A bowl full of rice, a mind full of questions

Everything you’ve always wanted to know about rice

Today, your Hungry Pumpkin team is diving into another of life’s great mysteries for you: rice! Did you know that in some Indian cultures rice is linked with prosperity and the Hindu god of wealth? Meanwhile, in Japan, it’s sometimes connected with the god of the sun. You’ve probably also seen (or participated in) throwing of rice at Western/Christian weddings; this is because it’s considered by some to be a symbol of life and fertility.

Now that we’ve shown off a bit, it’s time to admit that we also have a lot of questions about rice, so we decided to do some research and share our interesting finds with you.


Ok, so you know rice, but do you know rice?

Rice is a grain (like wheat or barley, for example) that belongs to the grass family. When people think of where rice originated from, it’s likely most of us think of Asia. Sure enough, Asian Rice (Oryza sativa) is indeed from Asia, as the name implies. There is also a type of rice from Africa known as Oryza glaberrima. Though this is a cool fact, it’s the Asian species that is most widespread in the world today and almost definitely the one that you’re acquainted with unless you live in the natural range of African rice. These two species both come from warm and humid tropical or subtropical regions of their respective continents of origin. Though it may have originally been confined to these areas, in the modern-day rice has spread around the world.

Through extensive genetic research, scientists have shown that the cultivation of Asian rice began 13500-8200 years ago somewhere in China. From this original plant, humans have since bred all of the different varieties that you have come to know today. From East Asia, rice spread to South and Southeast Asia, and then eventually made its way to Europe via Western Asia. Once in Europe, rice was also spread to the Americas during the colonial invasions.

Today there are over 40000 varieties of cultivated Asian rice. To put this into perspective for you, if you were to list every one of these varieties (assuming it would take you one second to say each name) you would still be rattling off the end of the list more than 11 hours later. Maybe a strange way to pass time, but hey, when you like rice, you like rice. Compared to Asian rice, African rice is a newcomer on the culinary scene, emerging about 3500 years ago. Though there are also several varieties, they have remained in their original area.

Perhaps one of the most important reasons for rice’s popularity is its adaptability; it can handle environments from soaked planes to steep hills and mountains so long as you have the irrigation set up well. It can also handle a temperature range between about 20 and 40 degrees celsius. Though rice is known for its growth in a watery environment, it is actually planted while the fields are dry. There are also some varieties that do not require very much water at all (known as dry or mountain rice), but they have a lower yield than water rice that is grown in flooded conditions.

The rice plant can grow between 1 and 1.8 meters in height, depending on the variety and the richness of the soil. Even though they are usually annuals (meaning they live their entire lifespan within a single year) some cultivars have been known to thrive for as much as 30 years in the right environment. Rice can also be harvested two times in a year, with the second harvest being larger due to increased sun later in the season. This also means the rice needs to be soaked though as the dry season’s arid weather produces drier rice.

After being harvested, the grain is separated from the rest of the plant. This rice, however, still has a husk that represents about 1/5th of the grain’s weight. This husk contains several vitamins, minerals, and fiber. It also needs to be cooked for longer and cannot be stored for the same duration as white rice. This is the rice that you are eating when you buy whole-grain rice.

Once husked, the grain is surrounded only by a vitamin-rich envelope. Depending on the variety, this part can come in a variety of colors. One such example is black rice, sometimes also known as forbidden rice; this rice was traditionally the food of emperors. In this variety, though the inner parts of the grain are also black, a result of black pigments called anthocyanins. These compounds have an antioxidant function and are also found in black soybeans, blueberries, currants, blackberries, eggplant, and also in red rice.

When the seed envelope (and thus also the germ) are mechanically removed, we obtain milled or white rice, which after further processing becomes polished rice which has a brightness due to its special coating. This rice is much less nutritious than whole-grain or even just husked rice as many fats, proteins, and minerals are lost. In particular, phosphorus, potassium, and vitamins B1 and B2 are greatly reduced.

If you think back to chemistry classes you’ve had, you may remember that starches consist of smaller glucose units that are connected to form a chain. More precisely, starches are composed of two types of chains (polymers): amylose, which accounts for 15-20%, and amylopectin, which accounts for the rest. The amylose consists of hundreds of glucose units that connect in a linear chain while the amylopectin molecule is branched but also composed of glucose units. The higher proportion of amylopectin in starch is what makes the rice sticky when cooking.

When shopping, you can also find rice marked as parboiled. This rice was exposed to hot steam at high pressure before being husked, thus causing the nutrients to move into the interior of the grain. It is also different in that the grains do not crack when cooking.

In addition to the manner of preparation, the variety of rice can also vary. You’re probably familiar with the labels for this, long-grain, medium-grain, and round grain rice. As the name implies, long-grain rice has grains that are long and thin. The grains are light, dry, and firm, and do not stick together when being cooked. In this category, you can find the famous Basmati rice. With its characteristic odor, it is aromatic rice. This unique form of rice is produced only in India and Pakistan. If you buy ground long grain rice, you are supposed to rinse the grains before cooking to remove starch dust, but this is a step you can skip at home without worrying.

Jasmine rice is also a long-grain variety of rice originally from Thailand. It earned its name from the smell it releases when being cooked, which is reminiscent of the odor of jasmine. As you may suspect, this means it is also aromatic rice, which means that it is characterized by the softness and polish of its grains. This, however, reflects a decreased proportion of nutrients when compared to other varieties, but is also responsible for the tender texture it lends to dishes. It is also slightly sticky and thus works well in dishes for people trying to learn to use chopsticks.

Medium and round grain rice differ from long-grain in that they contain more amylopectin in the starches, thus making them stick together more when cooked. These are the most common types of rice as the grains retain their shape yet the dish becomes creamy from the starches. In this group, you can find the famous Italian arborio rice, named for the town where it first appeared. Though it has relatively long and large grains, they contain a lot of starch. They are less solid though, so you need to be mindful of this and watch your cooking time.

The carnaroli variety also has a high starch content, giving it its creamy texture that is perfect for mantecatura. The grains do not crack during cooking, always giving them an al dente texture even with long cooking times. Carnaroli is a high-quality variety and thus more expensive than other rice.

Vialone nano is a variety that was created by crossing two older varieties (unsurprisingly, vialone and nano). It can most commonly be found being served in Venetian restaurants. With its round, medium-sized grains, this variety can absorb a lot of fluid which makes it useful in sucking up soup stock. The rice has a gentle fragrance reminiscent of butter and straw which leads to its use by culinary professionals with a variety of vegetables. This is also a more costly variety of rice.


What about sushi rice?

Sushi requires white, round grain rice with a high amylopectin content in order to hold the grains together when the sushi has been prepared. For anyone who has made sushi, you will recognize this as the reason for the sticky mess you have to clean up afterward. Ballila and tondo are both varieties that are suitable for this. Interestingly, a variety of rice from Macedonia is also used to make sushi some places (not exactly in the same neighborhood as Japan).

All this being said, sushi rice is very easy to identify at the store because it will almost certainly be marketed as such.

Along with wheat and maize, rice is one of the leading grains in the global diet. Altogether, grains account for 42% of the calories consumed by the world’s population, most of which is accounted for by rice. More than half of the world’s population depends on it, with rice representing more than 20% of their daily calories.

Rice consumption is, in fact, increasing. Both in the global East and West, this trend emerges, partially as a result of migration from Asia to the West. In 2010, 429 million tonnes of rice were produced, and by 2020 that figure is projected to be around 498 million tonnes. To throw some wild math at you, that’s about 17 172 414 000 000 000 grains of rice (assuming that google’s notion of the weight of a grain of rice is accurate). That’s about 2.5 million grains of rice per person on our planet! (Ok, there are a lot of estimations involved in this, but it was still fun to figure out, and you get the point: that is a LOT of rice).


How about nutritional value?

The nutritional value of rice depends on the way it is grown. As we previously mentioned, the more rice has been processed, the fewer nutrients it will contain. So brown whole-grain rice is much more nutritious than white polished rice. However, parboiled rice is just as white, but the process conserves most of the vitamins and minerals. Brown rice is also more difficult to digest due to its tougher parts being left intact, but it also has a higher content of fiber, fat, vitamins, and minerals. Potassium, magnesium, calcium, and zinc make up the bulk of the mineral profile, and at the same time, brown rice can contain as much as double the number of B vitamins seen in processed rice.

You can take a look at our table for a nutritional breakdown on rice. Keep in mind though, this is just a rough approximation since factors such as heat, growing medium, and many others will influence the final value.

Content per 100g

Whole-grain long-grain rice

Whole-grain medium-grain rice

White rice

Paraboiled

Energy

kcal

370

362

370

374

Proteins

g

7,94

7,5

6,81

7,51

Total Fats

g

2,92

2,68

0,55

1,03

Carbohydrates

g

77,24

76,17

81,68

80,89

Fibre

g

3,5

3,4

2,8

1,8

Calcium

mg

23

33

11

71

Iron

mg

1,47

1,8

1,6

0,74

Magnesium

mg

143

143

23

27

Potassium

mg

223

268

77

174

Sodium

mg

7

4

7

2

Zinc

mg

2,02

2,02

1,2

1,02

Copper

mg

0

0

0

0

Fluorine

µg

Manganese

mg

4

4

1

1

Selen

µg

23,4

15,1

19,9

Vitamin A

µg

0

0

0

Vitamin E

mg

0,59

0,03

Vitamin D

µg

0

0

0

0

Vitamin C

mg

0

0

0

0

Thiamin (B1)

mg

0

0

0,18

0

Riboflavin (B2)

mg

0

0

0

0,05

Niacin (B3)

mg

5

4

2

5

Pantothenic acid (B5)

mg

1

1

1

1

Vitamin B6

mg

1

1

0

0

Folic acid (B9)

µg

20

20

7

8

vitamin B12

µg

0

0

0

0

vitamin K

µg

1,9

0,1

 


Rice and the environment

As you may guess based on how much of it we cultivate, rice also has a large environmental impact. 2.5% of human greenhouse gas emissions can be attributed to rice production. This occurs mainly in the form of methane (CH4) since the flooded soils used for rice cultivation do not ventilate well and thus encourage anaerobic fermentation of organic matter. This estimate, however, is only based on methane and ignores other byproducts linked to global warming such as a nitrous oxide (N20), otherwise known as laughing gas.

In order to decrease the production of methane in rice cultivation, a method of occasional flooding of rice fields was introduced. This ended up having unpleasant side effects though: a study that was carried out in India displayed that occasional flash flooding of rice fields can lead to 30-45 times higher levels of nitrous oxide production than permanently flooded fields (Kritee K. et al., 2018). Additionally, rice takes more water to grow than other grains; globally, rice production is responsible for 1/3rd of the usage of freshwater on our planet.


Additional reading:  

Kritee, et al, 2018, High nitrous oxide fluxes from rice indicate the need for water management for both long- and short-term climate impacts; PNAS, vol. 115 | no. 39

M. S. de Miranda, et al, 2014, Environmental Impacts of Rice Cultivation; American Journal of Plant Sciences, 6

https://www.independent.co.uk/environment/rice-farming-climate-change-global-warming-india-nitrous-oxide-methane-a8531401.html

https://en.wikipedia.org/wiki/Rice#Distribution

http://ricepedia.org/rice-as-food/the-global-staple-rice-consumers

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