Help!! Meat tenderiser alternative

[RosalieL]

Hi everyone,
last minute request (not the teacher's fault) for the DNA extraction. We're using kiwi fruit. I could't get any meat tenderiser at coles this morning (the one close to school is a fairly small one) and I hoped the food tech kitchen would have some but no luck there either. Any suggestions for a substitute or do I need to do a mad dash to woolworths?
Thanks!

[RosalieL]

Never mind - crisis averted! Thanks to the previous labbie being so organised it was listed in the science inventory spreadsheet and stored somewhere I hadn't thought to look. Phew! Deep sigh of relief!

[bigmack]

curious to know what the meat tenderizer is Rosalie

For DNA (strawberry) extraction we use a solution or
1 cup Dish-washing liquid
1/4 cup Salt
4 1/4 cups water .
I know this also works on Kiwi fruit as a teacher used them once instead of strawberrys

[Merilyn1]

Seems like there are many different methods. We use isopropyl alcohol, salt and liquid soap. But have had to get meat tenderiser at other schools.
I'm going to get the teachers here to try kiwi fruit. This time of year, strawberries start getting expensive. We have used frozen strawberries without a problem but I have to remember to defrost them!

[karend]

This has always worked well and easier than most others......
Extracting DNA
* Peel kiwi fruit and chop into small pieces. Mash with a fork into a paste.
* Make Extraction solution - 3g salt, 10ml detergent, 100ml water.
* Mix kiwi fruit and extraction solution in a beaker, stir gently for 1 min.
* Heat 15 mins in a waterbath (around 60 degrees).
* Pour green paste through a sieve/coffee filter into a clean beaker.
* Drizzle about 100ml COLD methylated spirits down the side of the beaker. It should form a layer on top of the kiwi paste.
* You should see a white string-like layer form between the two fluids. This is your extracted DNA.

[bigmack]

This has always worked well and easier than most others......
Extracting DNA
* Peel kiwi fruit and chop into small pieces. Mash with a fork into a paste.
* Make Extraction solution - 3g salt, 10ml detergent, 100ml water.
* Mix kiwi fruit and extraction solution in a beaker, stir gently for 1 min.
* Heat 15 mins in a waterbath (around 60 degrees).
* Pour green paste through a sieve/coffee filter into a clean beaker.
* Drizzle about 100ml COLD methylated spirits down the side of the beaker. It should form a layer on top of the kiwi paste.
* You should see a white string-like layer form between the two fluids. This is your extracted DNA.

That's the method we use karend except we don't do the water bath stage . What does that do to to the process ?
We have found that Tulle is the best for separating the the "juice" from the pulp , anything finer doesn't work . Perhaps that's where the water bath stage helps ....maybe

[RosalieL]

curious to know what the meat tenderizer is Rosalie

For DNA (strawberry) extraction we use a solution or
1 cup Dish-washing liquid
1/4 cup Salt
4 1/4 cups water .
I know this also works on Kiwi fruit as a teacher used them once instead of strawberrys

I used 50ml dishwashing liquid, 15g salt, 1 teaspoon meat tenderiser and top up with water to 1L. I think the meat tenderiser is for breaking down some of the proteins? But perhaps it isn't necessary after all! It might be a carry over ingredient from back when schools used to use cheek cells. Perhaps they are harder to break into than the fruit cells?

[RosalieL]

Follow up question - Does anyone know how long the buffer solution will last? I've got classes doing this next week so it would be nice to not waste what's left. (I wouldn't expect it to last from year to year).

[melsid]

We use chux cloths to filter through, cheap and always around.
The buffer solution (salt, dishwashing liquid, water) lasts for years here - or until it runs out and I mix up another batch! This one works perfectly with both strawberries and kiwi fruit.

[bigmack]

The buffer solution (salt, dishwashing liquid, water) lasts for years here - or until it runs out and I mix up another batch!

Same here melsid .

I like the chux idea . But I'd miss my Tulle clothes line

[RosalieL]

We use chux cloths to filter through, cheap and always around.
The buffer solution (salt, dishwashing liquid, water) lasts for years here - or until it runs out and I mix up another batch! This one works perfectly with both strawberries and kiwi fruit.

Good to know the extraction buffer solution will last! What information do you have on the label for the bottle you store it in?

We use chux cloths for the filtering as well

[bigmack]

LOL , probably not compliant but this what we have. It's stored under the sink with the other detergent for no other reason . Probably should be in Chem store but my offsider figured this was the best place for it .

Haa I just noticed I had 4 1/4 L instead of Cups written on it

[melsid]

Good to know the extraction buffer solution will last! What information do you have on the label for the bottle you store it in?

We use chux cloths for the filtering as well

I made up a label on Risk Assess, "DNA Extraction Buffer", stating the ratio of water:dishwashing liquid:salt. Blue dot & non hazardous.

[Anna Z]

Does not need to be in Chemstore as it's all household items just mixed together, we keep ours until it runs out then make more.... in excess of 12 months.

[Wayne]

Attached is the procedure that we use

[Milo]

I went looking everywhere for meat tenderiser last year, and couldn't find it in any of the big supermarkets or smaller shops. I guess it's just gone out of fashion. I did eventually find some at my local Supa Express (Supa Barn), which works. It has added spices but that only affects the smell I think.

[Merilyn1]

I looked in Woolworths last week and couldn't buy any. We have an Extension Science student using it, thankfully I had stocked up last time someone needed it so the student should have enough. Something to think about for next time though.

[bindibadgi]

I was thinking of trying to make my own tenderiser powder by grinding up dried pineapple, & storing it in the fridge. I think you can get dried pineapple rings at supermarkets, so when I've got some spare time I might get a pack & try it out.
You could just use fresh, but I like the idea of having it powdered form on hand so I don't have to dash out to the shops if someone wants to do the prac.

[RosalieL]

I looked in Woolworths last week and couldn't buy any. We have an Extension Science student using it, thankfully I had stocked up last time someone needed it so the student should have enough. Something to think about for next time though.

It sounds like it's not needed according to some other recipes above. I wonder if it just produces a greater amount of extracted DNA or has no impact on the outcome at all? I might have to do my own comparison tests next week before I pack everything away as I am curious as to why it is in some recipes and not others.

[Labbie]

I would love to know the comparison;s RosalieL