Hello everybody
Through total phenolic assay I've obtained 47.6 mg/g plant sample as a final result, but this is presented in wet basis (w.b). It was recommended that moisture content (84.5%) must be applied to express the result in dry basis (d.b.) through the following operation:
47.6 x (100 / (100 - 84.5)) = 307.09 mg/g plant sample (d.b.).
As you see, this value is six times higher than initial one. If there is a mistake or it is not the appropriate operation, I'd like your advice about how to express mg/g (w.b.) in mg/g (d.b.).
Thank you in advance.
Dear Silva,
Your value 47.6 mg/g denotes 15.5% dry matter basis. So 1g dry matter contain (47.6/15.5) mg/g phenolics. Hence phenolics on 100% dry matter basis can be expressed as (47.6/15.5)x100. Your calculation is right only.
Dear Andrés Silva,
If your sample includes in %84.5 moisture content. You could calculate your total phenolic content;
100 g - 84.5g = 15.5 g dry matter in your sample
IF 47.6 mg total phenolic content / 0.155 g dry basis,
HOW MUCH X g total phenolic content / 1 g dry basis
47.6*1/0.155=307.1 mg TPC/ g dry sample.
Dear Silva,
Your calculation is correct however, the value you obtained looks strange as your sample shows, about 30% of phenolics on dry weight basis. By the way, which plant was used in your experiment?
Thank you all for replying
Great, Dr. Shiva could you explain why value is strange?
Please can any one explain this calculation from the extraction to final results by simple way???
Dear Silva,
Plants with high phenolic compounds are cloves, Star anise, Cocoa powder, Mexican oregano etc. They contain up to only 15188mg/100g. But your data shows 30700 mg/100g (30.7g/100g). For more details you can see the following link:
http://www.nature.com/ejcn/journal/v64/n3s/full/ejcn2010221a.html#bib11.
Also If you provide the information about the extraction process ( direct extraction, enzymatic extraction), plant name/parts, It will be easy to understand the matter.
Dear Dr. Shiva
I'm researching quinoa. Extraction was performed through solid - liquid extraction.
On the other hand, TPC of cloves, as other foods, are expressed in Fresh Weight according to information you gave. Their value would be higher in Dry Basis.
Thank you
The humidity content (h) for the humid sample can be given, in relative % basis, as: h = (mass of hygroscopic H2O / humid mass)·100%. Let us call the humid mass Mh, while the dry mass is denoted by Md, and the hygroscopic H2O by W = h·Mh (water balance). The total mass balance for either the humidification of the dry sample to obtain the humid sample, or for the opposite drying process, writes: Mh = Md + W = Md + h·Mh; or, [1/(1-h)]/Mh = 1/Md. Hence, the conversion formula of a given mass ratio expressed in humid basis as, wh = (m/Mh)·100%, to the corresponding dry basis, wd = (m/Md)·100%, is given by: [1/(1-h)]·wh = wd.
One more question:
If I do the following equation:
47.6 x (100 / (100 - 84.5)) = 307.09 mg/g plant sample (d.b.).
Then, is it based in 1 g of plant sample or 100 g of plant sample? Because it is multiplied by 100 in the numerator.
Thank you all for your answers.
Dear Andres Silva
In equation 47.6 x(100/(100-84.5), the 100 in numerator is not for conversion into 100 g dry basis. This 100 implies the 100% basis for dry mass basis. 307.09 mg is in one g of your sample on dry mass basis.
Alternately you can use
47.6/15.5 x100 = 307.09 mg/g DW.
While if you want in 100g you have to multiply 307.09 with 100 to get mg/100gDW
Dear Andres Silva
In equation 47.6 x(100/(100-84.5), the 100 in numerator is not for conversion into 100 g dry basis. This 100 implies the 100% basis for dry mass basis. 307.09 mg is in one g of your sample on dry mass basis.
Alternately you can use
47.6/15.5 x100 = 307.09 mg/g DW.
While if you want in 100g you have to multiply 307.09 with 100 to get mg/100gDW
- Badges
- Science topic
- Similar topics
- Microbiology
- Assays