JPH0556942B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an extruder, particularly an extruder for food processing, which is used when extruding a continuous structured molded product using protein-based food raw materials. It is something.

[Prior art]

Food processing using extruders has a long history, appearing in literature as early as the late 1800s. Initially, it was used for dehydration and juice extraction, but gradually it came to be used for processing and molding purposes as well. That is, the material is fed into the screw through the supply port, kneaded, heated, and sent forward, and then extruded through the die to give the product its specific shape.

Extruders are roughly classified mechanically into single-screw extruders, which have one screw, and twin-screw extruders, which have two screws. In addition, the twin-screw extruder has two
There are various classifications depending on the degree of engagement of book screws and the direction of rotation. Conventionally, extruders were simply compressed and
It has been thought of as a machine with kneading and swelling functions, but recently it has been actively used to utilize all the phenomena that occur inside an extruder, such as compression, mixing, kneading, shearing, melting, sterilization, chemical reactions, swelling, and molding. This is attracting attention.

A schematic diagram of a conventionally used extruder is shown in FIG. This is the simplest extruder, with 3 being a hopper, from which raw materials are supplied. 1 is a cylindrical cylinder barrel, 2 is a screw rotating within the barrel 1, and the screw 2 is rotated by a drive device. The raw material is compressed and kneaded by the rotation of the screw 2, conveyed, and extruded through a die hole of a die 4 provided at the outlet of the barrel 1. The screw tip 2' has a conical shape.

The barrel 2 may be heated from the outside by an electric heater or the like, or the temperature may be controlled by flowing a temperature regulating medium into a gap formed inside the barrel. Furthermore, the principle is fundamentally the same for those having a forced feed hopper and twin screw extruders having two screws.

FIG. 3 shows the tip of the twin-screw extruder. The die 4 of this extruder has two circular die holes 5 as shown in FIG. 4, but in the case of a slit die 4' as shown in FIG. ′. l shown in Figure 3
is called the "length of the die hole," d shown in FIG. 4 is called the "diameter of the die hole," and T shown in FIG. 5 is called the "thickness of the die hole."

Conventionally used die 4 (or 4' etc.)
In this case, the length l of the die hole does not exceed 10 times the diameter d of the die hole or the thickness T of the die hole (hereinafter generically referred to as the diameter d of the die hole for simplicity).

The reason for this is that foods traditionally processed using extruders have good moldability, such as snacks whose main ingredient is starch. This is because continuous molding was not necessary because the product came out of the die or was made into a granular product at the exit of the die.

However, recently, attempts have been made to obtain continuous meat-like products using defatted soybean flour as a raw material, and attempts have been made to extrude high-moisture food raw materials by taking advantage of the extremely good material transportability of twin-screw extruders. I'm starting to be able to do it. In such cases, if a conventional die with a die hole length l of 10 times or less than the die hole diameter is used, when processing defatted soybean flour, the product will not be continuous and will be powdery or It is ejected from the die in the form of granules. In addition, in the case of high-moisture raw materials, the processing temperature may exceed the boiling point of water, but the steam pressure causes the product to not only not be continuous, but also to cause traps within the product's tissue structure to break down. This will cause the moisture to escape.

[Purpose of the invention]

The present invention eliminates the above drawbacks and uses defatted soybean flour,
The object of the present invention is to provide an optimal extruder for producing meat-like structured protein using livestock meat with a high moisture content as a raw material.

[Structure of the invention]

The present invention has a cylindrical cylinder barrel, a screw rotating within the barrel, and a die attached to the tip of the barrel, and the die has a die hole extending longitudinally in the center of the barrel. The length of the die hole is formed to be 15 to 40 times the diameter of the die hole or the thickness of the die hole, and a jacket for temperature adjustment is provided along the periphery of the die hole. It has the following characteristics.

〔Effect of the invention〕

According to the present invention configured as described above, a temperature adjustment jacket is provided around the die hole, and a screw is used to mix, melt, and heat the material into the die hole, which is longer than the diameter of the die hole (thickness of the die hole). By passing denatured food raw materials such as defatted soybean flour,
This method has an excellent effect in that a structural change occurs in the same raw material and a continuous meat-like product can be reliably formed.

〔Example〕

The present invention will be explained below with reference to an embodiment of a die shown in FIG. The die of this embodiment consists of three parts: a die 7 fixed to the cylinder barrel 1 by a die holder 6, and dies 8 and 9 connected to the die 7, respectively. The die 7 has a tapered hole 7A that gradually becomes smaller continuously from the hole into which the screw 2 of the cylinder barrel 1 is inserted, and a cylindrical die hole 7B that follows the taper hole 7A. die 8 and 9
has linear die holes 8B and 9B with the same diameter d as the die hole 7B. In addition, each die 7, 8, 9 has a jacket 7C, 8C, 9C.
is provided to allow liquid to flow at a constant temperature. In addition, die holes 7B, 8
The distance between B and 9B is called the length l of the die hole.

Now, the raw material supplied to the barrel 1 from a supply section (not shown) is sent toward the die 7 while being compressed, mixed, melted, and thermally denatured by the screw 2 and the barrel 1. While passing through the die holes 7B, 8B, 9B of each die, a reaction, so-called texturing, takes place and a continuous meat-like product is formed. It is then sent to the tip of the die 9, cooled and shaped into an extrudate, and then passed through the die 9.
extruded from.

The reaction at this time requires a rather long time, and the structure formed by changing the cross-sectional shape of the die after the reaction has started is destroyed, so the distance from the reaction start point to the die exit is approximately Equal cross-sectional shape and dimensions are required. That is, die hole 7B
The above reaction, cooling, and shaping are performed while passing through the die hole, and the length l of the die hole is inevitably larger than the diameter d of the die hole. The inventor made various prototype dies and conducted experiments, but when extruding a meaty textured protein using defatted soybean flour as a raw material,
A good product could be obtained when the diameter was 20 times or more, and the best product was obtained when the diameter was 35 times. Also, the temperature near the die exit at this time was 70°C.

Of course, the length changes depending on the composition such as the moisture content of the food raw materials used, so it is desirable that the die can be assembled to various lengths by combining a plurality of dies as in the embodiments.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a die showing an embodiment of the present invention, Fig. 2 is an explanatory view of an extruder, Fig. 3 is a sectional view of the die, and Figs. 4 and 5 are front views of the die. . 1: cylinder barrel, 2: screw, 7,
8, 9: Die, 7B, 8B, 9B: Die hole, l:
Length of die hole, d: Diameter of die hole, T: Thickness of die hole.

Claims (1)

[Claims] 1. It has a cylindrical cylinder barrel, a screw that rotates within the barrel, and a die attached to the tip of the barrel, and the die has a die hole extending in the longitudinal direction in the center thereof, The length of the die hole is formed to be 15 to 40 times the diameter of the die hole or the thickness of the die hole, and a jacket for temperature adjustment is provided along the periphery of the die hole. Extruder for food processing.