JPH0420583B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for continuously treating high-temperature pasteurized soy sauce with a porous tabular membrane after pasteurization, preferably immediately after the pasteurization during the production of soy sauce. [Prior Art] The outline of the soy sauce manufacturing process consists of raw material processing, koji making, mash production by mixing, pressing and filtration, pasteurization, and post-processing. Press-filtered raw soy sauce is usually pasteurized at around 80℃. This pasteurization process is carried out to sterilize microorganisms, inactivate enzymes, and add fire to raw soy sauce, which has a low aroma, giving it a strong soy sauce-like aroma. After pasteurization,
Usually, by letting it stand for 2 to 10 days and allowing it to cool naturally, protein coagulum, phosphates, etc. will precipitate and become a pasteurized material. After a predetermined number of days have elapsed, the precipitate and supernatant are separated, and the supernatant is filtered through diatomaceous earth to improve transparency and remove fine solid matter. On the other hand, soy sauce is usually 70~
It contains 90% of the soy sauce, and the soy sauce is further recovered by returning it to the press-filtration process. However, after pasteurization, the taste and aroma of soy sauce differs from that of raw soy sauce, so there is a problem with this kind of recovery. In some cases, diatomaceous earth filtration is also performed to recover soy sauce from this sedimentation tank, and the disposal of diatomaceous earth, which is generated in large quantities and contains putrefactive components, has become a problem in recent years from the viewpoint of environmental problems. In order to solve these problems, a method is known in which raw soy sauce is pasteurized, the dried rice produced is filtered through a hollow fiber-like precision filtration membrane, and the soy sauce is recovered from the dried rice (Japanese Patent Application Laid-Open No. 1983-1999). Publication No. 45173,
Special Publication No. 60-12015). [Problems to be Solved by the Invention] However, the hollow fiber membrane has a low recovery rate of soy sauce from pasteurized soy sauce, and is economically disadvantageous. In addition, hollow fiber membranes have poor pressure resistance and have limitations in operating conditions, and are particularly difficult to process at high temperatures. In addition, these methods have the problem that the soy sauce is recovered from the lowered liquid by separating the lowered liquid from the supernatant liquid, which requires a long period of standing, and the process is complicated and uneconomical. Ta. Furthermore, a large number of tanks are required for long-term storage, which takes up space and has the disadvantage of poor productivity. There is also a known method in which pasteurized soy sauce is directly treated with an ultrafiltration membrane (Japanese Patent Publication No. 1360/1983), but because the pore size of this membrane is too small, nitrogen compounds, which are the components of umami, are removed. However, there was a problem that the taste deteriorated. [Means for Solving the Problems] The present invention has been made to solve the problems, and by treating pasteurized soy sauce at high temperatures using a specific microfiltration membrane, sufficient Soy sauce with umami can be economically produced. That is, the present invention provides a method for treating pasteurized soy sauce, which comprises bringing pasteurized soy sauce into contact with a porous tabular membrane having an average pore diameter of 0.1 to 0.6 μm at a liquid temperature of 40 to 80° C. and filtering the same. The soy sauces to which the present invention is applied are soy sauces that require pasteurization, such as light, dark, and tamari soy sauces. In the present invention, by subjecting pasteurized soy sauce to precision filtration immediately after pasteurization, protein coagulation, phosphates, microorganisms, etc. in pasteurized soy sauce are removed, and soy sauce containing valuable components such as nitrogen compounds is filtered. It can be recovered on the liquid side with a high yield of about 90-95%. The porous membrane used in the present invention has an average pore diameter of 0.1
It is a precision filtration membrane with a micropore structure of ~0.6 μm. If the average pore diameter is too small, nitrogen compounds that become umami components are removed too much and the taste deteriorates, which is not preferable. On the other hand, if the average pore diameter is too large, unnecessary substances such as coagulated substances will permeate into the filtrate side, and sludge will gradually occur in the obtained filtrate, which is not preferable. Further, the film thickness is usually 50 to 200 μm. Since the porous membrane has a flat plate shape, it has an advantage over hollow fiber membranes in that it can increase the filtration flux even for highly viscous liquids. Modules equipped with this membrane include plate-and-frame type and spiral type. Furthermore, the membrane material is preferably one having heat resistance since the liquid is processed at high temperatures, and examples thereof include hydrophobic membranes such as polytetrafluoroethylene (PTFE), polyethylene, and polypropylene. In addition, the filtration operation method of the membrane module is preferably a cross flow method (circulation filtration method) in order to obtain a stable filtration flux, and the linear velocity during circulation is usually 0.5 to 2.
m/sec, preferably 1 to 1.5 m/sec. In addition, the processing temperature is preferably as high as possible, that is, a temperature that is as low as possible from the heating temperature during pasteurization, usually 40 to 80 degrees Celsius, preferably 50 to 60 degrees Celsius.
It is ℃. If the temperature is too low, the viscosity of the liquid will increase, resulting in a decrease in processing capacity, which is not preferable. Further, the average pressure is usually 0.5 to 4 kgf/cm ² . [Effects of the Invention] The present invention uses a specific porous plate-like membrane to directly treat pasteurized soy sauce after pasteurization, thereby eliminating the need for recovery of soy sauce from the conventional pasteurization cage. There is no need to store the soy sauce in place, there is no need for a tank for standing it, and the soy sauce manufacturing process can be greatly shortened, making it economical. In addition, it is possible to obtain a product soy sauce with a high recovery rate and a high filtration flux in which the component composition, aroma, etc. of the soy sauce do not change at all. [Example] Examples and comparative examples of the present invention are listed below.
The present invention is not limited to this. Example Porous flat membrane with an average pore diameter of 0.2 μm (made of PTFE,
Nitto Denko Corporation: Product name: NTF-5200) plate-and-frame module (membrane area
0.38m ² ), the pasteurized soy sauce (liquid temperature: 60°C) immediately after pasteurizing (85°C) was heated to an average pressure of 3 kg.
f/cm ² , linear velocity 1.0 m/sec, concentration factor 20
It was processed so that the soy sauce recovery rate was 95%. Table 1 shows the analysis results of the properties of the filtrate.

[Table] The filtration flux is 110/m2^・h at the initial stage and ^10.5 /m2・h at the final stage (concentration magnification 20 times, soy sauce recovery rate 95%).
h, average was 48/m ² ·h. Comparative Example The same pasteurized soy sauce as in the example was filtered using a porous hollow fiber ultrafiltration membrane (nominal molecular weight cutoff 20,000, membrane inner diameter 1.1
mm, manufactured by Nitto Denko; product name NTU-3250-C1R)
The treatment was carried out under the conditions of an average pressure of 2 Kgf/cm ² and a linear velocity of 2.0 m/sec, but the concentration ratio was 3 times (soy sauce recovery rate 33
%). The analysis results of the properties of the filtrate are shown in Table 2.

【table】

[Table] The filtration flux is 45/m ² h at the initial stage, 8/m ² h at the final stage (concentration ratio 3 times, recovery rate 33%), on average.
It was 25/ ^m2・h. From these examples, it can be seen that in the comparative example, the recovery rate of soy sauce is low and the filtration flux is also low.

Claims (1)

[Claims] 1 The pasteurized soy sauce immediately after pasteurization is heated to a high liquid temperature of 40 to 80°C at the start of membrane treatment, and the average pore size is 0.1 to 80°C.
A method for processing pasteurized soy sauce, characterized by recovering product soy sauce with a high permeation flux by bringing it into contact with a porous flat membrane having a heat resistance of 0.6 μm.