DOMESTIC AND SMALL SCALE PRODUCTS 271 bath of caustic soda( 1%)for 25 sec at about 93C. water, and is most successful when the particle The dough pieces are then salted with 2% sodium size of the material is fine and the amount of chloride and baked in three stages: at 315C for water contained is just enough to fill the spaces 10 min, then at 218C to reduce the moisture between the particles. The masa is sheeted, cut content to 15%, and finally at 121 C for 90 min into triangular shapes and baked on a griddle (Hoseney, 1986) for 39 sec at 280%C to make tortillas The temperature used for baking the tortillas Products made from maize as high as possible, short of causing puffing Gomez et al., 1987, 1989; Hoseney, 1986; F and Serna-Saldivar, 1987; Serna-Saldivar et al 1988b) In Central america, tortillas are made from masa, which is obtained by the stone-grinding of nixtamal, or lime-cooked maize. Traditionally Nixtamalization and pellagra nixtamal, or hominy, was made by cooking maize The disease pellagra has been associated with in the leachate from wood ashes, the principal a deficiency of the vitamin niacin (nicotinic acid objective being to loosen and then remove the or niacinamide, and is prevalent among peoples cricarp. In the modern process, whole maize is who rely upon maize for a large proportion of cooked in excess water containing 0.5-2.0% of their daily food. Some 50-80% of the niacin in hydrated lime (on maize basis) at 830-100oc maize occurs in a bound form as niacytin or for 50-60 min, then cooled to about 68C and niacinogen, which is biologically unavailable, and allowed to steep for 8-24 h. This process is called renders the maize deficient in niacin(Mason et nixtamalization, and the resulting product is al. 1971). Pellagra is not suffered by Mexicans called nixtamal. During this process the endosperm who consume maize meal in the form of tortillas and germ are hydrated and softened, with partial The alkaline conditions obtaining during the lime gelatinization of the starch, and the alkali solubil- cooking(nixtamalization) release the bound niacin izes cell walls leading to weakening of the pericarp and make it biologically available and facilitating its removal. The nixtamal made However, there is some evidence that the onset by the traditional process is washed to remove of black tongue in dogs (a disease similar to pellagra loose pericarp and excess lime and is then stone- in humans )may be due to excessive intake of the ground to produce masa amino acid leucine in which maize is rich. In trials A modern commercial process for making with dogs on maize diets, black tongue developed ominy(nixtamal)uses lye(caustic soda)solution, only in dogs on high leucine diets. Alkaline in which the maize grains remain for 25-40 min treatment of maize to prepare masa or hominy until the pericarp is free. It is then boiled and has been shown to result in some loss of the amino washed to remove the pericarp and the lye. The acids arginine and cystine; commercially-made hominy is then salted and canned masa and tortillas contained lysinoalanine and An attrition milling process for grinding the lanthionine, which are breakdown products of nixtamal is essential, using synthetic, lava, or cystine and arginine(Sanderson et al., 1978) alumina stones that cut, knead and mash the nixtamal to form masa. The wet-ground product is obtained as a dough containing about 55%mc Snack products it consists of pieces of endosperm, ale Tortilla chips( tostados were traditionally pro- germ, pericarp, free starch granules, free lipids duced by frying stale, left-over tortillas, and are and dissolved solids which form a glue-like' still prepared in this way in Mexican restaurants material that holds together the masa structure. Alternatively, freshly-made masa, after sheeting There is no gluten in the masa dough: cohesion and cutting, can be fried for 1 min at 190C to of the mass is due to the surface tension of the produce tortilla chipsDOMESTIC 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