A method of making sterile cooked, or part-cooked, pasta products continuously

Abstract: A method is disclosed wherein a dough, prepared from flour and water, as well as other possible ingredients, is subjected to cooking and sterilization at temperatures in the 90°C to 170°C range by processing with saturated steam under a pressure, and then cooled inside an aseptic vacuum pan, in a sterile environment. From this vacuum pan, the dough, as sterilized, cooked, cooled, and brought to a predetermined moisture content level, is conveyed, again in a sterile environment, to a forming unit which delivers selected patterns of pasta for packaging in a sterile environment.

Description: This invention relates to a method of making sterile cooked, or part-cooked, long-life pasta products continuously on an industrial scale. In general, in the making of cooked or part-cooked long-life pasta products, it is necessary, on the one side, that the product stability and non-toxicity be ensured throughout its shelf life, and on the other side, that the product physical, organoleptic, and nutritional properties be retained, such that when dressed for immediate consumption, it will compare favorably with a similar traditional product (pasta dish) which has been freshly prepared. Of these requirements, non-toxicity and long-life preservability are prominent. To that aim, it is a regular and well-established practice in the art to pre-cook a suitable dough, to form it (e.g. by extrusion through dies yielding macaroni, spaghetti to different sizes and shapes, or by rolling out into a sheet of dough), dry it down to a moisture content below 12.5%, and finally package it into sealed containers. Since the pasta so obtained is evidently non-sterile according to the US Patent 4.529.609 teaching the pasta obtained from a salted dough is precooked by saturated steam at a temperature not exceeding about 100°C and then cooled and air dried. According to another technique of the prior art it is provided a pre-cooking step by superheated heat for freshly prepared pasta having a moisture content in the 25% to 32% range. However, the sterile condition thus provided for the product is subsequently defeated by the drying and packaging operations. It has therefore been proposed of packaging the pasta, as freshly prepared, into suitable containers, and then carrying out a heat sterilization step either before or after sealing the containers. This technique, while providing for a sterile product, is not devoid of some serious drawbacks. In fact, where heat sterilization is completed prior to the container sealing, despite the latter being immediate, there still exists a risk of losing, or at least significantly lowering, the degree of sterilization imparted to the product. Moreover, the process is of necessity a discontinuous one, and as such, unsuitable for application on an industrial scale. Where heat sterilization is carried out after sealing the containers, it must be protracted some time at a high temperature level to ensure that a safe sterilizing temperature is also achieved at the package core. Thus, the product is sterilized, but inevitably deprived of those organoleptic and physical properties which are recognized to constitute the discriminating factor in assessing the product quality and its acceptability from the merchandizing standpoint. Overcoming these and other drawbacks of the prior art is the problem that underlies this invention, the invention being therefore directed to a method of making sterile cooked, or part-cooked, long-life pasta products continuously on an industrial scale, which pasta retains unaltered all the physical, organoleptic, and nutritional characteristics of conventionally made dry pasta. This problem is solved, according to the invention, by a method comprising a step of continuous preparation of a dough from flour and water (and other possible ingredients), and being characterized in that it comprises the following steps carried out on a continuous basis: introducing said dough into a cooker-sterilizer wherein a temperature in the 90°C to 170°C range is maintained by means of satured steam; working said dough into a continuous shape of small thickness such as 0.2 to 2 mm immediately on its entering said cooker-sterilizer; advancing said continuous shape through the cooker-sterilizer, in which it is made to reside for a sufficiently long time period to have it throughly heat sterilized and cooked by the saturated steam; taking the so sterilized and cooked dough out of said cooker-sterilizer and transferring it into an aseptic vacuum pan, while maintaining said dough in a sterile condition; introducing the dough, as sterilized and cooked, into said aseptic vacuum pan to remove the excess moisture as absorbed during the sterilization step and at the same time have it cooled; taking the presently cooled dough out of said vacuum pan to a forming step, while still maintaining it in a sterile condition; and forming said dough into a desired pasta pattern e.g. spaghetti, noodles, lasagne and short cut pasta with said pasta held in a sterile enviroment. The prevision for heat processing with saturated steam at a high pressure a dough which has been reduced to a small thickness, e.g. preferably a thickness varying between 0.2 mm and 2 mm, enables a selected temperature level for optimum sterilization of the dough to be immediately and reliably attained throughout the dough. As a result, full de-activation of the enzymes and wipe-out of the heat-sensitive bacterial charge can be achieved within a short time. In addition, optimum gelling of the amylopectines can be achieved along with optimum cooking of the dough, which will exhibit enhanced homogeneity and firmness properties and have changes of its organoleptic and nutritional properties inhibited. In accordance with another aspect of this invention, in order to reduce the dough to a continuous shape of small thickness, it is arranged for it to be subjected to drawing or rolling out directly on entering the cooker-sterilizer, to yield a pasta pattern similar to freshly prepared spaghettis or sheet dough, respectively. Advantageously and in accordance with a further aspect of this invention, the cooker-sterilizer is arranged to extend along an essentially vertical direction, and the continuous dough patterns are fed into said cooker by letting them fall freely therethrough. The features and advantages of the invention will become more clearly apparent from the following detailed description of a method embodying it, to be taken in conjunction with the accompanying drawing which shows, by way of example and not of limitation, a diagramatic layout of a system for implementing the method. Separate flows of water, and flour such as wheat flour or similar pulverized ingredient, are conveyed from a silo 1 into a volumetric batcher 2, whence they are passed into a centrifugal mixer 3. From this mixer 3, wet flour is fed continuously into a kneader 4, from which the resulting dough, which has a moisture content in the 25% to 32% range by weight, is discharged into an auger press 5 suitably cooled to prevent any heating of the dough during its residence therein. By means of this press 5, the dough, which has been kneaded cold, is urged through a conduit 6 toward a cooker-sterilizer 7 laid out in a mainly vertical direction. Inside this cooker-sterilizer 7, a temperature of between 90°C and 170°C is maintained by means of saturated steam, which is supplied into it over a line 8. The cold dough, or better, the dough at the same temperature that it had within the auger press 5, is fed continuously into the cooker-sterilizer 7, and directly on entering it, said dough is worked into a continuous shape or pattern of small thickness, preferably within the range of 0.2 mm to 2 mm. For this purpose, at the inlet to the cooker-sterilizer 7, there is mounted, for example, a conventional extruder 9 which is suitably cooled and through which the dough, having substantially the same temperature and moisture content that it had while within the auger press, is extruded continuously in the pattern of plural threads or fresh spaghettis having a diameter of 0.2 to 2 mm. Alternatively, at the inlet to the cooker-sterilizer 7 there may be mounted a rolling apparatus effective to form the dough into a sheet, again having a thickness of 0.2 to 2 mm. While reduced to such continuous shapes, the dough is fed into the cooker-sterilizer 7 by letting it fall freely therethrough. Within the cooker-sterilizer 7, the continuous dough shapes or patterns undergo heat sterilization and cooking by saturated steam under a pressure. The residence time within said cooker, the saturated steam temperature, and the reduced thickness selected for the patterns (either spaghettis or sheet) are preset to provide for a uniform and homogeneous optimum sterilization thereof. A large contribution to this important result comes from that the dough has undergone no amount of heating in any way comparable to even the slightest pre-cooking within the auger press. Accordingly, it is highly important that the press 5 and extruder 9 be cooled. The dough, thus sterilized and cooked, which begins to re-establish itself at the bottom 7a of the cooker-sterilizer 7, is fed continuously into the auger press 10, which is kept aseptic and in which it is ultimately cooked to be then taken to an aseptic vacuum pan 11. The last-mentioned vacuum pan is also laid out mainly in a vertical direction, and the dough is fed continuously thereinto under the urge from the auger press 10 via a conduit 12. Directly on entering the aseptic vacuum pan 11, the dough is worked into a continuous shape or pattern having a reduced thickness of 0.2 to 2 mm, in exactly the same manner as on entering the cooker-sterilizer 7. Here too the continuous pattern may be obtained through the use of an extruder or a rolling apparatus. Within the aseptic vacuum pan 11, excess moisture is removed from the continuous dough patterns (either spaghettis or a sheet), as absorbed during the sterilization step, and such patterns are cooled at the same time. By control of the amount of the vacuum within the vacuum pan 11, the amount of residual moisture can be controlled in the product to be discharged from said vacuum pan. The bottom end 11a of the aseptic vacuum pan 11 opens to an aseptic auger press 13, into which the dough which has re-established itself at the bottom of the vacuum pan is discharged continuously. Within the aseptic press 13, the dough, now sterilized, cooked, cooled, and reduced to a set moisture content, undergo final kneading while being urged toward a forming unit 14, also kept aseptic. The latter unit may comprise a conventional extruder or a rolling apparatus, from which the various patterns or types of long or short pasta are delivered either by extrusion or rolling out in a sterile and cold condition at a predetermined moisture content. The extrusion or rolling takes place in a sterile environment, and in a sterile environment is also carried out the successive step of packaging the pasta products (e.g. spaghettis, noodles, lasagne, short cut pasta such as various macaroni sizes, including small sizes for pasta soups) inside sterilized containers.

Claims: A method of making sterile cooked, or part-cooked, long-life pasta products on a continuous basis, comprising a step of continuous preparation of a dough from a flour and water, as well as other possible ingredients, characterized in that it comprises the following steps carried out on a continuous basis: introducing said dough into a cooker-sterilizer wherein a temperature in the 90°C to 170°C range is maintained by means of saturated steam; working said dough into a continuous shape of small tickness such as 0.2 to 2 mm immediately on its entering said cooker-sterilizer; advancing said continuous shape through the cooker-sterilizer, in which it is made to reside for a sufficiently long time period to have it thorougly heat sterilized and cooked by the saturated steam; taking the so sterilized and cooked dough out of said cooker-sterilizer and transferring it into an aseptic vacuum pan, while maintaining said dough in a sterile condition; introducing the dough, as sterilized and cooked, into said aseptic vacuum pan to remove the excess moisture as absorbed during the sterilization step and at the same time have it cooled; taking the presently cooled dough out of said vacuum pan to a forming step, while still maintaining it in a sterile condition; and forming said dough into a desired pasta pattern for example spaghetti, noodles, lasagne and short cut pasta with said pasta held in a sterile environment. A method according to Claim 1, characterized in that in order to work the dough into said continuous shape, the dough is subjected to extrusion immediately on entering the cooker-sterilizer, to obtain a pattern like that of freshly prepared spaghetti or sheet dough. A method according to Claim 1, characterized in that to work the dough into said continuous shape, the dough is subjected to rolling out immediately on entering the cooker-sterilizer. A method according to Claim 1, characterized in that the cooker-sterilizer is laid out along a vertical direction, and that the continuous dough patterns having reduced thickness such as 0.2 to 2mm are fed into said cooker by letting them fall freely therethrough. A method according to Claim 1, characterized in that at the outlet from said cooker-sterilizer and during the transfer movement toward said aseptic vacuum pan, a dough is re-created from said sterilized and cooked continuous patterns. A method according to Claim 5, characterized in that at the inlet to said vacuum pan, the sterilized and cooked dough is worked into a continuous pattern having reduced thickness such as 0.2 to 2 mm by a selected operation from extrusion and rolling out. A method according to Claim 6, characterized in that at the outlet from said aseptic vacuum pan, a dough is re-created from said continuous patterns having reduced thickness, said dough being subjected to additional kneading during its transfer to said forming step. A method according to Claim 1, characterized in that prior to being introduced into said cooker-sterilizer, the dough is subjected to cold kneading. A method according to Claim 1, characterized in that the pasta patterns formed in a sterile environment are packaged in sterilized containers, again in a sterile environment.

Inventors: CATELLI CAMILLO, CATELLI, CAMILLO
Applicants: ROSSI & CATELLI SPA, ROSSI & CATELLI S.P.A.
Application year: 1989
Main classification: A23L1
IPC codes: A23L1, A21C11