KR100389142B1 - Pollution-free detergent using citron and process for preparation thereof - Google Patents

Abstract

The present invention relates to a pollution-free detergent using a citron, and a method for manufacturing the same. The detergent containing the citron juice or citron seed oil of the present invention is a combination of the natural cleaning power and the pollution-free surfactant of the citron juice, the foam is low, the foaming speed is fast, and the washing power is high. Not only is it excellent, it is also very toxic, so it is a natural cleanser that minimizes environmental pollution.In addition, citron juice and citron seeds contain a large amount of vitamins useful for skin and substances that suppress various cancers. It protects your skin and prevents skin damage.

Description

Pollution-free detergent using citron and manufacturing method thereof {Pollution-free detergent using citron and process for preparation

The present invention relates to a pollution-free detergent using citron and a method for producing the same. More specifically, the present invention relates to a detergent and a method for producing the same, which contain not only oil seed oil or citron juice, but also excellent washing power.

Citron is a fruit belonging to the citrus fruits produced in the southern coast around Korea's Geoje Island, and has a special characteristic compared to other citrus fruits. It is a rare fruit produced only in Japan, China, and some parts of the Middle East. It is also a fruit that can be recognized as a special product of the South coast of Korea. However, the ripe fruit of citron has a unique strong bitter taste, so it is only processed with citron and consumed as citron tea.

Currently, citron production in Korea is estimated to be about 5000 tons, but recently, due to the increase in production and the decrease in consumption, most farmers have given up their cultivation and left open fruits without even harvesting. The yujacheong is made by slicing the citron shell finely and adding about 50-60% of sugar. The storage period is seasonally limited during the winter months, which limits the sales volume. Currently, only half of the amount produced by farmers is consumed. Since the situation is being discarded, development of various products using citron is desired.

In the process of making yuzu, a lot of juice comes out when the citron is cut. However, in the case of citron farmers, since the method of using the juice is not developed, almost all of it is discarded. This juice contains a large amount of limonene and γ-terpinene, and vitamins C, E, and P, as well as recent studies by US and Japanese scholars on grapefruit and oranges, have been shown to be potent anticancer agents. It contains large amounts of limonoid compounds. Among them, limonin (limonin) and nomilin (nomilin) substances have been reported to have a strong anti-cancer effect on skin cancer, stomach cancer lung cancer and liver cancer. Limonene and γ-terpinene are unique monoterpenes found in citrus fruits and have been reported by many scholars for a long time to show strong anticancer activity against various cancers including skin cancer. In particular, limonene has strong washing power and is well known as a solvent for various materials. In addition, this citron juice contains a significant amount of pectin and has a strong adsorption capacity for various contaminants. Pectin is well known as a dietary fiber, and there are many studies showing that colon cancer is prevented because it absorbs various toxic substances from the large intestine and quickly discharges it to the stool. Pectin itself is expected to be a very good adjuvant for detergents because of its strong adsorption capacity for fats, proteins and other contaminants. It is a pity that raw materials containing a large amount of these precious substances are discarded as they are, and it is a waste of precious resources.

Citron has 20-40% of the whole fruit with seeds, which is the biggest weakness of other fruits. The most expensive cost for making a yuzaong is the labor cost of seed removal, which accounts for about 40% of the total cost. This seed is being disposed of entirely and has a serious impact on environmental pollution. This is mainly caused by incineration of the seeds by farmers, and if they are lit in autumn, they continue to burn until the next spring, causing air pollution. However, the seeds contain about 20% fat containing valuable unsaturated fatty acids. Recently, the present inventors have detected a large amount of limonoid and flavonoid compounds in citron seeds and a considerable amount of limonene. The results of the study were confirmed, and it is expected to be an important resource for the development of anticancer drugs. Currently, animal experiments on the mass extraction method and anticancer activity of this substance are underway. Since the fat must be extracted first before the extraction of these anti-fertilizers, using this fat as a raw material for detergents is very important in terms of efficient use of resources.

In view of the above, the present inventors manufactured a pollution-free detergent using natural washing power of citron juice and fat extracted from citron seeds, and the pollution-free detergent is environmentally friendly because it has superior washing power and hardly causes pollution compared to conventional detergents. The present invention was completed by confirming that the product.

Accordingly, an object of the present invention is to provide a detergent having excellent cleaning power and little pollution by containing fat or citron juice of citron seeds.

Another object of the present invention to provide a method for producing the detergent.

The above object of the present invention is to saponify citron seed oil in the fermentation tank, adjust acidity and viscosity, and add a nutrient such as vitamin to prepare a detergent containing citron seed oil, and in another way, citron juice in fermentation tank. After the detergent was prepared using only, it was achieved by examining the physical properties of each of the prepared citron seed oil-containing detergent and the citron juice-containing detergent, and the foam extinction rate and toxicity were compared with the general detergent.

Hereinafter, the configuration of the present invention will be described.

1 shows an apparatus for preparing a detergent using citron.

Explanation of symbols on the main parts of the drawings

1: fermentation tank 2: double jacket

3: rotation speed control device 4: rotation motor

5: Slot 6: Locking screw

7: sight window 8: pressure gauge

9: cooling tube 10: collecting bottle

11: temperature sensor 12: temperature controller

13: stirrer 14: 200 mesh

15 outlet valve 16 outlet

17: vacuum pump 18: ethanol collection tank

The present invention mixes citron seed oil and oleic acid in the fermentation tank, and rotates and saponified when the temperature is adjusted. After mixing the resulting soft soap and glycerin sufficiently, lowering the temperature to harden the curd (curd) and residual ethanol Removing and adjusting alkalinity, adding yuzu juice, adjusting viscosity, adding other vitamins, etc., to fully prepare a detergent containing yuzu seed oil; Filtering the citron juice, adding sodium bicarbonate, adding vitamins, and the like to prepare a detergent containing the citron juice by adjusting the viscosity; Measuring pH, viscosity, PO ₄ -P, COD, and heavy metal of the detergent containing the citron seed oil of the present invention and comparing the measured value with that of the general detergent; Measuring pH, viscosity, PO ₄ -P, COD, and heavy metal of the detergent containing the citron juice of the present invention and comparing the measured value with that of the general detergent; The present invention comprises the steps of mixing the detergent containing the citron seed oil and the detergent containing the citron juice with water to generate a foam and then the rate of foam extinction and comparing the measured value with the measured value of the general detergent; Each of the detergent containing the present invention citron seed oil and the detergent containing citron juice was dissolved in daphnia culture water, and the daphnia surviving water was examined over time. Comparing daphnia survivors.

In the present invention, the fatty acid composition of the citron seed oil used as the main ingredient is an excellent fat containing a considerable amount of DHA and a significant amount of essential fatty acids, which are known to be little in vegetable oil, as shown in Table 1, and the citron juice is shown in Table 2. As described above, it is a limonoid-type substance known as an anticancer substance and a large amount of pectin, and a large amount of limonene, which acts as a natural solvent, and thus can serve as an excellent cleaning agent even with citron juice itself. There is this.

Fatty acid composition of citron seeds (%) fatty acid Furtherance Palmitoreic acid 4.9 Palmitic acid 15.0 Linoleic acid 26.1 Linolenic acid 21.2 Oleic acid 9.9 Stearic acid 3.0 Elaidic acid 12.6 DHA 7.3

Content of Biologically Active Substances in Citron Juice Bioactive substances mg / 100mL Flavone 4.2 Coumarin 35 3.6 Limonene 23 Terpinene 3.3 Limonin 0.05 Nomilin 0.028 Pectin 25.5 Vitamin c 25.4 Vitamin P 2.8 Vitamin E 0.84 calcium 129.60 sign 0.54 iron 5.4 selenium 3.0 heavy metal Cadmium ND lead ND silver ND

The present invention is a decyl benzene as propylene glycol alginate, glycerol (glycerin), pollution-free surfactant, including citron seed oil and citron juice shown in Table 1 and Table 2, oleic acid (oleic acid), emulsifier Dodecylbenzene sulfonic acid sodium salt, citrlc acid, KOH, NaOH, vitamin A, and the like were used as materials.

Although the specific method of the present invention will be described in detail by way of examples, the scope of the present invention is not limited only to these embodiments.

Examples 1 to 5: Preparation of detergent containing citron seed oil

In Examples 1 to 5, by using the citron detergent manufacturing apparatus shown in Figure 1 as propylene glycol alginate, glycerol (glycerin), pollution-free surfactant, including oleic acid, oleic acid, emulsifier A detergent containing various amounts of dodecylbenzene sulfonic acid sodium salt, citrlc acid, KOH, NaOH, vitamin A and the like was prepared and described in detail by the following process.

Step 1: Soft Soap and Glycerin Blend

Mixing each of the citron seed oil and oleic acid in the range of 5 to 18% by weight according to the ratio shown in Table 3, about 1/4 in the fermentation tank (1) of the yuja detergent manufacturing apparatus as shown in FIG. Fill up to 3 volumes of 1.25 M NaOH + 2.9 M KOH / ETHANOL solution for the entire holding volume and operate the rotary motor (4) at a speed of about 120 revolutions, using a temperature sensor (11) and a thermostat (12). The temperature was adjusted to 50 to 75 ° C. After saponification at 75 ° C for about 5 hours and at 50 ° C for 24 hours to produce soft soap and glycerin, the rotation speed is increased to about 300 revolutions for about 2 hours so that the soft soap and glycerin can be sufficiently mixed. It was kept at 90 ° C.

Composition of raw materials in manufacturing detergents containing citron seed oil (unit: weight%) Raw material name Example 1 Example 2 Example 3 Example 4 Example 5 Citron seed oil 18 15 10 8 5 Oleic acid 18 15 10 8 5 Dodecylbenzenesulfonate sodium salt 4 6 10 13 19 glycerin 5 10 16 17 17 Water + citron juice 0: 1 = 50 1: 2 = 50 1: 1 = 50 2: 1 = 50 3: 1 = 50 Propylene Glycol Alginate 0.5 to 2.0 0.5 to 2.0 0.5 to 2.0 0.5 to 2.0 0.5 to 2.0 Retinol 0.2 0.2 0.2 0.2 0.2 Citric acid 0.5 to 1.0 0.5 to 1.0 0.5 to 1.0 0.5 to 1.0 0.5 to 1.0 NaHCO ₃ 4.3 to 1.8 3.8 to 0.8 3.8 to 0.8 3.8 to 0.8 3.8 to 0.8

Second Process: Curd Hardening

After mixing in the first step, the temperature of the fermentation tank 1 is rotated into the double jacket 2 of the tank to rotate the cooling water to lower the temperature of the internal solution to 20 ° C or lower, and then the stirring is stopped and the curd becomes firm. Waited.

Third Process: Curd Recovery

When the curd is completely hardened according to the second process, the curd is collected at the upper layer, so that the remaining ethanol alkali liquid is reacted by opening the discharge valve 15 of the lower outlet 16 and a vacuum pump. (17) was pulled out as much as possible through the 200 mesh net installed in the lower part of the tank.The extracted ethanol alkali liquid was left still and the 200 mesh net net 14 was placed in a vacuum pump (17). Some pulled curds gathered and hardened by the vacuum force generated by the vacuum, and the curds were collected and put into the road fermentation tank 1.

Fourth Process: Curd Purification

By the third step, the fermentation tank 1 contained 95% ethanol containing no alkali, about twice the amount of the curd, and the temperature was increased to about 70 ° C. to rotate the stirrer 13 at 120 revolutions per minute to melt the curd. This process was to dissolve the remaining NaOH and KOH in ethanol. After stirring at about 70 ° C. for about 15 minutes, the cooling water was rotated in the same manner as in the second process to harden the curd again, and then the discharge valve 15 at the lower part was opened, and the ethanol dissolved in alkali was discharged to discharge the collection tank 18. Was collected. After repeating this process once more, only the curd remained in the tank and the temperature was raised to 90 ° C., and the remaining ethanol was collected through the cooling tube 9 and collected in the collecting bottle 10. All recovered ethanol was reused by measuring the alkalinity in a ratio of NaOH 1: KOH 3.3 to have the original alkalinity.

5th Process: Curd Aging

To the curd in the fermentation tank (1) was added water in the ratio of Table 3 shown in the first step, 5% by weight of glycerin, 4% by weight of dodecylbenzenesulfonic acid sodium salt, and propylene glycol as an emulsifier. Alginate (propylene glycol alginate) was also added in the ratio of Table 3, and the temperature was 70 ° C, and the stirrer was mixed at about 300 revolutions per minute for about 2 hours. After mixing, the filtered citron juice was added in the ratio shown in Table 3 so that the viscosity was in the range of about 30 cps to 35 cps. In this case, 0.2% by weight of retinol (vit A), 0.7% by weight of citric acid, 3.0% by weight of NaHCO ₃ are added, and the pH is adjusted to 5.5-7.0 if necessary, and the inlet is not allowed to fly. The well was stirred and stirred at about 2 to 5 hours at 120 revolutions per minute to fully mature. Thereafter, the temperature was adjusted to 20 ° C., homogenized by passing through a homogenizer, and then filled and labeled in a filling bottle and stored in a 15 ° C. storage bin.

By the above process, detergents containing citron seed oil of Examples 1 to 5 were prepared, and the content of propylene glycol alginate in each detergent was 0.5 to 2.0% by weight, preferably 1.0% by weight, and the content of citric acid was 0.5 to 1.0%. %, preferably the content of the 0.7% by weight of NaHCO ₃ is yiyeotda 4.3 ~ 0.8% by weight, preferably 3.0% by weight.

Examples 6 to 10 Preparation of detergent containing only citron juice

Unlike Examples 1 to 5, Examples 6 to 10 manufactured detergent using the Citron Detergent Manufacturing Device of FIG. 1 using only citron juice without using citron seed oil at all.

First step: citron juice pH control

The juice obtained from the citron was filtered, mixed with water at various ratios, and sodium bicarbonate was mixed at the ratios shown in Table 4, and the pH was adjusted within the range of 5.5 to 7.0, and then placed in the fermentation tank (1).

Raw Material Composition of Detergent Containing Citron Juice (Unit: Weight%) Raw material name Example 6 Example 7 Example 8 Example 9 Example 10 Dodecylbenzenesulfonate sodium salt 30 25 20 15 10 glycerin 5 9 15 17 20 Water + citron juice 3: 1 = 62.3 2: 1 = 62.8 1: 1 = 61.3 1: 2 = 64.8 0: 1 = 65.8 Propylene Glycol Alginate One One One One One Vitamin A 0.2 0.2 0.2 0.2 0.2 Citric acid 0.5 0.5 0.5 0 0 NaHCO ₃ One 1.5 2 2 3

Second Process: Viscosity Control

In the first step, citron juice and water are added at a ratio of Table 4, and propylene glycol alginate, dodecylbenzene sulfonic acid sodium salt, and glycerine are prepared according to the embodiment. Also added in the ratio shown in Table 4 to adjust the viscosity to 33cp and retinol 0.2% by weight. In this case, the viscosity is preferably about 30 to 35 cp, preferably 33 cp.

Third Process: Homogenization

In order to prevent the citron aroma of the detergent whose viscosity is adjusted in the second process from being volatilized, the cap is sealed using the lock screw 6 of the fermentation tank and the temperature is adjusted to 50 ° C., and then the rotation speed of the stirrer 13 is about 120 rotations. After stirring for about 2 to 5 hours, the temperature was set to 20 ° C., the foam was completely changed, passed through a homogenizer, homogenized, filled in a filling bottle, labeled, and stored at 15 ° C. for sale.

Experimental Example 1: Physical properties of detergent containing citron seed oil

The pH, viscosity, Po ₄ -P, COD and heavy metal of the detergent containing the citron seed oil prepared in Examples 1 to 5 and the commercial product (manufacturer name: Aekyung Oil Holding Co., Ltd., Cree) were measured. Viscosity was measured using a viscometer and Po ₄ -P and heavy metals were measured using conventional methods, and COD measurements were determined by closed reflux, titrimetric method (standard methods for the examination of water and waterwaster, 1989, 17th ed., Editors; LS Clesceri, AE Greenberg, and RR Trussell, APHA-AWWA-WPCF, PORT CITY PRESS, BALTIMORE, MARYLAND. 5-14, 5220 C). The pH was adjusted to 5.5, and the pH was adjusted with citric acid and NaHCO ₃ .

As a result, as shown in Table 5, the content of phosphoric acid, which is a cause of environmental eutrophication, was extremely low and no heavy metals were detected.

Properties of Detergent Containing Citron Seed Oil Item / Detergent Example 1 Example 2 Example 3 Example 4 Example 5 Commercial product pH 5.5 5.5 5.5 5.5 5.5 6.0 Viscosity 35cp 34cp 33cp 34cp 35cp 33cp PO ₄ -P 0.005ppm 0.005ppm 0.004 ppm 0.003ppm 0.003ppm 0.05ppm COD 190mg / L 180 mg / L 185 mg / L 195mg / L 189mg / L 210mg / L heavy metal Pb ND ND ND ND ND 0.005ppm CD ND ND ND ND ND 0.01 ppm Hg ND ND ND ND ND 0.005ppm

Experimental Example 2: Physical Properties of Detergent Containing Citron Juice

The pH, viscosity, Po ₄ -P, COD and heavy metal of the detergent containing the citron juice prepared in Examples 6 to 10 and the commercial product (manufacturer name: Aekyung Oil Holding Co., Ltd., Cree) were measured. Measurement method was the same as in Experiment 1.

As a result, as shown in Table 6, there was no significant difference between the physical properties of Examples 1 to 5, but the COD was low.

Properties of Detergent Using Citron Juice Item / Detergent Example 6 Example 7 Example 8 Example 9 Example 10 Commercial product pH 5.5 5.5 5.5 5.5 5.5 6.0 Viscosity 33cp 32cp 33cp 33cp 33cp 33cp PO ₄ -P 0.004 ppm 0.004 ppm 0.005ppm 0.004 ppm 0.005ppm 0.05ppm COD 140mg / L 135mg / L 132mg / L 125mg / L 129 mg / L 210mg / L heavy metal Pb ND ND ND ND ND 0.005ppm CD ND ND ND ND ND 0.01 ppm Hg ND ND ND ND ND 0.005ppm

Experimental Example 3: Bubble disappearance rate of detergent containing citron seed oil

In this example, 5 g of the detergent prepared in Examples 1 to 5 and a commercial product detergent were added to a 500 mL volume cylinder, and 100 mL of water was added thereto. .

As a result of the experiment, as shown in Table 7, the detergents of Examples 1 to 5 of the present invention disappeared completely after 3 hours, but commercially available products (manufacturer: Aekyung Oil Holding Co., Ltd., Cree) remained foamed after 5 hours. I could confirm that. Therefore, it was found that the present invention citron seed oil-containing detergent is environmentally friendly.

Foam decay rate of detergent containing citron seed oil Detergent / hour Initial bubble volume (mL) 30 minutes 1 hours 2 hours 3 hours 4 hours 5 hours Example 1 230 120 10 0 Example 2 245 130 15 0 Example 3 255 145 23 5 0 Example 4 260 150 25 5 0 Example 5 265 155 30 5 0 Commercial product 375 340 315 270 241 205 150

Experimental Example 4: Bubble disappearance rate of detergent containing citron juice

In this embodiment, the foaming rate was measured in the same manner as in Experiment 3 using the detergents prepared in Examples 6 to 10 and detergents of commercial products.

As a result, as shown in Table 8, in the detergents of Examples 6 to 10 of the present invention, the foam disappeared in 4 hours. Although foam disappears faster than detergent containing citron seed oil, it can be seen that foam disappears at a much faster rate than commercial products (manufacturer: Aekyung Oil Holding Co., Ltd., name: Cree) and proved to be an environmentally friendly detergent. .

Foam decay rate of detergent containing citron juice Detergent / hour Initial bubble volume 30 minutes 1 hours 2 hours 3 hours 4 hours 5 hours Example 6 300 160 50 15 5 0 Example 7 290 150 35 10 5 0 Example 8 270 140 30 10 5 0 Example 9 260 130 20 5 0 Example 10 250 120 15 5 0 Commercial product 375 340 315 270 241 205 150

Experimental Example 5: Toxicity Study of Detergent Containing Citron Seed Oil

In this experimental example, the yuzu seed oil-containing detergents and commercial detergents prepared in Examples 1 to 5 were dissolved in daphnia magna cultured water at a concentration of 300 ppm, 200 mL were placed in a beaker, and 20 daphnias were added. The number was confirmed.

As a result, as shown in Table 9, in the detergents of Examples 1 to 5 of the present invention even after 24 hours had elapsed, surviving daphnia existed, while commercial products (Manufacturer: Aekyung Oil Holding Co., Ltd., Cree) Was wiped out.

Toxicity Test Results of Detergents Using Citron Seed Oil Using Daphnia Magna Time / detergent Blank Example 1 Example 2 Example 3 Example 4 Example 5 Commercial product 0 20 20 20 20 20 20 20 One 20 20 20 20 20 20 18 2 20 20 20 20 20 20 17 3 20 20 20 20 20 20 15 4 20 20 20 20 20 19 13 5 20 20 20 20 20 19 12 10 20 18 17 17 17 16 10 12 20 16 16 16 16 16 7 15 20 15 15 15 15 13 2 18 20 13 13 13 12 13 0 20 20 10 10 10 10 10 24 20 6 5 5 4 3

Experimental Example 6: Investigation of Toxicity of Detergent Containing Citron Juice

In this experimental example, the toxicity of the citron juice-containing detergents and commercial detergents prepared in Examples 6 to 10 was investigated in the same manner as in Experimental Example 5.

As a result of the experiment, as shown in Table 10, in the detergents of Examples 6 to 10 of the present invention even after 24 hours had elapsed, the surviving daphnia was present, while a commercial product (Manufacturer: Aekyung Oil Holding Co., Ltd., Cree) Was wiped out after 18 hours.

Toxicity Test Results of Detergent Containing Citron Juice Using Daphnia Magna Time / detergent Blank Example 6 Example 7 Example 8 Example 9 Example 10 Commercial product 0 20 20 20 20 20 20 20 One 20 20 20 20 20 20 18 2 20 20 20 20 20 20 17 3 20 20 20 20 20 20 15 4 20 18 19 20 20 20 13 5 20 16 17 18 19 20 12 10 20 14 15 16 16 18 10 12 20 13 14 15 15 17 7 15 20 12 13 13 14 15 2 18 20 10 10 11 12 13 0 19 20 6 7 10 10 10 20 20 2 4 5 7 9 24 20 0 One One 2 3

Therefore, according to the results of Experimental Examples 5 and 6, LT ₅₀ (median lethal time) in citron detergent was found to be very low toxicity as 20 hours. It was very low toxicity compared to commercial products, and detergent made with citron juice was slightly more toxic than detergent made with citron seeds.

As described above, the detergent containing citron juice or citron seed oil of the present invention is a combination of natural cleaning power and pollution-free surfactant of citron juice, low foaming, rapid foam disappearance, and excellent washing power. In addition, it is very toxic and has a great effect to minimize environmental pollution with a natural cleanser, and citron juice and citron seeds contain skin cancer and other substances that suppress various cancers and vitamins useful for the skin to prevent skin damage. At the same time, because it has an excellent effect of protecting the skin is a very useful invention in the detergent industry.

Claims (3)

(a) mixing 5-18% by weight citron seed oil and 5-18% by weight of oleic acid and saponifying to produce soft soap and glycine, followed by mixing soft soap with glycerin; (b) cooling the mixture mixed in the step (a) to 20 ° C. or less to harden the curd; (c) recovering the hard curd in the step (b); (d) purifying the curd by dissolving the curd recovered in the step (c) in 95% ethanol containing no alkali and then hardening the curd again and recovering the ethanol one to three times; (e) 50% by weight of the mixture obtained by mixing water and citron juice at a ratio of 0 to 3: 1 to 2, cured 5 to 17% by weight of glycerin, and dodecylbenzenesulfonic acid After mixing 4 to 19% by weight of sodium salt and 0.5 to 2.0% by weight of propylene glycol alginate, the viscosity was adjusted in the range of about 30 cps to 35 cps, 0.2% by weight of retinol, 0.5 to 1% by weight of citric acid, and 4.3 to 0.8% by weight of NaHCO _3. Pollution-free detergent production method using citron, comprising the step of adding and aging. (a) filtering the citron juice and adjusting the pH to within the range of 5.5 to 7.0; (b) 1 to 6% by weight of propylene glycol alginate and 10 to dodecylbenzenesulfonate sodium salt to 61.3 to 65.8% by weight of the mixed solution obtained by mixing the citron juice and water obtained in the step (a) at a ratio of 1 to 2: 0 to 3. Adding 30% by weight, 5 to 20% by weight of glycerin, adjusting the viscosity to 30 to 35cp and adding 0.2% by weight of retinol; (c) a method of preparing a pollution-free detergent using citron, characterized in that it comprises the step of homogenizing by completely stirring the foam after rotating stirring the mixture containing the citron juice obtained in the step (b). A pollution-free detergent using citron prepared by the method according to claim 1 or 2.