CONTINUOUS PRODUCTION OF A INSTANT MAIZE FLOUR FOR
AREPAS, TORTILLAS AND SANDWICHES, USING A PRESSURE PRESSURE WITH ACID
Field of the Invention The present invention relates to a pressurized and acid precooked process for the production of corn flour and, more particularly with one that achieves a continuous partial and pressurized precooking and the removal of corn bran with an acid reducing agent. as a feed processor additive used during the manufacture of instant corn flour for the production of arepas, tortillas, and sandwiches. BACKGROUND OF THE INVENTION The production of high quality dough for dough can be achieved by conventional techniques only if the food grade corn has the following characteristics: uniformity in the size and hardness of the grain, a low number of pressure fractures and grain damage , and ease of removal of the pericarp during the cooking process with lime and water. It is known that corn with hard endosperm (U.S. No. 2 USFGC, 1996) must be partially cooked before the final products are formed, to make it a precooked cornmeal. White grain corn may contain: 11.0-11.5% moisture, 72.2-73.2% starch, 9.8-10.5% protein, Ref .: 166192 3.7-4.0% fat and 2.1-2.3% ash and crude fiber. For example, a sample of dry milled corn could give, on a dry basis, 74.8-76.2% total endosperm, 18.9-20.5% germ and 3.3-6.3% bran. The mature tooth grain (atson, 1987) has four separable components, in dry base: cap (0.8-1.1%), pericarp or bran (5.1-5.7%), endosperm (81.1-83.5%) and germ (10.2-11.9) %). In dry or wet milling processes, the separate bran includes the pericarp, cap, aleurone layer and also adherent parts of the fecose endosperm. The nixtamalized corn flour (HM) is produced through the stages of alkaline corn cooking, washing, nixtamal grinding, and drying, thereby producing corn masa flour. This flour is sifted and combined for different product applications and is usually supplemented with additives before packing for production in commercial tables or packaged tortillas and sandwiches. Although the pericarp or bran is partially removed during the alkaline cooking and washing steps, there is still corn grain fiber (US Patent 4,513,018). Nixtamalized corn flour or dough flour typically contains 7-9% total dietary fiber or bran with 6-8% consisting mainly of insoluble fiber on a dry basis (Sustain, 1997). Cell walls or polysaccharides without starch (PSA) are the main components of dietary fiber of corn and are composed of hemicellulose (heteroxylan or pentosan and β-glucan: 4.4-6.2%), cellulose (2.5-3.3%) and some lignin (0.2%). According to Watson (1987: Tables IV and VII), the corn pericarp constitutes 5-6% of the grain on a dry basis. This pericarp also contains 90% insoluble fiber (67% hemicellulose and 23% cellulose) and only 0.6% soluble fiber (soluble arabinoxylan and β-glucan). It is estimated that dietary fiber in both bran (4.9%) and endosperm (2.6%) constitute 80% of the total dietary fiber. The insoluble fiber of corn is found mainly in the bran and the endosperm (aleurone and fecose), which make up 68% of the total dietary fiber (9.5% on dry basis). Unlike corn endosperm (corn grits), in which the amounts of soluble fiber make up 12% of the total fiber (4.1%), in all wheat, soluble fiber represents 22% of the total fiber ( approximately 20% of the water uptake of the flour is linked to the soluble pentosan fraction). During alkaline cooking and / or soaking, there are chemical and physical changes such as loss of nutrients along with partial removal of pericarp and bran, degradation of the periphery of the endosperm with gelatinization / swelling of starch and denaturation of protein in the precooked corn kernel . The most important nutritional modifications are: an increase in the level of calcium with improvement in the Ca to P ratio, a decrease in insoluble dietary fiber and protein zein, a reduction of thiamin and riboflavin, an improvement in the ratio of leucine to isoleucine that reduces the requirement of niacin, and leaching of insecticides, fungicides and aflatoxins, residuals in waste water ( Sustain, 1997). Properly processed maize flour or industrial dough simplifies the production of tortilla products, because the customer eliminates the management techniques required for wastewater treatment, assurance, handling and processing of corn to tortilla dough and sandwiches. However, an instant corn flour could have the following quality and cost limitations: high cost, lack of flavor, and poor texture in tortillas and sandwiches prepared from the flour for dough. Tortillas are the main edible corn product in North and Central America. It is a thin, flat, round, unleavened and cooked cake (flat corn bread) made from fresh dough or corn dough prepared from industrial nixtamalized corn flour (HMN). It should be mentioned that an omelette, when manufactured manually or mechanically and without additives of any kind, has a maximum shelf life of 12 to 15 hours at room temperature. Subsequently, it is spoiled by microorganisms and hardens or ages due to a physicochemical change in the starch that constitutes the tortillas either stored or reheated (retrogradation of starch). It is known that tortillas, even when kept under conditions in which there is no loss of moisture (as in a plastic package), however harden over time and break or crumble easily when folded. In the northern part of South America, particularly in Colombia and Venezuela, the hard endosperm is processed with dry milling technology without waste water and is also converted into a precooked, degerminated flour without bran for traditional maize food. Its consumption is mainly in the form of an "arepa", which is a thin flat cake or ovoid, unleavened and baked form made of dry ground corn flour. In other South American countries, corn feed and corn flour are used for different bakery and cake mixes as well as for sandwiches. Corn flour processors can generate added value from their industrial operations in one of three approaches: develop new products from new hybrids, increase the yield of traditional corn products, and improve the efficiency of the process at a lower unit cost. In the past, this has been done with methods and employing apparatus in which the grain is cooked and / or steeped in a lime-water solution such as that described in U.S. Patent Nos. 2,584,893, 2,704,257, 3,194,664, and 4,513,018. These prior art methods for the industrial production of dough flour involve accelerated cooking with lime and soaking times with large amounts of solids loss (approximately 1.5 to 3.0%) in the waste liquid or waste water ("nejayote "). In addition, essential nutrients such as vitamins and some amino acids are lost, depending on the severity of the cooking, washing and drying operations. Many and varied methods for the production of instant corn flour for food products that involve lower amounts of water with low temperature cooking and processing in a short time for a high yield of the final product have been developed, as reflected in the following US patents : 4,594,260, 5,176,931, 5,532,013, and 6,387,437. In this regard reference is made to U.S. Patent Nos. 4,594,260, 5,176,931, 5,532,013, and 6,265,013, which also require drying at low temperature. In contrast, U.S. Patent Nos. 4,513,018, 5,447,742, 5,558,898, 6,068,873, 6, 322,836, and 6,344,228 have used high temperature dehydration or fast cooking instead of low temperature cooking.
Bearing in mind the disadvantages of prior art methods, several studies have not only used a low temperature and fast precooking with a minimum of waste water, but also separate corn fractions as reflected in the following US patents: 4,594,260, 5,532,013 , 6,025,011, 6,068,873, 6,265,013 and 6,326, 045. A few applications have also been tried for pressurized precooking and acid soaking to convert traditional mass processing to a physicochemical process with reduced waste water (European Patent 0006369 and US Patent Nos. 3,083,103 , 6,068,873, 6,265,013, 6,387,437 and 6,344,228, WO 00/45647 and U.S. Patent Nos. 1,045,490 and 6,322,836). Two recent pilot processes have been tested (patent WO 00/45647 and US patent 6,428,828) for the preparation of a modified dough food product using either a reducing agent (metabisulfite) or dough flour with a commercial alkaline protease as an adjuvant of processing and adding to the corn before cooking / soaking in such a way that its native protein was partially modified. Although the prior art methods described above are capable of partially precooking or soaking all of the corn for an instant maize flour and corn with lime or dough, it is not yet available on the market at the time of the invention. a continuous industrial application that uses both pressurized precooking and acid soaking at the same time. BRIEF DESCRIPTION OF THE INVENTION Accordingly, an object of the present invention is to provide a total departure from the prior art and rapid precooking methods of thermal, mechanical, chemical and biochemical or enzymatic processing of all maize in order to control gelatinization. Fecose endosperm and protein denaturation using pressurized and acid precooking during the continuous production of instant corn flour for arepas, tortillas, and sandwiches. Another object of the present invention is to generate not only a reduced amount of waste water and loss of solids but also a high yield of corn flour with uniform properties. Another object is to achieve this objective by using an industrial method and an apparatus involving precooking under pressure and with acid with sulfites for a partial hydrolysis of the cell walls and proteins of the maize together with a diffusion of water effecting a controlled swelling of starch granules and of protein with a reduced loss of corn during the production of precooked corn flours. The above objects and advantages and others of the invention are achieved by means of a continuous process applied to the production of precooked corn flour or instant corn flour for arepas, tortillas, and sandwiches, whose modalities include a pre-cook under pressure in a time short with a solution of sodium metabisulfite, or sodium bisulfite or sodium sulfite as a processing aid in order to effect a partial hydrolysis of insoluble fiber and protein together with a controlled gelatinization and denaturation, a washing of grains and losses of reduced solids in the waste water, stabilization of the moisture content at a desired optimum level to grind, grind, and dry the preconditioned grain to produce a uniform partial cooking, cool and dry the dry ground particles, separating and recovering the fine grind produced from the coarsest grind while the latter is additionally aspirated to remove torque a fraction of corn bran for food or wholemeal, re-grind the coarser grind separated and further screen it for a corn flour, snap for arepas, and mixing only a fine flour with lime to produce a corn flour with lime or dough for tortillas and sandwiches. BRIEF DESCRIPTION OF THE FIGURES The invention will be more fully understood from the following description, and of the appended figure in which the single figure illustrates one embodiment of the present invention in a block-type flow diagram illustrating the continuous and industrial process using pressure and precooking with sulfites as processing aids. DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, an embodiment of the present invention is illustrated in flowchart form. This includes a pre-cooked pressure cooker 1; a scrubber 2; a preconditioner 3 with a feeder a primary mill 4; an oven 5; a dryer 6; a first cyclonic separator 7; a cooler 8; a second cyclonic separator 9; a screener 10; a vacuum system 11; and a secondary mill 12. The pre-cooked pressure cooker 1, whose design is known per se, is fed with cleaned corn and a solution of sodium metabisulfite together with hot soaking water (60 ° C to 70 ° C) recycled of scrubber 2 to form an acidic aqueous suspension (ratio of corn to water of about 1: 0.5 to about 1: 1). The solids content of the acid solution is regulated in the range of about 1.0% to about 3.0%. By regulating the heating with steam and the residence time of the grain, it is possible to pre-press maize under pressure. The corn suspension is heated with saturated steam (48.3 to about 144.8 kPa (7 to about 21 psig) and at 110 ° C to about 114 ° C) for a period of 17 to 34 minutes. This allows precooked grain to be produced under pressure with acid with moisture contents of between 35% and 37%, while the pH decreases from about 6.2 to about 6.8 with the addition of a 10% acid solution to provide an adjuvant of processing from 0.10% to 0.20% by weight (based on corn). The pressure precooking pot with sulfite solution causes an acid hydrolysis that promotes a rapid and uniform diffusion of the precooking water through the bran into the germ, the endosperm and its cell walls made of dietary fiber. Saturated steam and sulphite solution also effect controlled solubilization and swelling in the corn kernel, allowing from 45% to 65% reduction of waste solids as well as from 55% to 75% reduction of water effluent from waste (with lower sewerage cost) compared to applied processes of lime cooking (Alvarez and Ramírez, 1995). This loss of water in the precooking pot is replaced with recycled soaking water from the scrubber 2. The partially precooked corn slurry then passes to a scrubber 2 where it is sprayed with water heated with steam at a temperature of about 60 ° C to about 70 ° C for 30 to 60 seconds, which also serves to increase water absorption and wash soluble solids in the waste water. The washed corn is then passed to a preconditioner 3, where the precooked grain is equilibrated to obtain a moisture content of about 38% to about 39% for about 210 minutes. Subsequently, the maize preconditioned and washed is fed through a feeder to a primary mill 4, whose design is in itself known, such that pre-ground corn and hot air from a furnace 5, are mixed and partially cooked by means of an industrial dryer 6 whose design is known per se. The pre-ground grain is therefore subjected to instantaneous drying at a high temperature of 180 ° C to about 230 ° C for a short period of 5 seconds to about 30 seconds. Its fecose endosperm is partially gelatinized or precooked to give a moisture content of 16% to about 18% depending on the granulation that occurs. Warm air charged with humidity (130 ° C to 205 ° C, and 11% a
13% humidity) is extracted with a first cyclonic separator 7 in such a way that the extraction of moisture can take place by hitting the material of the dryer through a cooler 8, whose design is known per se, thus decreasing the moisture content from 16-18% to approximately 9-12% (similar to incoming corn). After an additional extraction of hot air charged with humidity (100 ° C to 110 ° C) with a second cyclonic separator 9, the dried precooked particle is directed to a screen 10 where the fines fraction (with mesh size) is separated. from 20 to 60) as instant corn flour and the coarser fraction is further separated. This latter coarser fraction is further separated in the suction system 11 where two fractions are obtained, a fraction of light bran which is separated as a feed or for whole meal with a moisture content between 9% to 12% (representing approximately 3%). % to about 7% of the total weight of incoming corn), and a heavier coarse fraction that is milled in a secondary mill 12. The milled product of the secondary mill 12 is recycled to a screen 10 for further screening and to produce a flour of homogeneous corn for arepas. If desired, the flour for arepas can be mixed with food grade lime (0.15% by weight based on precooked flour) to produce a corn flour with lime or dough for making tortillas and sandwiches. For use in the manufacture of arepas, the instant corn flour is rehxdratada preferably mixing with hot water from a weight ratio of 1: 1.3 to approximately 1: 1.4 to form a paste of corn (55% to 60% final moisture) for the production of arepas. In the manufacture of tortillas and sandwiches, the dough flour prepared from the present method can be rehydrated with water from a weight ratio of 1: 1.0 to approximately 1: 1.3 for a dough dough (50% to 55% final moisture content). ) used in tortillas or corn foods. In this method, the novel physicochemical precooking results in a 45% to 65% reduction in waste water solids and 55% to 75% waste water overflow, correspondingly with lower sewer and energy costs, in comparison with industrial methods (> 5.0%: Sahai and Jackson, 2001). In addition, the acid pressure precooking of the invention allows a 75% reduction in the lime used if a corn flour were produced with lime or dough to improve new flavors in corn based foods such as novelty toast or sandwiches. The rapid precooking at high temperature (110 ° C-114 ° C) using a sulphite solution (0.10% -0.20%) not only helps to hydrolyze the insoluble cell walls but also performs a gelatinization and controlled denaturation. It also dissolves the endosperm and the cell walls of the germ facilitating a simultaneous water diffusion with reduced gelatinization and denaturation without using a lime cooking (US Pat. Nos. 6,344,228 and 6,387,437) or more sulfite (US Patent No. 6,322,836). There is also a higher corn flour yield of 90% to about 95% of the total weight of cleaned corn grain compared to the commercial alkaline cooking process, which gives 88%. While the instant corn flour produced by the novel method can therefore comprise a yield greater than 90% flour per kilogram of corn, the unleavened and degerminated flour produced by a typical arepas process obtains only a yield of 55% to 70%, or a yield of 80% to 85% for an integral arepas flour (US Patent No. 6,326,045). Additionally, pre-cooked corn flour pressurized with acid produced by the present method has a higher nutritional value compared to conventional and commercial methods, with a higher content of dietary fiber and fat than commercial arepa or degerminated corn flours (INCAP). , 1961). The following table provides an average nutrient composition typical of precooked flours for corn and traditional arepa foods (Cuevas, 1985).
Nutritional Profile (g / 100 g): Precooked Corn Flour
Nutrient Corn with lime Corn Arepa Water 11.0 11.0 11.0 Protein 8.1 8.1 7.0 Fat 2.6 2.6 0.7 Ash: 1.4 1.3 0.3 Calcium 0.08 0.01 0.01
Dietary fiber: 7.0 7.0 3.0 Raw Fiber 1.5 1.5 0.5 Starch 70.0 70.0 78.0 Total Calories 350 350 370
From the above, it will be appreciated that it is possible to manufacture a pre-cooked corn flour under pressure with acid and with partially removed bran and corn flour with lime or dough with a novel physicochemical process which is efficient due to the partial hydrolysis of the walls cells or the solubilization of the periphery of the endosperm with pregelatinization of starch and denaturation of protein in the precooked corn grain, where some losses of nutrients and solids may be present but which by the characteristics of the present invention are avoided. It will be understood that the embodiments of the present invention illustrated here and described in detail are by way of example and not limitation. Other changes and modifications are possible and are present for those with experience in previous techniques. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.