May/June 2023 - 18

CA STORAGE
TAKING
CONTROL
CA storage of asparagus could
extend market window
BY GARY PULLANO
VGN SENIOR CORRESPONDENT
A
sparagus growers are intrigued with the
potential for extending the shelf life of the highly
perishable crop to boost its postharvest life and
lengthen a more profitable marketing window.
Some research has been done on the application
of controlled atmosphere (CA) technology, leading to
further interest in throttling asparagus senescence
processes that would enhance its potential for
commercial application.
United Kingdom studies investigated the link between
abscisic acid (ABA) and ABA catabolites and senescence in
asparagus stored under a range of different CA conditions.
Low oxygen and high CO2 conditions significantly
suppressed ABA and asparagine levels in asparagus
during storage, coinciding with lower metabolic rates,
higher sugars and more vibrant color compared to
control samples. That helped maintain asparagus
quality for at least two weeks of cold storage followed
by seven days of shelf life.
Similar work is being conducted by Randy Beaudry,
horticulture professor at Michigan State University
(MSU), and his colleagues, including Phil Engelgau,
a graduate student; Ben Werling, MSU Extension
vegetable educator and John Bakker, who was executive
director of the Michigan Asparagus Advisory Board for
almost 20 years before retiring in 2021.
At a 2018 advisory meeting, growers requested
researchers explore CA storage to extend the shelf life
of asparagus from production spikes and " meter it out "
to reduce downward pressure on prices, said Beaudry,
who shared an update on the project during the 2023
Oceana Asparagus Day in March in New Era, Michigan.
Most of Michigan's asparagus is the Millennium variety,
which is well-tailored for Michigan's growing conditions.
The cultivar has sharp production spikes during the third
18 | MAY/JUNE 2023
through seventh harvests, yielding more than 30% of the
annual crop within these five of the typically 40 annual
harvests, in the western part of the state.
" There's a huge glut at one point in time, " Beaudry
said. " This leads to severe
market imbalances of
supply and demand,
ultimately driving down
prices. What would be
better from a marketing
perspective would be
to stretch that out so
that we don't have an
overwhelming amount
of asparagus available
for the retail space. If we
can (spread it out), then
we can maintain a lower
price. If we can stretch
out the availability, and
keep it below that threshold where we're overwhelming
the market with available product, then we can keep the
prices up. "
RANDY BEAUDRY
High metabolic rate
A lot of biology occurs in a short period of time
while the asparagus plant develops as a fern, Beaudry
said. " The first postharvest action that takes place is
cutting the plant's spear from its resources, " he said.
" Everything that it had up to that point - the water, the
sugars that it had that grows that developing spear -
are cut away. "
As a result, the spear almost immediately begins to
change its metabolism. " That's the incredible part of the
story, " Beaudry said. " Not only is it growing and rapidly
changing during the days, but also when you cut it, it's
responding to the changes that it's made in its life. "
May/June 2023

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