mcspencah

The proteins we extract from the potato's are used as a replacement for animal proteins. They are used in plant based meat, dairy, cheese and ice cream! It's a relatively new process and really interesting.

Hello,

I'm doing analysis on potato juice and i just got the XRF analysis results from the lab. The results show many different metal concentrations dissolved in the juice(like potassium and sodium). What do these concentrations mean. Is it the overall metal concentration, including iron complexes for example? Or is it just the ion's in the sample like Fe2+ and Fe3+?

Thanks in advance.

12 hours ago, studiot said:

One thing you can say for sure.

If there were no dissolved ions conductivity would be very low.

I can see that English is not your first language, but the more information you can provide the better.

Do you still have access to the meter?
Can you tell us what make and model it is ?

If you know these things can you tell us if it is an ac or a dc type and if it is ac is it high frquency or low frequency?

It is a great shame you cannot investigae the variation of conductivity with amount (concentration) of the pulp material.

I did have a small wonder if the pulp fibres might spread out like tiny filaments and string out the ions along them so providing a network of conductive paths like tiny electric wires.

The point about polarisation is that ions congregate around electrodes of the opposite polarity to themselves and get in the way of each other.
This discourages futher ions from travelling towards that electrode. This may not happen in the original soup containing the pulp.
Overcoming this requires an additional voltage and a small handheld meter might not develop enough voltage to drive the measurement.

You say it was a conductivity/pH meter.

Did you also measure pH?

If so, was there any difference in reading between the 'soup' and the strained liquid?

Here is someone else who measured lower conductivity than expected in mixtures a bit like yours, due to pH.

 

Thank you for the great reply's but i already found the answer. It seems that during the centrifugal separation the fruit juice get's diluted by about 15% which explains the drop in conductivity.

58 minutes ago, John Cuthber said:

It's certainly odd. I'd have expected the opposite effect.
I can think of one possibility.

If the unfiltered juice contained intact cells and those were broken during the filtration process then it's possible that their contents were less conductive than the surrounding liquid.
That's possible, but seems unlikely- I'm not sure how you would test it.
 

Does it get hot during filtration?

Is it being filtered on an industrial scale- could you try with a smaller rig- say a laboratory scale  with a flask, funnel and filter paper?

Thank you for the reply.

I'm unfortunately not allowed back at the factory as an intern because of the current epidemic so I'm not able to do more experiments.

The separating(done mechanically with industrial decanters with centrifugal force) process runs at normal temperatures because higher temperatures will denature the wanted proteins in the fruit juice.  And i think all cells are broken when the potato's are grinded into a pulp.

So from my understanding so far suspended solids shouldn't have an impact on conductivity? I'm finding a lot about the relation between dissolved solids and conductivity but not about suspended ones.

2 hours ago, studiot said:

No answers to my two most crucial questions so read this for yourself.

http://www.vl-pc.com/index.cfm/technical-info/conductivity-guide/

Thank you for the reply. I'm having trouble understanding electrode polarization. Doesn't this only happen with dissolved ions? And would an over-voltage mean an higher measured conductivity?

1 hour ago, joigus said:

I assume it's an aqueous solution, which is polar. Starch has some polarity if I remember correctly, because carbohydrates have covalently-bond oxygen with unpaired electron pairs, although they're not very mobile, because they're macromolecules (very macro in the case of starch.) You should be watchful that you're not removing conductivity-enhancing ions like K⁺ or Ca²⁺ or similar also. But wait for the experts. I'm not one. Maybe just a cue for someone to further clarify.

I will look into the polarity, thank you for your answer. And the separating is done mechanically with centrifugal forces so they do not separate dissolved molecules.

34 minutes ago, studiot said:

This is posted in homework help, so was this a lab experiment you made?

If so can you provide more details for instance

How 'thick' was the original suspension ?
Did you make any tests with differeent amounts of particle removal?
How was the conductivity measured?
Have you heard of electrode polarisation?

No, i'm doing quality analysis in a running factory. I've only measured the conductivity with a simple pH/conductivity meter.

The juice is still full of other components like proteins,sugars and many other compounds.

But i'm seeing a pretty significant reduction in conductivity after the fibers and starch are separated from the juice so i was wondering if suspended solids do have an effect on electrical conductivity.

31 minutes ago, John Cuthber said:

Is anyone actually extracting juice from potato fruit?

Yes, to extract proteins

edit: from potato's, not potato fruit. The extracted juice from potato is called potato fruit juice 😛 

Hello, I'm writing my thesis and i was wondering the following;

Do suspended particles in a solution conduct electricity?

I see a decrease in conductivity after separating suspended solids in a solution (starch and fibers in a potato fruit juice solution).

It's 10-20% reduction in conductivity. I'm wondering if this is a result of the separating of the solids or if there is another reason.

Thanks in advance.