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MILLET | Minor
MILLET/Minor
Further Reading Dendy DAV (ed.) (1995) Sorghum and Millets: Chemistry and Technology. St. Paul, MN: American Association of Cereal Chemists. FAO (1995) Sorghum and Millets for Human Nutrition. Rome: Food and Agriculture Organization of the United Nations. ICRISAT and FAO (1996) The World Sorghum and Millet Economies. Patancheru, India: International Crops Research Institute for the Semi-Arid Tropics, Rome: Food and Agriculture Organization of the United Nations. National Research Council (1996) Lost Crops of Africa, vol. I, Grains, pp. 77125. Washington, DC: National Academy Press. Obilana AB and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer. Quin PJ (1959) Food and Feeding Habits of the Pedi. Johannesburg: Witwatersrand University Press.
Relevant Websites http://www.icrisat.org Website of the International Crops Research Institute for the Semi Arid Tropics, one of the 16 CGIAR (Consultative Group for International Agricultural Research) centers. ICRISAT carries out science-based agricultural development in sorghum, pearl millet, finger millet, chickpea, pigeonpea and groundnut. http://www.intsormil.org Website of the USAID (United States Agency for International Development) supported International Sorghum and Millet Collaborative Research Support Program (INTSORMIL). The program works with host country scientists in developing new technologies to improve sorghum and pearl millet production and utilization worldwide.
Minor D Baltensperger, University of Nebraska, Scottsbluff, NE, USA Y Z Cai, The University of Hong Kong, Hong Kong, People’s Republic of China ª 2004, Elsevier Ltd. All Rights Reserved.
Millet is a generic term implying ‘‘small seeded grain;’’ thus the variations in millet are quite large. The millets are all within the grass family (Poaceae or Gramineae), but include two tribes, Paniceae and Chlorideae (Table 1). The most widely grown millets include pearl millet (Pennisetum glaucum), proso
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millet (Panicum miliaceum), and foxtail millet (Setaria italica). However, smaller areas have meaningful production of brown top millet (Brachiaria ramosum), Japanese (Echinocloa frumentaceae), Shama (Echinocloa colonum), Australian (Echinocloa decompositum), and barnyard millet (Echinocloa frumentaceae). Finger millet (Eleusine coracana) is the most economically important member of the Chlorideae tribe, but teff (Eragrostis tef) plays a major role in Ethiopia. Black and white fonio millet (Digitaria iburua and Digitaria exilis, respectively), while grown in limited areas, are known for their good taste, short growing season and ability to produce on very poor soils. The variation represented by millets as a group, ranges from plants that grow to well over 4 m in height and take more than 150 days to reach maturity, to plants that seldom reach a height of more than 1 m and mature in less than 75 days. Production of millets can be found from the tropics, with rainfall averaging over 1200 mm per year, to the steppes of Siberia with rainfall averaging less than 300 mm. While all millets can be classified as cereals, in that they are grown for their edible starchy seeds, many are also important for annual forage production. Primary uses for millet grain vary as much as the species themselves, but include various forms of porridge for human consumption.
Millet Importance and Production Areas According to 2002 FAO reports, millet ranks fifteenth among all crops in terms of calories produced for human consumption. Of the minor millets, foxtail, proso, and finger millet account for the bulk of this production, but teff and fonio millets are regionally important. For example, a high portion of the cereal production of Ethiopia is dedicated to teff, and in West Africa, fonio is extremely important for the highly degraded soils (see Teff). Little millet (Panicum miliare or sumatrense) and kodo millet (Paspalum scrobiculatum) are primarily restricted to limited production in India and appear to be related to proso millet. Brown top millet (Brachiaria ramosum) has been used to a limited extent in India, but has played a role in the southeastern US as a cover crop and for wild bird hunting areas. Millet production data are elusive and frequently confusing because these sometimes include sorghum and the figures from subsistence agriculture production regions are often crude estimates. However, the total millet production probably provides a primary calorie source for more than 500 million people in the world. The bulk of this production is in China and India, with the next largest areas including West Africa and the former Soviet Union.
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Table 1 Classification of millets, family Poaceae Tribe
Genus
Species
Common names
Potential center of origin
Chlorideae Paniceae
Eleusine Brachiaria Digitaria Echinocloa
coracana (L.) Gaertn ramosum (L.) Stapf exilis (Kipp.) Stapf colona (L.) Link frumentacea Link miliaceum L. miliare Lam. scrobiculatum L. glaucum R. Br. italica (L.) P. Beauv.
Finger millet Brown top millet Fonio millet Shama millet Japanese, barnyard millet Proso, common, hog millet Little millet Kodo, ditch millet Pearl millet Foxtail, Italian millet
Africa Africa Africa India China China India India Africa China
Panicum Paspalum Pennisetum Setaria
Adapted from Rachie KO (1975) The Millets Importance, Utilization and Outlook. Hyderabad, India: International Crops Research Institute for the Semi-Arid Tropics.
Millets initially develop from seminal roots. These roots arise directly from the hypocotyl of the seedling. Further plant growth includes the development of a second set of roots, called the adventitious or crown roots, which form at a point on the plant just below the surface of the ground called the crown. Millet roots are characteristically fibrous rather than tap rooted like alfalfa or sunflower. Soil erosion is a limited problem with millet production because of this root system. Alternate two-ranked leaves are the identifying characteristic of cereals in general, but the millets are differentiated, by most taxonomists primarily, on the basis of their inflorescence. The stems are composed of nodes and internodes which elongate to varying degrees as the crop matures. The lower nodes on a plant have the potential to develop additional stems, which are referred to as tillers. Millets have wide variation in their ability to tiller, and the ability to regrow when harvested as forage. This is a primary selection criteria once a particular end use is determined. Millet seeds (correctly described as caryopses) are composed of three main parts, the endosperm, embryo (germ), and seedcoat (pericarp). Starch is the primary constituent of the whole grain, but is especially concentrated in the endosperm. Protein is found primarily in the embryo and to a lesser extent in the rest of the seed. Most of the oil is located in the embryo as well. The seedcoat consists mainly of cellulose and hemicellulose. Typical crude protein levels for the millets average 12% on a dry matter basis.
more cold-tolerant than either foxtail or pearl millet. Proso is considered a short-day plant and most US plantings are of an upright growth type with a relatively dense head compared with wild types. Recent studies suggest that proso plant development and maturity are heat-unit-driven across a wide range of day lengths. Proso is considered to be diploid by some, but 2n ¼ 4x ¼ 36 is a more appropriate discussion. While pairing is relatively normal during cell division, many alleles follow a tetraploid inheritance pattern. Self-pollination dominates in proso, but natural crosspollination may exceed 10%. Proso seeds are smaller than grain sorghum (Sorghum bicolor L.), generally oval in shape and about 3 mm long and 2 mm wide. Seed size selection has led to an increase in seed size in popular varieties along with most varieties being a light cream color (referred to as white proso). Some niche markets exists for red types and the germplasm base covers the breadth of seed colors. Little millet may be related closely enough to proso millet to be used as a germplasm source, but carries few traits of known economic importance, being smaller seeded and less productive. Most proso is swathed prior to harvest, allowed to dry and then combined. Selection has decreased seed shatter loss and increased uniformity of maturity so that increasing areas are harvested each year directly. Stripper headers and combines, better able to separate the green plant parts from the seed have, also helped to increase the amount of direct harvested proso millet. More primitive harvest techniques are still utilized in regions where proso is grown as a subsistence crop.
Proso
Pearl Millet
Proso is the most widely grown millet grain crop in the US. It is well adapted to short-season production with both quick maturity and a low water requirement. It is
Pearl millet (see Millet: Pearl) breeding has led to the development of some grain type hybrids adapted to US conditions, but most of the pearl millet produced in the
Millet Biology
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Table 2 Main uses of different millets Millets
Food use
Feed use
Other use
Proso millet
Steamed buns, cake, dumpling, oil pudding, sour meal, and popping food (Chinese traditional millet foods), snack foods
Pet and livestock feed
Therapeutic/healthy use, brewing Chinese white or yellow millet wines and vinegar
Foxtail millet
Thin or thick porridges (sargati, sankati, etc.), boiled rice-like products, snack foods
Forage or grain feed
Therapeutic/healthy use, brewing material of Chinese five-grain vinegar
Finger millet
Porridges or sweet gruel, ‘‘chapati’’ and ‘‘soda’’ (Indian unfermented and fermented breads), popping meal, snack foods, sweetmeats, weaning foods
Animal feed
Brewing traditional African beer
Teff
Porridges, fermented flat bread (e.g., ‘‘injera’’ in Ethiopia and ‘‘kisra’’ in Sudan), unleavened flat bread (‘‘kitta’’ in Ethiopia), cookies, muffins, waffles, soups, and pudding in Ethiopia
Forage or grain feed
Fonio
Porridge, composite flour bread, popping food
Forage or grain feed
Barnyard/Japanese millet
Rice substitute, Japanese traditional food
Kodo millet
Food uses are the same as for foxtail millet in India
Brewing African local beer
Sources: Murty and Kumar (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists; Corke and Lin (1998) Proceedings of the 1st International Conference on Asian Food Product Development Focus on Specialty Grains and Grain Products (September 610, 1998, Taiyuan, China). Beijing and New York: Science Press; Lin et al. (1998) Spotlight on shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192; McDonough et al. (2000) The millets. In: Kulp K and Ponte JG Jr (eds.) Handbook of Cereal Science and Technology, 2nd edn., pp. 177201. New York: Marcel Dekker; Dendy (2001) Sorghum and millets. In: Dendy DAV and Dobraszczyk BJ (eds.) Cereals and Cereal Products: Chemistry and Technology, pp. 341366. Gaithersburg, Maryland: Aspen Publishers; and Obilana and Manyasa (2002) Millets. In: Beton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer; and authors.
US is for forage production. This is in stark contrast to areas of Africa where it is a primary grain crop. Pearl millet is adapted to more acid soils, higher temperatures, and higher humidity than proso. It is more susceptible to injury by cold temperatures and most genotypes have a relatively long growing season compared to proso.
Foxtail Foxtail (Setaria italica) is one of the world’s oldest cultivated crops. Foxtail was the most important plant food in the neolithic culture in China, and its domestication and cultivation was the earliest identifiable manifestation of this culture. The US patent office introduced foxtail millet as a forage crop in 1849. It has since become well adapted to the western Great Plains. Nearly all foxtail millet cultivars grown in the US are the result of selections from land races rather than designed crosses and selections. Foxtail is recognized as a diploid (2n ¼ 2x ¼ 18), but is closely related to many tetraploid and higher ploidy level species. Foxtail millet grown in the US is typically less than 1.5 m in height with a stem intermediate in size between proso and pearl millet. Head length is variable like pearl millet, but shorter and more lax. Foxtail
is self-pollinated for the most part and, with a compact panicle and small florets, it is extremely difficult to cross. Improved techniques have been developed by Melicio Siles and others, but limited directed genetic improvement has been made due to this constraint.
Finger, Teff, and Browntop Finger millet (Eleusine coracana) and browntop millet (Brachiaria ramosum) have been utilized on a small regional basis and have characteristics that offer potential for further development. Browntop is grown in the southeastern US primarily as a cover crop and for wild game feed. Finger millet has been explored as a grazing and forage crop, but is currently used on only a limited basis.
Millet Uses Table 2 summarizes major uses of different millets. Millets have long been utilized as traditional staple foods for a large amount of the world’s poor, especially in Asia and Africa. Currently, millets are consumed in northern China, India, Africa, and southern Russia, with 80% of the world’s millet production directly consumed as human food. Other utilization of
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millets includes brewing use, therapeutic or healthfood use, feed use (bird feed, livestock feed, forage, etc.), and mushroom production. Different millets have been used to process numerous food products, such as thick or thin porridges, steamed food products, cakes, fermented and unfermented breads, snacks, weaning foods, and alcoholic and nonalcoholic beverages, etc. These millet foods originated from various places of the world with unique local flavors and rich nutritional profiles. Moreover, there are differences in the details of recipes and preparation for each kind of millet-based food between communities and regions in different countries. Frequently, the same millet food may have several different names because of language and custom differences. Foxtail millet is the most widely grown millet in China and millions of people depend on it as a primary calorie source. It is grown, to a lesser extent, in India, and throughout Europe and Asia. In northern China, minor crops including millets and their specialty foods are preferred. Major millets in China include proso millet, foxtail millet, and finger millet. There are many local traditional foods made from proso millet and foxtail millet with a long history and special flavor, such as proso millet oil pudding, sour meal, steaming buns, sweet cakes, pyramidshaped dumpling, foxtail millet porridge, cooked rice-like foods, etc. These traditional millet foods have been and are still popular throughout the rural areas and towns of northern China and also in many major cities of northern China (especially in Shanxi, Shaaxi, Ninxia, Inner Mongolia, and Gansu). Popped yellow millet grains are used as a major component of local milk tea or butter tea (famous in Inner Mongolia). Waxy proso millet has been used to brew local white millet wine and yellow millet wine in various regions of northern China for 2000 years. Millet grains are the brewing material base of Chinese five-grain vinegar (rice, buckwheat, millet, sorghum, and mungbean). Proso production is very important in China and the former Soviet Union, but is also used in Eastern Europe, the Middle East, India, and Southeast Asia. India and some African countries (Nigeria, Niger, Sudan, Ethiopia, etc.) are important areas of world millet production. In India, most millets (e.g., proso millet, finger millet, barnyard millet, kodo millet, little millet, foxtail millet, etc.) are used for many kinds of foods, including porridges, boiled rice-like products, steam-cooked products, baking foods, snacks, weaning foods, composite flours mixed with other cereals, and pulses for making common foods. In Africa, many millets (e.g., pearl millet, teff, finger millet, fonio, etc.) are consumed in the form of thick and thin porridges, fermented or unfermented
flat breads, steamed or boiled cooked millet foods, snacks, and composite flours mixed with other cereals for breads, cookies, noodles, etc. In India and Africa, millets are used or mixed with other cereals to make different local traditional foods. For example, pearl millet and finger millet are used to prepare ‘‘chapati’’ or ‘‘roti’’ (unfermented bread) and ‘‘soda’’ (fermented bread) in India and ‘‘ndaleyi’’ (local traditional food) in Nigeria. In Sudan and Ethiopia, fermented flat breads (‘‘kisra’’ and ‘‘injera’’) can be prepared using both pearl millet and teff. Unleavened flat bread (‘‘kitta’’) are made using teff in Ethiopia. These breads can be eaten in different ways for breakfast, lunch, and dinner. Also, they can be consumed with vegetables, sauces, milk, meat, curd, etc. Foxtail millet is used to make ‘‘sargati’’ (porridge) and pearl millet is blended with baobab flour to prepare ‘‘bulum mardam’’ (gruel) in India. Teff is employed to prepare ‘‘genfo’’ (stiff porridge) and ‘‘atmit’’ (thin porridge/ gruel) in central Ethiopia. Additionally, pearl millet, fonio, and finger millet are usually used or mixed with other cereals to brew traditional African alcoholic and nonalcoholic beverages with different local flavors, such as ‘‘chibuku’’ in Zimbabwe, ‘‘tchapalo’’ in Togo and ‘‘burujuto’’ or ‘‘pito’’ in Nigeria. Malting and brewing local beers using millets is significant in many countries of Africa, especially in eastern and southern Africa. Nonalcoholic beverages are also made from millets in West Africa. Proso is produced throughout the central and northern Great Plains of the US with more than 170 000 ha produced annually. Nebraska, Colorado, North Dakota, South Dakota, Kansas, Wyoming, and Minnesota account for more than 90% of all proso production. Proso is the primary millet traded across national borders and most world trade figures for millet consist primarily of proso. Interestingly, millets can be used for therapeutic purposes. Most millets are highly nutritious, for example, rich in protein, lipid, vitamins, and minerals compared to some other cereals. They also have a unique balance of amino acids that complements other cereals. In China and Japan, some food products made from proso millet, foxtail millet, and Japanese millet are considered to be functional or therapeutic foods to prevent and reduce incidence of certain human diseases. Regularly eating millets as a dietary and nutritional component in foods can reduce incidence of chronic human diseases. It is said that regularly drinking Chinese millet wine may improve human health, and yellow millet wine made in Shandong and Shanxi provinces of China is used for recovery of malaria patients. Special local millet foods (e.g., millet sour meal or porridges) are helpful in case of sunstroke. Japanese barnyard millet grains have
MILLET/Minor
been used as basic food materials for patients with allergic disease, including atopic dermatitis in Japan. Also, African, Indian, and Russian reports indicated that millets have a higher glycemic index than wheat breads, rice, potato, maize, and cassava. Russian millet is promising for use by diabetics because of moderating influence on blood glucose level. It has been observed that millet consumption is related to a lower incidence of pellagra (a niacindeficiency disease). Also, millet grains are commonly used as feed for pets and other animals. It is also extensively used for poultry feed and to a more limited extent as feed for other livestock. US proso is primarily consumed by the birdseed market, but poultry and other livestock are also major users. Human consumption, while prevalent elsewhere, accounts for a small proportion of US production. Foxtail millet has been playing an increasingly large role in wild bird feeding mixes in developed countries. Many reports have shown that animals fed pearl millet, finger millet, proso millet, and foxtail millet grains generally had better performance in bodyweight and body-condition scores than those fed corn or sorghum. It has been particularly valuable in the poultry industry. Since millet usually has a premium price for human use and the bird seed trade, it typically only finds its way to livestock rations in years of excess production. Extensive research supports the use of all millet grains as livestock feed from a nutritional standpoint, but corn is frequently less costly. One of the largest uses for millets is as forage. When green forage is harvested at plant heading up to the initiation of grain fill, the quality for livestock is excellent. With most millets, total energy per unit land area is maximized around heading. The millets are harvested for hay, green chop, silage, or grazed directly. Foxtail and pearl millet are primarily used as forages in the US, with foxtail millet being preferred as a hay crop and pearl millet preferred for grazing, but proso millet is also used as an emergency hay crop. Foxtail is easier to harvest for hay than pearl millet due to finer stems that cut and dry more readily. Under marginal conditions, due to limited rain or short growing season, it becomes the hay crop of choice. It is not as readily utilized for grazing with limited regrowth and a tendency to be pulled up by grazing animals. It is typically more productive as a forage than proso varieties, but has similar uses. Protein and energy values for millets have a very wide range with maturity and growing conditions, but protein levels of 1215% with TDN levels greater than 65% are common when hay is put up at the heading stage of plant development. Crop residues
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or straw of proso, teff, fonio, finger millet, and foxtail millet are fed to livestock, and are considered to be valuable forage with protein and energy levels higher than wheat or rice straw.
Millet Processing and Development Because millets are still a ‘‘poor man’s crop’’ in the developing countries, both milling and food processing of millets are considered to be mainly at traditional, manual, or household levels without industrial standardization compared to other important cereals. However, some small-scale mechanical operations have been used in modern millet food processing. Traditional milling methods, while labor-intensive and time-consuming, are still widely used in many developing countries. Millet grains are usually decorticated and ground with mortar and pestle or stone grinders by hand. Millet grains have been decorticated with mechanical de-hulling equipment and ground into flour with similar mechanical attrition or hammer mills in some villages and urban areas in India, northern China, and some African countries. Milling time and flour yields are normally dependent on millet grain size, shape, hardness, and thickness of pericarp. It is also reported that modern milling equipment for wheat flour has been used for milling proso millet into flour. Currently, most traditional millet foods are handmade. Germination (malting) and fermentation are major processing steps of millets, widely used for production of traditional millet foods. Malted and fermented millets (e.g., pearl millet, proso millet, finger millet, fonio, teff) can be used in the preparation of porridges, flat breads, and weaning foods and in the brewing of various traditional African beers and Chinese traditional millet wines. For instance, injera is a traditional Ethiopian fermented flat bread. Teff is considered to produce injera with better quality than sorghum. Figure 1 describes details of traditional processing procedures of injera made from teff. African opaque beer is brewed from sorghum and/or millets. The opaque beer production takes 57 days, depending on ambient temperature. Its processing procedure mainly includes grain malting, souring (lactic acid fermentation), cooking, mashing, straining, and alcoholic fermentation. The important stages are lactic acid fermentation, mashing, and alcoholic fermentation. African opaque beer usually has high levels of suspended solids, and has a sour taste and light pink color. Most common, of the many hand-made traditional millet foods in China, are the various types of foxtail millet porridges. Proso millet oil pudding is a famous local traditional food in Shanxi province. Detail of its
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MILLET/Minor
Teff grains
Proso millet grains
Hammer/stone-mill into flour Wash and soak in cool water for 2–6 h (depending on ambient temperature) Add water (water : flour ≈ 5 : 5) The soaked grains are milled into flour and steamed Mix and knead well to make suitable dough
Add starter culture from a previous fermentation into the dough - for 2–3 days of fermentation
~5% dough is taken to mix with water, and then cook this slurry to make warm gruel
Knead the steamed flour to smooth dough
The prepared dough is kneaded to rough strips, cut and pressed flat sheets
Add warm gruel back into the dough and mix thoroughly The flat sheets are wrapped around portions of cooked sweet red bean paste Add water into the dough again to make a batter
After standing for 2–3 h, the batter is spread and baked on a hot griddle
Teff injera (fermented flat bread)
Fry in hot oil for 3–5 min
Proso millet oil pudding
Figure 1 Processing procedure of injera made from teff millet Ethiopian traditional fermented flat bread. (Adapted from Obilana AB, and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer.)
Figure 2 Preparation method of proso millet oil pudding Chinese local traditional food. (Adapted from Lin RF, Li WD, and Corke H (1998) Spotlight on Shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192.)
preparation is shown in Figure 2. The millet oil pudding is immediately eaten after frying. Color of its outer surface is normally pale. It has a delicate texture inside and has a sweet aroma. Proso/broomcorn millet sour meal is another traditional local food in Shanxi province for 400 years. Millet grains are poured into the prepared special sour soup (made from fermented soybean flour) with sweet-sour flavor, stirred, and soaked overnight. The soaked sour millet grains are used to cook final sour meals (sour porridge or sour millet rice). Sweet potato or yam is added into the soaked sour millet grains to cook the best sour porridge. Indian chapati or roti (unfermented bread) is prepared from finger/pearl millet flour or composite flour
mixed with others (e.g., sorghum). The processing procedure is traditional and simple, as shown in Figure 3, although there are some minor regional variations in the procedures throughout India. Indian ‘‘dosa’’ is fermented bread prepared from millets or mixed with other cereals and pulses. Dosa preparation is different from chapati preparation and takes more time, mainly due to the addition of a fermentation operation. For instance, millet grains and black gram are mixed in a ratio of 3 : 1 by volume and wet-ground. The mixed batter needs to be fermented overnight. Additionally, popping of finger millet is common in India on a cottage-industry level. Some popped meal is packed in polythene pouches for marketing.
MILLET/Minor
Millets/sorghum grains
Mill to flour in a traditional stone mill
Add water (water : flour ≈ 0.9 : 1)
Mix and knead well into cohesive dough
The dough is pressed into thin circular piece (12–25 cm in diameter, 1.3–3.0 mm in thickness)
The dough piece is baked on a hot pan at 300–325°C for about 30 s
Turn over and bake for another 30 s
Indian “chapati ” or “roti ” Figure 3 Traditional preparation of ‘‘chapati’’ or ‘‘roti’’ made from finger/pearl millets or mixed with sorghum Indian unfermented bread. (Adapted from Murty DS and Kumar KA (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists.)
Most millets, like wheat, contain a similar level of protein and a large quantity of starch, but the physiochemical properties of millet flour are different from wheat flour. Because millet flour does not have gluten, it is difficult to use 100% millet flour to produce wheat flour-like food products. However, millet flour can be mixed with wheat flour and other cereal and pulse flours into composite flours to process baking foods, noodles, cookies, weaning foods, extruding foods, instant powders, healthy foods, etc. These milletbased foods are, to a certain extent, acceptable and their processing techniques are available in some millet production countries, especially in India and
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China. Their production can be carried out using modern baking, extruding or expansion technology and other ordinary processing methods. For example, both commercial and experimental weaning foods have been successfully made from millet flour mixed with other cereals and pulses in India. The millet-based weaning foods have good quality with desired nutrient compositions within the range prescribed by the India Standard Institute for processed weaning foods. In northern China, some village/town-owned and small state-owned food factories have commercially or experimentally produced a wide range of milletbased composite flour dry noodles and other local/ traditional food products containing various types of small grains. More research work is needed on minor millets to enhance large-scale industrial utilization and commercialization of traditional millet foods and development of millet-based specialty food markets. This work will be useful for alleviating food shortage of the poor and also helpful for increasing the value of millets and accelerating agricultural improvement in developing countries. See also: Cereals: Overview; Grain-Quality Attributes. Grain Production and Consumption: Cereal Grains in North America. Millet: Pearl. Teff. Variety Identification of Cereal Grains.
Further Reading Andrews DJ, Hanna WW, Rajewski JF, and Collins VP (1996) Advances in grain pearl millet: utilization and production research. In: Janick J (ed.) Progress in New Crops, pp. 170177. Proceedings of the Third National Symposium, Indianapolis, Indiana, 10/2225/96. Baltensperger DD (1996) Foxtail and proso millet. In: Janick J (ed.) Progress in New Crops, pp. 182190. Proceedings of the Third National Symposium, Indianapolis, Indiana, 10/2225/96. Baltensperger DD (2002) Progress with proso, pearl and other millets. In: Janick J and Whipkey A (eds.) Trends in New Crops and New Uses, pp. 100103. Proceedings of New Crops and New Uses Strength in Diversity, 5th. Atlanta, GA. Alexandria VA: ASHS Press. Corke H and Lin RF (eds.) Proceedings of the 1st International Conference on Asian Food Product Development Focus on Specialty Grains and Grain Products (September 610, 1998, Taiyuan, China). Beijing and New York: Science Press. Dendy DAV (1995) Sorghum and Millets: Chemistry and Technology. St. Paul, MN: American Association of Cereal Chemists. Dendy DAV (2001) Sorghum and millets. In: Dendy DAV and Dobraszczyk BJ (eds.) Cereals and Cereal Products: Chemistry and Technology, pp. 341366. Gaithersburg, Maryland: Aspen Publishers.
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FAO (1995) Sorghum and Millets for Human Nutrition. Rome: Food and Agriculture Organization of the United Nations. Lin RF, Li WD, and Corke H (1998) Spotlight on Shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192. Malm NR and Rachie KO (1971) Setaria Millets A Review of The World Literature. Experiment Station University of Nebraska College of Agriculture S.B. 513. McDonough CM, Rooney LW, and Serna-Saldivar SO (2000) The millets. In: Kulp K and Ponte JG, Jr (eds.) Handbook of Cereal Science and Technology, 2nd edn., pp. 177201. New York: Marcel Dekker. Murty DS and Kumar KA (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists. National Research Council (1996) Lost crops of Africa, vol. I Grains, pp. 77125. Washington DC: National Academy Press. Obilana AB and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer.
Rachie KO (1975) The Millets Importance, Utilization and Outlook. Hyderabad, India: International Crops Research Institute for the Semi-Arid Tropics. Wietgrefe GW (1989) Proso Millet: A Trade Summary. Pierre, SD. Wietgrefe GW (1990) How to Produce Proso Millet (A Farmer’s Guide). Pierre, SD.
Relevant Websites http://www.hort.purdue.edu/newcrop/ This website gives an overview of alternative crops and areas of adaptation. It includes descriptions of the millets. http://www.jeffersoninstitute.org/ This website includes information on alternative crop markets, production practices and updates on millets. http://www.ars-grin.gov/npgs/ This website offers descriptions of millet germplasm available through the National Plant Introduction System. http://www.ecoport.org/ This website is an international directory of crop descriptions, germplasm etc. http://apps.fao.org/ This website contains statistics on world crop production.
MILLING AND BAKING, HISTORY C E Walker and W D Eustace, Kansas State University, Manhattan, KS, USA ª 2004, Elsevier Ltd. All Rights Reserved.
Introduction The histories of milling and baking parallel each other, as have developments in their technologies. Mutually dependent upon each other, they originated together and remain inextricably linked, even though the two fields have specialized and separated to the point that many people no longer consider them together.
Flour Milling Volumes have been written on the history of milling and how it parallels the development of civilization. So much has been written that we can only hit the high points without much detail. It has been said that if we compare mankind’s time on earth to a 60 min period,
milling started 55 min after his appearance. Agriculture started 4 min later and recorded history 30 s after agriculture. These observations lead one to believe that grain milling may be the oldest manufacturing process in the world. Man probably used stones to break up nuts, berries, grains, and bones to produce food that was easier to chew. The basic process of pounding or rubbing between two stones went on for thousands of years. A saddle stone was found in an Egyptian tomb built around 366080 BC. Milling and baking scenes have been found on walls of Egyptian tombs dating from 2600 BC. The drawings show grinding with saddlestones and separating the meal with sieves made of papyrus or horsehair. Saddlestones produce a rubbing or attrition action, making a better separation of bran from endosperm as compared to pounding, which pulverizes the entire kernel. The use of sieves with saddlestones became a popular means to separate the meal from the bran particles. Many versions of the saddlestone have appeared but the back and forth
Further Reading Dendy DAV (ed.) (1995) Sorghum and Millets: Chemistry and Technology. St. Paul, MN: American Association of Cereal Chemists. FAO (1995) Sorghum and Millets for Human Nutrition. Rome: Food and Agriculture Organization of the United Nations. ICRISAT and FAO (1996) The World Sorghum and Millet Economies. Patancheru, India: International Crops Research Institute for the Semi-Arid Tropics, Rome: Food and Agriculture Organization of the United Nations. National Research Council (1996) Lost Crops of Africa, vol. I, Grains, pp. 77125. Washington, DC: National Academy Press. Obilana AB and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer. Quin PJ (1959) Food and Feeding Habits of the Pedi. Johannesburg: Witwatersrand University Press.
Relevant Websites http://www.icrisat.org Website of the International Crops Research Institute for the Semi Arid Tropics, one of the 16 CGIAR (Consultative Group for International Agricultural Research) centers. ICRISAT carries out science-based agricultural development in sorghum, pearl millet, finger millet, chickpea, pigeonpea and groundnut. http://www.intsormil.org Website of the USAID (United States Agency for International Development) supported International Sorghum and Millet Collaborative Research Support Program (INTSORMIL). The program works with host country scientists in developing new technologies to improve sorghum and pearl millet production and utilization worldwide.
Minor D Baltensperger, University of Nebraska, Scottsbluff, NE, USA Y Z Cai, The University of Hong Kong, Hong Kong, People’s Republic of China ª 2004, Elsevier Ltd. All Rights Reserved.
Millet is a generic term implying ‘‘small seeded grain;’’ thus the variations in millet are quite large. The millets are all within the grass family (Poaceae or Gramineae), but include two tribes, Paniceae and Chlorideae (Table 1). The most widely grown millets include pearl millet (Pennisetum glaucum), proso
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millet (Panicum miliaceum), and foxtail millet (Setaria italica). However, smaller areas have meaningful production of brown top millet (Brachiaria ramosum), Japanese (Echinocloa frumentaceae), Shama (Echinocloa colonum), Australian (Echinocloa decompositum), and barnyard millet (Echinocloa frumentaceae). Finger millet (Eleusine coracana) is the most economically important member of the Chlorideae tribe, but teff (Eragrostis tef) plays a major role in Ethiopia. Black and white fonio millet (Digitaria iburua and Digitaria exilis, respectively), while grown in limited areas, are known for their good taste, short growing season and ability to produce on very poor soils. The variation represented by millets as a group, ranges from plants that grow to well over 4 m in height and take more than 150 days to reach maturity, to plants that seldom reach a height of more than 1 m and mature in less than 75 days. Production of millets can be found from the tropics, with rainfall averaging over 1200 mm per year, to the steppes of Siberia with rainfall averaging less than 300 mm. While all millets can be classified as cereals, in that they are grown for their edible starchy seeds, many are also important for annual forage production. Primary uses for millet grain vary as much as the species themselves, but include various forms of porridge for human consumption.
Millet Importance and Production Areas According to 2002 FAO reports, millet ranks fifteenth among all crops in terms of calories produced for human consumption. Of the minor millets, foxtail, proso, and finger millet account for the bulk of this production, but teff and fonio millets are regionally important. For example, a high portion of the cereal production of Ethiopia is dedicated to teff, and in West Africa, fonio is extremely important for the highly degraded soils (see Teff). Little millet (Panicum miliare or sumatrense) and kodo millet (Paspalum scrobiculatum) are primarily restricted to limited production in India and appear to be related to proso millet. Brown top millet (Brachiaria ramosum) has been used to a limited extent in India, but has played a role in the southeastern US as a cover crop and for wild bird hunting areas. Millet production data are elusive and frequently confusing because these sometimes include sorghum and the figures from subsistence agriculture production regions are often crude estimates. However, the total millet production probably provides a primary calorie source for more than 500 million people in the world. The bulk of this production is in China and India, with the next largest areas including West Africa and the former Soviet Union.
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MILLET/Minor
Table 1 Classification of millets, family Poaceae Tribe
Genus
Species
Common names
Potential center of origin
Chlorideae Paniceae
Eleusine Brachiaria Digitaria Echinocloa
coracana (L.) Gaertn ramosum (L.) Stapf exilis (Kipp.) Stapf colona (L.) Link frumentacea Link miliaceum L. miliare Lam. scrobiculatum L. glaucum R. Br. italica (L.) P. Beauv.
Finger millet Brown top millet Fonio millet Shama millet Japanese, barnyard millet Proso, common, hog millet Little millet Kodo, ditch millet Pearl millet Foxtail, Italian millet
Africa Africa Africa India China China India India Africa China
Panicum Paspalum Pennisetum Setaria
Adapted from Rachie KO (1975) The Millets Importance, Utilization and Outlook. Hyderabad, India: International Crops Research Institute for the Semi-Arid Tropics.
Millets initially develop from seminal roots. These roots arise directly from the hypocotyl of the seedling. Further plant growth includes the development of a second set of roots, called the adventitious or crown roots, which form at a point on the plant just below the surface of the ground called the crown. Millet roots are characteristically fibrous rather than tap rooted like alfalfa or sunflower. Soil erosion is a limited problem with millet production because of this root system. Alternate two-ranked leaves are the identifying characteristic of cereals in general, but the millets are differentiated, by most taxonomists primarily, on the basis of their inflorescence. The stems are composed of nodes and internodes which elongate to varying degrees as the crop matures. The lower nodes on a plant have the potential to develop additional stems, which are referred to as tillers. Millets have wide variation in their ability to tiller, and the ability to regrow when harvested as forage. This is a primary selection criteria once a particular end use is determined. Millet seeds (correctly described as caryopses) are composed of three main parts, the endosperm, embryo (germ), and seedcoat (pericarp). Starch is the primary constituent of the whole grain, but is especially concentrated in the endosperm. Protein is found primarily in the embryo and to a lesser extent in the rest of the seed. Most of the oil is located in the embryo as well. The seedcoat consists mainly of cellulose and hemicellulose. Typical crude protein levels for the millets average 12% on a dry matter basis.
more cold-tolerant than either foxtail or pearl millet. Proso is considered a short-day plant and most US plantings are of an upright growth type with a relatively dense head compared with wild types. Recent studies suggest that proso plant development and maturity are heat-unit-driven across a wide range of day lengths. Proso is considered to be diploid by some, but 2n ¼ 4x ¼ 36 is a more appropriate discussion. While pairing is relatively normal during cell division, many alleles follow a tetraploid inheritance pattern. Self-pollination dominates in proso, but natural crosspollination may exceed 10%. Proso seeds are smaller than grain sorghum (Sorghum bicolor L.), generally oval in shape and about 3 mm long and 2 mm wide. Seed size selection has led to an increase in seed size in popular varieties along with most varieties being a light cream color (referred to as white proso). Some niche markets exists for red types and the germplasm base covers the breadth of seed colors. Little millet may be related closely enough to proso millet to be used as a germplasm source, but carries few traits of known economic importance, being smaller seeded and less productive. Most proso is swathed prior to harvest, allowed to dry and then combined. Selection has decreased seed shatter loss and increased uniformity of maturity so that increasing areas are harvested each year directly. Stripper headers and combines, better able to separate the green plant parts from the seed have, also helped to increase the amount of direct harvested proso millet. More primitive harvest techniques are still utilized in regions where proso is grown as a subsistence crop.
Proso
Pearl Millet
Proso is the most widely grown millet grain crop in the US. It is well adapted to short-season production with both quick maturity and a low water requirement. It is
Pearl millet (see Millet: Pearl) breeding has led to the development of some grain type hybrids adapted to US conditions, but most of the pearl millet produced in the
Millet Biology
MILLET/Minor
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Table 2 Main uses of different millets Millets
Food use
Feed use
Other use
Proso millet
Steamed buns, cake, dumpling, oil pudding, sour meal, and popping food (Chinese traditional millet foods), snack foods
Pet and livestock feed
Therapeutic/healthy use, brewing Chinese white or yellow millet wines and vinegar
Foxtail millet
Thin or thick porridges (sargati, sankati, etc.), boiled rice-like products, snack foods
Forage or grain feed
Therapeutic/healthy use, brewing material of Chinese five-grain vinegar
Finger millet
Porridges or sweet gruel, ‘‘chapati’’ and ‘‘soda’’ (Indian unfermented and fermented breads), popping meal, snack foods, sweetmeats, weaning foods
Animal feed
Brewing traditional African beer
Teff
Porridges, fermented flat bread (e.g., ‘‘injera’’ in Ethiopia and ‘‘kisra’’ in Sudan), unleavened flat bread (‘‘kitta’’ in Ethiopia), cookies, muffins, waffles, soups, and pudding in Ethiopia
Forage or grain feed
Fonio
Porridge, composite flour bread, popping food
Forage or grain feed
Barnyard/Japanese millet
Rice substitute, Japanese traditional food
Kodo millet
Food uses are the same as for foxtail millet in India
Brewing African local beer
Sources: Murty and Kumar (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists; Corke and Lin (1998) Proceedings of the 1st International Conference on Asian Food Product Development Focus on Specialty Grains and Grain Products (September 610, 1998, Taiyuan, China). Beijing and New York: Science Press; Lin et al. (1998) Spotlight on shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192; McDonough et al. (2000) The millets. In: Kulp K and Ponte JG Jr (eds.) Handbook of Cereal Science and Technology, 2nd edn., pp. 177201. New York: Marcel Dekker; Dendy (2001) Sorghum and millets. In: Dendy DAV and Dobraszczyk BJ (eds.) Cereals and Cereal Products: Chemistry and Technology, pp. 341366. Gaithersburg, Maryland: Aspen Publishers; and Obilana and Manyasa (2002) Millets. In: Beton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer; and authors.
US is for forage production. This is in stark contrast to areas of Africa where it is a primary grain crop. Pearl millet is adapted to more acid soils, higher temperatures, and higher humidity than proso. It is more susceptible to injury by cold temperatures and most genotypes have a relatively long growing season compared to proso.
Foxtail Foxtail (Setaria italica) is one of the world’s oldest cultivated crops. Foxtail was the most important plant food in the neolithic culture in China, and its domestication and cultivation was the earliest identifiable manifestation of this culture. The US patent office introduced foxtail millet as a forage crop in 1849. It has since become well adapted to the western Great Plains. Nearly all foxtail millet cultivars grown in the US are the result of selections from land races rather than designed crosses and selections. Foxtail is recognized as a diploid (2n ¼ 2x ¼ 18), but is closely related to many tetraploid and higher ploidy level species. Foxtail millet grown in the US is typically less than 1.5 m in height with a stem intermediate in size between proso and pearl millet. Head length is variable like pearl millet, but shorter and more lax. Foxtail
is self-pollinated for the most part and, with a compact panicle and small florets, it is extremely difficult to cross. Improved techniques have been developed by Melicio Siles and others, but limited directed genetic improvement has been made due to this constraint.
Finger, Teff, and Browntop Finger millet (Eleusine coracana) and browntop millet (Brachiaria ramosum) have been utilized on a small regional basis and have characteristics that offer potential for further development. Browntop is grown in the southeastern US primarily as a cover crop and for wild game feed. Finger millet has been explored as a grazing and forage crop, but is currently used on only a limited basis.
Millet Uses Table 2 summarizes major uses of different millets. Millets have long been utilized as traditional staple foods for a large amount of the world’s poor, especially in Asia and Africa. Currently, millets are consumed in northern China, India, Africa, and southern Russia, with 80% of the world’s millet production directly consumed as human food. Other utilization of
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MILLET/Minor
millets includes brewing use, therapeutic or healthfood use, feed use (bird feed, livestock feed, forage, etc.), and mushroom production. Different millets have been used to process numerous food products, such as thick or thin porridges, steamed food products, cakes, fermented and unfermented breads, snacks, weaning foods, and alcoholic and nonalcoholic beverages, etc. These millet foods originated from various places of the world with unique local flavors and rich nutritional profiles. Moreover, there are differences in the details of recipes and preparation for each kind of millet-based food between communities and regions in different countries. Frequently, the same millet food may have several different names because of language and custom differences. Foxtail millet is the most widely grown millet in China and millions of people depend on it as a primary calorie source. It is grown, to a lesser extent, in India, and throughout Europe and Asia. In northern China, minor crops including millets and their specialty foods are preferred. Major millets in China include proso millet, foxtail millet, and finger millet. There are many local traditional foods made from proso millet and foxtail millet with a long history and special flavor, such as proso millet oil pudding, sour meal, steaming buns, sweet cakes, pyramidshaped dumpling, foxtail millet porridge, cooked rice-like foods, etc. These traditional millet foods have been and are still popular throughout the rural areas and towns of northern China and also in many major cities of northern China (especially in Shanxi, Shaaxi, Ninxia, Inner Mongolia, and Gansu). Popped yellow millet grains are used as a major component of local milk tea or butter tea (famous in Inner Mongolia). Waxy proso millet has been used to brew local white millet wine and yellow millet wine in various regions of northern China for 2000 years. Millet grains are the brewing material base of Chinese five-grain vinegar (rice, buckwheat, millet, sorghum, and mungbean). Proso production is very important in China and the former Soviet Union, but is also used in Eastern Europe, the Middle East, India, and Southeast Asia. India and some African countries (Nigeria, Niger, Sudan, Ethiopia, etc.) are important areas of world millet production. In India, most millets (e.g., proso millet, finger millet, barnyard millet, kodo millet, little millet, foxtail millet, etc.) are used for many kinds of foods, including porridges, boiled rice-like products, steam-cooked products, baking foods, snacks, weaning foods, composite flours mixed with other cereals, and pulses for making common foods. In Africa, many millets (e.g., pearl millet, teff, finger millet, fonio, etc.) are consumed in the form of thick and thin porridges, fermented or unfermented
flat breads, steamed or boiled cooked millet foods, snacks, and composite flours mixed with other cereals for breads, cookies, noodles, etc. In India and Africa, millets are used or mixed with other cereals to make different local traditional foods. For example, pearl millet and finger millet are used to prepare ‘‘chapati’’ or ‘‘roti’’ (unfermented bread) and ‘‘soda’’ (fermented bread) in India and ‘‘ndaleyi’’ (local traditional food) in Nigeria. In Sudan and Ethiopia, fermented flat breads (‘‘kisra’’ and ‘‘injera’’) can be prepared using both pearl millet and teff. Unleavened flat bread (‘‘kitta’’) are made using teff in Ethiopia. These breads can be eaten in different ways for breakfast, lunch, and dinner. Also, they can be consumed with vegetables, sauces, milk, meat, curd, etc. Foxtail millet is used to make ‘‘sargati’’ (porridge) and pearl millet is blended with baobab flour to prepare ‘‘bulum mardam’’ (gruel) in India. Teff is employed to prepare ‘‘genfo’’ (stiff porridge) and ‘‘atmit’’ (thin porridge/ gruel) in central Ethiopia. Additionally, pearl millet, fonio, and finger millet are usually used or mixed with other cereals to brew traditional African alcoholic and nonalcoholic beverages with different local flavors, such as ‘‘chibuku’’ in Zimbabwe, ‘‘tchapalo’’ in Togo and ‘‘burujuto’’ or ‘‘pito’’ in Nigeria. Malting and brewing local beers using millets is significant in many countries of Africa, especially in eastern and southern Africa. Nonalcoholic beverages are also made from millets in West Africa. Proso is produced throughout the central and northern Great Plains of the US with more than 170 000 ha produced annually. Nebraska, Colorado, North Dakota, South Dakota, Kansas, Wyoming, and Minnesota account for more than 90% of all proso production. Proso is the primary millet traded across national borders and most world trade figures for millet consist primarily of proso. Interestingly, millets can be used for therapeutic purposes. Most millets are highly nutritious, for example, rich in protein, lipid, vitamins, and minerals compared to some other cereals. They also have a unique balance of amino acids that complements other cereals. In China and Japan, some food products made from proso millet, foxtail millet, and Japanese millet are considered to be functional or therapeutic foods to prevent and reduce incidence of certain human diseases. Regularly eating millets as a dietary and nutritional component in foods can reduce incidence of chronic human diseases. It is said that regularly drinking Chinese millet wine may improve human health, and yellow millet wine made in Shandong and Shanxi provinces of China is used for recovery of malaria patients. Special local millet foods (e.g., millet sour meal or porridges) are helpful in case of sunstroke. Japanese barnyard millet grains have
MILLET/Minor
been used as basic food materials for patients with allergic disease, including atopic dermatitis in Japan. Also, African, Indian, and Russian reports indicated that millets have a higher glycemic index than wheat breads, rice, potato, maize, and cassava. Russian millet is promising for use by diabetics because of moderating influence on blood glucose level. It has been observed that millet consumption is related to a lower incidence of pellagra (a niacindeficiency disease). Also, millet grains are commonly used as feed for pets and other animals. It is also extensively used for poultry feed and to a more limited extent as feed for other livestock. US proso is primarily consumed by the birdseed market, but poultry and other livestock are also major users. Human consumption, while prevalent elsewhere, accounts for a small proportion of US production. Foxtail millet has been playing an increasingly large role in wild bird feeding mixes in developed countries. Many reports have shown that animals fed pearl millet, finger millet, proso millet, and foxtail millet grains generally had better performance in bodyweight and body-condition scores than those fed corn or sorghum. It has been particularly valuable in the poultry industry. Since millet usually has a premium price for human use and the bird seed trade, it typically only finds its way to livestock rations in years of excess production. Extensive research supports the use of all millet grains as livestock feed from a nutritional standpoint, but corn is frequently less costly. One of the largest uses for millets is as forage. When green forage is harvested at plant heading up to the initiation of grain fill, the quality for livestock is excellent. With most millets, total energy per unit land area is maximized around heading. The millets are harvested for hay, green chop, silage, or grazed directly. Foxtail and pearl millet are primarily used as forages in the US, with foxtail millet being preferred as a hay crop and pearl millet preferred for grazing, but proso millet is also used as an emergency hay crop. Foxtail is easier to harvest for hay than pearl millet due to finer stems that cut and dry more readily. Under marginal conditions, due to limited rain or short growing season, it becomes the hay crop of choice. It is not as readily utilized for grazing with limited regrowth and a tendency to be pulled up by grazing animals. It is typically more productive as a forage than proso varieties, but has similar uses. Protein and energy values for millets have a very wide range with maturity and growing conditions, but protein levels of 1215% with TDN levels greater than 65% are common when hay is put up at the heading stage of plant development. Crop residues
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or straw of proso, teff, fonio, finger millet, and foxtail millet are fed to livestock, and are considered to be valuable forage with protein and energy levels higher than wheat or rice straw.
Millet Processing and Development Because millets are still a ‘‘poor man’s crop’’ in the developing countries, both milling and food processing of millets are considered to be mainly at traditional, manual, or household levels without industrial standardization compared to other important cereals. However, some small-scale mechanical operations have been used in modern millet food processing. Traditional milling methods, while labor-intensive and time-consuming, are still widely used in many developing countries. Millet grains are usually decorticated and ground with mortar and pestle or stone grinders by hand. Millet grains have been decorticated with mechanical de-hulling equipment and ground into flour with similar mechanical attrition or hammer mills in some villages and urban areas in India, northern China, and some African countries. Milling time and flour yields are normally dependent on millet grain size, shape, hardness, and thickness of pericarp. It is also reported that modern milling equipment for wheat flour has been used for milling proso millet into flour. Currently, most traditional millet foods are handmade. Germination (malting) and fermentation are major processing steps of millets, widely used for production of traditional millet foods. Malted and fermented millets (e.g., pearl millet, proso millet, finger millet, fonio, teff) can be used in the preparation of porridges, flat breads, and weaning foods and in the brewing of various traditional African beers and Chinese traditional millet wines. For instance, injera is a traditional Ethiopian fermented flat bread. Teff is considered to produce injera with better quality than sorghum. Figure 1 describes details of traditional processing procedures of injera made from teff. African opaque beer is brewed from sorghum and/or millets. The opaque beer production takes 57 days, depending on ambient temperature. Its processing procedure mainly includes grain malting, souring (lactic acid fermentation), cooking, mashing, straining, and alcoholic fermentation. The important stages are lactic acid fermentation, mashing, and alcoholic fermentation. African opaque beer usually has high levels of suspended solids, and has a sour taste and light pink color. Most common, of the many hand-made traditional millet foods in China, are the various types of foxtail millet porridges. Proso millet oil pudding is a famous local traditional food in Shanxi province. Detail of its
266
MILLET/Minor
Teff grains
Proso millet grains
Hammer/stone-mill into flour Wash and soak in cool water for 2–6 h (depending on ambient temperature) Add water (water : flour ≈ 5 : 5) The soaked grains are milled into flour and steamed Mix and knead well to make suitable dough
Add starter culture from a previous fermentation into the dough - for 2–3 days of fermentation
~5% dough is taken to mix with water, and then cook this slurry to make warm gruel
Knead the steamed flour to smooth dough
The prepared dough is kneaded to rough strips, cut and pressed flat sheets
Add warm gruel back into the dough and mix thoroughly The flat sheets are wrapped around portions of cooked sweet red bean paste Add water into the dough again to make a batter
After standing for 2–3 h, the batter is spread and baked on a hot griddle
Teff injera (fermented flat bread)
Fry in hot oil for 3–5 min
Proso millet oil pudding
Figure 1 Processing procedure of injera made from teff millet Ethiopian traditional fermented flat bread. (Adapted from Obilana AB, and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer.)
Figure 2 Preparation method of proso millet oil pudding Chinese local traditional food. (Adapted from Lin RF, Li WD, and Corke H (1998) Spotlight on Shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192.)
preparation is shown in Figure 2. The millet oil pudding is immediately eaten after frying. Color of its outer surface is normally pale. It has a delicate texture inside and has a sweet aroma. Proso/broomcorn millet sour meal is another traditional local food in Shanxi province for 400 years. Millet grains are poured into the prepared special sour soup (made from fermented soybean flour) with sweet-sour flavor, stirred, and soaked overnight. The soaked sour millet grains are used to cook final sour meals (sour porridge or sour millet rice). Sweet potato or yam is added into the soaked sour millet grains to cook the best sour porridge. Indian chapati or roti (unfermented bread) is prepared from finger/pearl millet flour or composite flour
mixed with others (e.g., sorghum). The processing procedure is traditional and simple, as shown in Figure 3, although there are some minor regional variations in the procedures throughout India. Indian ‘‘dosa’’ is fermented bread prepared from millets or mixed with other cereals and pulses. Dosa preparation is different from chapati preparation and takes more time, mainly due to the addition of a fermentation operation. For instance, millet grains and black gram are mixed in a ratio of 3 : 1 by volume and wet-ground. The mixed batter needs to be fermented overnight. Additionally, popping of finger millet is common in India on a cottage-industry level. Some popped meal is packed in polythene pouches for marketing.
MILLET/Minor
Millets/sorghum grains
Mill to flour in a traditional stone mill
Add water (water : flour ≈ 0.9 : 1)
Mix and knead well into cohesive dough
The dough is pressed into thin circular piece (12–25 cm in diameter, 1.3–3.0 mm in thickness)
The dough piece is baked on a hot pan at 300–325°C for about 30 s
Turn over and bake for another 30 s
Indian “chapati ” or “roti ” Figure 3 Traditional preparation of ‘‘chapati’’ or ‘‘roti’’ made from finger/pearl millets or mixed with sorghum Indian unfermented bread. (Adapted from Murty DS and Kumar KA (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists.)
Most millets, like wheat, contain a similar level of protein and a large quantity of starch, but the physiochemical properties of millet flour are different from wheat flour. Because millet flour does not have gluten, it is difficult to use 100% millet flour to produce wheat flour-like food products. However, millet flour can be mixed with wheat flour and other cereal and pulse flours into composite flours to process baking foods, noodles, cookies, weaning foods, extruding foods, instant powders, healthy foods, etc. These milletbased foods are, to a certain extent, acceptable and their processing techniques are available in some millet production countries, especially in India and
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China. Their production can be carried out using modern baking, extruding or expansion technology and other ordinary processing methods. For example, both commercial and experimental weaning foods have been successfully made from millet flour mixed with other cereals and pulses in India. The millet-based weaning foods have good quality with desired nutrient compositions within the range prescribed by the India Standard Institute for processed weaning foods. In northern China, some village/town-owned and small state-owned food factories have commercially or experimentally produced a wide range of milletbased composite flour dry noodles and other local/ traditional food products containing various types of small grains. More research work is needed on minor millets to enhance large-scale industrial utilization and commercialization of traditional millet foods and development of millet-based specialty food markets. This work will be useful for alleviating food shortage of the poor and also helpful for increasing the value of millets and accelerating agricultural improvement in developing countries. See also: Cereals: Overview; Grain-Quality Attributes. Grain Production and Consumption: Cereal Grains in North America. Millet: Pearl. Teff. Variety Identification of Cereal Grains.
Further Reading Andrews DJ, Hanna WW, Rajewski JF, and Collins VP (1996) Advances in grain pearl millet: utilization and production research. In: Janick J (ed.) Progress in New Crops, pp. 170177. Proceedings of the Third National Symposium, Indianapolis, Indiana, 10/2225/96. Baltensperger DD (1996) Foxtail and proso millet. In: Janick J (ed.) Progress in New Crops, pp. 182190. Proceedings of the Third National Symposium, Indianapolis, Indiana, 10/2225/96. Baltensperger DD (2002) Progress with proso, pearl and other millets. In: Janick J and Whipkey A (eds.) Trends in New Crops and New Uses, pp. 100103. Proceedings of New Crops and New Uses Strength in Diversity, 5th. Atlanta, GA. Alexandria VA: ASHS Press. Corke H and Lin RF (eds.) Proceedings of the 1st International Conference on Asian Food Product Development Focus on Specialty Grains and Grain Products (September 610, 1998, Taiyuan, China). Beijing and New York: Science Press. Dendy DAV (1995) Sorghum and Millets: Chemistry and Technology. St. Paul, MN: American Association of Cereal Chemists. Dendy DAV (2001) Sorghum and millets. In: Dendy DAV and Dobraszczyk BJ (eds.) Cereals and Cereal Products: Chemistry and Technology, pp. 341366. Gaithersburg, Maryland: Aspen Publishers.
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FAO (1995) Sorghum and Millets for Human Nutrition. Rome: Food and Agriculture Organization of the United Nations. Lin RF, Li WD, and Corke H (1998) Spotlight on Shanxi province China: its minor crops and specialty foods. Cereal Foods World 43: 189192. Malm NR and Rachie KO (1971) Setaria Millets A Review of The World Literature. Experiment Station University of Nebraska College of Agriculture S.B. 513. McDonough CM, Rooney LW, and Serna-Saldivar SO (2000) The millets. In: Kulp K and Ponte JG, Jr (eds.) Handbook of Cereal Science and Technology, 2nd edn., pp. 177201. New York: Marcel Dekker. Murty DS and Kumar KA (1995) Traditional uses of sorghum and millets. In: Dendy DAV (ed.) Sorghum and Millets: Chemistry and Technology, pp. 185221. St. Paul, MN: American Association of Cereal Chemists. National Research Council (1996) Lost crops of Africa, vol. I Grains, pp. 77125. Washington DC: National Academy Press. Obilana AB and Manyasa E (2002) Millets. In: Belton PS and Taylor JRN (eds.) Pseudocereals and Less Common Cereals, pp. 177217. Berlin: Springer.
Rachie KO (1975) The Millets Importance, Utilization and Outlook. Hyderabad, India: International Crops Research Institute for the Semi-Arid Tropics. Wietgrefe GW (1989) Proso Millet: A Trade Summary. Pierre, SD. Wietgrefe GW (1990) How to Produce Proso Millet (A Farmer’s Guide). Pierre, SD.
Relevant Websites http://www.hort.purdue.edu/newcrop/ This website gives an overview of alternative crops and areas of adaptation. It includes descriptions of the millets. http://www.jeffersoninstitute.org/ This website includes information on alternative crop markets, production practices and updates on millets. http://www.ars-grin.gov/npgs/ This website offers descriptions of millet germplasm available through the National Plant Introduction System. http://www.ecoport.org/ This website is an international directory of crop descriptions, germplasm etc. http://apps.fao.org/ This website contains statistics on world crop production.
MILLING AND BAKING, HISTORY C E Walker and W D Eustace, Kansas State University, Manhattan, KS, USA ª 2004, Elsevier Ltd. All Rights Reserved.
Introduction The histories of milling and baking parallel each other, as have developments in their technologies. Mutually dependent upon each other, they originated together and remain inextricably linked, even though the two fields have specialized and separated to the point that many people no longer consider them together.
Flour Milling Volumes have been written on the history of milling and how it parallels the development of civilization. So much has been written that we can only hit the high points without much detail. It has been said that if we compare mankind’s time on earth to a 60 min period,
milling started 55 min after his appearance. Agriculture started 4 min later and recorded history 30 s after agriculture. These observations lead one to believe that grain milling may be the oldest manufacturing process in the world. Man probably used stones to break up nuts, berries, grains, and bones to produce food that was easier to chew. The basic process of pounding or rubbing between two stones went on for thousands of years. A saddle stone was found in an Egyptian tomb built around 366080 BC. Milling and baking scenes have been found on walls of Egyptian tombs dating from 2600 BC. The drawings show grinding with saddlestones and separating the meal with sieves made of papyrus or horsehair. Saddlestones produce a rubbing or attrition action, making a better separation of bran from endosperm as compared to pounding, which pulverizes the entire kernel. The use of sieves with saddlestones became a popular means to separate the meal from the bran particles. Many versions of the saddlestone have appeared but the back and forth