June/July 2021 Issue
Colored Rice — Whole Grain Goodness Offering a Greater Nutrition Boost to the Diet
By Densie Webb, PhD, RD
Today’s Dietitian
Vol. 23, No. 6, P. 22
When clients ask about the nutritional contribution rice makes to their diets, colored rice is probably not what they have in mind. It’s true that most rice (Oryza sativa L.) is white, but some varieties offer phytochemicals (mainly polyphenols and anthocyanins) in the outer bran layer, which not only imbues them with hues of a different color but also boosts their nutrient content.
Colored rice, or pigmented rice, which has long been used in other countries, is gaining popularity here in the United States. In fact, these varieties often can be found on the shelves of supermarkets and in specialty dishes in restaurants. Despite its growing availability, colored rice still has a very small market compared with white rice, and it costs considerably more. The two types of colored rice most widely available are red rice and black rice, though there’s some disagreement about whether purple rice is a third type, or simply another name for black rice, as it tends to take on a purplish hue when cooked.
Whatever one calls it, colored rice has much to offer. “Black, purple, and red rice offer adventure in flavor, texture, and nutrition,” says Isabel Maples, MEd, RD, a Washington, D.C.–based spokesperson for the Academy of Nutrition and Dietetics (the Academy).
What Is Colored Rice?
All rice grains have a hard outer husk. After removal of the bran and embryo, the remaining endosperm is known as polished white rice. While colored or pigmented rice generally is categorized as black or red rice, the colors range from dark red, dark purple, and dark blue to red-brown, black-purple, and dark red-purple, depending on the mixture of anthocyanins. As with white rice, there’s a wide variety of types of colored rice—glutinous and nonglutinous, scented and nonscented, short- and long-grained.
Rice that has a red bran layer is referred to as “red rice.” While the color, which can range from amber to burgundy, is confined to the bran layer, a lighter hue of red may remain, even after milling. However, the inner portion of red rice is white, just like its white cousin, which is far more common in the United States. Varieties include Himalayan Red Rice, Thai Red Cargo Rice, Bhutanese Red Rice, and a US variety known as Scarlett Rice.
As demand for black rice increases in the United States, it’s imported from China, the Philippines, India, and Thailand. While both red and black rice are more resistant to insect infestation than traditional brown rice, farmers can face issues with crop rotation between white and colored rice, which can contaminate the white and colored rice, affecting color and quality.1
What’s interesting is that black/purple and red rice have much mythology surrounding them. In Japan, the rice plant is said to have failed to bear grains, and so the goddess Kuan Yin sprinkled her milk over the plant and white grains appeared; but when squeezed, blood came out and some grains turned red. In Balanese mythology, the god Ciwa sent down a bird that carried seeds of four different colored rice: yellow, black, red, and white. On the way, the bird ate the yellow seed and only three were left.2
Rather than a gift from the gods, today, colored rice varieties are mostly the result of cultivation, though wild colored rice is consumed in some countries. Wild rice is likely to be lighter in color and may cook faster than cultivated rice. Cultivated rice is more consistent in color and taste. Black rice (not to be confused with wild rice, which also is dark but technically is a grass seed), also called “forbidden rice” or “Emperor’s rice,” was once reserved for the Chinese Emperor and the upper class in ancient China as a tribute food.3 The origins of black rice aren’t entirely clear; researchers have suggested that the black trait originated as a mutation in one specific gene that triggered anthocyanin production in the grain.2
Colored rice may be gaining in popularity today, but according to the Asian Agri-History Foundation, the earliest record of colored rice dates to 7000 BC. Back then, rice was an important part of ritual offerings to the gods. Different types of rice were offered to different divinities. In addition to black rice being revered, ancient Ayurvedic medicine considered red rice to have medicinal value. In Korea, seeds of wild and cultivated red rice were found embedded in a Buddha statue in a 1,300-year-old shrine. In Indian culture, red rice is sometimes given as a gift for marriage, religious ceremonies, or the birth of a child. It also can be given when someone is sick or when a death occurs.4 In some parts of Japan, children are given red and white rice cakes to eat on their first birthday to acknowledge the special occasion.2
Nutrition Rundown
While there’s not much difference in the nutrient content of colored rice varieties—they’re rich in carbohydrates, sodium-free, and a source of iron—there are significant differences in the phytochemicals they provide, especially compared with white rice. The grains of black rice varieties identified throughout Asia are inky black in color when raw. As they cook, the grains turn a deep iridescent purple. Black rice varieties include Indonesian black rice, Philippine galatinaw rice, and Thai jasmine black rice. Blanca Isabel Purple Rice is a black rice variety grown in the United States.
The bran layer of red rice contains polyphenols and anthocyanins, not found in white rice, that are believed to bolster cellular antioxidant defenses and support maintenance of healthy brain function.5 These compounds are what give red rice its distinctive coloring. Red rice is high in procyanidins, which are similar to the tannins found in red wine.
In traditional Chinese medicine, red rice is believed to promote blood circulation and is used to treat upset stomach, indigestion, bruised muscles, and hangovers. Possibly the most familiar of red rice products is red rice yeast, which is made by fermenting yeast over red rice and is promoted as a cholesterol-lowering supplement.6 But this is different from cooked red rice.
Colored rice also differs from white rice in that it isn’t enriched. White rice is enriched with iron and the B vitamins thiamine, folate, and niacin—nutrients that are removed during milling. So, while phytochemicals are much higher in colored rice, it doesn’t contain the vitamins of enriched rice. The nutritious bran and germ layers of colored rice are intact similar to brown rice, though brown rice also isn’t enriched. The result is a fiber content similar to that of brown rice.
Colored rice contains not only a variety of phytochemicals but also amino acids and essential oils known to have free radical–scavenging antioxidant capacities.1 When red, black, and brown rice bran were analyzed, the concentrations of phytochemicals and antioxidant activities were highest in black rice bran, followed by red and brown rice. The natural compounds that give them their distinct color are similar to those found in blueberries and blackberries. Catechin and myrectin were found to be abundant in red and brown rice bran, while quercetin and catechin were abundant in black rice bran. Because of the concentration of phytochemicals, it’s been suggested that black rice, in particular, may have pharmaceutical activity.7
Laboratory studies have found that an extract of black or purple rice has neuroprotective and anticancer effects on human cells and an anti-inflammatory effect in mice.8-10 Whether this translates into real-world health benefits for humans is unknown, but years of research shows that the polyphenols and anthocyanins found in black and red rice are associated with disease prevention.11,12
Also in the lab, red and black/purple bran extracts have shown antidiabetic activity by increasing the expression of genes that encode insulin-signaling proteins.13 The antidiabetic action is believed to be due to the anthocyanins and procyanidins present in the colored rice bran. Though not completely understood, there are many aspects to the role anthocyanins play in the body. Plants that produce anthocyanins do so as protective mechanisms against environmental stressors, such as ultraviolet light, cold temperature, and drought.
In the United States, colored rice is seldom, if ever, mentioned in recommendations for healthful eating. In France, however, the government has promoted regular consumption of colored rice, along with brown rice, as part of a healthful diet.1 “Phytonutrients found in colored rice, the same compounds that give fruits and vegetables their colors, enhance health by preventing damage at the cellular level,” says Debbie Petitpain, RDN, chief operating officer at Synergasia Health Technologies, Inc, in Charleston, South Carolina, and spokesperson for the Academy.
As with white rice, colored rice is gluten-free and can be included in the diets of patients with celiac disease or non-celiac gluten sensitivity, offering variety as well as health benefits. The table below compares the nutrient content of black and red rice. However, nutrient content varies among brands and varieties and therefore may include other nutrients, including the minerals iron and zinc found in some red rice.4
Culinary Uses
Varieties of red and black/purple rice vary not only in color and nutrition but in texture and taste. Both black and red rice are available in short, medium, and long grain. As with white rice, the shorter the grain, the stickier it is. According to Maples, black rice stays a deep purplish-black when cooked. To avoid adding a purplish tinge to light-colored foods such as chicken, she suggests combining colored rice at the end of preparation. Most red rice takes on a rich brick red color that lightens a bit when cooked.
Red and black rice are whole grains but tend to cook in less time (as little as 20 minutes) than brown rice (about 45 minutes) but take longer than white rice.14 Black rice can be used for creating porridge, desserts, bread, and noodles. Moreover, red and black rice can be made into rice flours, but these may be difficult to find in stores. One study found that while black rice is higher in antioxidant activity than red, both lose some antioxidant potential during cooking, although the risotto cooking method, which enables complete absorption of water, allows for great retention of antioxidant compounds.15 A wide range of recipes for black and red rice can be found online, ranging from pudding to gazpacho. Because they’re whole grains, they offer a chewy texture and most offer a sweet, nutty flavor.
Several brands of colored rice also are available in supermarkets and online. Companies that sell black rice include Ralston Farms, Lundberg Family Farms, Lotus Foods, Thrive Market, and Nature’s Earthy Choice. Those that sell red rice include Dragonfly, Lotus Foods, Foods to Live, Ariya, and Jordan Farms.
Bottom Line
“Black or purple and red rice offer clients adventure in flavor, texture, and nutrition,” Maples says. Their contribution of phytochemicals associated with a wide range of health benefits makes them a welcome addition to any diet. If they fit into clients’ budgets and they’re open to trying new foods, suggest nutritious black and red rice as healthful additions to their weekly menu planning.
— Densie Webb, PhD, RD, is a freelance writer, editor, and consultant based in Austin, Texas.
References
1. Napasintuwong O. Thailand’s colored rice standard and markets. FFTC Agricultural Policy Platform website. https://ap.fftc.org.tw/article/1756. Published February 21, 2020. Accessed April 4, 2021.
2. Ahuja U, Ahuja SC, Chaudhary N, Thakrar R; Asian Agri-History Foundation. Red rices — past, present, and future. https://www.asianagrihistory.org/pdf/articles/Red-Rices-Uma-Ahuja.pdf. Accessed April 2, 2021.
3. The origin and spread of 'Emperor's rice': scientists solve the mystery of black rice. ScienceDaily website. https://www.sciencedaily.com/releases/2015/09/150926191819.htm. Published September 26, 2015. Accessed April 2, 2021.
4. Santiaguel AF. Red pearls of the Himalayas. Rice Today website. https://ricetoday.irri.org/red-pearls-of-the-himalayas/. Published July 1, 2014. Accessed April 2, 2021.
5. Larson Duyff R. Academy of Nutrition and Dietetics Complete Food & Nutrition Guide. 5th ed. New York, NY: Houghton Mifflin Harcourt; 2017.
6. Cicero AFG, Fogacci F, Banach M. Red yeast rice for hypercholesterolemia. Methodist Debakey Cardiovasc J. 2019;15:192-199.
7. Ghasemzadeh A, Karbalaii MT, Jaafar HZE, Rahmat A. Phytochemical constituents, antioxidant activity, and antiproliferative properties of black, red, and brown rice bran. Chem Cent J. 2018;12:17.
8. Thummayot S, Tocharus C, Pinkaew D, Viwatpinyo K, Sringarm K, Tocharus J. Neuroprotective effect of purple rice extract and is constituent against amyloid beta-induced neuronal cell death in SK-N-SH cells. Neurotoxicology. 2014;45:149-158.
9. Banjerdpongchai R, Wudtiwai B, Sringarm K. Cytotoxic and apoptotic-inducing effects of purple rice extracts and chemotherapeutic drugs on human cancer cell lines. Asian Pac J Cancer Res. 2014;14(11):6541-6548.
10. Choi SP, Kim SP, Kang MY, Nam SH, Friedman M. Protective effects of black rice bran against chemically-induced inflammation of mouse skin. J Agric Food Chem. 2010;58(18):10007-100015.
11. Koch W. Dietary polyphenols-important non-nutrients in the prevention of chronic noncommunicable diseases. A systematic review. Nutrients. 2019;11:1039.
12. Kimble R, Keane KM, Lodge JK, Howatson G. Dietary intake of anthocyanins and risk of cardiovascular disease: A systematic review and meta-analysis of prospective cohort studies. Crit Rev Food Sci Nutr. 2018;59(18):3021-3043.
13. Boue SM, Daigle KW, Chen MH, Cao H, Heiman ML. Antidiabetic potential of purple and red rice (Oryza sativa L.) bran extracts. J Agric Food Chem. 2016:64:5345-5353.
14. Rice of many colors. Oldways Whole Grains Council website. https://wholegrainscouncil.org/blog/2017/09/rice-many-colors. Published September 27, 2017. Accessed April 4, 2021.
15. Zaupa M, Calani L, Del Rio D, Brighenti F, Pellegrini N. Characterization of total antioxidant capacity and (poly)phenolic compounds of differently pigmented rice varieties and their changes during domestic cooking. Food Chem. 2015;187:338-347.