Rice as a Food

There are some countries with high annual rice consumption per capita (up to 130–180 kg, equal to 55–80 percent of total caloric source) such as Bangladesh, Cambodia, Indonesia, Laos, Myanmar, Thailand, and Vietnam (Chang 2000). Even in most parts of Africa, rice is a secondary staple food next to cassava, yams, corn, and millet. However, in the following African countries rice is consumed as a staple food: Liberia, Sierra Leone, Guinea, Ivory Coast, Ghana, Madagascar, and part of Nigeria. By comparison with the rice production and consumption in Asian countries, Latin America is often overlooked. However, annual rice consumption in the following countries exceeds more than 32 kg per capita: Brazil, Columbia, Ecuador, and the Dominican Republic.

Rice is the best cereal crop in terms of food energy per production area and is consumed in various forms, including plain rice, noodles, puffed rice, breakfast cereals, cakes, fermented sweet rice, snack foods, beer, wine and vinegar. Rice starch is used as a thickener in baby foods, sauces, and desserts or can be made into sweet syrup. However, most consumption of rice is as cooked rice served simultaneously with vegetable, poultry, beef, seafood, and other dishes. Rice as a comfort food is economical, delicious, nutritious, versatile, easy to prepare, and bland enough to pair with other foods. Rice is convenient to store on shelves in cupboards and pantries.

Preparation and Consumption

Rice consumption falls into the following three categories: direct food use, processed foods, and brewer's use. Detailed methods and recipes for rice food preparations were described by Bor S. Luh (1991), Sri Owen (1993), Jeffrey Alford and Naomi Duguid (1998), and Bor S. Luh (1999).

Direct food use. Rice is easy to prepare, has a soft texture for the human palate and stomach, and has the ability to absorb flavors while retaining its texture. Therefore, rice has gained popularity as "the pasta of the 1990s" in the West. Both the short-grain japonica and the long-grain indica rice include non-glutinous and glutinous types. Non-glutinous rice is somewhat transparent and is less sticky than glutinous rice when cooked. There are some rice varieties with an attractive aroma, such as basmati. Parboiled rice was originally produced in Asia, but the parboiled rice produced in the United States now, such as by the company Uncle Ben's, is of high quality. Arborio rice has large tan grains with central white dots and, because of its creamy, chewy texture, can be used to make risotto.

American wild rice is a coarse grass (not a true rice by taxonomy), and now has become more and more popular in the United States and Canada. It is grown in shallow waters and has medium to long grains and a nutty flavor.

Rice is cooked by heating (either boiling or steaming) soaked rice for full gelatinization of the kernels and evaporation of excess water. Generally there are three rice cooking methods: large-amount-of-water method, absorption method, and steaming method. The lot-of-water technique is good for arborio, basmati, or parboiled rice, but not for Thai jasmine or japonica rice with low amylose content, which should be cooked by steaming. Rice cooking methods also include rinsing, boiling, baking, roasting, frying, and pressure-cooking. It is customary to wash rice before cooking to remove dust, husks, insects, and other impurities. American-grown rice does not require washing or rinsing before cooking because these "cleaning" processes further remove nutrients, including vitamins and minerals that were added before packaging by fortification or enrichment.

Juliano (1985) indicated that rice cooking methods vary with different countries. Either uncooked rice or fully cooked rice combines well with other protein-rich foods such as meat, poultry, fish, cheese, and eggs because rice is bland in flavor and carries the flavor of the mixed ingredients. People in the Middle East lightly fry rice before boiling. Americans often add salt, butter, or margarine to soaked rice. People in China, Korea, and Japan add extra water to cook rice into porridge (thick gruel) or congee (thin soup). Rice can be cooked with curries (in India and Malaysia) or sauce (in the Philippines) or combinations of various ingredients, including pork, shrimp, chicken, and vegetables (in China) (Boesch 1967). Steamed rice is preferred in some countries because more vitamins and minerals are retained. Rice can be steamed in a bamboo steamer or, currently, in an electric metal steamer. Steamed rice can be served plain or mixed with other ingredients. Mixed steamed rice also varies among countries. For example, Malaysians steam glutinous rice with mixed meat in a bamboo joint over a fire. Cambodian kralan is steamed rice mixed with grated coconut and beans. Iranians steam rice with oil or with butter, and sometimes with yogurt, while rice is cooked with water and oil in Brazil, Chile, Ecuador, Germany, Mexico, and Peru. Some countries, such as France, Korea, Burma, Thailand, Japan, and the Philippines, add rice to cold water for cooking. Presoaking is a common practice in India. Detailed descriptions of recipes from different countries for cooked rice are provided by Virmani (1991). Rice can be kept as long as five days in the refrigerator. The leftover rice is good for stir-frying into egg fried rice with chopped carrots and the like. Rice can also be cooked with certain amounts of water and meat, seafood, vegetables, or other additions in clay pots or high-pressure metal pots to make thin or thick congee (or juk ) or gruel (okayu, in Japanese).

Parboiled rice: Parboiling is popular in India, Sri Lanka, Pakistan, Brazil, the United States, and Italy. Parboiling changes rice starch from the crystalline form to an amorphous form by a series of procedures including cleaning, grading, soaking, steeping, steaming, drying, tempering, milling, color sorting, and finally packaging. It involves the treatment of grains in cold water and then hot water with low pressure. The treated rice can be dried by the steam or sun. Problems of off-color and offflavor that resulted from conventional parboiling procedures have been overcome by various inventions, such as the H. R. Conversion and Malek Processes (D. H. Grist, 1986). Major advantages of parboiling over ordinary milling include easier dehulling; less breakage in milling; higher retention of nutrients after milling, washing, and cooking; and better resistance to insect and fungus infestation, which makes it possible to store the rice for longer periods of time. Also, parboiled rice gelatinizes the starch and makes better consistency, greater hardness, and better vitreousness of the kernel. The main disadvantages of parboiling include greater rancidity during storage, longer cooking time, greater difficulty in milling, and additional cost (De Datta, 1987).

Rice-flour products: Rice flour does not contain gluten and therefore its dough cannot retain gases during baking as wheat flour does. Therefore, rice flour is widely used in making baby foods, breakfast cereals, unbaked biscuits, snack foods, pancakes, and waffles. For example, a composite baking flour, made by adding 10 percent rice flour to wheat flour, is used to make pastry products in Italy.

Rice-flour products are exemplified by the following foods: yuan zi (or tong yuan ) is a popular food in China. It is made from glutinous rice flour and water by adding sweet or savory fillings to the rice dough. The quality of yuan zi preparation depends on the amylopectin content, the flour particle size, and the recipe for the fillings. (The higher the amylopectin content, the softer and more sticky the rice flour becomes when the same amount of water is added.) Yuan zi is fried with vegetable oil or thoroughly cooked in boiling water and served with sugar or other condiments.

Rice bread is a good substitute for other gluten-containing cereal flour, as some people are allergic to these flours. The medium-and short-grain rice varieties are preferable to the long-grain type for making rice bread. Formulation is important in making rice bread by adjusting the levels of sucrose, yeast, water, nonfat dry milk, and other additives.

Processed foods. Rice noodles: Rice noodles are called mi fen in Chinese, sen mee in Thai, and harusame in Japanese. Mi fen is often produced from non-glutinous rice by soaking, grinding, steaming, kneading, and drying. If dehydrated, it can be stored up to two years. In Thailand, mung bean is added to rice to make a special rice noodle called fung-shu (or tong-fun ) that is more resistant to texture changes during reconstitution. In Asia, rice noodles are consumed in soups or as snacks. Mi fen is served with water, meat or chicken, green vegetables, soy sauce, and other ingredients.

Rice snacks: Rice snacks have an attractive taste, flavor, texture, and aroma.They are often made from glutinous rice because of its sticky characteristics and easy expansion into a porous texture. However, non-glutinous rice also can be used for making some rice snacks.

The rice cracker is a typical rice snack. The Japanese soft rice cracker made from glutinous rice is called arare or okaki in comparison with the less popular and tougher senbei (the rice cracker made from non-glutinous rice). The production process involves washing, grinding, steaming, kneading, cooling, pounding, drying, baking, seasoning, cutting, and packing. The production of rice crackers is now developed as a continual process that takes place within 3– 4 hours. To add flavors and color to rice crackers, the following ingredients are often added: seaweed, sesame, red peppers, sugar, food pigments, and spices. Moreover, high-quality, refined oil should be used for oil-fried crackers.

Rice fries can even compete with the French fries made from potatoes because rice fries have a crisp exterior crust and fluffy interior. To make rice fries, rice should be fully cooked with butter, salt, and other seasonings.

Rice cakes: Rice cakes are popular in China, Japan, and other Asian countries. They can be made either from glutinous or non-glutinous rice by soaking and steaming. Before steaming, various ingredients can be added for more flavor, such as sugar, salt, monosodium glutamate, crushed radish, crushed mung bean (for lu du gao, a special cake in China), and crushed taro.

Glutinous or waxy rice is very sticky when cooked and is mainly consumed in northern Burma, northern Thailand, Laos, and Vietnam. It is often used to make rice cakes. However, fermented rice cakes, such as fakau in China and bibingka in the Philippines, can also be made from non-glutinous rice.

Puffed rice cakes are popular in China and the United States because they are rich in taste, low in calories, and free from cholesterol. To make puffed rice cakes, some minor ingredients, such as sesame seed, millet, and salt, should be added to brown rice.

The Chinese rice cake zong zi, the same as chimaki in Japan, is made from glutinous rice and soda ash, wrapped in bamboo leaves to form a tetrahedron, bound with string, and served with honey or sugar. There are two main categories of zong zi : chien zong and rou zong. The difference between chien zong and rou zong is that pork or ham and other ingredients are added to rou zong to enrich the flavor and nutritional value. Other ingredients include mushrooms, soy sauce, monosodium glutamate, sugar, black pepper, sherry wine, fried garlic, cooking oil, and shrimp meat.

Neng gao or nian gao (mochi in Japanese) is also a special rice cake for the celebration of the Chinese Lunar New Year. It is produced either from glutinous rice or from nonglutinous rice. The main production procedures involve soaking, steaming, kneading, and packing. For better taste and flavor, neng gao is sometimes sweetened with sugar or enriched with lard and cinnamon flour.

In Japan, sushi is a rice cake or roll or cube topped with raw fish or other delicacies and served with wasabi (Japanese horseradish). Fresh raw fish used in sushi include tuna, bonito, shrimp, squid, and shellfish. Vegetables such as cucumber and seasoning gourd also can be put in the middle of the rolls, which are then wrapped with seaweed (nori ). Sushi usually is served with rice vinegar and soy sauce (shoyu ).

There are many other types of rice cakes made in Asia. For example, biko, cuchinta (or kutsinta), puto, suman, and other rice cakes are made in the Philippines.

Rice puddings: Rice can be made into creamy puddings by mixing cooked rice with milk and sugar. Indian consumers sweeten rice pudding with palm sugar. Rice puddings were served to the rich during the time of the ancient Romans. Now, rice pudding has become a popular dish for children. A delicious Chinese pudding is the Eight Jewel Rice Pudding, prepared from eight different kinds of fruit and steamed glutinous rice with honey.

Quick-cooking rice: The preparation and cooking of conventional rice take about one hour. Now, quick-cooking rice product is popular in developed countries, such as Japan, the United States, and other Western countries. Completely precooked rice requires no further cooking. However, quick-cooking rice often requires five to fifteen minutes for cooking. To produce quick-cooking rice, rice should be precooked by gelatinizing the rice starch in water and/or steam and then dried. Quick-cooking rice mainly is produced by the soak-boil-steam-dry, freeze-thaw-drying, expansion–pre-gelatinization, and gun puffing methods.

Canned and frozen rice: For convenience of consumption, canned and frozen rice are produced in Japan, Korea, the United States, and other countries. After precooking, canned rice is sold by wet pack and dry pack. The preparation of frozen cooked rice includes soaking, draining, steaming, boiling, and freezing. To serve the frozen cooked rice, microwave heating is a common practice. Frozen rice also can be made into freeze-dried rice by sublimation under high vacuum. This rice has a long storage life of one to two years.

Rice breakfast cereals: Some rice breakfast cereals require cooking before eating, while others can be eaten directly. They commonly are fortified with minerals and heat-stable vitamins, such as niacin, riboflavin, and pyridoxine. The ready-to-eat breakfast cereals include oven-puffed, gun-puffed, extruded, and shredded rice. Oven-puffed rice is made from short-grain rice with sugar and salt by cooking, drying, tempering, enriching, and packaging. Gun puffing is a traditional method and is still practiced in some Asian countries, such as China. The procedure consists of heating, cooking with high pressure in a sealed chamber or gun, and suddenly releasing the high pressure. Because of the lack of continuity in processing, gun puffing is less popular in developed countries. Instead, making extruded rice has high and continuous production rates, great versatility in product shape, and ease of controlling product density. The production of extruded rice can be accomplished by extruding superheated and pressurized doughs. Shredded rice is produced by washing, cooking, drying, tempering, shredding, fortifying, and packing.

Baby foods: Rice has highly digestible energy, net protein utilization, and low crude fiber content. Therefore, it is suitable for baby food. Although baby foods can be in the form of rice flour or granulated rice, precooked infant rice cereal is the most common use of rice for baby food. The key to making this type of cereal is ensuring the ease of reconstitution with milk or formula without forming lumps. The starch is converted from crystalline to amorphous form by the addition of amylase, which breaks down starch into dextrin and oligosaccharides. Ingredients in this baby food include rice flour, rice polishings, sugar, dibasic calcium phosphate, glycerol monostearate (emulsifier), rice oil, thiamine, riboflavin, and niacin or niacinamide. Sometimes, fruit is added to these precooked rice cereals.

Rice-bran products: Rice bran can be sprinkled on a dinner salad or used as a major ingredient of ready-toeat cereals, baked products, pasta, and other foods. Like oat bran, rice bran has high-quality protein, laxative properties, and dietary fiber components. Rice bran can lower serum cholesterol in humans and reduce the risk of cardiovascular disease and colon cancer. The bran also contains most of the vitamins in the rice kernel, including 78 percent of its thiamine, 47 percent of its riboflavin, and 67 percent of its niacin. The major carbohydrates in the rice bran are cellulose, hemicelluloses (or pentosans), and starch.

Rice bran has hydrolytic rancidity after milling. Therefore, the following treatments are necessary before it is processed as a food: indigenous lipase inactivation by parboiling, or moisture-added or dry extrusion, or other alternative methods.

Rice bran has 16–32 percent oil, including palmitic, oleic, linoleic, and other fatty acids. Therefore, rice bran can be processed into rice oil of the highest quality in terms of cooking quality, shelf life, and fatty acid composition. Oil extraction can be carried out with a variety of solvents using a hydraulic press or specially designed extractors before refining by dewaxing, degumming, neutralization, bleaching, winterization, and deodorization. After these steps, rice bran oil has greater stability than any other vegetable oil. Rice oil also can be used in cosmetics and paints.

Brewer's use. Rice alcohols include rice beer and rice wine, which is usually served at weddings and other annual rituals. Rice wine is distilled spirits having about 20 percent alcohol content. China has a long history of making rice wine, such as wang tsiu ("Shao Shing rice wine"). Nepal also has a slightly sweet rice wine called nigar. Other rice wines include tapuy in the Philippines, mukhuli in Korea, lao rong in Thailand, and moonshine rice wine and ba-xi de (a glutinous rice wine) in Vietnam.

In China, tian jiu niang is a popular mixture of rice grains, alcohol, lactic acid, and sugar. It is made from steamed glutinous rice. Jiu qu, containing Rhizopus, Mucor, Monilia, Aspergillus, and in some cases, yeast or bacteria, is used to ferment the steamed rice.

Sake is a brewed alcoholic beverage having 14– 16 percent alcohol content. The production of sake began in third century Japan. Sake is made from highly-polished rice, water, koje, and sake's yeast. Koje are microbes similar to those used in the production of cheese, shoyu (soy sauce), and miso (soy bean paste). Sakamai or shinpakumai rice should be selected for sake production for better quality because of its high starch content and its large and soft grain. Another important ingredient is the spring water, which leads to rich flavor.

The processes to make sake can be summarized as the following: (1) saccharification: conversion of the starch in cooked rice into glucose with koje or koji ; (2) fermentation: conversion of the rice sugar into alcohol by sake's yeast. Fermentation for 20– 25 days (three or four times longer than the fermentation in normal wine production) produces a balanced taste and fresh flavor from a wide variety of amino acids and low alcohol content (8– 15 percent); and (3) further steps including filtration, setting, heating, aging, and bottling. Sake should be preserved in a cool and dark place without any exposure to light and open air.

Nutritive, Health-related, and Psychopharmacological Value

Rice ranks high among the most nutritious foods available because brown rice provides high levels of fiber, complex carbohydrates, certain B vitamins, vitamin E, lysine, calcium, iron, and phosphorus. Furthermore, many fewer people are allergic to rice than to wheat or other cereals. Rice can be included in a weight-loss diet because it has no cholesterol, a trace of fat, and about 160 calories per cooked cup.

Recent studies have indicated that rice hull or bran contains antioxidants such as isovitexin (a C-glycosyl flavonoid), and it has been demonstrated that rice bran oil can lower both the total and the low-density lipoprotein cholesterol in non-human primates (Nicolosi et al., 1990). Some health problems, such as beriberi (thiamin deficiency), growth retardation, marasmus, and vitamin A deficiency, can result from consumption of only white rice, from which a portion of the proteins and most of the fat, vitamins, and minerals are removed. Rice bran (tiki-tiki ) is used to cure beriberi in the Philippines.

Since rice is low in sodium and fat and free of cholesterol, it can help relieve mental depression. Rice starch can substitute for glucose in an oral rehydration solution for infants suffering from diarrhea caused by a spleen-pancreas deficiency (Juliano 1985). Rice oil is believed to reduce the likelihood of ischemic heart disease.

Although not scientifically proven, rice is believed to have medicinal uses. Powdered rice is used to treat certain skin ailments, and boiled rice "greens" are used as an eye lotion in Malaysia. A thick paste made from rice grains and water is used in India for massage for curing arthritic pain. The Chinese believe that rice can increase appetite and cure indigestion. Rice water (a decoction of rice) is prescribed as an ointment for skin inflammation. Glutinous rice is believed to strengthen the kidneys, spleen-pancreas, and stomach because of its easier digestion compared to regular rice. The Chinese also believe that rice mixed with honey butter and water can build energy and blood and counter emaciation and other disorders (Wood 1999).

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Jiming Li