On Food and Cooking

carbon dioxide, and just enough oxygen (8%
or less) to keep the plant cells functioning
normally; and they use bags whose gas
permeability matches the respiration rate of
the produce. (Too little oxygen and fruits and
vegetables switch to anaerobic metabolism,
which generates alcohol and other odorous
molecules characteristic of fermentation, and
causes internal tissue damage and browning.)
Home and restaurant cooks can
approximate such a controlled atmosphere by
packing their produce in closed plastic bags
with most of the air squeezed out of them. The
plant cells consume oxygen and create carbon
dioxide, so the oxygen levels in the bags
slowly decline. However, a major
disadvantage of a closed plastic bag is that it
traps the gas ethylene, a plant hormone that
advances ripening in fruits and induces
defensive activity and accelerated aging in
other tissues. This means that bagged fruits
may pass from ripe to overripe too quickly,