Jang, Won-cheoul (607-302, Daewoncantavil Buldang-don, Cheonan-shi Chungnam 330-230, KR)
Heo, Seung-hyuk (987-36, Hogye 1-dong Donaan-k, Anyang-shi Kyonggi-do 431-081, KR)
Kim, Yong-gon (33/5, 1021-19 Bangbae 3-don, Seocho-ku Seoul 137-851, KR)
Jang, Won-cheoul (607-302, Daewoncantavil Buldang-don, Cheonan-shi Chungnam 330-230, KR)
Heo, Seung-hyuk (987-36, Hogye 1-dong Donaan-k, Anyang-shi Kyonggi-do 431-081, KR)
| 1. | A coagulant for preparing bean curds without salt water comprising cactus powder, an extract of cactus with at least one solvent selected from the group consisting of water, or methanol, acetone, ethanol, propanol, butanol, spirit alcohol or a mixture thereof, a low temperature extract of cactus or fermented liquid of cactus with a microorganism as a main component. |
| 2. | The coagulant according to claim 1, which further comprises chi tooligosaccharide and salt. |
| 3. | The coagulant according to claim 1, in which the cactus is Opuntia ficusindica L. var. saboten. |
| 4. | The coagulant according to claim 1, in which the microorganism is selected from bacteria and fungi. |
| 5. | A method for preparing bean curds using a coagulant defined in any one of claim 1 to claim 4, instead of salt water. |
PROCESS FOR PREPARING BEAN CURDS WITHOUT SALT
WATER
Technical Field
[1] The present invention relates to a process for preparing bean curds without salt water, and more particularly, a method for preparing bean curds by using a natural plant extract, instead of salt water or a chemical coagulant, to coagulate proteins of soymilk.
Background Art
[2] Bean curds are representative processed food of soy bean, including, for example, general bean curds, dumpling bean curd, soft bean curd, uncurdled bean curd, fried bean curd and the like. These bean curd products have used soy bean it self, so far, but recently, seek various functions of high-quality, health improvement and convenience due to advancement of life style.
[3] Bean curds having a simple and plain taste is a vegetable protein product containing amino acid and a great amount of mineral nutrients such as calcium and iron which are indispensable for body metabolism and growth and development and is an important and high quality source of protein supply to people who do not diet on meat but take proteins from cereals. Also, lipids of bean curds does not contain cholesterol at all but contain various bioactive substances such as lecithin and isoflavone which rather help to reduce a cholesterol level and thus, play a critical role as a health food to prevent adult diseases.
[4] Conventionally, bean curds are mainly prepared using salt water, which is a liquid having an astringent taste which is melted out of sun-dried coarse salt when magnesium chloride contained in the sun-dried coarse salt absorbs moisture in the air and becomes sticky. The salt water chemically comprises magnesium chloride (15-19%), magnesium sulfate (6-9%), potassium chloride (2-4%), sodium chloride (2-6%) and magnesium bromide (0.2-0.4%). The magnesium component, which gives the astringent taste, is an indispensable component for coagulating bean curds. However, the salt water may contain heavy metals such as arsenic, which is harmful to the human bodies, due to pollution of the sea and thus is prohibited from being used as a coagulant.
[5] Therefore, bean curds are recently made using a chemical coagulant instead of salt water. Now, chemicals which are approved as a coagulant of bean curds are four types: magnesium chloride, calcium chloride, calcium sulfate and Glucono-δ-Lactone. However, these chemicals also may cause problems with respect to human body
safety. Many methods for producing bean curds without salt water use vinegar and salt.
[6] As a technique for producing bean curds without using salt water, Korean Patent
Application No. 2001-3625, filed on January 22, 2001, discloses a method for producing bean curds using an extract of fruit of Maximowiczia chinesis, squash, Big Blue Lilyturf (Liriope platyphylla), Astragalus uliginosus and ginseng, as a coagulant. This method, though being an epoch technology by using oriental medicinal herb extracts as a coagulant, is insufficient in terms of proper harmony between the medicinal herbs and the food or economical efficiency of materials, astringent taste resulting from the plant extracts and needs more or less time to satisfy the requirements of consumers.
[7] Therefore, it is desired to develop a novel coagulant which can substitute the conventional chemical coagulant and provide functions to bean curds. Disclosure of Invention Technical Problem
[8] The present inventors have conducted researches to solve the problems involved in the prior art and found that when bean curds is prepared using cactus powder, cactus extract or fermented liquid thereof as a coagulant, bean curds can be readily coagulated and the coagulant which is derived from natural substances is safe to human bodies and provide sufficient nutrients since the components derived from the natural substances show synergic effect and supplementation effect with the nutrients of bean curds. Based on these discoveries, the present invention has completed. Technical Solution
[9] Therefore, in order to solve the problems involved in the prior art, it is an object of the present invention to provide a coagulant for preparing bean curds without using salt water, in which the bean curds are safe to human bodies and have various functions, and a method for preparing bean curds without salt water. Advantageous Effects
[10] By the coagulant for preparing bean curds without salt water according to the present invention and the bean curds prepared by using the same, it is possible to avoid harmfulness argument of the convention coagulant used to prepare bean curds since the coagulant according to the present invention uses edible material derived from natural plants and to provide a functional food having a synergic effect of nutrition with various pharmacologically beneficial ingredients contained in the bean curds since various minerals, amino acids, unsaturated fatty acids, saponin and other nutrients, that is, amino acids, calcium, iron, vitamins and the like contained in the plants can be transferred into the bean curds. Also, according to the present invention, by using
natural materials as they are, the treatment process is simple and stable. Best Mode for Carrying Out the Invention
[11] According to the present invention, there is provided a coagulant for preparing bean curds using a natural food extract instead of salt water and a method for preparing bean curds using the same. Mode for the Invention
[12] The coagulant for preparing bean curds without salt water according to the present invention comprises cactus powder, an extract of cactus with at least one solvent selected from the group consisting of water, or methanol, acetone, ethanol, propanol, butanol, spirit alcohol or a mixture thereof, a low temperature extract of cactus or fermented liquid of cactus with a microorganism as a main component, and may further comprise chitooligosaccharide and a salt to flavor the bean curds in a small amount.
[13] For cactus, the main component of the coagulant, its fruit or stem can be used. Particularly, Opuntiaficusindica L. var. saboten or Opnutiaficus indica are preferably used.
[14] Palm cactus (Opuntiaficus-indica L. var. saboten) is a perennial plant derived from the tropical regions and is naturally grown and cultivated in Jeju island, Korea. Its fruit is edible and from ancient times, as a folk remedy, people drinks juice of its stem or fruit for treatment of constipation, diuretic effect, activation of bowl movement and stimulation of appetite. The stem of cactus is known to have effect in the treatment of dermal diseases, rheumatism and skin burn. According to the traditional oriental medical science, it is a curative herb which has been used for a long period of time. Particularly, it has been used for treatment of nervous pain, as a stomachic, a nutritional tonic agent, an antipyretic sedative agent, an antiphlogistic detoxicant, and a therapeutic agent for acute breast infection or dysentery. Also, it has been used for the purpose of making the blood clear and treating melaena. Further, its radical removal effect, tyrosinase-inhibiting effect and anti-allergy effect are recently recognized and thus, medicines and functional cosmetic products using cactus are actively developed. Particularly, since people at the present are exposed to allergens in various forms as industrialization is accelerated, its function to improve allergic and atopy dermal disease are under examination.
[15]
[16] *Cactus is rich in various nutrients and minerals, as shown in Table 1 and Table 2 and is developed into favorite foods in various forms for sale. Also, it is added to cosmetic products such as soap.
[17] Table 1
[18]
[19] It is known that among the above-listed nutrients, that monounsaturated fatty acid lowers cholesterol level in the blood to reduce risk of development of cardiac diseases and w-3 type fatty acids which are polyunsaturated fatty acids reduce neutral fat level in the blood, thereby preventing blood from clotting and development of cardiac diseases. Ingestion of these fatty acids in an amount of about 25Og per week is of benefit. Though w-6 type fatty acids can reduce the risk of development of cardiac diseases by lowering the cholesterol level in the blood, it may lower HDH-cholesterol, which is known to transfer cholesterol in the blood to the liver to facilitate the blood circulation. Further, palm cactus is rich in minerals and vitamins.
[20] As described above, since cactuses, including palm cactus, contains a substance to cause coagulation of bean curds, it can be used as a coagulant in preparation of bean curds without using salt water. Also, by using the cactus, according to the present invention, various minerals, amino acids, unsaturated fatty acids, saponin, other nutrients, that is, amino acids, calcium, potassium and vitamins, which are contained in the cactus can be transferred to the produced bean curds, whereby it is possible to expect synergic effect in terms of nutrition science. Particularly, since cactuses contain calcium 50 times more than milk and 5 times more than anchovy, it is possible to provide functional bean curds suitable for young people. In addition, according to the present invention, the bean curds can be made by using a natural material without additional treatment and thus, the process for preparation is advantageous in its convenience, cheapness and stability.
[21] According to the present invention, the bean curds is prepared by using 1) cactus powder obtained by pulverizing the cactus into fine powder, 2) an extract or a low temperature extract of cactus extracted with at least one solvent selected from water, methanol, acetone, ethanol, propanol, butanol, spirit alcohol or a mixture thereof, or 3) a fermented liquid of cactus with a microorganism, instead of salt water.
[22] When the cactus powder is used, the powder is prepared by pulverizing cactus using a continuous mill, such as a colloid mill.
[23] Also, when the cactus extract is used, the extract is prepared by extracting cactus with at least one solvent selected from water, methanol, acetone, ethanol, propanol, butanol, spirit alcohol or a mixture thereof, or a mixture of organic solvents, preferably by low temperature extraction. Particularly, with respect to the low temperature extraction, Korean Patent Application No. 10-2005-0006059, filed on January 22, 2005 by the present application may be referred to and the entire disclosure is incorporated by reference herein. The extraction solvent which can be used in the present invention includes water, methanol, acetone, ethanol, propanol, butanol, spirit alcohol or a mixture thereof, with preference being water, ethanol or spirit alcohol.
[24] Also, according to the present invention, a fermented liquid of cactus may be used as a coagulant. Cactus contains a great amount of polysaccharides having a high molecular weight. Therefore, it is preferred that those polysaccharides are degraded into low molecular weight to provide readiness of preparation (ex., readiness of handling or filtration) and to facilitate coagulation. More concretely, screened row material is washed with clean water and finely crushed in a continuous pulverizer. The resulting powder is mixed with water in a mixing ratio of cactus powder: water of about 1:2-5, while stirring. Then, the mixture is ground into a gel state using a mill to form a flowable liquid, which is transferred to a fermentation tank. Sugar is added to the tank in an amount of half of the cactus powder to make a sugar content of about 15 Brix. Next, microorganisms and enzymes are added thereto and cultured at a temperature between 28 C and 33 C for 7 to 10 days.
[25] In a preferred embodiment according to the present invention, by using a fermented liquid of cactus with microorganisms, it is possible to enhance the coagulation of bean curds. The fermentation is preferably performed by using a combination of various microorganisms for an optimal result, as compared to a single microorganism or a single microorganism group.
[26] Examples of the microorganisms which can be used in the fermentation according to the present invention include, but are not limited to, bacteria and fungi, preferably, Lactobacillus sp., Bacillus sp., Streptomyces sp., Eumycetes, yeasts or a mixture thereof.
[27] Examples of lactobacillus or combined lactobacillus includes, but is not limited to,
Streptococcus lactis, Lactobacillus plantarum, Lactobacillus acidophillus, Lactobacillus brevis, Lactobacillus casei, Lactobacillus fermentum, Streptococcus lactis , Pediococcus acidlacticii, Pediococcus cerevisiae and the like and a lactobacillus strain on the FDA list of GRAS (Generally Regarded As Safe) microorganisms may be cultured and fermented. It is known that Lactobacillus sp. have excellent degradability
of cellulose of a substrate and strengthen immune function of human beings, animals and fishes. Examples of Bacillus sp. include Bacillus subtilis, Bacillus natto, Bacillus megaterium, Bacillus amyloliquefaciens, Bacillus brevis and the like and examples of Streptomyces sp. include Streptomyces griseus, Streptomyces expoliatus and the like. In addition, microbes of Micrococcus sp. (ex., Micrococcus leteus), microbes of M- trosomonas sp. (ex., Nitrosomonas monocella), microbes ofAerobactor sp. (ex., Aerobactor cloacae) may be used alone or in combination. Examples of Eumycetes include Saccharomyces cerevisiae, Candida sake, Mortierella elongata, Mucor circinelloides, Aspergillus sp., such as Aspergillus japonicus, Aspergillus oryzae and Aspergillus sojae, Penicillium waksmani, Tricoderma lignorum, Rhizopus sp., such as Rhizopus oligosporus and the like.
[28] Examples of yeast include Sacchromyces sp. (ex., Sacchromyces cerevisiae, Saccharomyces carlsbergenais), Trulopsis sp. (ex., Torulopsis versatillis, Torulopsis ethellsii), Debaryomyces sp. (ex., Debaryomyces hancenii), Pichia sp. (ex., Pichia fabianii, Pichia guilliermondif), Hypopichia sp. (ex., Hypopichia burtonii), Galactomyces sp. (ex., Galactomyces geotrichum), Zygosaccharomyces sp. (ex., Zy- gosaccharomyces rouxii, Zygosaccharomyces sulsus, Zygosaccharomyces major, Zygosaccharomyces soya, Zygosaccharomyces japonicus) and the like.
[29] The foregoing microorganisms are only for the purpose of illustration and it is clear that a person skilled in the art may select the known microorganisms in accordance with his technical knowledge. Also, the microorganisms may be those existing in the nature, or commercially available as a type strain, for example, a spawn (zymogen, Korean organic agriculture resource center) or a strain mixture, or distributed from a depository institution of microorganisms.
[30] Examples of enzymes include protease, cellulase, amylase, or phytase. During the fermentation process, it is preferred that temperature adjustment and foam removal are performed twice per day. At the end of the fermentation, residue and foam are settled down and the liquid is subjected to microfiltration. The resulting filtrate is put in a vacuum distiller, kept at 65 to 68°C, to remove alcoholic components and other odors. The fermented liquid thus obtained is then used as a coagulant derived from cactus.
[31] In addition to the cactus derived extract, chitooligosaccharide, salt, and other common supplements may be added to the coagulant for preparing bean curds without salt water, as needed.
[32] Chitooligosaccharide has a polymerization degree of chitosan with D-glucosamine of 2 to 10 or 2 to 15 bonds and a molecular weight of about 2,500 or less. Its preparation is performed by chemical degradation using HCl and enzymatic degradation. The enzymatic degradation produces chitooligosaccharides with relatively high safely. The chitooligosaccharides may be commercially available from various
suppliers. Salt is added to flavor the bean curds and the added amount is preferably adjusted in the range of 0.3 to 2% according to the taste or final purpose of the food. The common supplements include carageenan, sodium alginate, agar, lecithin, and other chemical coagulants which are commonly used, in a small amount, as needed.
[33] The preparation of the bean curds prepared using the coagulant according to the present invention, instead of salt water, is performed by the convention methods. Now, the method for preparing the bean curds without salt water is described in detail.
[34] a) Screening and washing of soy beans
[35] The given soy beans are screened to remove crumbled beans, wormy beans, other grains and foreign substances and thoroughly washed. Since soil and dust contain thermal resistant microorganisms, which may cause decomposition of bean curds when they are introduced to the bean curds, such foreign substances should be properly treated. The washed soy beans are soaked in water and ground with water to form soymilk which is a colloidal suspension having proteins and various salts of soy beans dissolved in water.
[36] b) Coagulation and shaping
[37] This step is for treating the soymilk with a coagulant to coagulate proteins and fats in the soymilk. While the soymilk is boiled with a coagulant at a temperature of 100 C or less, colloidal proteins precipitate and are solidified to form gel. Here, the added amount of the coagulant is important. The coagulant is added in an amount of about 1 to 15% relative to the volume of the soymilk. When the coagulant is prepared using the powder of cactus stem, the coagulant comprising an aqueous solution of 5 to 20 wt%, preferably 10 wt%, of cactus powder and 3 to 10 wt%, preferably 5 wt%, of chi- tooligosaccharide is mixed with soymilk in an amount of 5 to 15%, preferably 10 % based on the soymilk.
[38] When the coagulant is prepared using an extract or a low temperature extract of cactus with water or organic solvents, the coagulant is used in an amount of 3 to 20%, preferably about 10%.
[39] When a fermented liquid of cactus is used as the coagulant, a mixture of cactus and water in a weight ratio of cactus: water of 1 :5 (preferably about 1:2) is condensed to two times to prepare the coagulant, which is then added to the soymilk in an amount of about 1 to 10% based on the volume of the soymilk. Here, the amount of chi- tooligosaccharide is used in the same amount, though it is not particularly limited.
[40] The water used to prepare the coagulant is suitably functional water comprising non-toxic strong alkali material synthesized by combining an extract of natural minerals and shell fish with metal ions, though it may be purified water. Such functional water has various functions and can radiate far-infrared ray. Thus, it is a multi-functional material which can lead various chemical changes by a minimum
activation energy. Its preparation method is disclosed in Korean Patent Application No. 10-2001-0023306, filed on April 30, 2001 by the present applicants, the entire disclosure of which is incorporated herein by reference.
[41] By the coagulant for preparing bean curds without salt water according to the present invention and the bean curds prepared by using the same, it is possible to avoid harmfulness argument of the convention coagulant used to prepare bean curds since the coagulant according to the present invention uses edible material derived from natural plants and to provide a functional food having a synergic effect of nutrition with various pharmacologically beneficial ingredients contained in the bean curds since various minerals, amino acids, unsaturated fatty acids, saponin and other nutrients, that is, amino acids, calcium, iron, vitamins and the like contained in the plants can be transferred into the bean curds as functional nutrients. Also, according to the present invention, by using natural materials as they are, the treatment process is simple and stable.
[42] Now, the present invention is explained in detail by the following examples.
However, it should be understood that the present invention is not limited thereto.
[43]
[44] Example 1 : Preparation of chitooligosaccharide solution
[45] 50 g of chitooligosaccharide powder, supplied from Kunpoong Bio Co., Ltd. was taken in 11 of water while stirring to form an aqueous solution of chitooligosaccharide.
[46]
[47] Example 2: Preparation of bean curd using cactus powder instead of salt water
[48] 10 Kg of Palm cactus (Opuntiaficus-indica L. var. saboteή) cultivated in a farm located in Cheonan-si, Choongnam, Korea was pulverized with a colloid mill to obtain cactus powder. 100 g of the resulting cactus powder was added to 11 of the chitooligosaccharide solution prepared in Example 1, while stirring, to form the cactus powder coagulant.
[49] Meanwhile, 10 kg of sorted soy beans were thoroughly washed, soaked in 100 1 of distilled water and ground with water to form soymilk. Thereto, the coagulant solution was added in an amount of 12% based on the volume of the soymilk to coagulate the soymilk. After about 30 minutes, when the coagulation was completed, the coagulated soymilk was transferred to a mold and pressed to remove water.
[50]
[51] Example 3: Preparation of bean curd using a coagulant of fermented cactus extract instead of salt water
[52] 100 kg of cactus was mixed with 2001 of water, while stirring. The mixture was ground with a colloid mil into the gel phase to form a flowable liquid. The resulting liquid was transferred to a fermentation tank and 45 kg of sugar was added thereto to
set the sugar content of 15 Brix. Then, 500 g of Saccharomyces cerevisiae (KCTC 7238) and 350 g of protease were added to the tank and the content was cultivated at a temperature of 30 C for one week. Here, bubbles were periodically removed. At the end of the fermentation, residue and bubbles were removed and the cultivate was passed through a filter paper of 10OD. The resulting filtrate was placed in a vacuum distiller, kept at 65 C, to completely removed alcohols and other odors to prepare a fermented concentrate.
[53] Next, the chitooligosaccharide solution prepared in Example 1 was mixed with the fermented concentrate of cactus in a mixing ratio of 3:8, while stirring, to prepare a coagulant of fermented cactus concentrate.
[54] 10 kg of sorted soy beans were thoroughly washed, soaked in 100 1 of distilled water and ground with water to form soymilk. Thereto, the coagulant solution was added in an amount of 12% based on the volume of the soymilk, and kept at 100 C to coagulate the soymilk. After about 30 minutes, when the coagulation was completed, the coagulated soymilk was transferred to a mold and pressed to remove water.
[55]
[56] Example 4: Preparation of bean curd using a coagulant of water extract of cactus
[57] 100 kg of cactus was mixed with 2001 of water, while stirring. The mixture was ground with a colloid mil into the gel phase to form a flowable liquid. Residue and bubbles were removed and the cultivate was passed through a filter paper of 10OD. The resulting filtrate was placed in a vacuum distiller, kept at 65 C, to completely remove alcohols and other odors. Next, the mixture was mixed with the chitooligosaccharide solution prepared in Example 1 and the in a mixing ratio of 3: 10, while stirring, to prepare a coagulant of cactus water extract.
[58] 10 kg of sorted soy beans were thoroughly washed, soaked in 100 1 of distilled water and ground with water to form soymilk. Thereto, the coagulant solution was added in an amount of 13% based on the volume of the soymilk, and kept at 100 C to coagulate the soymilk. After about 30 minutes, when the coagulation was completed, the coagulated soymilk was transferred to a mold and pressed to remove water.
[59]
[60] Example 5: Preparation of bean curd using a coagulant of ethanol extract of cactus
[61] 200 kg of cactus was mixed with 1001 of aqueous ethanol (70%), while stirring.
The mixture was ground with a colloid mil into the gel phase to form a flowable liquid. Zeolite was added to the liquid to remove residue and bubbles and the cultivate was passed through a filter paper of 10OD. The resulting filtrate was placed in a vacuum distiller, kept at 65 C, to completely remove alcohols and other odors. Next, the bean curd was prepared by following the procedures described in Example 4.
[62]
[63] Example 6: Preparation of bean curd using a coagulant of spirit extract of cactus
[64] 200 kg of cactus was mixed with 1001 of alcohol spirit (30%), while stirring. The mixture was ground with a colloid mil into the gel phase to form a flowable liquid. Zeolite was added to the liquid to remove residue and bubbles and the cultivate was passed through a filter paper of 10OD. The resulting filtrate was placed in a vacuum distiller, kept at 65 C, to completely remove alcohols and other odors. Next, the bean curd was prepared by following the procedures described in Example 4.
[65]
[66] Experimental example 1 : Examination of coagulation of bean curds
[67] The coagulant comprising the cactus powder, fermented liquid or water extract of cactus, chitooligosaccharide and a small amount of salt according to the present invention and the coagulant of 20% MgCl as control showed similar coagulation time, when they were added to soymilk in a ratio of 2%(v/v). Both of them completely coagulated the soymilk in about 30 minutes. Therefore, it was proven that the coagulant according to the present invention could substitute the chemical coagulant in terms of coagulation time and coagulation rate. Industrial Applicability
[68] As described above, the coagulant for preparing bean curds according to the present invention has functions and preference improved by using an edible plant, particularly, an extract of cactus and a functional food material such as chitooligosaccharide. Concretely, since a chemical coagulant is not used, the coagulant is safe to human bodies. Also, since nutrients derived from plant components are transferred through the coagulant to the bean curds, it is possible to provide nutrients with multiplied functions at firsthand and to increase the income of rural household growing cactus and to reduce the preparation cost of bean curds at secondhand.
[69]
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