I am trying to study on minerals, amino acids, vitamins and enzymes of different fruit juices/natural syrups. However, because of a high concentration of polysaccharides and sugars (e.g., glucose and fructose), it is difficult to get high concentrations of the interested above compounds. Moreover, most of available procedures are performed under intensive conditions (e.g., using acidic and alkaline conditions) or expensive (e.g., HPLC). Could you please guide me in this respect?
As I recall (its been 40 years), I used a Biorad(?) S15 media which only elutes small molecules and not polymers like carbohydrates.
Dear Bruce,
Many thanks for your answer. But, what about bio-molecules like glucose and fructose?
They are not really bio-molecules like proteins and will pass through as they have low molecular weight. However, the primary end will not react as long as the sample is not heated or immersed in acid or base.
Dear Alireza Golnaraghi
What worked for me in the past was to treat the sample with a cation exchanger. Any compound interacting with the cation exchange resin will be retained, while the carbohydrates will pass. Then elute the "cationic" species of the resin and perform the analytical determination you need.
Treatment with an anion exchanger will work similarly if you keep the sample pH below 12. Most carbohydrates deprotonate at pH > 12 and would therefore be retained. We used commercially available ion exchange resin in bulk and prepacked SPE cartridges depending on the specific workflow demands.
To create a proof of principle, I'd suggest the bulk approach first - usually less expensive. Once you know the general route to take for your sample, switch to the SPE cartridges - I would suggest.
I hope this helps!
Good luck with your research!
Cheers
Detlef.
Thanks for your technical notes. Another question: can we remove such monosaccharide sugars by enzyme polymerization, and making big polysaccharides? Such big molecules could remove easily by ultrafiltration.
If possible, which enzymes and protocols should be employed?
Not really. Most of the enzymes I have encountered have cleaved the covalent bond holding two monsaccarides together (like the bond that is cleaved in sucrose by isomerase to produce glucose and fructose).
I feel that the presence of sugara and polysac. won’t alter the estimation of proteins, minerals and vitamins
Dear Rohit,
I agree with you that the presence of sugars and polysac won't alter the estimation of proteins, etc. But we need their removal for detailed characterization and measurement of the remaining components.
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