MXPA05000891A - Nixtamalization method and device for implementing same. - Google Patents

Abstract

The invention relates to the dough and pancake industry, and all new industries wherein a product undergoes nixtamalization. The invention more particularly relates to a nixtamalization process involving a rotary reactor, having improved operation parameters that are defined for optimum operation. The conditions of the inventive system are advantageous over those of prior art systems in that the resulting rotary reactor parameter levels produce a good-quality product while reducing the amount of fuel consumed per amount of finished product. The aforementioned conditions are as follows: the speed of rotation of the reactor, which is between 25 and 30 seconds per revolution; the temperature of the heating jacket, which is between 130 and 300 degree C; the supply of steam to the nixtamalization chamber is either continuous or intermittent with a break period of between 20 and 120 seconds and injection of steam for between 30 and 90 seconds; the start nixtamalization temperature which is mainta ined at least between 60 and 70 C and the end nixtamalization temperature which is maintained at between 85 and 90 C. while the post-nixtamalization conditioning water is maintained at a temperature between ambient temperature and 55 degree C.

Description

NIXTAMALIZATION PROCEDURE AND EQUIPMENT APPLYING SUCH PROCEDURE FIELD OF THE INVENTION The present invention is related to the industry of dough and tortilla, and any new industry in which the nixtamalization of any product is required, more specifically it is related to a process of nixtamalization with a rotating reactor, with a better capacity of application of the temperature required for nixtamalization and a process with more interesting results in the resulting product.

BACKGROUND OF THE INVENTION It is important to mention here that the definition of nixtamalization is the alkaline treatment with heat of any grain. That nixtamalization results in a series of physical and chemical transformations of the grain or its components. Although at lower temperatures the changes produced are less drastic and observable, they occur and we can not indicate with precision to what temperature there is or does not exist nixtamalization.

In the present description, we mention as heat nixtamalization that which is carried out in the rotating reactor, but we must say that the nixtamalization continues even during the rest of the grain.

From the development of a rotary reactor described in the now Mexican patent 191,283, it was possible to verify the difficulties to provide the heat that would allow the thermal treatment required for the nixtamalization. In the design of the reactor object of this patent, two jackets were handled around the nixtamalization chamber. An external chamber of hot combustion gases, as a source of heat and an intermediate chamber, containing thermal oil, oil that served as a buffer for the temperature, having a significant caloric inertia.

This inertia that had been sought originally, later was one of the reasons why it was difficult to handle said reactor.

A nixtamalization process includes a heating step until reaching the desired nixtamalization temperature, a preservation step of this temperature, and a cooling step to the desired temperature for rest. It is desirable that the first and third stages be short to achieve a rapid process. In addition, of course, to reach the nixtamalization temperature as high as possible, without reaching the evaporation temperature of the water, but high enough to have a nixtamalization as short as possible, without demeriting the characteristics of the product.

With the reactor of the Mexican patent 191,283, and especially due to the inertia of the thermal oil, the heating process had to be reached to reach the optimum temperature of 90 ° C, it was too long and often was not reached. The heating process was thermodynamically complex and had to do with the temperature differentials between the working fluids between them and between these and the trinomial water-corn-lime, the phenomena of interface between the working fluids and the walls of the different camera or jackets, the circulation or flow regime of fluids, etc. This hindered the determination of the thermodynamic conditions of the process.

On the other hand, the design of said reactor, although it achieved a certain fiomogenisation of temperature and concentration of lime in the trinomial, some temperature differentials and concentration of lime could still be detected, demonstrating that homogenization was not achieved. fully.

Then, trying to achieve a homogenization of the temperature within the water-corn-lime trinomial, a rotary reactor with the characteristics described in the Mexican patent application PA / a / 2003/5529 was designed.

The design of this reactor allowed, in addition to a better homogenization of the lime concentration at the "long" and at the "wide" of the reactor, a homogenization of the prevailing temperature at the different height levels of the components of the trinomial, since with the previous reactors, it could be observed that due to the heat transfer phenomena, the temperature in the center of the trinomial semen was lower than the temperature reached in the trinomial layers in contact with the walls of the reactor. The above in spite of the heat transfer phenomena provided by natural convection.

The description of the Mexican patent application PA / a / 2003/5529 is added in full for consultation in the present invention.

On the other hand, in some efforts to improve heat transmission, a reactor was designed with a series of external conduits attached to the outer walls of the reactor, forming helical conduits, to increase the contact surface between the working fluid and the reactor. .

With the rotary reactors of the state of the art, very often the temperature of 90 ° C, which was considered optimal, was not reached, The inclusion of external ducts attached to the outer walls of the reactor, in addition to increasing the contact surface, also allowed the increase of the residence of the working fluid in contact with the reactor.

The Mexican patent application PA / a / 2004/1693, which is added to the present in its entirety for consultation, describes this innovation in the reactor.

However, despite the fact that the transmission of heat from the reactor wall to the trinomial water-corn-lime was greatly improved, it could be perceived that, especially at the end of the process, the temperature of the nixtamalization process could not reach the desired temperature.

It could be perceived that near the end of the process, the temperature differential between the temperature of the reactor wall and the temperature of the grain at a given point, was getting larger.

This situation meant having to increase the flow of working fluid with the consequent waste of energy and the unequal distribution of temperature throughout the grain, despite the movement of the grain, with the different effects on the nixtamal.

A design that would allow a more effective heat transmission even in the last moments of nixtamalization before resting would allow a more controlled nixtamalization process.

In addition, the nixtamalized corn flour obtained with the processes of the state of the art using the rotary reactor, still presented undesirable organoleptic characteristics, such as blackening, coal spots, undesirable odors, etc.

An important step in the processes of nixtamalization, which consists of washing the corn grain before its nixtamalization, is already in the state of the art. This step demonstrated its importance in the Mexican patent application PA / a / 1994/09276 where a modernization of the traditional nixtamalization equipment is disclosed, basically consists of three steps that are: first the cleaning of the maize by means of water with which the final washing of the corn is avoided, as the second step is the knowledge of the corn by means of an electric and electronic tub that works by means of electricity that heats some resistances that are located around the ink that heat the oil that is in a chamber with this system heats the water that will serve to cook the corn, this tub as can be observed does not consume gas and therefore does not contaminate and finally a cooling ink by means of air, with which the final washing is eliminated and therefore, contamination of the drain is also eliminated. With this invention, process times and contamination of both air and water are reduced and the product is improved since it does not let the waste go in the water, which allows it to be more integral.

Although there was already talk about the washing of corn as a way to optimize the use of lime in the process, the washing conditions had not been determined, that is to say, it has not been done in the state of the art how to achieve that washing , the temperature of the washing water, the ratio water quantity of grain, how to put the grain in contact with water, etc.

Then, in addition to its facet related to the modifications to the rotating reactor, the present invention also deals with a modification in the nixtamalization process including the passage of the repose thereof, the pre-treatment of the grain, the conditioning of the nixtamalized corn for its rest , etc., for the nixtamal that will later be used for the production of nixtamalized corn flour.

OBJECTIVES OF THE INVENTION One of the objectives of the present invention is to make possible a process that allows to reach the desired temperature within the trinomial water-lime-corn as quickly as possible.

Another objective is to achieve a nixtamalization process that allows a nixtamalized corn flour without blackening or undesirable odors.

Still another objective of the present invention is to make possible a team that allows the application of the process that has the above qualities.

Other objects and advantages of the present invention may be apparent from the study of the following description and the accompanying drawings for illustrative and non-limiting purposes only, BRIEF DESCRIPTION OF THE INVENTION In short, the present invention will be reflected in a nixtamal production process and on the other hand in the equipment required for the application of this process, On the side of the process, new steps were added in the production of nixtamal that manage to improve the final product, consisting of nixtamalized corn flour.

The step of washing with maize water is included, where said washing is carried out by unloading the corn in a container containing the water and subtracting the water that was in contact with the water, by means of a conveyor, subtracting the corn by the opposite end to which the corn was discharged. This step is pre-seen with nixtamalization with added heat.

There is another additional step after the nixtamalization with added heat and prior to rest. This step allowed to lower the temperature for rest and an additional water absorption by the grain.

As already mentioned, it is sought that the decrease of the temperature of the grain in the last stage of the nixtamalization was made as quickly as possible, however, to carry out this drop in temperature in the rotary reactor itself presented a very important technological problem and it was solved by removing the nixtamal from the reactor immediately after finishing the time of the treatment at high temperature, and carrying out the cooling on another side.

This came to achieve an additional effect of greater water absorption during rest. This step involves passing the nixtamal through a container of water, similar to how the raw corn is washed. However, while in the washing of the grain the impurities of the corn are eliminated, in the conditioning of the grain in this step it simply cools the grain and then some water is adsorbed in the nixtamal grain, so that during the rest, this water absorb The third modification of the process, since even with the modification of the jackets of the rotating reactor did not reach the desired temperature in the trinomial corn-water-lime, was to add an additional source of heat: steam pressure injected directly into the breast of the corn-water-lime trinomial.

This modification in the process should be reflected in modifications in the reactor by adding a means to inject direct steam into the trinomial.

This option increases the possibilities of heating, it can be heated by means of various working fluids in the outer jacket or chamber or even by means of electrical resistances attached to the outer wall of the nixtamalization chamber and in addition, this in combination with injection of steam within the trinomial. However, it is also possible to use only steam injection as a single source of heat.

This steam is characterized by having a pressure between 2 and 10 kg / cm2. And the added amount is the necessary to reach and maintain the nixtamalization temperature.

In order to better understand the characteristics of the invention, the present description, as an integral part thereof, is accompanied by the drawings, which are illustrative but not limitative, which are described below.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the scheme of the process object of the present invention.

Figure 2 illustrates the modification carried out in the rotary reactor for steam injection.

For a better understanding of the invention, a detailed description will be made of some of the modalities thereof, shown in the drawings that are attached to the present description for non-limiting illustrative purposes.

DETAILED DESCRIPTION OF THE INVENTION As already mentioned, the present invention has two aspects, on the one hand the teachings on a new process of nixtamalization for the production of nixtamal which is subsequently ground and dried to obtain nixtamalized corn flour. On the other hand, it discloses the equipment required for the application of this new process.

With respect to the process, the invention consists of a series of modifications consisting of three additional steps to the process and a modification of the form of heating in the reactor that is carried out the nixtamalization with heat.

With respect to the modification of the reactor to adapt the modification of the heating form consists in the inclusion in said reactor of a steam injection means for the direct heating of the corn-water-lime trinomial.

Up to now, the process of nixtamalization with a rotating reactor was carried out in the following way: 1) the grain is cleaned by means of screens, 2) the grain is washed by means of water, 3) the nixtamalization is started in the reactor, 4) the nixtamal is sent to the resting tanks and subsequently 5) said nixtamal is milled.

This process presented some drawbacks that were reflected in the organoleptic characteristics, and in its variability, of the flour produced from the nixtamal thus produced.

One of the modifications is the determination of the washing step with water of the grain in terms of temperature and amount of water and as to how to carry out said washing. The washing step is carried out by unloading the corn in a container containing the water and subtracting the water that was in contact with the water.

Although in one of the modalities of this step is carried out by means of a conveyor, which reaches the bottom of the container, generally inverted pyramid, subtracting the corn at the opposite end to which the corn was discharged. Other forms of container and means of withdrawal of corn may exist. For example, the removal of corn can be carried out through the bottom of the container. A stirring means may also be incorporated into the container to improve the removal of the powders adhered to the external surface of the corn.

This step is prior to the nixtamalization with added heat.

The amount of water used for this wash has been tested between 120 to 1000 liters per ton of processed corn, presenting improvement throughout the interval, however, it was found that the optimum would be around 355 liters per ton of processed corn to wash, for a corn powder with impurities of average powder particle size.

The temperature of the water is another parameter to be taken into account, since with water at a higher temperature it allows a better cleaning. Washing temperatures were tested between ambient temperature and 90 ° C. The optimum for fuel economy and washing effect was determined at 85 ° C.

Another modification consisted in the conditioning of the nixtamal before sending it to the resting hopper. This conditioning involves passing the nixtamal through a certain amount of water at a certain temperature. This conditioning is not a wash since the nixtamal that is passed absorbed the added lime and all the water that was added in the reactor, on the other hand, in the residual water after having passed the nixtamal through it, does not contain important amounts of neither lime nor nixtamal components.

Rather, this conditioning has two functions, one of them is for any type of corn flour and the other depends on the application of said flour. The function that is general is that of adding surface water to the nixtamal to be absorbed in the rest tank.

The other function, which is exclusively for the production of corn flour for the manufacture of tortillas, is to lower the temperature to the nixtamal. For the flours that will be used for frying, one would even try to increase the temperature of the grain in the repose.

The characteristics of the process are based on the amount of water through which the nixtamal and the temperature of this water will be passed. Water temperature ranges were tested, being found suitable from ambient temperature up to 90 ° C, being the optimum, for nixtamalized corn flour with application in the production of tortillas, the ambient temperature and for nixtamalized corn flour for application in the fritu-ra production between 37 and 80 ° C.

The amount of water through which the nixtamal will be passed was determined between 13 and 180 liters per ton of maize transformed into nixtamal, the optimum interval being between 97 and 106 liters per ton of corn transformed into nixtamal.

After the nixtamal passage through the conditioning water, the non-adsorbed water is eliminated. In one of the embodiments, the non-adsorbed water is removed by means of one or several screens.

The third modification of the process, since even with the modification of the jackets of the rotating reactor, the desired temperature in the trinomial corn-water-lime was not attained, it consisted of adding an additional source of heat: steam at direct injected pressure. in the trinomial corn-water-lime.

For the injection of heat, various means of injection can be used, from a simple tube with gradations, to conduits with nozzles or outlet nozzles. Obviously, the placement of these means must free the trailing screeds located inside the nixtamalization chamber, a somewhat complicated aspect due to the inclination of the reactor.

This modification in the process should be reflected in modifications in the reactor by adding a means to inject direct steam into the trinomial.

This option increases the possibilities of heating, it can be heated by means of various working fluids in the outer jacket or chamber or even by means of electrical resistances attached to the outer wall of the nixtamalization chamber and in addition, this in combination with injection of steam within the trinomial. However, it is also possible to use steam injection as a single source of heat.

The vapor pressure determined to be appropriate is between 2 and 10 kg / cm2. And the added amount is the necessary to reach and maintain the nixtamalization temperature. Understandably, it is necessary to take into account the amount of water that will be added in the form of steam to make the balance with the amount of water that is going to be added in the form of a whitewash, because at the end of the process of cooking the corn there should be no cooking residue (nejayote).

Now, with respect to the figures, it will be indicated that figure 1 shows the scheme of the process object of the present invention. In this scheme, the position occupied by the new stages is indicated.

In the preferred embodiment, the process begins with the reception of the corn in the silo of corn sifted 1. From here, the corn is sent in a continuous way, to the washing hopper 2, where by the effect of the displacement of the corn inside the water and by effect of the temperature of the same, the washing of the powders that are on the outside of the grain is carried out. The conditions of this wash have already been described in this chapter.

A conveyor removes the washed maize from the washing hopper and deposits it on the scale for weight control. From the scale, through another conveyor 5 and an elevator 6 the corn is deposited in the feed hopper 7 of the nixtamalization reactor 8. The inclusion in the process of a feed hopper of the reactor, significantly reduces this operation of feeding. Since the hopper can be loaded while the reactor is nixmalizing a load, the feed hopper can be fed to complete another load, so that this operation, the reactor loading operation is carried out in 1 / 3 of what was normally carried before the inclusion of said hopper.

The reactor 8 is then charged with the corn and the lime milk and the nixtamalization step is carried out with heat. After the treatment, when the maize absorbed substantially all the water and all the lime and most of the transformations that transform the corn into nixtamal were carried out, it is emptied into the hopper 9.

The hopper 9 deposits the still hot nixtamal in the conveyor belt 10 that carries the nixtamal to the conditioning tub 11, where the nixtamal adsorbs the water and reaches the temperature thereof. With the nixtamal conditioned, it is extracted from the tub and carried to an excess water removing means, in order to only conserve the adsorbed water.

The nixtamal with the adsorbed water is sent to the resting vessel 15 through a conveyor 14, the container is given the time required for this step, thereby achieving that the nixtamal is stabilized and the adsorbed water is absorbed.

With this step, the nixtamalization process is finished and the nixtamal is sent to grind to dry said ground grain and obtain the nixtamalized corn flour in this way.

Figure 2 illustrates the modification carried out in the ro-tatory reactor for steam injection. The modification consists in providing the reactor with steam injection means 21 as indicated in the scheme of said Figure 2.

The invention has been sufficiently described so that a person with average skill in the art can reproduce and obtain the results that we mentioned in the present invention. However, any person skilled in the art who is competent in the present invention may be able to make modifications not described in the present application, however, if for the application of these modifications in a certain structure or in the manufacturing process thereof, the subject matter claimed in the following claims is required, said structures should be understood within the scope of the invention.

Claims (6)

R E I V I N D I C A C I O N S Having sufficiently described the invention, it is considered as a novelty and therefore it is claimed as property what is expressed and contained in the following claim clauses.

1. Nixtamalization process, characterized in that it comprises a step of conditioning the grain prior to rest and after removing the grain from the reactor, said conditioning consists in passing the grain through a quantity of water determined to provide water adsorbed to the grain.

2. Nixtamalization process, as claimed in the preceding claim, characterized in that the total water used in the conditioning is between 13 and 180 liters per ton of processed corn, with a temperature between room temperature and 92 ° C.

3. Nixtamalization process, as claimed in the preceding claim, characterized in that the total water used in the conditioning is between 97 and 106 liters per ton of corn processed at a temperature between room temperature and 92 ° C.

4. Nixtamalization process, as claimed in any of the preceding claims, characterized in that a washing step with water of the corn to be nixtamalized is also included, this washing being carried out with water between room temperature and 90 ° C; in an amount between 120 and 1000 liters per ton of processed corn.

5. Nixtamalization process, as claimed in the preceding claim, characterized in that this washing is carried out with water at a temperature of 85 ° C in an amount of 355 liters per ton of processed corn.

6. Nixtamalization process, as claimed in any of the above indications, characterized in that the heating for nixtamalization is carried out by injecting into the rotating reactor, within the maize-aguacal trinomial, steam at a pressure between 2 and 3 kg / cm2, until reaching and maintaining a temperature between 72 and 90 ° C. SUMMARY The present invention is related to the dough and tortilla production industry, and any new industry in which the nixtamalization of any product is required, more specifically relates to a process of nixtamalization with a rotating reactor. The advantages of this process with respect to those of the state of the art lie in reaching the desired temperature within the trinomial water-lime-corn as quickly as possible, achieving a process of nixtamalization that allows a corn flour nixtamalizado without blackening or undesirable odors and make possible a team that allows the application of the process that has the above qualities. The process is characterized by comprising a step of conditioning the grain prior to rest and after removing the grain from the reactor, said conditioning consists of passing the grain through a quantity of water determined to provide water adsorbed to the grain.