KR19990042882A - Long-term preservation method of tofu using ozone water and its tofu products - Google Patents

Abstract

The present invention relates to a long-term preservation method of tofu that greatly increases the storage and shelf life of the tofu without using any chemicals harmful to the human body using ozone water.

The present invention, by immersing the tofu made through the normal tofu manufacturing process in ozone water (3mg / L) for 30 to 45 minutes instead of water tofu immersion liquid to kill various microorganisms contaminated tofu and also suppress the reproduction of any chemicals It is possible to extend the shelf life of tofu about 3 days (at 30 ℃) or 6 days (at 6 ℃) without sanitary tofu. In addition, when deterioration occurs in tofu, pH, acidity and turbidity increase, and the production of viscous substances increases. Ozone water treatment shows signs of such deterioration about 3 to 6 days later than untreated tofu, which preserves tofu. It has an excellent effect on extending the period. On the other hand, tofu products immersed in ozone water have an excellent effect of extending the shelf life of tofu in its original state.

Description

Long-term preservation method of tofu using ozone water and its tofu products

The present invention relates to an increase in shelf life which extends the shelf life of tofu using ozone water. More specifically, by using preservatives or harmful chemicals in water, the tofu dipping solution, or directly immersing in ozone water without pasteurization or sonication, the microorganisms are killed for hygienic tofu storage period. To extend the process.

Ozone is a substance that combines three oxygen atoms, but is easily decomposed (O ₃ → O ₂ + O) to generate generator oxygen, and has strong oxidizing power. Because of its oxidizing power, it is used for sterilization, deodorization, decolorization and various organic matter removal.

Ozone, which has strong oxidizing power, is naturally decomposed and becomes harmless oxygen, and there is no fear of secondary environmental pollution, and ozone water produced by dissolving gaseous ozone in water does not produce toxic substances such as chlorine compounds such as trichloromethane (THMs). Since the reaction point is limited to the food surface and does not deteriorate the inside of the food, it has a feature that can be very useful for processing and storing food.

Soybean, which is the source of tofu, contains 40% protein, 22% fat, 4% fiber, 28% soluble nitrogen, and about 5% ash, which is an important food resource with grains. In addition, the protein of soybeans is the highest quality of vegetable foods, and about 40% of them are made of essential amino acids, so it has been called beef from the field since ancient times. In particular, soybean contains lecithin, saponin, isoflavone, etc. It is known to prevent brain aging, adult disease, liver function recovery, thrombosis prevention, various heart diseases and cancer prevention and treatment.

Tofu is made by grinding soy, a good food resource. If you eat soybeans, they are almost indigestible and can be digested by only about 60%, but tofu can be digested by about 95%. To make the valuable nutrients of beans ours, it is very effective to eat them with tofu. .

Tofu is produced by immersing soybeans as raw materials, crushing, heating, separating sewage, and treating them with water, and this process does not completely remove various microorganisms including contaminated bacteria during raw bean or tofu production. In the later storage and distribution, these microorganisms are easily deteriorated by propagation.

Conventionally, since tofu produced by a conventional method easily changes within about 1 day, the pH of the tofu is added to the topping solution after preparation to extend the shelf life, pasteurization or ultrasound. Attempts have been made to extend the shelf life by processing and packaging, but there are still many issues to be solved in practical use. Therefore, very few tofu makers and distributors use human harmful chemicals such as formalin which cannot be used tofu as a means to increase the shelf life of tofu, which poses a great threat to national health and food safety.

Therefore, an object of the present invention is to increase the shelf life of the tofu by killing and removing microorganisms contaminated on the surface of the tofu by immersing the tofu prepared in accordance with the above fact in ozone water. In addition, the present invention has an object of producing and distributing sanitary tofu without using any harmful chemicals such as formalin while using the sterilizing power of ozone which is naturally decomposed and has no residual toxicity.

In order to achieve the above object, the inventors of the present invention show that when deterioration occurs during storage of tofu, the amount of viscous substances increases with the increase of total bacterial count, pH, acidity and turbidity of tofu, which causes a serious problem in food safety as well as To prevent deterioration of the merchandise, the tofu prepared in the usual way is prepared with ozone water in which ozone is dissolved at a certain concentration, and then immersed therein for a certain time, followed by 6 ^o C (cold storage) and 30 ^o C (room temperature Storage of the tofu was investigated.

Hereinafter, with reference to the accompanying drawings and embodiments the specific configuration and results of the present invention will be described in detail.

Figure 1 shows the change in total bacterial counts when treated with ozone water to 6 ^o C and stored at 30 ^o C.

Figure 2 shows the change in pH when treated with ozone water to the head and stored at 60 ℃ and 30 ℃.

Figure 3 shows the change in acidity when treated with ozone water to the head and stored at 6 ℃ and 30 ℃.

Figure 4 shows the turbidity change according to the storage period of tofu treated with ozone water.

Figure 5 shows the change in viscous material according to the storage period of tofu treated with ozone water.

Detailed configurations and operations of the present invention will be described with reference to the accompanying drawings.

Figure 1 shows the change in total bacterial count according to ozone water treatment time when treated with ozone water (3mg / L) and stored at 30 ^o C, just 4.9 x 10 ³ CFU per gram of tofu immediately after tofu production In the case of non-treatment using tofu soak solution simply as water (hereinafter referred to as "no treatment"), the number of bacteria rapidly increased to 9.0 x 10 ⁷ CFU / g after 1 day of storage, but treated with ozone water for 30 minutes immediately after making tofu. In the stored tofu, the increase in the number of bacteria was significantly suppressed even when stored for 3 days at 1.9 x 10 ⁴ CFU / g until the 3rd day of storage, thereby preventing the deterioration of the tofu and extending the storage period. The present invention is shown as an embodiment for extending the storage period of tofu using ozone water, and in any other case does not limit the scope of the present invention.

Hereinafter, the specific configuration and operation of the present invention will be described with reference to Examples.

Example 1 Tofu Preparation and Soybean Dipping Treatment

Soybean (variety: Gwanggyo), which is a raw soybean tofu, was immersed in water for 12 hours, and then 10 times of water was added to the weight of the raw soybean, ground in a grinder for 5 minutes, heated at 100 ° C. for 15 minutes, and filtered through a filter cloth. The sesame oil was removed to obtain soy milk.

The coagulation of soy milk was coagulated by adding calcium chloride at 0.180% to the soy milk flow at about 80 ° C. and transferred to the bean curd, and the tofu was molded and processed by a 3,800 g pressing device. At this time, all the tofu manufacturing equipment was sterilized and used in advance.

Cut the tofu immediately after molding to a certain size (5.0x5.0x1.8cm ³ ), immerse it in water or ozone water for a certain time, put it in a petri dish and store it for 6 to 9 days at 6 ℃ and 30 ℃, Changes in pH, acidity, turbidity, and product formation were compared.

The production of ozone water is described in Dong-A Pharm. Co., Ltd. produced gaseous ozone using an ozone generator, which was prepared by blowing gaseous ozone to 3.0 mg / L of dissolved ozone at a water temperature of 20 ° C. , Ozone treatment was performed by immersion for 45 minutes.

Experimental Example 1. Change in Total Bacteria

1 g of the sample of each ozone water treatment group was mixed and pulverized at a rate of 9 ml of sterile physiological saline, and the mixture was taken and diluted by decimal method, followed by Nutrient medium (Peptone 10g, Lab-lemico meat extract 10g, Sodium chloride 5g, Agar 15g, 1 liter of distilled water, pH 7.0) was used to measure the colony counter after incubation for 24 to 48 hours at 30 ℃.

As a result of the experiment, when the tofu treated with ozone water was stored at 30 ° C. for 6 days, the change in the total bacterial count is shown in FIG. 1A. In other words, in untreated tofu, the total bacterial count was stored in a sanitary state until 12 hours after storage, but the total bacterial count increased rapidly by about 18,000 times as much as 9.0 x 10 ⁷ CFU / g on the first day of storage. , Tofu treated with ozone water (3.0mg / L) for 30 minutes showed excellent preservation effect without increasing the total bacterial count to 1.9 x 10 ⁴ CFU / g until storage for 3.5 days. In addition, the tofu treated for 15 minutes did not show a sharp increase in the total bacterial counts until 2 days, and 45 minutes of tofu showed a similar effect to that of 30 minutes.

On the other hand, when stored for 30 minutes in ozone water (3.0mg / L) and ozone-treated tofu and untreated tofu at 6 ^° C low temperature changes in total bacterial counts as shown in Figure 1b in storage untreated tofu until 2 days There was little change in the total number of bacteria, and thereafter, there was a sharp increase, so that untreated tofu was relatively stable up to about 2 days at 6 ^o C, while ozone-treated tofu had no effect compared to the total number of bacteria at the beginning of tofu production until 5.5 days In total bacterial counts, ozone-treated tofu had an effect of extending the shelf life about 3 days longer than untreated tofu.

Experimental Example 2. pH change of tofu

The pH change was measured while tofu was stored at 30 ^° C. for 6 days. The pH was measured directly with a pH-meter (Corning-240) and the results are shown in Figure 2a.

The initial pH of tofu was 5.8, which tended to increase with storage period. In untreated tofu, the pH dropped slightly to 5.5 on the first day of storage, and continued to increase thereafter, indicating that the tofu was deteriorated. However, the pH of tofu treated with ozone water for 30 minutes or 45 minutes was maintained at the initial pH of 5.8 until 3 days, and then increased thereafter. The pH change of tofu was also about 2 days longer than that of untreated tofu. The value is maintained, indicating that the retention period has been extended.

The change of pH was measured while soaking in ozone water (3.0 mg / L) for 30 minutes and storing the tofu treated with ozone and untreated tofu at 6 ° C., as shown in FIG. 2B.

In untreated tofu, the initial pH was maintained at 5.8 until 2 days of storage, and it increased with the storage period.In the tofu treated with 30 minutes of ozone water, the initial pH was maintained without change in pH until 5 days of storage. Increasingly, the effect of ozone water on the tofu preservation was excellent by maintaining the initial pH even longer (5 days) in ozonated tofu even at pH changes.

Experimental Example 3. Acidity Change of Tofu

10 g of tofu immediately after preparation was pulverized and mixed with 20 ml of distilled water, and titrated until neutralized with 0.1 N NaOH. As a result of measuring the change in acidity while storing tofu at 30 ° C. for 6 days, the result is shown in FIG. 3A. The pH of fresh tofu was about 4.5. In untreated tofu, the acidity gradually increased from the beginning of storage, and it increased to 6.5 at 1.5 days and to 8.0 at 2.5 days. However, in the ozone-treated tofu, the acidity increased from 2.5 days after 15 minutes and 3.5 days after 30 minutes and 45 minutes.

Soaked in ozone water (3.0mg / L) for 30 minutes, ozone-treated tofu and untreated tofu stored for 6 days at 6 ^o C while the change of acidity during storage is shown in Figure 3b. Experimental results showed that the initial acidity of tofu treated with ozone water was maintained for up to 6 days at 6 ℃ storage, and the initial acidity was maintained for a much longer time than that of untreated tofu (1.5 days).

Experimental Example 4. Turbidity of Tofu

The turbidity of the tofu suspension was pulverized, mixed, mixed with 2 times the amount of tofu, and filtered. The absorbance of the filtrate was measured at 600 nm by colorimeter (Shimazu UV-160A).

The turbidity of tofu immediately after preparation was about 0.05, but in untreated tofu, it increased about twice as much as one day of storage, and in tofu treated with ozone water for 2 days (15 minutes), 4 days (30 minutes, 45 minutes) It took about Here too, it was confirmed that the turbidity increase of the tofu suspension due to the increase of microorganisms was greatly delayed by ozone water treatment.

Experimental Example 5. Viscous substance generation of tofu

When the tofu starts to deteriorate due to the propagation of microorganisms, sticky viscous substances such as carcasses, metabolites, and tofu alterations of microorganisms are produced, which causes deterioration of mercury and odor.

Viscous substance determination was made by 10 sensory personnel who were trained by sensory tests. No viscous substance was produced (1 point), some (2 points), normal (3 points), many (4 points) and very high (5 points). ) And a little (2 points) was determined to be preservable.

In the tofu-free tofu, the production of viscous substance increased from 2 days after storage, but in the ozone-water treated tofu, the viscous substance was hardly produced until 3.5 days after storage, and the result was much after 4 days, and the result is shown in FIG. 5.

Example 2 Distribution of Tofu Products Soaked in Ozone Water

Tofu products prepared as in Example 1 and treated with ozone water were placed in a distribution container and distributed on the market. Similar results to Experimental Examples 1 to 6 were obtained.

As described in the above Examples and Experimental Examples, the present invention immerses tofu in ozone water 3.0 mg / L) for 30 to 45 minutes and greatly suppresses the propagation of various microorganisms contaminated with tofu without using any chemicals. There is a dramatic effect to extend the shelf life of tofu. In addition, when tofu is deteriorated, pH and acidity increase, and turbidity is increased due to microbial propagation, and viscous substances are produced. Tofu treated with ozone water has an excellent effect on suppressing the increase and production of these factors. It is a very useful invention for food storage and hygienic tofu distribution industry because it has a dramatic effect to extend the shelf life of tofu without using any material.

Claims (2)

Long-term preservation of tofu, characterized by inhibiting the propagation of various microorganisms contaminated with tofu and delaying deterioration by immersing tofu prepared in a conventional manner in water with 3 mg / L of ozone water for 30 to 45 minutes. Way. Tofu products with ozone water.