Someday, watermelon may play a part in fighting cancer. It may save lives in the poorest regions of Africa. It may even stave off a nasty sunburn at the beach.
One thing is for sure: Watermelon isn’t just for eating anymore.
The fruit and vegetable (it’s part of the Cucurbitaceae family, so it’s kin to the squash, cucumber and pumpkin) has a few secret ingredients researchers are studying for health benefits.
One of them is called lycopene – an antioxidant responsible for watermelon’s red pigment. Researchers have also discovered the little red flecks to be an effective tool for maintaining human health.
“If you’re looking at them with a really high magnification, they look like little needles,” said Penelope Perkins-Veazie, a post-harvest physiologist with the N.C. State University Plants for Human Health Institute at the North Carolina Research Campus, in Kannapolis.
Perkins-Veazie has been studying the properties of watermelon for the last 15 years, dating back to her time at the U.S. Department of Agriculture in Oklahoma.
She first noticed the potential of the fruit when a colleague placed lycopene extracted from a watermelon into a petri dish with cancer cells.
“The lycopene was killing the cancer cells,” Perkins-Veazie recalled. “They’re a good scavenger for things that are bad for you, so if you are exposed to certain toxins in your diet or in your job, they’re really good as radical scavengers to go and attach to them.”
Lycopene is also found in tomatoes, but it’s harder to access for research purposes.
“With tomato, you have to cook it to get rid of those proteins and cell walls to release the lycopene,” said Perkins-Veazie. “With watermelon, it just falls out easily.”
In Perkins-Veazie’s fourth-floor lab on the North Carolina Research Campus, her own investigations have begun to unlock more secrets about lycopene, such as its potential use as a sunscreen.
“What we found is that it’s also extremely effective at protecting DNA, so when you have too much UV light, the lycopene will block it and protect your DNA from being affected.”
In her lab, experiments to test watermelon’s SPF strength come in the form of small cosmetic jars of cream, each labeled with different watermelon percentages.
“A 20 percent watermelon cream comes out having an SPF of about 32,” said Perkins-Veazie, who added that if a cosmetic company became interested, watermelon could someday be listed as a common ingredient in makeup, moisturizers and sunblock lotions.
Still it’s not all sunshine and sweetness. Watermelon has its downsides. It only tastes good when it’s fresh – a factor that so far has limited food companies from developing products that people find palatable.
“How can you store a watermelon?” Perkins-Veazie asked. “You can’t freeze watermelon. It tastes terrible when you thaw it. You can’t cook it. It tastes like squash.”
Also, lycopene has proved its prowess in a small pond arena such as the petri dish, but not in a big lake such as the human body – which involves complex inlets and outlets to maneuver. “It’s very effective on a cellular level outside the body,” said Perkins-Veazie. “The problem is how do we prove it’s effective in the body?”
Still, scientists are confident the solutions will one day be found.
This year, Perkins-Veazie assisted an African researcher who found a way to deliver citrulline – another amino acid found in watermelon – to those suffering from sarcopenia, a muscle-wasting condition that runs unchecked in many of Africa’s poorest countries.
When soaked in watermelon juice, rice – that region’s main carbohydrate source – picks up the amino acid, which is crucial at combatting sarcopenia.
“That’s the sort of thing that’s going to put watermelon on the map,” said Perkins-Veazie.
How to choose a watermelon – scientifically
“We have almost no sophisticated means of testing watermelon quality, still, in the field,” said Penelope Perkins-Veazie, of the North Carolina Research Campus, in Kannapolis.
To find the best watermelon, Perkins-Veazie offers her advice:
▪ Forget thumping. There are too many variables – size, thickness of the rind and whether they’re seeded or seedless – all of which can throw off the acoustics.
▪ Instead, look for a watermelon with a fairly yellow ground spot.
Stay away from ones that feel waxy – they’re most likely immature, and from the rubbery ones, which signal they’re past their prime.