JPH0725B2 - Foods that can suppress the growth of thermophilic bacteria - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-sterilized food containing iron or containing iron and capable of suppressing the growth of thermophilic bacterium upon reduction in use or reconstitution in hot water.

Technical background Conventionally, when liquid food is sterilized, it is generally 100 to 1
Although heat treatment is performed at a temperature of 30 ° C, thermophilic bacteria do not completely die at this temperature because they form heat-resistant spores.

Further, the heat-resistant spores do not die even if dried and pulverized after sterilization treatment at the above temperature, so this powdered spore,
For example, if infant milk powder is reduced to warm water or the like to contain water in an amount of 20% by weight or more and kept at a temperature of 35 ° C or more for 2 hours or more, the heat-resistant spores will germinate and grow. There's a problem.

As a method for sterilizing the heat-resistant spores of the thermophilic bacterium, an increase in sterilization temperature or an extension of sterilization time is considered, but complete sterilization of the heat-resistant spores by these methods is a component due to heating of the target food. It cannot be said to be a practical method because there are quality problems such as the above modification and thickening of foods.

Iron has recently been recognized for its importance in foods containing iron from the health concern of preventing iron deficiency anemia and the like.

On the other hand, lactoferrin is an iron-binding protein that is present in exocrine fluid such as milk, and inhibits the production of peroxides that occur in the body; pathogenic bacteria that enter the body (eg, Staphylococcus aureus) It has been attracting attention in recent years because it exhibits an effective action of inhibiting proliferation; being an essential factor for growing human lymphocytes; and being a form in which iron is easily absorbed in the human body.

On the other hand, it has also been reported that when the iron content of an iron-containing food is excessive, the suppression of bacterial growth in the food is significantly inhibited [Biochemica.
Etobio Deer Actor (Biochim.Biophys.Acta)
170 , 1968, p351-365; Infection and Immunity 0ct.1976, p911
~ 918; NATURE vol.216, 0ct.28, 1967, p
328-330].

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been made in view of the gradual problem in suppressing the growth of thermophilic bacteria in foods, particularly foods containing iron. That is, it is an object to effectively suppress the growth of thermophilic bacteria upon reduction or reconstitution in hot water of the above food that has been sterilized at a normal sterilization temperature of 100 to 130 ° C.

The present invention will be described in detail below.

Composition of the Invention A feature of the present invention is a heat-sterilized food in which iron is contained or blended, lactoferrin is blended in an amount of 1 to 690 times the iron (weight ratio), and heat-sterilized.

That is, in the present invention, containing iron or blended with iron, by adding lactoferrin to the food to be heat-sterilized, to suppress the growth of thermophilic bacteria upon reduction or reconstitution in hot water of the food It is a thing.

Means for Solving the Problems Lactoferrin, which is an active ingredient of thermophilic bacterium growth inhibitory action according to the present invention, is obtained by separating and purifying human milk, milk, horse milk, milk of goat milk and the like, For example, as a method of separating from milk, an affinity column obtained by immobilizing a monoclonal anti-bovine lactoferrin antibody on an insoluble carrier is used, and a method of separating and purifying lactoferrin by subjecting the column to treatment with milk ( JP 61-
No. 145200).

That is, in the present invention, lactoferrin purified by the above method or commercially available lactoferrin can be used.

On the other hand, iron in the food subject to thermophilic growth inhibition according to the present invention, those that are originally present in the food are used (for example, matcha is 17.0 mg / 100 g, cocoa is 14.0 mg / 100.
g, coffee powder contains 4.2 mg / 100 g, brown sugar 4.7 mg / 100 g and mass potato contains 3.1 mg / 100 g of iron) or
Alternatively, it is an iron compound compatible with food. Iron compounds compatible with such foods include ferrous gluconate,
Ferric chloride, ammonium iron citrate, citric acid second
Those which are recognized as food additives such as iron, sodium iron citrate citrate, ferrous lactate, ferrous sulfate and the like can be used.

That is, the present invention relates to a food containing iron as described above and a food containing each of the above-mentioned iron agents, and when applied, the lactoferrin content is about 1 to the iron content in the food. Add ~ 690 times (weight ratio).

If the amount of lactoferrin added to the food is less than 1 time the iron content, the thermobacterium growth inhibitory effect in the food is lost, while if added in excess of 690 times the effect is not substantially improved. Not economical. In the present invention, the iron present in the food is not bound to all lactoferrin, that is, iron is present in the food, even in the state where all lactoferrin is bound to iron, this lactoferrin iron conjugate itself is thermophilic. Proliferation can be suppressed. This is completely different from the fact that the antibacterial action of lactoferrin has been conventionally caused by the fact that lactoferrin binds to iron to deprive the iron required for bacterial growth and prevent free iron from existing. It is due to the action of.

In addition, in the above target food, in addition to general food, dairy products,
There are a wide range of beverages and health foods, and the form may be powder, solid, gel, paste and liquid. However, in actual use, 20
There is a remarkable effect when the food of the present invention is maintained in a state of containing water in an amount of not less than wt% and kept at a temperature of 35 ° C. or more for at least 2 hours. In particular, since powdery and solid foods usually have a water content of 5% by weight or less, it is advisable to dissolve these foods in warm water or the like to bring them into the above-mentioned state in order to exert the effect of suppressing the growth of thermophilic bacteria according to the present invention. As the food used in such a state, for example, powdered milk (whole milk powder, skim milk powder, baby milk powder, follow-up milk, etc.)
There is. When targeting these milk powders, iron is mixed in an amount of 3 to 30 mg per 100 g of milk powder, and lactoferrin in an amount of 30 to 4000 mg.
It is possible to suppress the growth of thermophilic bacteria in milk powder by dissolving the additives added in the range of mg in hot water of about 40 ° C. at a solid content of 13% by weight and holding at that temperature for at least 2 hours.

In addition, powdered milk dissolved in warm water at the above solid content is a necessary iron intake of 14 to 25 mg per day for pregnant and lactating women by ingesting 200 ml per day for pregnant and lactating women and 800 ml for infants. 1/2 to 1/3 (when the iron content is 30ml / 100g), and about 1/2 to the required amount of 5 to 7mg, which is the same iron intake of infants (iron content is 3 to 7mg) / 100g) can be taken.

Next, the thermobacterium growth inhibitory effect of the present invention is shown based on the following test results.

Test methods: Bacillus stearothermo philus, Bacillus coagulans, Bacillus circrans, Bacillus bacterus, fixed and separated from whole milk powder, skim milk powder, pregnant and lactating milk powder and formula The growth inhibition of major thermophilic bacteria such as circulans) was investigated by the following procedures (a) and (b).

(B) 3 mg of ferrous gluconate as iron per 100 g of commercially available whole milk powder, and 30 mg, 50 mg, 100 mg, 1 of lactoferrin
Solid content of 1 is obtained by blending 000mg and 4000mg respectively.
It was completely dissolved in warm water of 40 ° C so as to be 3%, and intermittent sterilization was performed at 100 ° C. Each of the obtained solutions was inoculated with the above-mentioned thermophilic bacterium so that the initial number of bacteria was 10 ² to 10 ³ / ml, put in a thermostat and kept at a temperature of 55 ° C. Proliferation was measured. In addition, as a control, the growth of each bacterium was measured in the same treatment as above except that lactoferrin was not added.

The results are as shown in the attached FIG. 1 to FIG.
The growth inhibitory effect of thermophilic bacterium by adding lactoferrin is clearly recognized.

(B) Commercially available whole milk powder, skim milk powder, modified milk powder for pregnant and lactating women and modified milk powder, as iron for each 100 g of each
30mg ferrous sulfate was added, while lactoferrin was added to formula milk powder at 50mg per 100g, maternal and lactating formula milk powder at 100mg per 100g, and skim milk powder at 1000mg per 100g.
And the whole milk powder was mixed with 4000mg per 100g, dissolved in 50 ℃ sterilized hot water so that the solid content becomes 13%, and kept at a temperature of 55 ℃ in an incubator at regular intervals. Growth was measured. In addition, as a control, the growth of the bacteria was measured for those treated in the same manner as above except that lactoferrin was not added.

The results are shown in FIGS. 4 to 7, and the growth inhibitory effect of thermophilic bacterium by the addition of lactoferrin is recognized. In addition, FIG. 4 shows the modified milk powder, FIG. 5 shows the milk powder for pregnant and lactating women, FIG. 6 shows the skim milk powder, and FIG. 7 shows the whole milk powder.

The present invention and its effects will be specifically described below with reference to examples.

Example 1 280 kg of raw milk, 660 kg of skim milk and 10 kg of vegetable oil were mixed and homogenized, sterilized at 125 ° C., concentrated and dried to obtain 100 kg of milk powder.

14.7 g of ferrous sulfate and 30 g of lactoferrin were mixed and uniformly mixed with this powdered milk, and 10 g thereof was dissolved in 67 g of warm water sterilized at 50 ° C. and placed in an incubator and kept at a temperature of 55 ° C. for a fixed time. The growth of thermophilic bacteria was measured for each.

Further, as a control, the growth of thermophilic bacteria was measured in the same manner as the one treated in the same manner as in Example 1 except that lactoferrin was not added.

The results are shown in FIG. 8, and the effect of suppressing the growth of thermophilic bacteria by Example 1 containing lactoferrin is clearly recognized.

Example 2 10 kg of skim milk (solid content 8.8%) was mixed with 0.13 g of ferric chloride and sterilized at 125 ° C., and then 35.7 g of lactoferrin was mixed and dissolved.

The skim milk thus prepared was put in a thermostat and kept at a temperature of 55 ° C., and the growth of thermophilic bacteria was measured at regular intervals.
As a control, the growth of thermophilic bacterium was measured in the same manner as in Example 2 except that lactoferrin was not added.

The results are shown in FIG. 9, and the effect of inhibiting the growth of thermophilic bacterium by adding lactoferrin in Example 2 is clearly recognized.

As shown in Examples 1 and 2, the lactoferrin blended according to the present invention showed almost no growth of thermophilic bacterium even in the food containing iron, and the number was rather small. It can be seen that is decreasing. On the other hand, in the control containing no lactoferrin, thermophilic bacteria start to grow after 2 to 6 hours, and the growth rate thereof is logarithmically increased with time.

Therefore, according to the present invention, the growth of thermophilic bacteria can be effectively suppressed without accompanying the quality change of the food due to the sterilization treatment at high temperature, which is beneficial for the preservation of food.

[Brief description of drawings]

FIG. 1 to FIG. 9 show the bacterial growth inhibitory effect in foods having a thermophilic bacterial growth inhibitory rate containing lactoferrin as an active ingredient according to the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Supervised by Kazutomo Imahori, published by Tokyo Kagaku Dojin, “Biochemistry Dictionary”, 1st edition, 5th edition, published March 1, 1986, page 1318, "Lactoferrin" section

Claims (4)

[Claims] 1. A heat-sterilized food in which iron is contained or blended, lactoferrin is blended in an amount of 1 to 690 times (weight ratio) with respect to iron, and heat-sterilized. 2. The food product according to claim 1, wherein the content of lactoferrin is at least 30 mg% based on the food product. 3. The food according to claim 2, wherein the food is a food in which thermophilic bacteria may grow during use. 4. The food according to claim 3, wherein the food in which thermophilic bacteria may grow during use is milk powder.