While researching methods to increase the already well-recognized anti-cancer properties of broccoli, researchers at the University of Illinois also found a way to prolong the vegetable’s shelf life.
And, according to the recently published study, the method is a natural and inexpensive way to produce broccoli that has even more health benefits and won’t spoil so quickly on your refrigerator shelf.
Jack Juvik, a U of I crop sciences researcher, explained that the combined application of two compounds, both are natural products extracted from plants, increased the presence of cancer-fighting agents in broccoli while prolonging the post-harvest storage period.
“We had figured out ways to increase the anti-cancer activity in broccoli, but the way we figured it out created a situation that would cause the product to deteriorate more rapidly after application,” Juvik said. “For fresh-market broccoli that you harvest, it’s not too big a deal, but many of these products have to be shipped, frozen, cut up, and put into other products. Usually the idea is to get it from the farm to at least the distributor (grocery store) within two to three days.
“If we could figure out a way to prolong the appearance, taste, and flavor long after harvest and maintain the improved health-promoting properties, that’s always of great interest to growers,” he added.
The researchers first used methyl jasmonate (MeJA), a non-toxic plant-signal compound (produced naturally in plants) to increase the broccoli’s anti-cancer potential, which they sprayed on the broccoli about four days before harvest. When applied, MeJA initiates a process of gene activity affiliated with the biosynthesis of glucosinolates (GS), which are compounds found in the tissue of broccoli and other brassica vegetables (such as cauliflower, cabbage, and kale).
All cruciferous veggies (think cauliflower, cabbage, kale) contain cancer-fighting properties, but broccoli is the only one with a sizable amount of sulforaphane, a particularly potent compound that boosts the body’s protective enzymes and flushes out cancer-causing chemicals, says Jed Fahey, ScD. A recent University of Michigan study on mice found that sulforaphane also targets cancer stem cells - those that aid in tumor growth.
Helps fight: breast, liver, lung, prostate, skin, stomach, and bladder cancers
Your Rx: The more broccoli, the better, research suggests - so add it wherever you can, from salads to omelets to the top of your pizza.
Glucosinolates have been identified as potent cancer-preventative agents because of their ability to induce detoxification enzymes, such as quinone reductase (QR), that detoxify and eliminate carcinogens from the human body.
However, during this process, MeJA also signals a network of genes that lead to plant decay by inducing the release of ethylene, Juvik explained. “While we can use MeJA to turn on phytochemicals like the glucosinolates and dramatically increase the abundance of those helpful anti-cancer compounds, MeJA also reduces the shelf life after harvest,” he said.
So the researchers tried using the recently developed compound 1-methylcyclopropene (1-MCP), which has been shown to interfere with receptor proteins in the plant that are receptor-sensitive to ethylene. They applied the compound after harvesting the same broccoli that had already been treated with MeJA before harvest.
Broccoli contains certain chemicals that may reduce the risk of colorectal or other cancers, although it is not clear which individual compounds may be responsible for the protective effects. While research in this area continues, the best advice at this time to reduce cancer risk is to eat a wide variety of vegetables. It is reasonable to include broccoli as part of a balanced diet.
How is it promoted for use?
Broccoli is considered a good source of nutrients because it is rich in vitamin C, carotenoids (vitamin A-like substances), fiber, calcium, and folate. Broccoli is also a source of many substances called phytochemicals, or plant chemicals, that may have anticancer properties. For example, broccoli contains several compounds called isothiocyanates, including sulforaphane and indole-3-carbinol (I3C), which have been touted as possible anti-cancer agents in recent years. Early studies have shown these substances may act as anti-oxidants and may boost detoxifying enzymes in the body. Some studies have also suggested they may alter the levels of estrogen in the body, which might affect breast cancer risk.
The chemical composition of broccoli and other cruciferous vegetables is complex, which makes it hard to determine which compound or combination of compounds may provide protection against cancer. Eating a wide variety of plant-based foods may be the best way to get the necessary components.
Some researchers suggest that small amounts of broccoli sprouts may protect against the risk of cancer as effectively as much larger amounts of the mature vegetable. We are not aware of any clinical studies that have been done in humans to verify this claim.
What does it involve?
Broccoli can be eaten raw or cooked in a variety of ways. It can be purchased fresh or frozen in most grocery and organic food stores. Broccoli retains the most nutrients when eaten raw. Cooking reduces some of the benefits of broccoli because the heating process seems to destroy some anti-cancer compounds.
Some chemicals found in broccoli, such as indole-3-carbinol, are also available in pill form as dietary supplements.