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Light shield technology for potatoes?

Updated: Mar 6, 2020

"Light Shield Technology blocks out light and seals in the freshness. Our potatoes are packed in a specially designed Greenguard® bag, protecting them agains the detrimental greening effect of light to keep them fresher for longer."

I bought a bag of potatoes in Coles today - not this variety but same kind of packaging. And as I picked it up David asked what was 'Light shield technology'. I confess I hadn't noticed it, but maybe I would have done eventually. It's quite large after all.

Anyway - a good question. I had no idea so said I would look it up and do a post on it. And I have, and It will be brief I think.

I found this particular picture on somebody's blog or website, and as the blogger says underneath it's literally just a non-see through plastic bag. That's what it looks like anyway.

A cynic might say that this is (a) a marketing ploy and (b) an effort to hide inferior product. Because of course with a thick non-transparent and sealed plastic bag you cannot see what is inside. Actually if you turn over the bag, a section of the back of the bag is transparent, with a few holes punched in it to let air in as well, so you can see inside. I was really bad today though, and did not turn it over. It was on a special and I took it on trust. I needed some potatoes and wasn't sure when I would next be going to the market. Normally I wouldn't buy potatoes like this - I much prefer to hand pick my own. So I was sucked in. Not by the 'light shield technology'. Just the price. And just for the record the potatoes do look to be pretty good quality. Which to be fair to Coles I could have checked anyway, simply by turning the bag over.

As to the marketing ploy - why would you put those fairly meaningless words on a packet without an explanation of what it was? (not quite true I suppose - above the 'shield' is written "Blocks out the daylight, Seals in the freshness." And there actually is some science behind it.

"Unfortunately, when potatoes are exposed to light, the surface of the tuber will turn a green color. This green pigmentation is due to chlorophyll formation and renders the potato unacceptable in the marketplace. Coinciding with the chlorophyll formation is an increase in glycoalkaloid levels. The chlorophyll formation may be aesthetically unappealing but does not impart a taste or toxicity concern like elevated glycoalkaloid levels. Elevated potato tuber glycoalkaloid levels can produce a bitter taste and levels of 20 mg/kg or higher can be a health concern for human consumption" (Percival, 1999)

You probably sort of knew that. Well I knew that green potatoes were bad and potentially poisonous, although I have eaten potatoes that were a little bit green and lived to tell the tale. And I knew that you were supposed to store potatoes in the dark for just this reason. I didn't know there were two aspects of it though. So now I (and you) know.

And once again, just to demonstrate that I'm not really a careful shopper, on the bag is that explanation at the top of the page of what 'Green Light Technology' is, aside from marketing speak that is. The particular packaging used here is from Amcor who have a registered trademark for their Greenguard products. Oh the things you learn from packaging.

So I guess I can't fault Coles - or Amcor, but it's plastic packaging isn't it and we don't need any more, although - again on the back of the packet - there is a reminder to recycle your plastic bags at Coles (or Woolworths) and a bit of blurb about what the recycled bags are used for. I'll still continue to try and pick out my own potatoes though. And also did you know that potatoes with dirt on are better because the dirt keeps the light off.

The back of this packet, now that I look at it is a mine of information. Sort of. In big letters it says NOT FOR PLANTING. In fact these are the largest letters on the packet - even bigger than 'Coles'. No explanation of why though. Do the big letters signify danger or are they simply either protecting the growers, or telling you that for some reason these potatoes won't grow if you plant them in the ground? I should try it and see.

Then there's a chart showing what this particular type of potato (kestrel) is best for - well just about anything it seems. For the record though, other types of potatoes are not. So kestrel is obviously a good all-rounder. There is also a list of hints for the various basic methods of cooking. Very useful for the novice cook and I actually learnt that if you put a bit of vinegar in the water when boiling potatoes with the skins on, the skins won't split. Now I never knew that.

They also recommend refrigerating the potatoes in the bag before use. Why? They don't tell you although they do say you should store in a cool dry place out of the sunlight. But we all knew that didn't we?

The things you learn from the back of the packet and the small print. Oh - I forgot - also Australian grown.



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