Lynn Savage, Features Editor, email@example.com
Barely seven steps into most supermarkets and
you are confronted with a wall of green – rows of packaged lettuce and spinach
hoping to lure you toward healthy eating habits. Spinach, in particular, is full
of nutrition, but how healthy can it be after being drenched in the glow of whitish-yellow
fluorescent light for hours on end?
According to researchers in Texas and Nova Scotia, very healthy
Fresh spinach, especially the smaller, younger leaves called baby
spinach, is one of the most nutritionally dense foods on the market. It is loaded
with vitamins C, β9, E and K, as well as carotenoids such as ?arotene. Most of
these provide antioxidant functions; all provide healthful benefits.
Once packaged produce reaches the store shelves, though, it typically
remains refrigerated for days under artificial light 24/7. The packaging itself
is transparent, not counting any labeling, which means that the spinach leaves are
left to soak up the multiwavelength radiation. Gene E. Lester and Donald J. Makus
of the US Department of Agriculture in Weslaco, Texas, and their colleague, D. Mark
Hodges of Agriculture and Agri-Food Canada in Kentville, Nova Scotia, wanted to
know what effect the light had on the food.
The group harvested and refrigerated various sizes of two varieties
of spinach leaves, then stored the samples in either dark or light conditions for
zero to nine days. They then measured the samples’ dry weight, plasticity
and nutritional composition. They found that, for the most part, the amount of each
of the nutrients remained steady – in some cases, even increased – when
exposed to 24-h light. Vitamin C, curiously, increased over the first three days,
then gradually reverted to baseline over the next six days.
Unfortunately, as the team reports in the March 10, 2010, Journal
of Agricultural and Food Chemistry, wilting began to increase after the third day
of light exposure. The scientists also found that the light intensity is greatest
for the packaged produce closest to the top of a stack compared with the light struggling
to reach the depths of a display. If the spinach isn’t visibly at its peak,
it might entice shoppers to move on to the ready-made pizza section of the market.
The group did not address how light levels might affect spinach
as it is transported – sometimes for hundreds or thousands of miles –
inside dark trucks. Still, its work could result in new ways for growers and grocers
to illuminate their products, thus improving, or at least maintaining, the goodness
in every bite.