JPS6156071A - Method of sterilizing raw material to be fermented - Google Patents

Abstract

PURPOSE:To prevent deposition of sludge, and to sterilize effectively a raw material to be fermented by steaming or boiling, by making the raw material to be fermented flow in the interior of a pipe consisting of a sintered metal, feeding steam from the outside into the interior. CONSTITUTION:The raw material P1 to be fermented, such as waste mollasses, etc. is made to flow in the interior of the pipe P consisting of a sintered metal, and steam is fed from the outside of the pipe P into the interior. Consequently, deposition of sludge during steaming or boiling will not occur, and a long-period use is made possible, and extraordinariness such as contamination by various germs are few because of neither precipitation nor deposition of sludge. Occurrence of noise is more reduced than a conventional method because low-pressure steam with 2.5-4kg/cm<2>G is used.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for sterilizing fermented raw materials by steaming.

More specifically, the present invention relates to a method for sterilizing fermentation raw materials, which is characterized by flowing the fermentation raw materials inside a metal tube made of sintered metal and supplying steam from the outside of the tube.

(Conventional technology) Fermentation when producing useful substances by fermentation methods.

In order to remove bacteria present in raw materials, a heat sterilization process using steam is usually used. Blackstrap molasses is widely used as one of the cheapest raw materials for fermentation.

(Problems to be Solved by the Invention) When blackstrap molasses is used as a fermentation raw material, a major problem is that a large amount of sludge (mud or sediment) is generated during heating and steaming and accumulates on piping and cypress wood.

In other words, the generated sludge is usually removed by centrifugation or sedimentation, but sludge adheres to and accumulates on steaming pipes and piping that are heated to high temperatures, causing bacterial contamination, so periodic decomposition and cleaning is necessary. It will stop moving.

(Means for Solving the Problems) As a result of extensive research into an effective steam sterilization method for fermentation raw materials that prevents sludge deposition, the present inventors discovered that steam is brought into contact with fermentation raw materials through pores in sintered metal. We studied a method of sterilizing and sterilizing the bacteria, and confirmed that it was an extremely effective method, and completed the present invention.

That is, the present invention involves a method of steam-sterilizing the fermentation raw material by flowing the fermentation raw material inside a tube made of sintered metal and supplying steam from the outside of the tube.

The inventors found that the vapor that came into contact with the light trail feed liquid through the sintered metal capillary condensed on the surface of the tube and formed a film of water, or that a thin layer of steam was formed on the surface of the tube, resulting in sludge. We conducted an experiment and confirmed that it had the expected effect.

Sintered metal is an element with countless capillaries made of sintered metal such as bronze or stainless steel, but it is a porous metal with large mechanical properties such as heat resistance and impact resistance.
It is used for filtration, dehydration, and foaming of various substances. However, there is no known method of using sintered metal for the purpose of steam sterilization of fermentation raw materials.

There are no particular limitations on the material, pore diameter, shape, etc. of the sintered metal used in the present invention, but it is convenient to use a cylindrical stainless metal with a pore diameter of 1 to 100 μm, preferably 10 to 20 μm. with sintered metal.

A fermentation raw material, such as molasses diluted with water (for example, 30 to 35% sugar concentration), is fed from one side of the prepared steaming tube. Low pressure steam is sent to the outside of the sintered metal steamer tube. The length of the steamer tube is determined to ensure a certain residence time. Sintered metal tubes can be used for part or all of the steamer tube. It is preferable to install a drain trap in order to discharge the vertical drain (pseudo condensation water) outside the sintered metal tube to the outside of the system.

(Effects) The advantages of the present invention are that when fermentation raw materials such as blackstrap molasses are used, there is no sludge attached during steam sterilization and it can be used for a long period of time, and since there is no sludge deposition, abnormalities such as bacterial contamination may occur. I can point out that there are few points.

Another great advantage is that the noise during sterilization is extremely low. In the case of conventional steam sterilization using a super jar or mixer, high pressure steam with a steam pressure cuff of ~10 kVcd G is used to maintain the temperature above 120°C, which is known to generate quite a lot of noise. However, in the case of the method of the present invention, compared to the conventional method, low-pressure steam (2.5 to 4 kg/CjiG) can be used, and therefore less noise is generated.

(Examples) Examples will be described below, but the present invention is not limited thereto.

Example 1 A steaming tube having the shape shown in FIG. 1 was prepared by having a sintered metal (stainless steel) element with a pore diameter of lOμ as an inner tube.

That is, a steaming tube with a structure in which fermentation raw materials were poured into a sintered metal tube and steam diffused from the outside into the inside through the pores of the sintered metal was fabricated. Setobi Toden was diluted with water and a solution set to a sugar concentration of approximately 35% was flowed at a flow rate of 0.8 nVHr.

The pressure (P2) of the steam supplied from the outside of the sintered metal tube was set higher than the pressure (PI) of this M electrolyte (P2>
Pl). That is, ΔP=P2-P, = 0.5-1.0
Heat sterilization (approximately 120°C) was performed under JIG conditions.

The scale (deposits) inside the steaming tube was measured after 2 hours of 120°C steaming and 100 hours of use, 50 times.

As a result, only a scale of about Q, 5 txm (forming a soft layer) was observed at the inlet, and a scale of about 1 to 1.5 fl (forming a fixed layer) at the outlet. Almost no scale deposition was observed other than coloring. As a control, a test was conducted under the same conditions using an ordinary stainless steel steaming tube instead of the sintered metal, and 5-7H scale deposits were observed in the tube after 168 hours of use.

Example 2 Firitubin molasses (sugar content 55% W/W') 15
After sending the tonne to a steaming tank and diluting it to 40°B
Through the sintered metal heating system shown in the figure, the temperature in the steamer tank is 1
At 20°C, the residence time of the molasses passed was about 8 seconds. Thereafter, the sugar solution was retained in the tank at 90°C for 4 hours, and after removing sludge components using a centrifuge, it was supplied to the culture process.

After carrying out this experiment 60 times over a period of approximately one month, the sintered metal heating section was disassembled and inspected, and almost no scale formation was observed.

On the other hand, as a control, heating was performed in a stainless steel double tube, and the
After repeating the experiment 60 times in a month, the heating section was inspected and scale adhesion of about 3rdR was observed all over the inner wall of the tube.

[Brief explanation of drawings]

FIG. 1 is an explanatory vertical cross-sectional view of a steamer tube using a sintered metal element for use in the present invention.

Claims (1)

[Claims] (1) A method for sterilizing fermentation raw materials by steaming, which is characterized by flowing the fermentation raw materials inside a tube made of sintered metal and supplying steam from the outside of the tube.