[shel]

I saws these Green Bags Foodsaver Bags advertised on the TV yesterday. Has anyone tried them? Do they work as advertised?

shel

[KYHeirloomer]

I saw those ads, Shel. My immediate reaction: Who the H is Debbie Meyer. They're presenting her as if she were some world-famous culinary star. If so, I must have been living under a rock, cuz I've never heard of her.

The theory of those bags is ok. Fruit (and, to a lesser degree, vegetable) ripening is hastened by ethylene gas---which is a byproduct of the fruits themselves. Applies are one of the major producers---which is why your tomatoes will turn color faster if they are confined with an apple.

In theory, if you put the fruit in a plastic bag that's been perforated with lots of holes you'll accomplish the same thing. The open question is: Where does the ethylene go? If the bag is in the fridge, the gas remains present, and concievably passes back and forth.

I'm sure Luc can provide a more insightful answer.

More to the point, I can't think of the last fruit or vegetable I bought or grew that sat around for more than a few days. So my reaction to the bags was that they're an expensive solution to a problem I don't really have.

[lentil]

I put slightly unripe fruit in brown paper bags. They're free!

[shel]

Originally Posted by lentil

I put slightly unripe fruit in brown paper bags. They're free!

The Green Bags are supposed to keep ripe fruits and vegetables in the refrigerator fresh for longer periods of time than other storage methods. It's not for "ripening" fruit - in fact, from what I understand about the Green Bag technology, the bags will prevent or dramatically slow down the ripening process.

Happy Gnu Year,

shel

[shel]

Originally Posted by KYHeirloomer

[...] My immediate reaction: Who the H is Debbie Meyer. They're presenting her as if she were some world-famous culinary star.
[...]
In theory, if you put the fruit in a plastic bag that's been perforated with lots of holes you'll accomplish the same thing. The open question is: Where does the ethylene go? If the bag is in the fridge, the gas remains present, and concievably passes back and forth.
[...]
More to the point, I can't think of the last fruit or vegetable I bought or grew that sat around for more than a few days. So my reaction to the bags was that they're an expensive solution to a problem I don't really have.

I feel the same about this Debbie Meyer character. Perhaps I'll do a search on her name and see what turns up besides the Green Bags.

I have noticed that, as produce gets older and the gasses escape into the fridge, the gasses can sometimes impart an off taste, and certainly a smell, to whatever else is stored in the box.

My situation wrt produce is similar to yours - I buy fresh and ripe produce and use the items within a couple of days. I'm in a position where I can shop frequently, and don't use the fridge for storage. However, I have a friend who's always throwing out carrots, celery, greens, and variouis fruit. I thought if the Green Bags were any good, and really worked as advertised, I might get him a package for his birthday, which is coming up in a few weeks.

shel

[bstinson]

My wife and I were out at Central Market in Plano, TX on Sunday and we came across the green bags (not the Debbie Meyer brand) in the store and decided to give them a try. We buy things in greater quantities sometimes and they have a tendency to go bad before they have been eaten. I will let you know how the bags worked. The pricing at Central Market was a little better than the bags advertised on TV.

[FR33_MASON]

There are three types of membranes and they are:
1. Permeable

2. Semi-permeable

3. Impermeable

What we are dealing with is a material that is a semi permeable membrane. This particular membrane is specifically engineered to allow ethylene gas to pass through and with great efficiency to the point of where it almost pulls the gases out of the enclosed bag.

It works on the pricipal of osmosis but instead of water, it is engineered for ethylene (C2H4 for you fellow geeks).

[phatch]

Clarification of terms.

Diffusion is the general term for balancing concentrations of unlike solutions. In a free flowing solution, this moves from high concentration to lower concentration.

Osmosis is a special case of diffusion. First, the solutions are not free to mix--the semi-permeable membrane blocks free mixing. Next osmosis moves material from the Low concentration to the high concentration. For example, a cell in salt water pumps water out of the cell until the salt concentration is the same on both sides of the membrane.

So the green bag is not normal osmosis. It might be catalyzed diffusion or even reverse osmosis.

Phil

[KYHeirloomer]

or Maxwell's Demons might be messing with our heads.

[Luc_H]

From what I understand is these bags are impregnated with a microporous silica powder. The pores are about the same size as the chemical molecule of ethylene gas. This material is supposed to adsorb (not absorb in this case) and trap the gas in the pores. (when washed or left to air out, the gas is released)

Fruits ripen in certain conditions like temperature, humidity, exposer to light, etc.. When fruits ripen they emanate a chemical called ethylene gas. when ethylene gas is present in the air around fruit they ripen quickly. It is a self reinforcing cycle to ripen quickly all the fruits in the vicinity. (this may be an evolution thing where it is better for a plant to ripen all it's fruits at once).

On a commercial level, ethylene gas filters are installed in warehouses to reduce the amount of ethylene gas in the air to slow the ripening process of fruits when store. This is possible is you also monitor and control relative humidity, temperature and light. All conditions that are difficult to reproduce at home.

My conclusion: I won't spend money on those bags even if the science is sound to a certain extent. I'd be very curious to try them just to prove a point though.

To prevent bananas from ripening they are place in sealed bags that the air is vacuumed out and replaced by a specific inert gas (probably nitrogen).
Greenish unripe tomatoes can be coaxed to ripen by exposing them to ethylene gas.

Luc H.

[KYHeirloomer]

"Greenish unripe tomatoes can be coaxed to ripen by exposing them to ethylene gas."

The problem is, Luc, that ethylene can promote color changes without actually causing the fruit to ripen. That's why supermarket tomatoes taste (or, rather, don't taste) the way they do. They are hard, green orbs, taken from cold storage, gassed with ethylene to change color, and sent on to the stores.

If you grow your own tomatoes you know there is a point, easier to see than describe, where they go from a sort of matte green to green with a sort of sheen to them. Once that sheen appears they will ripen, even sitting on your counter (or, to put a point on it, if gassed with ethylene). Before that sheen, nothing you do will get them to ripen once picked---although they will change color.

[Luc_H]

Originally Posted by KYHeirloomer

...
The problem is, Luc, that ethylene can promote color changes without actually causing the fruit to ripen. That's why supermarket tomatoes taste (or, rather, don't taste) the way they do....

You are right KYH. I said they are <coaxed> to ripen. I did not say it was any good.
For most fruit the ripening process starts by a build up of protopectin in the fruit. This material is quite dry and solid. Then when ripening starts, the protopectin converts to pectin (gel like) then to pectic acid (liquidy). Of course during the process the fruit changes colour, becomes sweeter and usually increases its vitamin (c) content. If tomatoes are picked before the protopectin build up then not enough material will convert to pectin during ripening hence leave the tomato kinda semi-solid and pasty. Also the varieties of tomatoes chosen for supermarkets have a though skin and texture to start for <handling and transportability>.

Luc H.

[KYHeirloomer]

"have a though skin and texture to start for <handling and transportability>."

Absolutely, Luc. But that's a different issue from ripening. The fact is, if left on the vine to do so, supermarket tomatoes would have ripened. But they would still have thick, tough skins. And suffer from other problems---such as tasting like wet cardboard.

Tomatoes, like all produce destined for non-farm markets, are chosen for their ability to withstand the rigors of the food distribution system. If you start listing desired characteristics this would include resistence to diseases and pests; uniformity of size, shape, color; in some cases, uniformitry of ripening; durability to withstand truck, rail, and air transport; ability to keep in cold storage; plants that lend themselves to mechanical handling (i.e., sowing, chemical treatments, harvesting).

Nowhere in that list, however, does flavor appear. Flavor, in today's produce world, is not a selected-for criteria. So when any hybrid vegetable does have flavor it sneaks in on its own.

Now add to all that the fact that the produce is picked green, and held in cold storage, it's no wonder that it's all so tasteless and texturally bad.

In the markets they then undergo those constant showers as well. Which contributes to the produce not lasting once you get it home. On average, veggies treated that way last longer in the market (reduces waste from 8% to 3%, according to some studies), but turn bad in about half the time in the home fridge.

[Luc_H]

Originally Posted by KYHeirloomer

....Nowhere in that list, however, does flavor appear.....

Nowhere on that list, however, does nutritional value appear....

(I hear you KYH, I know also...)

Luc H.

[FR33_MASON]

Well after some thought last night I suddenly realised that the material might be impregnated with a scavenging material which Luc H. mentioned.

I took a good look on the net and sure enough that is the case. So now that I have my foot in my mouth I'll stop right there on that point.

My father used to force ripen green tomatoes en masse by placing them in the darkest corner of the basement and on a blanket. worked like a charm.