Question: Why is purple rice colored as it is?
About the article "Rice", section "Nutrients and the nutritional importance of rice".

Candidate passages:
Black rice (also known as purple rice or forbidden rice) is a range of rice types, some of which are glutinous rice.
Varieties include but are not limited to Indonesian black rice and Thai jasmine black rice.
Black rice is high in nutritional value and contains 18 amino acids, iron, zinc, copper, carotene, and several important vitamins .
The grain has a similar amount of fiber to brown rice and like brown rice, has a mild, nutty taste.
In China, black rice is claimed to be good for the kidney, stomach and liver; these claims have not been independently verified.
Black rice is a deep black color and usually turns deep purple when cooked.
Its dark purple color is primarily due to its anthocyanin content, which is higher by weight than that of other colored grains but more limited in the number of different anthocyanin species present.
It is suitable for making porridge and it can also be used for making dessert, traditional Chinese black rice cake or bread.
Black rice was proclaimed as a 'superfood' worldwide largely thanks to an important piece of research by Dr. Zhimin Xu, titled "Black rice rivals pricey blueberries as source of healthful antioxidants".
The research stated that “just a spoonful of black rice bran contains more health promoting anthocyanin antioxidants than are found in a spoonful of blueberries, but with less sugar and more fiber and vitamin E antioxidants".
Several value-added products have since been launched using Black Rice.
These include noodles and Black Rice Cracker Chips.
In China, noodles made from black rice have been produced.
Thai black jasmine rice, while not as prevalent as the white and brown varieties, adds more vibrant color to meals, as well as providing additional health benefits. 
Nutrition and health.
Nutrients and the nutritional importance of rice.
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.
In central parts of India, the yam (Khamalu or Chupri alu) is prepared by being finely sliced, seasoned with spices and deep fried.
In southern parts of India, known as Karunai Kizhangu (கருணைக்கிழங்கு) in Tamil, the vegetable is a popular accompaniment to rice dishes and fish curry.
Also eaten in India, "Dioscorea alata", a purple-pigmented species, is known as "ratalu" or "violet yam".
In the southern part, especially in Kerala, you can see both purple and white colored yams, locally known as "Kaachil or Kavuttu".
In southern part of India, Karnataka, it is known as Suvarna gadde. 
  Ketan - traditionally refers to the glutinous rice itself as well as sticky rice delicacy in its simplest form.
The handful mounds of glutinous rice is rounded and sprinkled with grated coconut, either fresh or sauteed as serundeng.
Ketupat - square shaped crafts made from the same local leaves as "palas", but it is usually filled with regular rice grains instead of "pulut", though it depends on the maker.
Lemang - wrapped in banana leaves and inside a bamboo, and left to be barbecued/grilled on an open fire, to make the taste and texture tender and unique  Lemper - cooked glutinous rice with shredded meat inside and wrapped in banana leaves, popular in Java  Nasi kuning - either common rice or glutinous rice can be made into ketan kuning, yellow rice colored with turmeric  Tumpeng - glutinous rice can be made into tumpeng nasi kuning, yellow rice colored by turmeric, and shaped into a cone.  
Eight cars are available to choose from in the game, and a secret ninth car known as the Warrior, which is in purple and is a special car rather than being a licensed model.
It can be accessed via a special game code if entered correctly.
The eight cars featured (besides the Warrior) include the Toyota Supra Turbo (colored red), Acura NSX (colored silver), Mazda RX-7 (colored yellow), Porsche 911 Carrera (colored dark blue), Dodge Viper RT-10 (colored royal blue), Chevrolet Corvette C4 ZR-1 (colored dark green), Lamborghini Diablo VT (colored navy blue), and the Ferrari 512TR (colored red).