Rice

 

 

Rice is the seed of the monocot plants Oryza sativa (Asian rice) or Oryza glaberrima (African rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia. It is the grain with the second-highest worldwide production, after corn, according to data for 2010.

Since a large portion of maize crops are grown for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one fifth of the calories consumed worldwide by humans.

Chinese legends attribute the domestication of rice to Shennong, the legendary Emperor of China and inventor of Chinese agriculture. Genetic evidence has shown that rice originates from a single domestication 8,200–13,500 years ago in the Pearl River valley region of China.^[5] Previously, archaeological evidence had suggested that rice was domesticated in the Yangtze River valley region in China. From East Asia, rice was spread to Southeast and South Asia. Rice was introduced to Europe through Western Asia, and to the Americas through European colonization.

There are many varieties of rice and culinary preferences tend to vary regionally. In some areas such as the Far East or Spain, there is a preference for softer and stickier varieties.

Rice is normally grown as an annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop for up to 30 years. The rice plant can grow to 1–1.8 m (3.3–5.9 ft) tall, occasionally more depending on the variety and soil fertility. It has long, slender leaves 50–100 cm (20–39 in) long and 2–2.5 cm (0.79–0.98 in) broad. The small wind-pollinated flowers are produced in a branched arching to pendulous inflorescence 30–50 cm (12–20 in) long. The edible seed is a grain (caryopsis) 5–12 mm (0.20–0.47 in) long and 2–3 mm (0.079–0.118 in) thick.

Rice cultivation is well-suited to countries and regions with low labor costs and high rainfall, as it is labor-intensive to cultivate and requires ample water. However, rice can be grown practically anywhere, even on a steep hill or mountain area with the use of water-controlling terrace systems. Although its parent species are native to Asia and certain parts of Africa, centuries of trade and exportation have made it commonplace in many cultures worldwide.

The traditional method for cultivating rice is flooding the fields while, or after, setting the young seedlings. This simple method requires sound planning and servicing of the water damming and channeling, but reduces the growth of less robust weed and pest plants that have no submerged growth state, and deters vermin. While flooding is not mandatory for the cultivation of rice, all other methods of irrigation require higher effort in weed and pest control during growth periods and a different approach for fertilizing the soil.

The name wild rice is usually used for species of the genera Zizania and Porteresia, both wild and domesticated, although the term may also be used for primitive or uncultivated varieties of Oryza.

 

Nutrition and health

Nutrients and the nutritional importance of rice

Rice, white, long-grain, raw
Nutritional value per 100 g (3.5 oz)
Energy	1,527 kJ (365 kcal)
Carbohydrates	80 g
Sugars	0.12 g
Dietary fiber	1.3 g
Fat	0.66 g
Protein	7.13 g
Vitamins
Thiamine (B1)	(6%) 0.0701 mg
Riboflavin (B2)	(1%) 0.0149 mg
Niacin (B3)	(11%) 1.62 mg
Pantothenic acid (B5)	(20%) 1.014 mg
Vitamin B6	(13%) 0.164 mg
Trace metals
Calcium	(3%) 28 mg
Iron	(6%) 0.80 mg
Magnesium	(7%) 25 mg
Manganese	(52%) 1.088 mg
Phosphorus	(16%) 115 mg
Potassium	(2%) 115 mg
Zinc	(11%) 1.09 mg
Other constituents
Water	11.61 g
·         Units ·         μg = micrograms • mg = milligrams ·         IU = International units
Percentages are roughly approximated usingUS recommendations for adults. Source: USDA Nutrient Database

Rice is the staple food of over half the world's population. It is the predominant dietary energy source for 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa. Rice provides 20% of the world’s dietary energy supply, while wheat supplies 19% and maize (corn) 5%.

A detailed analysis of nutrient content of rice suggests that the nutrition value of rice varies based on a number of factors. It depends on the strain of rice, that is between white, brown, black, red and purple varieties of rice – each prevalent in different parts of the world. It also depends on nutrient quality of the soil rice is grown in, whether and how the rice is polished or processed, the manner it is enriched, and how it is prepared before consumption.

An illustrative comparison between white and brown rice of protein quality, mineral and vitamin quality, carbohydrate and fat quality suggests that neither is a complete nutrition source. Between the two, there is a significant difference in fiber content and minor differences in other nutrients.

Brilliantly colored rice strains, such as purple rice, derive their color from anthocyanins and tocols. Scientific studies suggest that these color pigments have antioxidant properties that may be useful to human health. In purple rice bran, hydrophilic antioxidants are in greater quantity and have higher free radical scavenging activity than lipophilic antioxidants. Anthocyanins and γ-tocols in purple rice are largely located in the inner portion of purple rice bran.

Comparative nutrition studies on red, black and white varieties of rice suggest that pigments in red and black rice varieties may offer nutritional benefits. Red or black rice consumption was found to reduce or retard the progression of atherosclerotic plaque development, induced by dietary cholesterol, in mammals. White rice consumption offered no similar benefits, and the study claims this to be due to absent antioxidants in red and black varieties of rice.

Comparison of rice to other major staple foods

The table below shows the nutrient content of major staple foods in a raw form. Raw grains, however, are not edible and cannot be digested. These must be sprouted, or prepared and cooked for human consumption. In sprouted and cooked form, the relative nutritional and anti-nutritional contents of each of these grains is remarkably different from that of raw form of these grains reported in this table.

Health Benefits of Rice

While all whole grains share similar health benefits, each individual whole grain also offers its own special advantages. Here is some of the recent research related to rice.

BLACK RICE RIVALS BLUEBERRIES AS ANTIOXIDANT SOURCE

Scientists working with Zhimin Xu at the Louisiana State University Agricultural Center have found that black rice (sometimes called “forbidden rice”) contains health-promoting antioxidants called anthocyanins, at levels similar to those found in blueberries and blackberries.

BLACK RICE BRAN PROTECTS AGAINST INFLAMMATION

S.P. Choi and colleagues from Ajou University in Suwon, South Korea tested both black rice bran and brown rice bran for their effectiveness in protecting against skim inflammation. In mouse tests, they found that the black rice bran did suppress dermatitis, but the brown rice bran did not. The scientists suggest that black rice may be a “useful therapeutic agent for the treatment and prevention of diseases associated with chronic inflammation.”

BLACK RICE BRAN HIGH IN ANTIOXIDANTS

A team of researchers at Cornell University, including WGC Scientific Advisor Rui Hai Liu, analyzed the phenolic content and antioxidant activity of 12 diverse varieties of black rice, and found that antioxidants were about six times higher in black rice than in common brown/white rice. The black rice bran had higher content of phenolics, flavonoids and anthocyanins.

SWITCH TO BROWN RICE REDUCES DIABETES RISK IN MEN AND WOMEN

Scientists at the Harvard School of Public Health followed 39,765 men and 157,463 women as part of the Health Professionals Follow-up Study and the Nurses’ Health Study I and II. They found that those eating several servings of white rice per week had a higher risk of Type 2 diabetes and that those eating 2 or more servings of brown rice had a lower risk. They estimate that replacing about two servings a week of white rice with the same amount of brown rice would lower diabetes risk 16%.

BLACK/BROWN RICE MORE EFFECTIVE IN WEIGHT CONTROL

At the Department of Food and Nutrition at Hanyang University in Seoul, Korean researchers randomly assigned forty overweight adult women to two groups. For six weeks, one group ate meals containing white rice, while the other consumed otherwise-identical meals with a mix of black and brown rice. While both groups showed significant reductions in weight, BMI and body fat, the whole grain rice group surpassed the white rice group in all three measures. The whole grain group also saw an increase in HDL (good) cholesterol and in antioxidant activity.

BROWN RICE, FOR LOWER BLOOD GLUCOSE IN HEALTHY AND DIABETIC SUBJECTS

Lower post-prandial blood glucose response can be important both for preventing and for controlling diabetes. In a study at the University of the Philippines, researchers used a randomized cross-over design to compare the effects on blood glucose of brown rice and white rice on 10 healthy and nine Type 2 diabetic volunteers. In healthy volunteers, the glycemic area and glycemic index were, respectively, 19.8% and 12.1% lower with brown rice than with white rice; with diabetics, the same values for brown rice were 35.2% and 35.6” lower than with white rice.

PHENOLS IN BROWN RICE MAY INHIBIT BREAST AND COLON CANCER

Rice is a staple in Asia, where breast and colon cancer rates are markedly lower than in the Western world. Scientists at the University of Leicester, UK, analyzed the phenolic compounds in brown rice, brown rice bran, and white milled rice (from the same varietal) to look for known cancer-suppressive compounds. They discovered that several such compounds were present in all three samples, but were found in much lower levels in the white rice. They postulated that consuming rice bran or brown rice instead of white rice may be advantageous with respect to cancer prevention.

The Different Types of Rice

The different types of rice include the following:

Short-grain rice is very starchy and cooks up soft and sticky. It’s used in things like sushi, paella, and risotto.

Long-grain rice contains less starch so the cooked grains are drier and more separate. It’s often used in pilafs or dishes with a lot of sauce.

Jasmine and basmati are long-grain varieties that have been cultivated to bring out distinctive flavor profiles. They often turn up in Indian and Asian food.

Brown rice—which is also available in long and short grains—is a lot chewier and heartier than white rice and takes about twice as long to cook.