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Subject:
From:
Rakesh Bhardwaj <[log in to unmask]>
Reply To:
Rakesh Bhardwaj <[log in to unmask]>
Date:
Mon, 25 May 2015 00:38:26 -0700
Content-Type:
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Dear all

It to clarify any doubts w.r.t. estimating ash and protein in dietary fiber estimatioon.

If we go by protocol you will find we use protease to digest protein and convert it to amino acids and small peptides which are filtered through dried and pre weighed sintered disc cruicbles having celite bed. Hence amount of protein left after this step is very small but that can not be ignored.

Similarly in entire process of dietary fiber estimation we are using buffers (which can increase minerals!! and solublisation of minerals in samples can reduce the minerals!!) hence amount of minerals in residue after digetion by enzymes, precipitation and drying is not the same as was in the sample initially.

Hence it is essential to estimate ash and protein after enzymatic treatments and other steps of dietary fiber estimation. if we will use original protein and ash value it will give erronious results.

One may counter if that is so, we can avoid atleast using protease in dietary fiber estimation, but proteases play vital role in loosening the food matrix and thus helps in compleate extraction of non-fiber components. Moreover, suposidely if one does't uses protease (it will be big deviation from official method) even then we will be loosing soluble proteins to buffers and alcohol and again the ammount of protein will be much less in dietary fiber extraction residue than to initial ammount in sample.

I hope it clarifies the doubts.


Dr. Rakesh Bhardwaj
Senior Scientist (Biochemistry)
Germplasm Evaluation Division
National Bureau of Plant Genetic Resources (NBPGR)
PUSA Campus, New Delhi - 110 012
India
Phone (+91)11-25848074(O),(+91)11-25842495(Fax)
      (+91)9560487889 (M), (+91) 9015405449

--------------------------------------------
On Mon, 5/25/15, Najma Memon <[log in to unmask]> wrote:

 Subject: dietary fiber
 To: [log in to unmask]
 Date: Monday, May 25, 2015, 3:12 AM
 
 Dear
 all,
 we are working on
 determination  of  dietary fiber by Prosky method. It says
 that after enzymatic treatment, weigh the residue and
 calculate the difference by subtracting ash and
 protein.
 Do we need to
 determine ash and protein of residue after all enzymatic
 treatments or it is fine to subtract protein and ash values
 obtained for whole food?
 Thank you in
 advance.
 Dr. Najma
 Memon,
 
 Associate
 Professor
 NCE in Analytical
 Chemistry,
 University of
 Sindh, Jamshoro,
 Sindh,
 PakistanEditor:
 Pakistan Journal of Analytical and Environmental
 ChemistryAssociate
 Editor: Journal Chemical society of
 Pakistan
 Tel:
 +92(22)9213429
 Fax:+92(22)9213431
 
 
 
 
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