This series of posts will highlight the plants that help you celebrate the Yuletide season.
Let’s continue with another healthy fruit in season during our winter celebrations- pomegranates. You may be familiar with the dark juice and may even recognize the whole fruit as part of a decorative centerpiece, but how much do you really know about the plant?
Its common name pomegranate means seeded apple, but its botanical name is Punica granatum. It grows as a shrub with beautifully ruffled orange-red flowers and characteristic red globed fruit filled with jewel-like edible seeds. The native range spans from Iran to the Himalayas in northern India. Prized for its beauty and taste, pomegranates have been cultivated since ancient times so that cultivars are currently found worldwide. The plants can take the heat for hot summers, but are also somewhat cold-hardy (more so than many citrus trees). However, too much winter moisture makes Louisiana and other places in the southern United States a less than ideal growing environment for pomegranates. If you’d still like to try it, find the ‘Wonderful’ cultivar, and don’t worry about committing too much space for multiple trees because pomegranate trees are self-pollinating. The majority of commercial pomegranate production in the U.S. occurs in California and Arizona. In California, orchards produce more than 100,000 tons of the fruit worth more than $100,000,000.
The pomegranate fruit is technically a berry with a leathery husk surrounding the juicy-fleshed arils (plant biology/culinary word of the day). Check out this presentation for pictures of pomegranate development from frilly flower to crowned fruit. The deep red arils are the edible portion of the fruit.* Eat them out of hand, on salads or juice them. Pick out the best fresh pomegranate by judging its weight, not its color. Confused about how to extract the tasty arils from the whole fruit? Check out this link.
The sour to bitter flavor of pomegranates comes from acidic tannins produced by the fruit. Tannins are phenolic type molecules with high molecular weights that are used as a feeding deterrent for vertebrates. Any wine enthusiasts reading this may be familiar with tannins because they add to the complex flavors of wine as well. Compounds like punicalin and punicalagin are responsible for the antioxidant properties of pomegranate products. Of course, antioxidants are marketed for their health-promoting benefits related to everything from clear complexion, cancer, obesity and diabetes, but see also this link.
While we’re on the topic of tannins, here’s some exciting new science from 2013. Scientists have discovered a new plant organelle dubbed the tannosome where plants produce and store their tannins. That’s right, here we are in the 21st century and scientists are discovering new cellular components. That’s chapter-one-basic-textbook stuff. Plants that produce high levels of tannins re-purpose their chloroplasts as tannosomes for tannin production. There is a dramatic rearrangement of thylakoid membrane structure accompanied by changes in the types of proteins synthesized. Tannins are made and fill vesicles of thylakoid remnants in what was once the lumenal space. As these vesicles fill, they aggregate, bud off of the tannosome and travel to the central vacuole where they are stored. Check out this graphic from the paper describing tannosome synthesis.
Pomegranates are typically available in North American grocery stores from October to January. Now that you’ve been formally introduced to this fruit, resolve to get brave enough to use it for more than just winter decoration.
*Funny but embarrassing story- I definitely have experimental evidence to attest to this fact. Let’s just say, I was overzealous with the capabilities of a newly acquired Jack Lalanne Power Juicer (it will juice entire chunks of the fruit). By the time I finished a walk around the block with our dogs, I was running for the bathroom to hurl up sour pink juice.
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