Korean sweet potato and the breathtaking Okinawan sweet potato are two exotic types of potatoes that captures  attention with their purple colors.

In this article, we introduce you to Okinawan and Korean sweet potatoes, a historical overview, their health benefits and uses.

Sweet potatoes overview:

Sweet potatoes are among the sweet vegetables that are full of nutritional value.

Originated first in South and Central America, sweet potatoes do have the word “potatoes” in their name even though they are not like classic potatoes.

While potatoes are among the nightshade family “Solanaceae”, sweet potatoes are among the morning glory family “Convolvulaceae”. (1)

As for the global production, China is the number one producer of sweet potatoes.

Since sweet potatoes come from Central America, it was China that introduced these potatoes to most Asian countries.

Sweet potatoes have many varieties, in fact they are more than 400! (2)

In fact, it comes in many different shapes and colors varying from classic brown to vibrant purple.

The color shade is usually due to the presence of carotenoids.

Although very famous in the US, sweet potatoes are much more famous in Latin America and Asia.

Since then, countries like Korea and Japan have grown different varieties with the most famous ones the:

• Korean sweet potato.
• Okinawan sweet potato.

Korean sweet potato:

What is a Korean sweet potato?

Distinguished by a sweeter taste than the American sweet potato, Korean sweet potato AKA “Goguma”, made it to Korea through Japan.

However, even the Korean variety of sweet potatoes traces back to its origins in Mexico.

In fact, 260 years ago it was a guy called “Hewasa” who was a representative of the royal dynasty who led the politics.

People were still suffering from famine and they were looking for solutions.

Then, news spread about the growth of sweet potatoes in Japan so he sent 460 people to stay in Japan for 11 months.

When they came back, they brought sweet potato seeds with them and started cultivating them in Korea.

Even though the first cultivations were unsuccessful but they were able to secure the growing techniques after 9 years.

In 1813, they mastered it and the rule of the Joseon dynasty was to spread the cultivation of sweet potatoes.

One of the Korean writers of that time said “if you plant dozens of sweet potatoes in a small piece of land, you will not starve”.

This shows us how Koreans at that time owe their survival from famine to the sweet potatoes. (3)

As a result, many people’s lives were saved from famine and since then sweet potatoes became a huge part of the Korean diet.

Since then and until the second world war, this vegetable was consumed exclusively as food.

But in the past few decades, 30% of the Korean sweet potato have been used for industrial purposes since they contain a lot of starch. (4)

They are used as a raw material for many products including sweets, syrup, glucose, pharmaceuticals, cosmetics, alcohol, and whiskey.

It usually has purplish-brown skin and yellow color inside.

Korean sweet potato fries:

We chose one of the easiest Korean sweet potato recipes for you to help you introduce this amazing vegetable to your diet.

Ingredients:

• 1 large Korean sweet potato.
• 5 cups of corn oil (or vegetable oil).

Preparation:

• Start by washing your Korean sweet potato and then dry it with a piece of cloth.
• Cut the potatoes into fingers about half an inch in width and 2 inches in length.
• Heat your pan 1 minute before adding the oil, this will ensure nothing sticks on the pan.
• As soon as you notice that the oil became hot (liquid like water), drop the potato fingers in and let them fry for 8 minutes.
• Don’t forget to stir especially in the beginning since that’s when starch is still sticky and you don’t want your fries to stick together.
• When the fries look golden, take them out and place them on a towel to dry them out.
• You can now eat your Korean sweet potato fries as a snack on their own or added to your salad or any dish of your choice.

Tip: To get more crispy fries, fry them for 2 minutes then take them out to cool down for 2 minutes then fry them again for 6 minutes.

Okinawan sweet potato:

Okinawan sweet potato: backstory

Okinawa is located in the warmer part of Japan, which makes it perfect for growing sweet potatoes.

Sweet potatoes were first introduced to Japan back in 1604 through China and not from Central America.

It is said that it began when noguni sokan brought the sweet potato vine back to Ryukyu from Fujian province, china.

After that, Gima Shinjo spread cultivation in the prefecture and from there to the whole country. (5)

Okinawan sweet potatoes were a very essential food as the Japanese counted on potatoes to survive famine.

The first cultivation was in the Japanese prefecture Ryukyu, specifically in Okinawa where they called it “Karaimo” or “Kansho” then it spread across Japan. (6)

In fact, if it wasn’t for Okinawa these sweet potatoes may have not spread across Japan.

The main reason is because of its soil as it has very good drainage which makes it very suitable for cultivating this vegetable.

A few centuries later, Japan started crossing different potato seeds together.

However, there was one specific cultivar that the Japanese perfected in Okinawa where they eat it all year round.

Many types then originated in Japan, specifically the “Okinawan sweet potato” in the mid-’40s.

Okinawan sweet potato characteristics:

The shape and the size of Okinawan sweet potatoes are not different from the classic potatoes.

Nonetheless, the color is completely stunning as they are known for their purple color both inside and on the skin.

When you cut it, the inside is purple that starts light in the center, and spreads darker, even the cross-section is purple!

The incredible reddish-purple color remains after heating and people in Asia use it for decoration and of course for its many nutrients as well.

Even though they have the word “sweet” in their name, Okinawan sweet potatoes are not that sweet.

But when cooked, it produces a very deep purple color that makes the dish look vibrant!

Nowadays, Okinawan sweet potato is only produced in Okinawa and a nearby city called Kagoshima. (7)

The production volume is extremely small which explains why this amazing potato is rarely seen in our grocery stores.

Okinawan sweet potato: law restrictions

Classic raw sweet potatoes and red potatoes are prohibited in Okinawa as they spread Cylas Formicarius, a weevil that eats up these vegetables. (8)

Also, people are not allowed to take Okinawan sweet potatoes outside the prefecture not even through the mail.

You are not even allowed to smuggle sweet potatoes from Okinawa in your suitcase and you’ll be in great trouble if you get caught.

Nonetheless, Okinawan sweet potatoes are processed into many sub-products which you are allowed to take out of Okinawa.

Okinawan sweet potato nutrition and uses:

Nutritional characteristics of Okinawan sweet potato:

In addition to glucose, vitamins especially C and A, Okinawan sweet potato contains good amounts of potassium.

Also, the unique purple color of these sweet potatoes comes from Anthocyanin, a coloring pigment with excellent antioxidant properties. (9)

In fact, several pieces of research show that anthocyanin can lower blood pressure, fight inflammation, and reduce the risks of cancer.

Okinawans eat sweet potatoes to increase their physical strength or to deal with constipation.

Uses of Okinawan sweet potato:

The taste of an Okinawan sweet potato is elegantly sweet with a pleasant moist texture.

Japanese people cook Okinawan sweet potato in many ways as they eat it raw, steamed, added to desserts, or savory dishes.

Also, it can be baked to make the famous tempura or umukuji dishes. (10)

 

 

References:

(1): sweet potato | Plant, Root, Description, Uses, & Facts | Britannica
(2): The Best Sweet Potatoes to Grow | HGTV
(3): Superfood Profile: The Sweet Potato | Seoul Mills
(4): Expanding industrial uses of sweetpotato for food security and poverty alleviation (degruyter.com)
(5): Okinawa’s History (open.ed.jp)
(6): The history behind the sweet potato in Japan | Stripes Okinawa
(7): Japanese Sweet Potato – A Delightful Staple to Enjoy During Autumn in Japan! | Arigato Travel (arigatojapan.co.jp)
(8): Prohibited and Restricted Things in Okinawa | VISIT OKINAWA JAPAN
(9): What Is a Purple Sweet Potato and How Do You Cook With It? | Allrecipes
(10): Local specialties of Okinawa: the soft and chewy “umukuji tempura” | Best information for your Okinawa Trip (okinawaclip.com)