used Kjehldahl's method and provided equation for calculation based on the difference steps of this method. So, please study about Kjehldahl's method to get proper explanation. Thank you.
How to find factor value
Factor is defined by AOAC. AOAC method did not explained the derivation of factors
How to prepare the catalyst
czcams.com/video/ApdUDq9EhLE/video.html
i font understand the dilution factor.which chemicals dilution factor are we taking?
Your question is no clear. Please rephrase it
sorry. i didn't understand the dilution factor.could you please explain it. how did dilution factor become 10
Sir distillation collecting reaction name
Condensation
What about blank value?
Blank should be carried out to get more accurate results
Do you have aoac procedure pdf?
No
what is the exact calculations for conversion factor 6.25? pls
There is no calculation to be known for the conversion factors. AOAC gives the factors, thats all.
@@MicroChemsExperiments ok. Thank you.
@@mujahidkhan1692 You are welcome
Why did you use the dilution factor?
the AOA didn't use it.
please provide a reasonable answer
thank you
During the distillation, We used 10 ml digestion juice from 100ml total volume. Thats why the dilution factor is (100/10) 10.
@@MicroChemsExperiments I mean why was there a need for the dilution factor?
thank you
@@bandaid.7878 when you analyze a portion of digested sample (rather than using total volume of sample), then you need to use the factor
Nice
Thank you so much.
Stay with us.
What are the limitations of this protein determination experiement.... And why we use NaOH??
We will make video later explaining the chemical reactions
OK I can wait for it.... Thank you
Can I get limitations. Also tell what are the precautions need to take to get accurate result. I mean during digestion, distillation etc.
I have added in hot digested sample 10 ml distilled water and than 40 percent naoh there is so much splashes coming from the flask and than flask was broken.
I need to get proper results. Can I follow same way u shown in vedio to get protien in soymilk because I m not getting proper result. May be doing some mistakes somewhere