Can I use blanched spuds for osmosis practical?

Julie Delaney

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Hi All,
HOD has decided it is now my job to cut up the spuds for the osmosis practical because one of our illustrious teachers had the cork borers nicked from his lesson. To this end, can I cut up, blanch and freeze a job lot and defrost as necessary?

Thank you.
 
Hi All,
HOD has decided it is now my job to cut up the spuds for the osmosis practical because one of our illustrious teachers had the cork borers nicked from his lesson. To this end, can I cut up, blanch and freeze a job lot and defrost as necessary?

Thank you.
I've never tried blanching and only ever used fresh I think you'd have to trial it if you went down that route. Have you tried using a chipper rather than cork borers? Get lots of identical tubes of potato (all be it square rather than round) very quickly that fit a boiling tube perfectly. If they want cylinders here they cork bore themselves. We're happy to 'chip' the potatoes for them though.
 
https://www.lakeland.co.uk/15842/Ch...nAzoyK5QIVj0PTCh3YtQYzEAQYAyABEgLZ2_D_BwE:G:s

I use this one. Good for potato and beetroot (with care). Don't use it for sweet potato though or you will wreck it! Produces chips that will need to be cut to the same length (by you or the students!) No need to peel first as the ones around the edges with skin on will be the wrong shape anyway!
i have one of these
https://www.amazon.co.uk/KitchenCraft-Potato-Chipper-Vegetable-Machine/dp/B0001IWVO4
(make sure the levers are metal, had one from argos that was plastic it went back broken after one lesson)
, cut the potato to length and bosh it through the chipper.

Much less waste. :)
 
I find that, with the lever chippers, tapping the handle (albeit quite heavily) rather than trying to gorilla it through a spud makes for less pain, breakage and distortion. It's so much easier using the chipper that a little bit of extra time spent is as nothing to using cork borers. And there's less wastage.

Part (maybe all) of the reason for using discs is to make the students work out the volume of a cylinder. When this was pointed out to me the first time I used a chipper, I gave the teacher one potato and asked them to make as many cylinders out of it as they could. I think they managed three before they gave up - and in.
 
Hi All,
HOD has decided it is now my job to cut up the spuds for the osmosis practical because one of our illustrious teachers had the cork borers nicked from his lesson. To this end, can I cut up, blanch and freeze a job lot and defrost as necessary?

Thank you.
The answer to blanching and freezing or freezing with or without blanching - definitely NOT - freezing will causing crystals of ice to form and will most likely disrupt the cell membranes which would render them useless for osmosis - you can try if you want. You might get away with it if the tissue is in small quantities and you immerse it in liquid nitrogen which will freeze the water in the cells too quickly for crystals and form.
 
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Chip cutter all the way for me. I use one like Paul posted (2nd time around, for the same reason as Paul). Chipped some spuds for first lesson today, only took a couple of minutes.
 
Two years ago I had to cut 450 x 4cm long pieces of potato for an exam practical - I got through two sacks of potatoes as there was a lot of wastage trying to get the 4cm long pieces. If it wasn't for my chipper I would have gone crazy!!!

I would not used blanched/frozen potatoes for the reasons outlined by Peter
 
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Hi All,
HOD has decided it is now my job to cut up the spuds for the osmosis practical because one of our illustrious teachers had the cork borers nicked from his lesson. To this end, can I cut up, blanch and freeze a job lot and defrost as necessary?

Thank you.
Two years ago I had to cut 450 x 4cm long pieces of potato for an exam practical - I got through two sacks of potatoes as there was a lot of wastage trying to get the 4cm long pieces. If it wasn't for my chipper I would have gone crazy!!!

I would not used blanched/frozen potatoes for the reasons outlined by Peter
The answer to blanching and freezing or freezing with or without blanching - definitely NOT - freezing will causing crystals of ice to form and will most likely disrupt the cell membranes which would render them useless for osmosis - you can try if you want. You might get away with it if the tissue is in small quantities and you immerse it in liquid nitrogen which will freeze the water in the cells too quickly for crystals and form.
Blanching is a new one on me Julie. I agree with Peter and Lesley about the disruption of cell membrane integrity. Also if your aim is to determine the Osmotic Potential within the Potato the timing of Chipping or Boring the spuds is critical- this should be done no more than an hour before the practical.:);)
 
Blanching is a new one on me Julie. I agree with Peter and Lesley about the disruption of cell membrane integrity. Also if your aim is to determine the Osmotic Potential within the Potato the timing of Chipping or Boring the spuds is critical- this should be done no more than an hour before the practical.:);)
I agree as the 'chips' start to degrade quite quickly (dry out/form an impervious layer or take up water/lose water if you keep them in a solution) - that's why you should let them do it themselves during the lesson.
 
I agree as the 'chips' start to degrade quite quickly (dry out/form an impervious layer or take up water/lose water if you keep them in a solution) - that's why you should let them do it themselves during the lesson.
Wish I'd had the option of having the pupils cutting their own chips for the exam. Not only did I have to chip the potatoes, I also had to weigh them, put them in 5 different salt solutions and write the weights on the test tubes; for 450 different pieces. These were the instructions from the exam board! I practically did the whole experiment for around 90 pupils! Quite the responsibility!!
 
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Wish I'd had the option of having the pupils cutting their own chips for the exam. Not only did I have to chip the potatoes, I also had to weigh them, put them in 5 different salt solutions and write the weights on the test tubes for 450 different pieces. These were the instructions from the exam board! I practically did the whole experiment for them!
LOL, sounds like here!
We techs prepare them, using No 5 Cork Borer, & cut them to all similar length. We do this in the morning for an after lunch lesson. We then lay them on Damp paper towels in a tub, cover with damp paper towel & all good for lesson. We used to put them in water but that was bad idea. Ooops.
Heaven forbid they should deviate from worksheet/ workbook and use slices or square chips:eek:. That would be a heinous crime here!!
 
LOL, sounds like here!
We techs prepare them, using No 5 Cork Borer, & cut them to all similar length. We do this in the morning for an after lunch lesson. We then lay them on Damp paper towels in a tub, cover with damp paper towel & all good for lesson. We used to put them in water but that was bad idea. Ooops.
Heaven forbid they should deviate from worksheet/ workbook and use slices or square chips:eek:. That would be a heinous crime here!!
I normally cut them before the lessons too - only because the pupils seem to struggle to get everything done in a single lesson! I normally wrap them up tightly in cling film and stick them in the fridge - seems to work. But the prac exam was a whole other level :)
 
I normally cut them before the lessons too - only because the pupils seem to struggle to get everything done in a single lesson! I normally wrap them up tightly in cling film and stick them in the fridge - seems to work
Same here, we have single lessons. By the time the teacher has finished their intro, half the lesson has gone. Sometimes we find experiments are crammed into the last 10 minutes. V annoying when you have taken so long to prepare it.
Tbh I don't mind doing the potatoes for them. Did a class this morning & only took me 10 mins max.
We make the sugar solutions way in advance & freeze any left from year before in drinks bottles. We have already chopped & frozen into portions the strawberries for DNA extraction. ( have to pre weigh the salt for this & fill syringes with Fairy Liquid too. :rolleyes: Anything to save a bit of time.
 
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