JPH084453B2 - Mutagenic substance removal method - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a method for removing mutagenic substances in dairy products. More specifically, it relates to a method for removing mutagenicity by causing an enzyme to act on a peroxide in a dairy product.

BACKGROUND ART In recent years, attention has been paid to a peroxide as one of carcinogenic substances contained in foods and drinks, and when a peroxide is present in food in a certain amount or more, a carcinogenic effect may be exhibited. Reported [(Ito A. et al, Gann, 72, 174 (1981
Year)〕. From such a viewpoint, it is suggested that the removal of peroxides in foods that are ingested daily is a very important issue.

As an attempt to eliminate mutagenic substances in foods and drinks with an enzyme, coffee was allowed to act with peroxidase (JP-A-60-62945), and coffee was allowed to act with catalase (JP-A-59-232049). , A vitamin C preparation with catalase acting (JP-A-60-54317),
Coffee with tyrosinase acting (JP-A-60
-256348) and so on.

As described above, although there are reports that enzyme treatment is performed on foods having mutagenicity, which is generally widely known, no report has been made on dairy products.

Milk is mainly used as a raw material for dairy products. Milk is sterilized by ultra-high temperature (120-150 degrees, 1-3 seconds) or high-temperature short-time sterilization (72-75 degrees or more, 15 seconds-15 minutes). Since the peroxidase originally contained in raw milk is inactivated by the sterilization treatment, it can be a problem if a large amount of peroxide is present in the dairy product. Therefore, despite the ever-increasing consumption of dairy products, the lack of reports that question the safety of the product is truly alarming considering the daily intake by consumers. .

Problems to be Solved by the Invention In view of the above circumstances, the present invention focuses on peroxides contained in foods in order to provide safe dairy products, and examines the presence or absence of peroxides in various dairy products. did.
As a result, it was found that, surprisingly, dairy products contain peroxides of several to several tens of ppm. Examples of dairy products used include skim milk, powdered milk, city milk, skim milk powder, yogurt and the like. The results of measuring the amounts of peroxide contained in these are shown in Table 1.

Lactoperoxidase is normally present in milk in about 0.1 units /
It is known that the enzyme is contained in an amount of at least ml, but it is considered that the enzyme is deactivated during the sterilization treatment of dairy products, which makes it difficult to remove the peroxide.

Means for Solving the Problems Examples of the peroxide include hydrogen peroxide and lipid peroxide. In the case of hydrogen peroxide, oxygen or an electron donor is mainly involved, and in the case of a peroxide, unsaturated fatty acid and enzyme are mainly involved as precursors (substrates).

In addition to reaction substrates, substances that donate or withdraw electrons or substances that catalyze their reactions, such as reducing agents such as pyrogallol and ascorbic acid, xanthine oxidases, and aldehydes are involved in peroxide generation. Oxidases such as oxidases, oxygenated metalloproteins such as oxyhemoglobin, autoxidation of pheledoxins and flavodoxins, photoexcitation products of flavins and protoporphyrins,
X-ray irradiation, ultraviolet irradiation, O ₃ , metal, etc. It is a well known fact that the peroxide thus generated causes various diseases such as arteriosclerosis, liver disease, inflammation and carcinogenesis and aging. Therefore, the means for decomposing and removing the peroxide from the food is roughly classified into two means: blocking the peroxide generation system or decomposing the generated peroxide. As the former, so-called "antioxidants" belong to this, and L-ascorbic acid, glutathione (reduced form), uric acid, vitamin E, β-carotene, butylhydroxyanisole, butylhydroxytoluene, propylgallate, gallic acid, etc. Can be mentioned. The latter also includes reducing agents such as sulfite and enzymes that decompose peroxides. As enzymes, catalase, various peroxidases, phosphiolipase, glutathione transferase, etc. are known. Generally, for the purpose of decomposing and removing peroxides in foods and drinks, the base used must satisfy the following conditions.

(1) It does not adversely affect the sensory characteristics of the product.

(2) The base material itself and the reaction product are safe.

(3) Do not promote deterioration in quality such as browning.

(4) The amount used should be as small as possible.

Enzymes seem to be the most suitable as the base material satisfying these conditions.

Therefore, the present inventors examined the use of an enzyme, particularly peroxidase, for decomposing and removing the peroxide present in the dairy product.

Peroxidase is an enzyme that catalyzes the reaction of electron donor + peroxide → oxidized electron donor + 2H ₂ O, and peroxide is rapidly removed. The peroxidase may be derived from plants such as horseradish, Japanese radish and turnip, derived from animals such as milk and white blood cells, and derived from microorganisms, and the purity thereof is not limited. The amount of enzyme used is usually 0.1
A dairy product close to natural can be obtained by leaving it at a concentration of 1 unit / ml at room temperature for a certain period of time. The reaction temperature and reaction time can be adjusted as appropriate, and it is not necessary to wait for enzymatic chemistry to discuss the amount of enzyme to be selected accordingly.

Next, the present inventors tried a sensory test when peroxidase was allowed to act on commercially available milk.

Test Example Lactoperoxidase was added to commercially available milk to a concentration of 0.2 μ / ml, and stored in the refrigerator for 2 days, then 10 panelists were selected arbitrarily, and the taste, smell, appearance, etc. I did a test.

Regarding the change in appearance and odor, all 10 panelists judged that there was no difference compared with the control (without addition of lactoperoxidase). Regarding the taste, 8 out of 10 judged that it was lighter than the control, and 2 judged that there was no difference.

In this way, since the dairy product treated with the enzyme does not contain any peroxide, it is possible to provide a safe product.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

"Peroxide determination" 4-aminoantipyrine 8 mg, TOOS (trade name) 32 mg and peroxidase (derived from horseradish) 150 units 0.1 N
-Dissolved in 100 ml of Tris-HCl buffer (pH 7.0) to give a reaction solution. Add 1 ml of sample to 2 ml of this reaction solution, leave it at room temperature for 15 minutes, then compare with a control (use water instead of 1 ml for the same operation) or measure at 555 nm for positive and negative peroxides. Alternatively, a hydrogen peroxide conversion value was obtained from a calibration curve using hydrogen peroxide.

Example 1 Peroxidase was added to skim milk, city milk, and yogurt in the presence of peroxide in the range of 0.01 to 0.5 unit / ml, and allowed to stand at room temperature for 15 minutes, and then the amount of peroxide was measured. The results are shown in Table 2.

As can be seen from Table 2, the amount of enzyme was changed by leaving it at room temperature for 15 minutes.
Peroxides can be removed by adding peroxidase to dairy products at 0.1 unit / ml.

Example 2 Lactoperoxidase (derived from milk), peroxidase (derived from horseradish), and perooxidase (derived from microorganisms) were added to 10 ml of city milk at 0.1 unit / ml each, and 25
After standing for 15 minutes, 1 ml of each was taken and added to 2 ml of the reaction solution for peroxide measurement, and after 15 minutes, the color development was confirmed.
As a result, color development was positive in the case where the enzyme was not added, whereas it was negative in the case where the enzyme was added.

Example 3 50 ml of city milk was centrifuged at 10,000 rpm for 20 minutes. After adjusting the pH of the middle layer solution to 4.5 with 2N acetic acid, 10,00
After centrifugation at 0 rpm for 20 minutes, the supernatant was adjusted to pH 7.0 with 2N sodium hydroxide solution and further centrifuged at 10,000 rpm for 20 minutes. Example 2 was added to the acid whey solution thus obtained.
The same enzymatic treatment as in (2) above was carried out to measure the peroxide. As is apparent from Table 3, the peroxide was completely removed by the peroxidase treatment.

EFFECTS OF THE INVENTION The method for removing peroxide in a dairy product using the peroxidase of the present invention is a safe and reliable method and can provide an excellent dairy product.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-60-62945 (JP, A)

Claims (2)

[Claims] 1. A method for removing a mutagen, which comprises allowing a peroxidase to act on a mutagen in a dairy product. 2. The method for removing a mutagenic substance according to claim 1, wherein the dairy product is selected from the group consisting of milk, milk powder and yogurt.