Agriculture Reference
In-Depth Information
diately goes rancid, flavoring every salad you make thereafter.) Place the washed and thor-
oughly dried leaves in the bowl (one of those salad spinners is a great cheap tool). Drizzle
over just enough oil to lightly moisten the leaves when you toss them. There should not be
any oil left in the bottom of the bowl. Sprinkle with good vinegar - red wine, champagne
and sherry all have their attributes - and toss again. The classic proportion of oil to vinegar
is 3 to 1; taste and see what works best for you. Finally, sprinkle with salt, toss once more
and serve.
PRECUT VEGETABLES
You chop up some vegetables, put them in a plastic bag and stick them in the refrigerator.
You come back the next day, and they're wilted. You come back the day after that, and
they're halfway to rotten. And yet you go to the grocery store and see bags of precut greens
and vegetables that look nearly perfect. What's the deal? The packaging of precut veget-
ables is one of the most amazing advances in technology in the produce world, the result
of years of research and cooperation between scientists who study plants and plastics.
Remember that vegetables continue to respire, or "breathe," after they've been harvested:
they take in oxygen, and they give off carbon dioxide and ethylene. The rate at which they
do this determines how quickly they spoil. Vegetables that have been cut up deteriorate
even faster than whole vegetables.
At first researchers believed that if you could reduce the amount of oxygen reaching the
vegetables, you could slow down the rate of respiration and extend their shelf life signi-
ficantly. This worked in part - it delayed the kinds of spoiling associated with respiration.
But another problem popped up. It turns out that when deprived of oxygen, vegetables be-
gin to draw energy from their own tissues and so start on another kind of decay.
But what if you could create an atmosphere with only a little bit of oxygen and just the
right amount of carbon dioxide and ethylene? By experimenting with different kinds of
plastic films for the bags, scientists found a way to do this. Different types of plastic allow
different flows of different gases. By combining several films, scientists were able to cre-
ate plastic bags that allow a slow intake of oxygen and a rapid venting of carbon dioxide
and ethylene. This extends the life of cut vegetables for days, if not weeks.
Of course, it was not quite that simple. Each vegetable has its own ideal mixture of gases
and so requires its own special type of film. In addition, some vegetables require different
mixes depending on the season and on harvest conditions. Last but not least, the plastic
