GB2172787A

GB2172787A - Method of producing textured food

Info

Publication number: GB2172787A
Application number: GB08606888A
Authority: GB
Inventors: Kiyoe Sato; Hisashi Nozaki
Original assignee: Kibun KK
Current assignee: Kibun KK
Priority date: 1985-03-29
Filing date: 1986-03-20
Publication date: 1986-10-01
Also published as: CA1299428C; DE3610402A1; FR2579422B1; FR2579422A1; GB2172787B; GB8606888D0; JPS61224940A; DE3610402C2

Abstract

A meat-like textured protein food is produced by processing a soy-bean flour and/or okara (by-product obtained in the making of soy-bean curd or soy milk) consisting of 8 to 38 wt% protein and not greater than 7 wt% fat using a twin-screw extruder having an orifice and provided with a cooling die. The protein, fat and water contents of the material are adjusted, the water content is preferably between 50 and 60%, and the material is extruded by the twin-screw extruder with the barrel temperature preferably set, between 175 DEG C and 205 DEG C thereby obtaining a food having a meat-like texture.

Description

SPECIFICATION Method of producing textured food The present invention relates to a method of producing a textured food. More particularly, the present invention pertains to a method of producing a processed food having a meat-like texture from soy-beans.

In conventional methods of producing meat-like textured foods from soy-beans, extruders have heretofore been employed to obtain ground, meat-like, granular or fibrous fragmentary food materials which give the sensation of eating real meat. In another conventional method, soy-bean protein is dissolved in an alkaline solution and is then fiber-spun by an extruder into a product with fibrous texture similar to muscular fibers. However, the product obtained by this process is not satisfactory and must be further processed to obtain the consistency necessary to give the sensation of eating real meat. The products obtained by these conventional methods are able to give the sensation of eating real meat when they are granular or fragmentary, but fail in giving that sensation when they are in the shape of a relatively large lump.This is because the extruders employed are of the single-screw type and the water content of the materials must be relatively low. Researches into the application of twi n-screw extruders have recently advanced, and this type of extruder has been introduced into the food industry to process raw materials having relatively high water contents. Certain methods have already been proposed for texturing proteins such as defatted soy-bean flours having relatively high water contents by utilizing twin-screw extruders.

With these proposed methods, the degree to which the proteins are textured is so small that the texture of the products is far from the desired meat-like consistency.

In view of the above-described circumstances, it is a primary object of the present invention to provide a method of producing a heterogeneousíy textured meat-iike processed food from soy-beans, particularly a soy-bean flour and/or okara (by-product from the making of soy-bean curd or soy milk), using a twin-screw extruder.

The present inventors made various studies and have successfully found that, when an extruder having an orifice and provided with a cooling die is used, a meat-like texture food can be obtained when the protein and fat contents of a soy-bean material are specified such that they respectively fall within predetermined ranges, thus accomplishing the present invention.

The present invention, therefore, provides a method for producing a textured food characterized in that a soy-bean flour and/or okara having 8 to 38 wt%, preferably 16 to 30 wt% protein and not greater than 7 wt%, preferably not greater than 4 wt% fat is processed by employing a twin-screw extruder having an orifice and provided with a cooling die.

The present invention will be described hereinunder in detail.

The present inventors first carried out a texturing test by employing a soy-bean flour (12.5 % water, 35.3 % protein, and 19.0 % fat) and a twin-screw extruder having an orifice and a cooling die, at a barrel temperature of 1 700C, and found that it was difficult to obtain the required texture. Since the fat content in the soy-bean flour was seen to be too high, the present inventors continued the examination employed defatted raw materials. More specifically, a soy-bean flour and okara (80.3 % water, 6.5 % protein, and 4.0 % fat) were dried and defatted to prepare a defatted dry okara (11.1 % water, 36.1 % protein, and 1.8 % fat) and a defatted soy-bean flour (12.9 % water, 46.3 % protein, and 2.1 % fat).Various amounts of water were added to these raw materials and mixed together to produce five kinds of raw-material sample respectively having final water contents falling within a range of from 45% to 70%, as shown in Table 1.

Then, a texturing test was carried out on these samples by employing the same machine as that in the case of the first soy-bean flour at various barrel temperatures, i.e., from 150 to 21 00C.

As a result, the defatted soy-bean flour containing 46.3 % protein was transformed into a lump having no linear fiber or fibrous property in any of the aforementioned conditions.

Table 1

Barrel temperature ( C) 150 160 170 180 190 2000 210 Water content No directional No directional -- -- Linear Linear - 45 property, property, fibers fibers easyto easyto break break Heterogeneous Heterogeneous Linear 50 -- ditto Linear Linear meat-like meat-like fibers, fibers fibers fibers fibers scorched Heterogeneous 55 -- -- ditto meat-like ditto ditto ditto fibers Lumpwithout 60 -- -- -- directional ditto ditto ditto property stickylump stickylump stickylump 70 -- -- -- -- without without without directional directional directional property property property From the results shown in Table 1, the present inventors have found that a heterogeneous meat-like extruded product can be obtained having a water content of 55% when the barrel temperature is 180"C and a water content of 50 to 60% in the case of barrel temperatures of 190"C and 200 C: Next, the conditions of a barrel temperature of 180"C and a water content of 55 % which showed excellent results in the aforementioned test were further examined. More specifically, various amounts of soy oil were added to, and uniformly mixed with, the defatted okara as shown in Table 2 to prepare rawmaterial samples, and a texturing test was carried out on these samples in a manner similar to the above.

As a result, it has been found that heterogeneous meat-like properties can be obtained when the fat content is not greater than 6 %, preferably not greater than 4 %.

Table 2 Fat content (%) Fiber condition of extruded product 0.5 heterogeneous meat-like lump 1.0 ditto 2.0 ditto 4.0 ditto 6.0 ditto 7.0 low directional property 8.0 crumbly lump without directional property Next, a vegetable fibrous material was mixed with dried okara containing 55 % water and 1.2 % fat at various rates to prepare raw-material samples differing in protein content as shown in Table 3, and these samples were subjected to a test similar to the above at a barrel temperature of 1 900C. Table 3 shows the results of the test.

Table 3 Protein content (%) Fiber condition of extruded product 7 no fibrous aspect 10 heterogeneous meat-like lump 16 ditto 21 ditto 24 ditto 30 ditto 34 ditto 38 slightly linear fibers 41 linear fibers From the results shown in Table 3, it has been found that extruded products can possess the characteristic property of exhibiting a meat-like texture when the protein content is between 10 % and 34 %, preferably 16 % and 30 %.

Finally, a test was carried out on the protein aspect. A vegetable fibrous material was added to a defatted soy-bean powder such as to obtain a specified protein content of 25 %, and this powder was subjected to a heat treatment to prepare raw-material samples differing in NSI (nitrogen solubility index), the water content of these samples being adjusted to 60 %. The result of this test showed that when the NSI was no greater than 64, the desired physical properties were obtained.

As has been described above, the present invention provides a method wherein a soy-bean material having a specified protein content of 8 to 38 wt%, preferably 16 to 30 wt%, and a specified fat content of 7 wt% or less, preferably 4 wt% or less, is processed by a twin-screw extruder having an orifice and a cooling die at a barrel temperature of 175 to 205"C, preferably 180 to 200"C, whereby it is possible to obtain an adequately textured meat-iike processed food. Thus, it is possible, according to the method ot the present invention, to obtain a processed food containing textured vegetable protein which has characteristic toughness and flavor in a single step using a twin-screw extruder by specifying the protein and fat contents of the material.

The following Examples are provided for further illustration of the present invention.

EXAMPLE 1 An extrusion experiment was carried out by employing a twin-screw extruder having an orifice and provided with a cooling die. As the raw material, defatted and dried okara (10.9 % water, 48.1 % protein, and 2.2 % fat) was employed and supplied to the extruder from a feeder. As to the water content, water was supplied by a peristaltic pump so that the water content eventually reached 55 %. The barrel temperature was set at 180 C, and the screw speed at 60 rpm. The temperature of water for cooling the die was 2 to 6"C.

The extruded product obtained under thins set of conditions had heterogeneous properties which were extremely similar to those of real meat.

EXAMPLE 2 An extrusion experiment was carried out by employing completely the same material and apparatus as those employed in Example 1 except for the water content, which was set at 60 % in this Example. The barrel temperature was set at 200 C, and the screw speed at 120 rpm. The product thus obtained had physical properties similar to those of real meat.

Claims

1. A method of producing a textured food characterized in that a soy-bean flour and/or okara (byproduct obtained in the making of soy-bean curd or soy milk) containing 8 to 38 wt% protein and'not greater than 7 wt% fat is processed by employing a twin-screw extruder having an orifice and provided with a cooling die.

2. A method according to Claim 1 wherein the protein content is between 16 wt% and 30 wt%, and the fat content is not greater than 4 wt%.

3. A method according to Claim 1 wherein the barrel temperature of said twin-screw extruder is set at between 175"C and 205"C.

4. A method according to Claim 1 wherein the water content of the material which is to be extruded is between 50% and 60%.