13 Domestic and Small Scale Products Introduction Cereals are prepared for consumption by domestic processing on a small scale in many parts of the world, but particularly in the less industrialized countries. The types of cereal grains so used are principally wheat, maize, sorghum and the millets, each of which finds greatest use in those countries in which it grows indigenously. Thus, wheat and sorghum are widely used for Chapattis domestic processing in the Indian subcontinent; maize is similarly used in Mexico and many African countries; sorghum and the millets are In West Pakistan wheat comprises about 60% also used in many African countries. of the total cereal crop. None is exported, and The types of product made domestically are about 90% of it is ground to make wholemeal many and varied, and go by many names in the called ‘whole atta’, a meal of near 100% extraction various countries. The categories of product rate, from which chapattis - essentially whole- include pancake-like flat breads, which may be meal pancakes or flat bread - are made. Chapattis unfermented (e.g. chapatti, roti, tortilla) or fer- are also commonly eaten in India, Tibet, China mented (e.g. kisra, dosa, injera); porridges, which and the Near East. may be stiff porridges (e.g. ugali, tuwo, asida) or To provide for the increasing demand for white thin porridges (e.g. ogi, ugi, nasha, madida); flour, and with rollermills replacing stone mills, steam-cooked dumpling-like foods (e.g. couscous, the milling of wheat in IndiaPakistan has been burabusko, kenkey); boiled products (e.g. acha, modified so as to produce white flour (‘maida’) kali); snack foods, which may be popped, parched, and semolina (60-65%), bran (10-15%) and a puffed or fried (e.g. tortilla chips, corn chips, taco residue called ‘resultant atta’ (25-35%) from shells) and beverages, either alcoholic (e.g. buru- which chapattis are made. kutu, bantu beer, kaffir beer) or non-alcoholic For making chapatti flour the wheat should (e.g. mahewu). have a high 1000 kernel weight, plump grains, As countries become more industrialized, so light-coloured bran, and a protein content of commercial processes are introduced to make 10.5-11.0%. A strong gluten is not required, but products that resemble or imitate those made by water absorption of the flour should be high. The traditional domestic methods. Such products, alpha-amylase activity need not be very low: a now made commercially, include dry masa flour Falling Number (cf. p. 184) of 65 is satisfactory. (from maize), kisra, wheat flour tortillas, while a process for making tortillas by extrusion cooking has been described. Thus, while traditional foods continue to be available, the local people are relieved of the daily tedium of domestic preparation. Products made from wheat 269 270 TECHNOLOGY OF CEREALS Flour of fine granularity yields chapattis of Tortilas superior quality. of Asian immigrants is a granular fine wheatmeal of about 85% extraction rate, made by blending white flour with fine offal or bran so that the background colour is white and the large brown specks of bran are conspicuous. Chapattis are made by mixing whole atta or resultant atta with water to form a dough, which is rested for 1 h. The dough is then divided into portions of 50-200 g, which are flattened by hand. The dough discs are baked on an iron plate over an open fire. Types of chapatti include Tanoori Roti (baked inside a mud oven), Khameri Roti (containing yoghurt or buttermilk, sugar and salt, and the dough allowed to ferment), and Nan (made from white flour of 75% extraction rate by a yeasted addition of sugar, salt, skimmed milk, ghee and gram flour or eggs (Chaudhri and Muller, 1970)). The hardening or firming of chapattis may be delayed by the inclusion of shortening (3%) or 0.5% of either glyceryl monostearate or sodium stearoyl-2-lactylate, thereby increasing the shelf- life to 72 h. The best results were obtained by a combination of shortening and glyceryl mono- stearate (Sidhu et al., 1989). Germination of wheat leads to an increase in reducing sugar content, diastatic activity and production of damaged starch, while decreasing water absorption. The chapattis made from sprouted wheat had a better (sweetish) flavour but slightly harder texture. However, after storage for four days, the chapattis made from sprouted wheat had improved texture and overall quality (Leelavathi et al., 1988). The inclusion of 10% of full fat soya flour made from steamed soya beans with 90% of wheat flour for making chapattis almost completely elimin- ated the activity of trypsin inhibitor (Verma et al., 1987). The use of triticale flour in partial replacement of wheat flour for making chapattis has been suggested, the quality of the chapattis was not impaired (Khan and Rashid, 1987). A flour tortilla is a flat, circular, light-coloured 6-13 in. in diameter, made from wheat flour. Wheat flour tortillas are widely consumed in Mexico and the United States. Traditionally, tortillas were made domestically by mixing wheat flour with water, lard and salt to make dough. The dough was divided and rolled or hand-shaped to make tortilla discs which were baked on a hot griddle (Serna-Saldivar et al., 1988a). More recently, tortillas have been pro- duced commercially, using hot-press, die-cut or hand-stretch procedures. Hot-press tortillas are baked for a relatively longer time at lower temper- ature and puff while baking; they resist tearing and have a smooth surface. Die-cut tortillas use stronger doughs with greater water absorption, resulting in a product of lower moisture content Hand-stretch tortillas are irregular in shape and intermediate in quality (Serna-Saldivar et al. , 1988a). The loss of flexibility of tortillas during storage may be due to retrogradation of starch, and may be prevented by the use of plasticizers, which increase flexibility and extensibility. Water is the most important plasticizer for starch and poly- saccharides and should contribute 3445% of the dough by weight. The plasticizer components should also include glycerol or sorbitol, 5-7% by wt, also oil and fat, 7-9% by wt. Addition of of flavour (U.S. Pat. No. 4,735,811). Chapatti flour mi11ed in the U*K* for the use bread, about one sixleenth of an inch thick and sponge-and-dough process (cf. Po 202)Y with the and less resistance to cracking and breaking. the Fa1'ing NumberY gluten 'Ontent and chapatti yeast, 1-3% on dough Wt, helps the development Pretze,s Pretzels, crisp knot-shaped biscuits, flavoured with salt, are made from wheat flour plus shorten- ing (1.25% on flour wt), malt (1 Z%), yeast (0.25%), ammonium bicarbonate (0.04%) and water (about 42%). A dough made from these ingredients is rolled into a rope, then twisted and allowed to relax for 10 min. The rope is passed through rollers, to set the knots, and allowed to ferment for 30 min. The starch on the surface is then gelatinized by passing the rope through a DOMESTIC AND SMALL SCALE PRODUCTS 271 water, and is most successful when the particle size of the material is fine, and the amount of water contained is just enough to fill the spaces between the particles. The masa is sheeted, cut into triangular shapes, and baked on a griddle for 39 sec at 280°C to make tortillas. The temperature used for baking the tortillas is as high as possible, short of causing puffing. (Gomez et al., 1987, 1989; Hoseney, 1986; Rooney and Serna-Saldivar, 1987; Serna-Saldivar et al., 1988b). Nixtamalization and pellagra The disease pellagra has been associated with a deficiency of the vitamin niacin (nicotinic acid) or niacinamide, and is prevalent among peoples who rely upon maize for a large proportion of their daily food. Some 5040% of the niacin in maize occurs in a bound form as niacytin or niacinogen, which is biologically unavailable, and renders the maize deficient in niacin (Mason et al., 1971). Pellagra is not suffered by Mexicans who consume maize meal in the form of tortillas. The alkaline conditions obtaining during the lime cooking (nixtamalization) release the bound niacin and make it biologically available. However, there is some evidence that the onset of black tongue in dogs (a disease similar to pellagra in humans) may be due to excessive intake of the amino acid leucine, in which maize is rich. In trials with dogs on maize diets, black tongue developed only in dogs on high leucine diets. Alkaline treatment of maize to prepare masa or hominy has been shown to result in some loss of the amino acids arginine and cystine; commercially-made masa and tortillas contained lysinoalanine and lanthionine , which are breakdown products of cystine and arginine (Sanderson et al., 1978). Snack products Tortilla chips (tostados) were traditionally pro- duced by frying stale, left-over tortillas, and are still prepared in this way in Mexican restaurants. Alternatively, freshly-made masa, after sheeting and cutting, can be fried for 1 min at 190°C to produce tortilla chips. bath of caustic soda (1%) for 25 sec at about 93°C. The dough pieces are then salted with 2% sodium chloride and baked in three stages: at 315°C for 10 min, then at 218°C to reduce the moisture content to 15%, and finally at 121°C for 90 min (Hoseney, 1986). Products made from maize Tortillas In Central America, tortillas are made from masa, which is obtained by the stone-grinding of nixtamal, or lime-cooked maize. Traditionally, nixtamal, or hominy, was made by cooking maize in the leachate from wood ashes, the principal objective being to loosen and then remove the pericarp. In the modern process, whole maize is cooked in excess water containing 0.5-2.0% of hydrated lime (on maize basis) at 83"-100°C for 50-60 min, then cooled to about 68°C and allowed to steep for 8-24 h. This process is called nixtamalization, and the resulting product is called nixtamal. During this process the endosperm and germ are hydrated and softened, with partial gelatinization of the starch, and the alkali solubil- izes cell walls leading to weakening of the pericarp, and facilitating its removal. The nixtamal made by the traditional process is washed to remove loose pericarp and excess lime and is then stone- ground to produce masa. A modern commercial process for making hominy (nixtamal) uses lye (caustic soda) solution, in which the maize grains remain for 25-40 min until the pericarp is free. It is then boiled and washed to remove the pericarp and the lye. The hominy is then salted and canned. An attrition milling process for grinding the nixtamal is essential, using synthetic, lava, or alumina stones that cut, knead and mash the nixtamal to form masa. The wet-ground product is obtained as a dough containing about 55% m.c. : it consists of pieces of endosperm, aleurone, germ, pericarp, free starch granules, free lipids and dissolved solids which form a 'glue-like' material that holds together the masa structure. There is no gluten in the masa dough: cohesion of the mass is due to the surface tension of the I for 12-18sec) Bake (at 40O"-45O0C 1 I Cool (to 60°C) t Fry (at 210°C for I 5min) 1 Form and fry for 2 min) Fry (at 180°C 1 DOMESTIC AND SMALL SCALE PRODUCTS 273 859'0, comprising 39% of coarse semolina, 16% of fine semolina, and 30% of flour. Porridges made from cereal flours, such as sorghum flour, are the most important dishes con- sumed by the people living in Africa south of the Sahara. Both thick porridges and thin porridges are made, differing in the flour/water ratio required. Thick porridges use about 1 flour: 2 water, whereas thin porridges use 1 flour: 3-4 water. To make the porridge, the flour of sorghum, millet or maize, or a blend of these, is just boiled with water. Nasha is a thin porridge made from a fermented batter. Sorghum flour is mixed with a starter and water, and left to ferment for 12-16 h. The fermented batter is then diluted with water, cooked, and flavoured with spices or fruit juices. Wholemeal flour from sorghum may be cooked with water to make semi-solid dumplings. From the flour or meal, unleavened bread or chapattis are made, or the ground product may be used to make a beverage. Millet may be consumed in the form of porridge (called kasha in the former Soviet Union) made from dry parched grain, or it may be cooked with sugar, peanuts or other foods to make desserts. Massa is made from millet flour by cooking a por- tion of the flour to make a thin porridge, while making a batter from the remainder of the flour, mixing it in, and leaving the mixture to ferment Products made from sorghum and the overnight. The mixture is flavoured with salt, millets pepper and onions, and fried. The product is Most of the products made from maize, men- spongy in texture, and eaten with sorghum, maize tioned above, can also be made from sorghum, or millet porridge (Economic Commission for or from a blend of sorghum and maize, and some Africa, 1985). also from pearl millet. However, the traditional In Nigeria, sorghum and pearl millet are used methods of preparation vary from country to in four ways: country, as the following brief survey indicates. The traditional method of preparation in African 1. The dry grain is ground to make either (a) a countries and India where sorghum and the meal or flour, from which porridge (tuwo) is millets form the staple food is simple pounding prepared, or (b) grits, from which burabusko, in a mortar to loosen the husk and to reduce the a food resembling couscous, is prepared. The grain to wholemeal or semolina, followed by grits are agglomerated by blending with water, winnowing. The grain is stored as such, and from and then steamed for three successive periods it the day's requirements of meal or flour are of 15 min each (Galiba et al., 1987). Pancakes prepared. Preparation of larger quantities of meal may be made by frying a pasta. is not practised because of the rapidity, in hot 2. The dry grain is roasted and then ground to climates, with which the unde-germed meal make roasted meal or flour, from which snacks becomes rancid. The yield of edible products is for particular uses, and packed (Gomez et al., 1987). Tortillas are eaten alone, like bread, or fried (taco shells), or with fillings or toppings (nachos, tostadas, enchiladas, taquitos, burritos, tamales). In Colombia, maize grain is pounded with potash and a little water in the domestic preparation of maize meal. The alkaline effect of the potash is to loosen the bran and also to unbind the bound niacin. Kenkey In Ghana, traditional foods prepared from maize are known as kenkey. Cleaned maize grain is steeped in water for 3 days, the grain ground to flour, dough prepared from flour and water, spontaneous fermentation of the dough allowed for 3 days, part of the fermented dough partly cooked and then mixed with the uncooked part, the dough mass moulded into balls, the balls wrapped in maize cob sheaths and boiled to produce kenkey. Levels of niacin and lysine increase during the period of dough fermentation, but fall to the original levels during the partial cooking. There is further loss of niacin during preparation of the kenkey (Ofosu, 1971). (guguru, adun) are prepared. 274 TECHNOLOGY OF CEREALS 3. The grain is steeped in water and a lactic If chapattis are made with cold water, the fermentation allowed to proceed for 1-4 days. dough lacks cohesiveness because the protein in The moist grain is then pounded and used to sorghum and millet is not gluten-like. The use prepare a fermented porridge product (ogi, of boiling water to make the dough results in akamu) . partial gelatinization of the starch and imparts 4. The grain is soaked and allowed to sprout. sufficient adhesiveness to permit the rolling out of The sprouted grains are dried and ground to thin chapattis. The water absorption of sorghum make a malt from which beverages (pito, flour is higher than that of wheat flour; thus, the burukutu) are prepared. baking time for sorghum chapattis is longer than that for wheat chapattis. A blend of about 30% In the Sudan and Ethiopia the flour or meal is sorghum flour with 70% of wheat flour produces used for making flat cakes (kisra, injera) or it may chapattis of improved eating quality. be mixed with cassava flour. Kisra, a staple food In India and Africa, whole sorghum grain, or in the Sudan, is made by mixing sorghum flour, dehulled and polished sorghum grain (pearl dura) of 80-85% extraction rate, with water and a may be boiled to make balila, which is used in a starter, and leaving it to ferment overnight, and similar way to rice. Sorghum may also be eaten then baking at 160-180°C for 30 sec. Kisra is now as a stiff porridge. also made commercially, and has a shelf-life of In India, grain sorghum and pearl millet may 48 h at room temperature (Economic Commission be popped, but whereas maize is popped in hot for Africa, 1985). oil, the sorghum and millet grains are popped The grain may be parched, popped or boiled in hot sand (Hoseney, 1986). A more detailed whole. account of traditional foods made from sorghum in In Ethiopia, injera are made from the flour of various countries, including methods of prepara- teff (Eragrostis tef), an indigenous type of millet. tion, is given by Rooney et al. (1986). In the traditional domestic process, teff flour is Sorghum and maize react in the same way when mixed with water and allowed to ferment over- subjected to the alkaline cooking process of night by action of endogenous microflora to nixtamalization. This process causes the hull produce a sour dough, and then baked in the or pericarp to peel away from the kernels, facili- metad, or injera oven, to make injera, a pancake- tating its subsequent removal. The starch like unleavened bread. The fermentation may be granules throughout the kernel swell, but some promoted by using a starter culture, called irsho, of the granules in the peripheral endosperm are a thin paste saved from a previous fermentation. destroyed. Tortillas made from a blend of 80% Fermented teff flour is also used for making pearled or unpearled sorghum plus 20% yellow porridge, beer (tella) and spirits (katikalla) (Umeta maize by the alkaline cooking process had an and Faulks, 1989). acceptable flavour and a soft texture. The reduced In Uganda, sorghum grain is malted and cooking and steeping times required by sorghum sprouted, the radicle removed, and the remainder as compared with maize are advantageous, and of the grain dried. Some of the pigment and the the cooking time is further reduced by using bitter tannins are thereby removed. The sugars pearled, rather than unpearled, sorghum (Bressani produced by the malting make a sweet-tasting et al., 1977; Bedolla et al., 1983; Gomez et al., porridge. The grain is also used for brewing. 1989). In India and other Asian countries wholemeal Tortilla chips could be made from white sor- flour from sorghum or millet may be used to make ghum by lime-cooking at boiling temperature for dry unleavened pancakes (roti, chapatti, tortilla). 20 min, using 0.5% lime, quenching to 68°C and It has been estimated that 70% of the sorghum then steeping the grains for 4-6 h to produce grown in India is used for making roti, a propor- nixtamal, which was then stone-ground to masa tion that increases to 95% in Maharashtra state (a coarse dough). The masa was sheeted, cut into (Murty and Subramanian, 1982). pieces, baked at 280°C for 39 sec and then fried DOMESTIC AND SMALL SCALE PRODUCTS 275 ROONEY, L. W. and SERNA-SALDIVAR, S. 0. (1987) In: Corn: chemkw and Technology. WATSON, S. A. and ~STAD, P. E. (Eds.) Amer. Assoc. Cereal Chem., St Paul, MN, U.S.A. SANDERSON, J., WALL, J. S., DONALDSON, G. L. and CAWUS, J. F. (1978) Effect of alkaline processing of corn on its amino acids. Cereal Chem. 55: 204-213. SERNA-SALDIVAR,~. O., ROONEY, L. W. and WANISKA, R. References D. (1988a) Wheat flour tortilla production. Cereal Fds WM, 33 (10): 855-864. BEDOLLA, S., DE~ALACIOS, M. G., ROONEY, L. W., DIEHL, SERNA-SALDIVA, s. o., TELLEZ-GIRON, A. and ROONEY, L. K. C. and KHAN, M. N. (1983) Cooking characteristics W. (1988b) Production of tortilla chips from sorghum and of sorghum and corn for tortilla preparation by several maize. J. Cereal Sci., 8: 275-284. cooking methods. Cereal Ch. 60 (4): 263-268. SIDHU, J. S., SEIBEL, W. and BRUEMMER, J. M. (1989) Effect BRESSANI, R. I., ELIAS, L. G., ALLWOOD PAREDAS, A. E. of shortening and surfactants on chapati quality. Cereal and HUEZO, M. T. (1977) Processing of sorghum by lime- Fds WM, 34 (March): 286-290. cooking for the preparation of tortillas. Proceedings of UMETA, M. and FAULKS, R. M. (1989) Lactic acid and Symposium on Sorghum and Millets for Human Food, volatile (Cd,) fatty acid production in the fermentation DENDY, D. A. V. (Ed.). Tropical Products Institute, and baking of tef (Eragrostis ref). J. Cereal Sci., 9: 91-95. London. chapatti flour. Milling 152 (11): 22. pendium on composite fiun, KENT, N. L. (Tech. Ed.). United Nations Economic Commission for Africa, Addis GALIBA, M., ROONEY, L. W., WANISKA, R. D. and MILLER, F. R. (1987) The preparation of sorghum and millet ADRIAN, J., FRANGUE, R., DAWN, A., GALLANT, D. and couscous in West Africa. Cereal Fds Wld 32 (12): 878-884. CAST, M. (1967) The problem of the milling of millet. GOMEZ, M. H., ROONEY, L. W., WANISKA, R. D. and Nutritional interest in the traditional African process and PFLUGFELDER, R. L. (1987) Dry corn masa flours for attempts at mechanisation. Agrmie troplcale, 22 (8): 687. tortilla and snack food production. Cereal Fds WM 32 (5): ASP, N.4. and BJORCK, I. (1989) Nutritional properties of 372-377. extruded foods. In: Exmcsia Cooking, Ch. 14, MERCIER, GOMEZ, M. H., MCDONOUGH, C. M., ROONEY, L. W. and C., LINKO, P. and HARPER, J. (Eds.). Amer. Assoc. Cereal WANISKA, R. D. (1989) Changes in corn and sorghum Chem., St Paul, MN, U.S.A. during nixtamalization and tortilla baking. J. Fd Sci., 54 AYKROYD, W. R., GOPOLAN, C. and BALASUBRAMANIAN, (2): 336336. S. C. (1963) The nutritive value of Indian foods and the HOSENEY, R. C. (1986) Principles of Cereal Science and planning of satisfactmy diets. Indian Council of Medical Technology. Amer. Assoc. Cereal Chem., St Paul, MN, Recearch, New Delhi, Spec. Rpt Ser. No. 42. U.S.A. DESIKACHAR, H. S. R. (1975) Processing of maize, sorghum KHAN, M. N. and RASHID, J. (1987) Nutritional quality and and millets for food uses. J. sci. indust. Res. 34 (4): 231. technological value of triticale. Asian Fd J., 3 (March): DESIKACHAR, H. S. R. (1977) Processing of sorghum and 17-20. millets for versatile food uses in India. Proceedings of a LEELAVATHI, K. and HARIDAS RAO, P. (1988) Chapati from Symposium on Sorghum and Millets for Human Food DENDY, germinated wheat. J. Fd. Sci. 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(1971) Changes in the levels of niacin and lysine MN, U.S.A. during the traditional preparation of kenkey from maize RAGHAVENDRA RAO, S. N., MALLESHI, N. G., SREEDHARA- grain. GhanaJ. am. Sci., 4: 153. MURTHY, S., VIRAKTAMATH, C. S. and DESIKACHAR, ROONEY, L. W., KIRLEIS, A. W. and MURTY, D. S. (1986) H. S. R. (1979) Characteristics of roti, dosa and vermicelli Traditional foods from sorghum: their production, evalua- from maize, sorghum and bajra. J. Fd Sci. Techml., 16: 21. tion and nutritional value. In: Advances in Cereal Science WATSON, S. A. and RAMSTAD, P. E. (Eds.) (1987) Corn: and Technology, Vol. VIII, Ch. 7, POMERANZ, Y. (Ed.) Chemistry and Technology. Amer. Assoc. Cereal Chem., St Amer. Assoc. Cereal Chem., St Paul, MN, U.S.A. Paul, MN, U.S.A. in oil at 190°C for 1 min. The tortilla chips thus made from sorghum had a bland flavour; a more accept- able product, with the traditional flavour, could be made similarly from a blend of equal parts of make and sorghum (Serna-Saldivar et al., 1988b). U.S. PAT. SPEC. No. 4,735,811 (Plasticizers for tortillas). CHAUDRI, A. B. and MULLER, H. G. (1970) Chapattis and VERMA, N. S., MISHRA, H. N. and CHAUHAN, G. S. (1987) Preparation of full fat soy flour and its use in fortification ECONOMIC COMMISSION FOR AFRICA (1985) Technical com- ofwheat fl0ur.J. FdSci. Technol., 24 (SeptJOct.): 25s260. Ababa. Further Reading