JPH0338857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly efficient method for sterilizing powder and granular materials of water-soluble natural polymer substances.

Water-soluble natural polymer substances have viscosity, gel-forming properties,
It has unique properties such as emulsion stability, water retention, and binding properties, and is widely used for food and industrial purposes. However, since it is a natural product, problems such as contamination with microorganisms such as bacteria and mold and resulting spoilage cannot be avoided, and it is essential to thoroughly sterilize it, especially when used in foods.

Many methods have been proposed for sterilizing powder and granular materials, but each method involves difficult problems.
In other words, gas sterilization has disadvantages such as residual sterilizers in food and toxicity, ultraviolet sterilization has low efficiency due to insufficient penetration of ultraviolet rays, and microwave sterilization has disadvantages such as restrictions on the form of raw materials and high cost, so it is not used. Rare. Furthermore, heat sterilization, which is relatively commonly used, processes spore-formed bacteria in conditions with little moisture, so it requires harsh conditions such as heating at 100°C or higher for several minutes. Therefore, depending on the substance to be treated, especially water-soluble natural polymer substances, many of them lack thermal stability, which poses the problem of easily causing deterioration of physical properties. Furthermore, solvent sterilization such as alcohol is less effective against dormant bacterial spores.

Many attempts have been made to increase the sterilization effect by coexisting various substances during sterilization treatment. For example, sterilization efficiency is improved by coexisting alcohol with organic acids, amino acids, proteins, surfactants, sugars, etc. It has been known. However, this method requires a large amount of coexisting substances, which has drawbacks such as changes in the inherent performance of the object to be sterilized.
Also, depending on the combination of the material to be treated and the coexisting substances, for example, if a large amount of protein or sugar coexists when treating natural polysaccharides, these substances may act protectively and reduce the sterilization efficiency. After all, the effects of coexisting substances vary depending on the substance to be sterilized, the species of bacteria, the type and amount of coexisting substances, etc., and the combination must be selected depending on each case.

In view of the above-mentioned current situation, the present inventors conducted research to develop a highly efficient sterilization method for powder and granules of water-soluble natural polymer substances. By adding trace amounts of commonly assimilated sugars such as glucose and sucrose as coexisting substances and arranging appropriate temperature and time conditions, highly resistant bacterial spores germinate once, making them susceptible to external environmental factors. It was discovered that the efficiency of sterilization can be dramatically increased by sterilization.

The present invention provides powder and granular materials of a water-soluble natural polymer substance,
For water and powder with a specific moisture content of 0.4 to 1.0
Add 0.025% or more monosaccharides or disaccharides, 20 to 40
This is a method for sterilizing water-soluble natural polymer substances, which is characterized by performing sterilization treatment after mixing at ℃ for 4 hours or more.

In the present invention, the specific water content is a value obtained by dividing the water content of a substance by the water content when equilibrium is reached when the substance is placed in a saturated steam atmosphere, and a high specific water content provides favorable conditions for the growth of microorganisms. If the moisture content (constant depending on the substance) at equilibrium with a saturated steam atmosphere is determined, the specific moisture content can be converted to moisture based on the ratio with that value, and the specific moisture content can be adjusted using a normal moisture adjustment method.

According to the method of the present invention, it is possible to significantly improve the sterilization efficiency, and a hygienic water-soluble natural polymer substance with excellent performance can be obtained.

In the present invention, ultraviolet irradiation, superheated steam, dry heat,
Any sterilization method can be used, such as solvents. The monosaccharide or disaccharide used in the present invention may be any sugar that can be generally assimilated, such as glucose, fructose, sucrose, and lactose.

Examples of water-soluble natural polymer substances include seaweed extracts such as agar, fur-cerelan, carrageenan, alginic acid or its salts, natural polymer substances present in plant seeds such as guar gum, locust bean gum, and tamarind gum, gum arabic, and gum karaya. Examples include plant exudates, plant extracts typified by pectin, water-soluble polymeric substances derived from animals such as gelatin and casein, and fermentation products such as xanthan gum, sclero gum, and pullulan. Both crude products and purified products can be used.

When carrying out the present invention, water in an amount such that the specific moisture content is 0.4 to 1.0 and 0.025% or more of a monosaccharide or disaccharide relative to the powder are added to a powder or granule of a water-soluble polymeric substance. It is preferable that the monosaccharide or disaccharide is dissolved in water, and this solution is added to the powder by spraying.

The reason for adding water to powder and granules is to temporarily provide moisture necessary for germination of microbial spores, since powder and granules generally have a low water content and are unsuitable for the growth of microorganisms as they are. For this purpose, it is necessary to set the specific moisture content to 0.4 or more. If the specific moisture content exceeds 1.0, the surface of the powder particles will dissolve and swell, making it impossible to maintain the shape of the powder particles and hindering fluidization. Generally assimilated carbohydrates such as glycose and sucrose exist, and microorganisms grow under certain conditions of temperature and moisture, but according to the research of the present inventors, but
Sufficient growth will occur if the amount is 0.025% or more, preferably 0.03% or more, and even if this small amount of carbohydrate is present, the original performance of the water-soluble natural polymer substance will not be impaired.

Note that the ratio of monosaccharides or disaccharides is preferably 1.5% or less. If the ratio is higher than this, the gel properties, viscosity characteristics, etc. of the water-soluble natural polymer substance may change.

This mixture is then mixed for at least 4 hours at 20-40°C. If the temperature is lower than 20°C, microbial spores will not germinate sufficiently, and if it exceeds 40°C, the growth of microorganisms will be inhibited, which is not preferable. In order to germinate microbial spores, it is necessary to maintain the temperature at 20 to 40°C for 4 hours or more, and to mix continuously or intermittently during this time. In the present invention, these pretreatments are essential in order to facilitate the sterilization of bacterial spores and the like contained in the water-soluble natural polymeric substance.

After pretreatment, when the mixture is subjected to the above sterilization treatment,
Contaminating microorganisms can be almost completely killed. This is because the microorganisms in the pretreated powder are easily affected by the addition of chemicals such as alcohol, external environmental factors such as heat, steam, and radiation, and are easily killed.

Example 1 10 kg of locust bean gum powder was placed in a conical blender, and a solution of 4 g of sucrose dissolved in 1.5 of pure water was sprayed to bring the specific moisture content to 0.7, and the mixture was heated at 30°C.
The mixture was mixed for 10 hours. The pretreated locust bean gum was sterilized with 70% ethyl alcohol, and then dried under reduced pressure to remove the alcohol content to obtain powdered locust bean gum. While the general number of viable bacteria in the raw material powder was 5.6 x 10 ³ cells/g, it was 120 cells/g after the sterilization treatment. There was no difference in physical property values such as viscosity before and after the treatment. As a comparative example, 70% ethyl alcohol sterilization was performed without pretreatment, and the general viable bacterial count was 5.2 x ¹⁰³ //
g, and it is known that there is a large difference in bactericidal effect.

Example 2 A solution prepared by dissolving 3 g of glucose in 8 g of pure water was sprayed onto 5 kg of guar gum powder in a conical blender to give a specific moisture content of 0.8, and then mixed at 28° C. for 6 hours. After pretreatment, this powder was heated to 140℃ and 0.3
Steam sterilization was performed using superheated steam at Kg/cm ² for 15 seconds. The treated powder did not aggregate, and the number of general viable bacteria that existed in the raw powder was 1.8 x ¹⁰⁴ /g.
The number of particles per gram had decreased dramatically. The general number of viable bacteria when sterilized with superheat steam without pretreatment is 1.6×
The bactericidal effect was ¹⁰³ particles/g, but the bactericidal effect was lower than in the case of pretreatment.

Example 3 A solution prepared by dissolving 5 g of sucrose in 10 parts of pure water was sprayed onto 15 kg of carrageenan powder (pet food raw material) in a conical blender to give a specific moisture content of 0.6, and then mixed at 35°C for 5 hours. After pretreatment, 75%
It was sterilized with isopropyl alcohol and dried under reduced pressure to remove the isopropyl alcohol to obtain a powder. The number of viable bacteria in this powder was 20/g, while the number of viable bacteria in the raw material powder was 1200/g. Although the sample was sterilized without pretreatment, the number of viable bacteria was 1120/g, and no sterilization effect was observed.

Claims (1)

[Claims] 1 Add water in an amount such that the specific water content is 0.4 to 1.0 and monosaccharide or disaccharide of 0.025% or more to the powder and granule of a water-soluble natural polymer substance, and heat at 20 to 40℃ for 4 hours. A method for sterilizing a water-soluble natural polymer substance, which comprises performing sterilization treatment after the above mixing.