HK1051951B - Water-soluble bean-based extracts - Google Patents

Description

Water-soluble bean extract

Background

One of the latest and most interesting areas in nutritional research includes food ingredients called phytochemicals. Phytochemicals, such as isoflavones and their derivatives, are found only in plants, and although not classified as nutraceuticals, they profoundly affect our health. See, e.g., the w.r.bidestack et al: phytochemicals, a new paradigm, published by Technomic press, 1998.

The discovery of phytochemicals has led to the dawn of a new era of nutrition. Phytochemicals found in legumes such as soybeans are of particular importance. Legumes and products thereof, such as soybeans and soy products, provide a particular avenue for reducing the occurrence of many chronic diseases such as cancer. See journal of agro-food chemistry, 42, 1666 (1994); and 43, 1184 (1995). Recent studies have shown that a daily meal of soy food is sufficient to obtain the benefits of these food chemicals (see M.Messina et al: pure soy and our health, NY, Garden City park, published by Avery Press, 1994).

However, most of people do not want to eat soybean food because of its bad smell and coarse texture. To avoid dislike of soybean foods, one solution has been to use soybean isoflavones as dietary supplements, but unfortunately soybean isoflavones and their derivatives have not been utilized because of their low water solubility. See r.elkinsa: genistin, utah, happy valley, published by Woodland press, 1998.

Summary of The Invention

In one aspect, the invention features a wet or dry extract of water-soluble legumes that includes one or more isoflavone derivatives represented by the formula:

in the formula R₁Hydrogen or hydroxy, R₂Is hydrogen or methoxy, R₃Is hydrogen or CO-R₁，R₄Is methyl or carboxymethyl. The water-soluble bean extract comprises about 5 to about 50 parts by weight of isoflavone derivative in dry state, and has a solubility in water of about 10 to about 1000mg/ml at about 25 deg.C. Examples of isoflavones present in the water-soluble bean extract include daidzin (daidzin), genistin (genistin), daidzin (glycitin), 6 ' -O-acetyl daidzin, 6 ' -O-acetyl genistin, 6 ' -O-acetyl daidzin, 6 ' -O-malonyl genistin, or 6 ' -O-malonyl daidzin.

The water-soluble legume extract of the present invention includes one or more isoflavone derivatives, such as an isoflavone glycoside, which complex with the other ingredients of the legume and unexpectedly increases water solubility.

In another aspect, the present invention features a method of preparing a water-soluble bean extract, comprising mixing a powdered crude bean extract with water, heating the mixture, adding a coagulant to the mixture to form a suspension, heating the suspension, and collecting the supernatant to obtain the water-soluble bean extract. The water-soluble bean extract has good flavor, and can be used as a suitable composition for food with good performance. It can be mixed with food such as milk, tea, soft drink, fruit juice, coffee, flavoring agent, grain, water, beer, cracker, chewing gum, chocolate or soup.

Other features and advantages of the invention may be apparent from the following further description, and from the claims.

Brief description of the drawings

FIG. 1 is an HPLC chart of the main components in the water-soluble bean extract prepared in example 1.

Detailed description of the invention

The present invention relates to a water-soluble bean extract comprising one or more isoflavone derivatives of the formula

In the formula R¹Is hydrogen or hydroxy, R²Is hydrogen or methoxy, R³Is hydrogen or CO-R¹，R⁴Is methyl or carboxymethyl.

Examples of isoflavones present in the water-soluble bean extract of the present invention include daidzin (daidzin), genistin (genistin), daidzin (glycitin), 6 ' -O-acetyl daidzin, 6 ' -O-acetyl genistin, 6 ' -O-acetyl daidzin, 6 ' -O-malonyl genistin, or 6 ' -O-malonyl daidzin. Isoflavone glycosides such as soybean isoflavone glycoside and genistin are absorbed in stomach or small intestine, and are metabolized into isoflavone via aglycone by microorganisms producing rhamnose, exo- β -glucoside, and endo- β -glucoside in human small intestine. See, e.g., biol. pharm. bull, 22 (1998); biol.pharm.bull, 17, 1369 (1994); arch.pharm.res., 21, 17 (1998).

The water-soluble bean extract of the present invention enhances water solubility, which improves physiological absorption of isoflavone derivatives when used in foods. For example, genistein glycoside has a solubility of about 5mg/ml in methanol at 25 ℃ and about 1mg/ml in water at 25 ℃, whereas the water-soluble bean extract of the present invention comprising about 10% isoflavone derivatives has a solubility of about 300mg/ml in water. Typically, the water-soluble bean extract of the present invention increases the solubility of isoflavone derivatives by about 30-fold. Comprising from about 10 to about 50 parts by weight of an isoflavone derivative when dry, having a solubility in water of from about 10 to about 1000mg/ml at about 25 ℃; preferably, from about 10 to about 20 parts by weight of isoflavone derivative, having a solubility in water of from about 30 to about 300 mg/ml; more preferably, the isoflavone derivative is present in an amount of about 10 to about 20 parts by weight and has a solubility in water of about 50 to about 200 mg/ml. Of course, the weight percentage of isoflavone derivatives affects the overall solubility of the water-soluble bean extract. For example, higher weight percentages of the extract containing isoflavone derivatives have lower total solubility than lower weight percentages of the extract containing isoflavone derivatives.

Any beans can be used to make the water-soluble bean extract of the present invention. The beans used to produce the water-soluble bean extract of the present invention include, but are not limited to, soybeans, mung beans, black beans, and kidney beans. The preferred legume is soybean. The water-soluble bean extract of the present invention can be generally produced from two different types of soybeans, such as an edible bean and an oil-producing bean. The oil-producing beans are more preferable than the edible beans because the protein content of the oil-producing beans is smaller. Typically, the oil content of the oil-producing beans is first removed to produce processed beans. Oil removal methods can be found in k.s.liu: soybean chemistry, technology and utilization, published by Aspen press, 1999, gaikubao.

The method of preparing the water-soluble bean extract of the present invention comprises mixing about 1 part to about 50 parts by weight of a crude extract of bean flour and about 100 parts of hot or cold water. The crude extract of soybean flour can be prepared by extraction with about 50-90% aqueous alcohol or 100% organic solvent, such as ethanol, methanol or acetonitrile. An example of a crude extract of soybean flour is soybean paste. The soy paste represents about 1% by weight of the soybeans, however, contains a higher concentration of isoflavone derivatives relative to the remaining soybean fraction. For example, the isoflavone derivatives in the soybean paste are about 30 times higher than the remaining soybean part. See k.s.liu: soybean chemistry, technology and utilization, published by Aspen press, 1999, gaikubao. Soybean flour crude extracts such as soybean paste are available from Schousten, USA, such as SoyLife150 and SoyLife 25. Alternatively, the crude extract of soy flour is available from Archardianies Midland, USA, such as NOVASOY.

The mixture of water and the crude extract of the bean flour is then heated to a temperature of between about 60 and 100 c for about 10 to 120 minutes, and about 2.0 parts by weight of a coagulating agent is added per 100 parts by weight of water to form a suspension, which is then heated to a temperature of between about 30 and 100 c for about 1 to 120 minutes. The supernatant is collected by filtration or centrifugation to obtain a water-soluble bean extract having increased solubility. In addition, an acid or base may be added to adjust the Ph of the suspension or supernatant to avoid precipitation of the isoflavone derivative. Typically, the Ph is adjusted to about 6.0.

The resulting supernatant can be decolorized to remove any undesirable color. Decolorizing methods include, but are not limited to, hydrogenation of nickel Ni catalysts and bleaching processes for making soybean oil. The decolorization method can be found in k.s.liu: soybean chemistry, technology and utilization, procrastina, maryland, gezibao, published by Aspen press, 1999, and p.j.wan: oil & fat technology, illinois, wilderness, AOCS press. The supernatant may also be concentrated using known distillation systems including, but not limited to, molecular distillation or evaporation. An example of a molecular distillation system is the Wiped-Film Still available from the INC company, 351N.Dekora Woods Blv.Saukville, WI53080, POPESCIENTIFIC, USA. Further, this supernatant may be dried by any known drying method such as lyophilization or spray drying (UPS5,882,717).

The water-soluble bean extract of the present invention may be prepared by a batch process or a flow process, i.e., a continuous extraction and filtration process. Typically, a flow process is used to maintain reasonable manufacturing costs.

To increase the solubility of the isoflavone glycoside, about 0.001 to 3.0 parts by weight of a coagulant, such as CaCl2, CaSO4, MgCl2, MgSO4, any organic or inorganic acid (e.g., citric acid, fumaric acid, lactic acid, malic acid, tartaric acid, H2SO4, H3PO4 or HCl), saccharin, glucono-D-lactone, and papain, is added to 100 parts by weight of water. In the production of the extract, a coagulant is added to form insoluble aggregates of soy protein or polysaccharide by simple cross-linking or modification. The concentration of the coagulant directly affects the amount of soy protein or polysaccharide in the extract. For example, a greater amount of coagulant results in the formation of more insoluble aggregates. This effect allows to control the total amount of water-soluble proteins and polysaccharides in the extract and the solubility of isoflavone derivatives. The amount of coagulant added is determined by measuring the fat, protein and inorganic acid content of the resulting bean extract. Generally, sufficient coagulant is added to produce about 1% or less fat, about 1 to 5% protein, about 0.01 to 3% Na, about 0.01 to 3% Ca, and about 0.01 to 3% of any acid. The amount of, for example, fat, protein, Na, Ca, acid in the water-soluble bean extract can be determined by any known analytical method, for example, an analytical method according to the Food and Drug Administration (FDA) recommendation. Typically, about 0.3 parts by weight of citric acid is added to the extract. Generally, if the coagulant is added too much, water-soluble soy proteins, polysaccharides or isoflavone derivatives are co-precipitated from the extract, thereby reducing the concentration or solubility of the isoflavone derivatives in the extract. If the coagulant is added too little, the bean mixture becomes gelatinous, and it is difficult to separate the water-soluble bean extract therefrom.

The water-soluble bean extract of the present invention may be added to foods in a dry state or a wet state. The food product may be solid, paste or liquid, such as milk, tea, soft drink, juice, coffee, sauce, cereal, water, beer, cracker, chewing gum, chocolate or soup.

The water-soluble bean extract of the present invention also includes co-extracts of other grains such as barley, rice, malt, etc. For example, one or more other grains and legumes may be processed as described above to form the water-soluble legume extract of the present invention. In addition, the water-soluble legume extract may be enhanced with electrolytes, flavors, preservatives, and other additives (e.g., vitamin supplements and maltodextrins). Examples of preservatives include, but are not limited to, ascorbic acid and propyl gallate, and examples of electrolytes include, but are not limited to, magnesium sulfate and potassium chloride.

Without further elaboration, the foregoing description has fully disclosed the invention. The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto. All publications, including patent publications, are incorporated herein by reference.

Example 1

To 1 kg of the crude extract of soybean flour extracted with about 90% aqueous ethanol, 3 liters of hot water at 70 ℃ was added, for example, to SoyLife150 available from Schousten, USA. After stirring at 90 ℃ for 30 minutes and 50 ℃ for 30 minutes, the residue and the solution were roughly separated by centrifugation at 10,000 Xg at 50 ℃. After decantation, 6 g (about 0.02M) of food additive grade calcium chloride was added to the supernatant and after stirring for a further 30 minutes at 30 ℃ the supernatant was filtered through a 1 μ M microfilter to give a yellow solution (2.5 l). The filtrate was transferred to a 5-L glass flask and hydrogenated in the presence of a catalytic amount (about 3 g) of 5% pd/c at 10 atm for 5 hours. The decolorized mixture was filtered through a 0.2 μm microfilter to give a clear water-soluble bean extract solution (2.3 liters).

The water-soluble bean extract solution was characterized by High Pressure Liquid Chromatography (HPLC). HPLC is a C18 reversed phase column 150X 4.6mm symmetrical masked RP18 from Waters corporation, which was dissolved at 30 ℃ for 20 minutes at 1ml/min with 15-40% acetonitrile in water and 0.1% trifluoroacetic acid according to gradient elution. The HPLC apparatus was set at 254 nm. FIG. 1 shows an HPLC chart of the main components in the water-soluble bean extract of example 1. The respective peaks, residence times, peak areas and area percentages are shown in Table 1. Several components in the extract were identified by comparing the retention time of the unknown components with the retention time of the known isoflavone glycosides analyzed by HPLC under the same experimental conditions.

The water-soluble bean extract solution is also characterized by measuring the relative amount of the extract components. A sample of the extract was sent to a food laboratory company located in bordeaux, usa and analyzed according to the FDA recommended method, resulting in a composition containing < 0.1% fat, 5% protein, 65% carbohydrate (polysaccharide), 20% isoflavone, 8% mineral and 1% moisture.

TABLE 1 HPLC analysis of soluble Soy product from example 1

#	Residence time (minutes)	Peak area	Area%	Compound (I)
					123456789101112131415161718192021	6.9407.2317.6618.0908.50710.37610.65211.06911.68511.99012.76613.04813.46113.77115.72315.94217.26517.73718.23618.82225.657	56.9585.42164.095129.912722.5819.6823.8934.82367.981378.4975.1952.953038.541421.8833.0843.6358.45867.85288.12196.9947.89	0.350.531.0231.8516.900.120.150.222.288.560.470.3318.868.830.210.270.365.391.791.220.30	Uncertain soy isoflavone glycoside the daidzin acetyl daidzin glycyl genistin uncertain genistin glycyl daidzin glycyl genistin
	Total up to	16108.41	100.00

Example 2

The crude extract (1 kg) of soybean flour extracted with about 90% aqueous ethanol was added with 27 liters of hot water at 70 ℃ to SoyLife150 available from Schousten, USA, and after stirring at 90 ℃ for 15 minutes, 3 liters of 90 g aqueous citric acid was injected. After stirring at 90 ℃ for 15 minutes, it was filtered through a celite bed filter under vacuum. The filtrate was a pale yellow clear solution (27 liters). Potassium carbonate (50 g) was added to adjust the pH to 6.0. After purification by filtration through a 0.45 μm pore filter (Millipore) under vacuum, the extract was concentrated with a 2-inch Wiped-Film Still (HOPE science) at 70 ℃ under 20mm Torr to give a pale yellow water-soluble bean extract solution (18L).

Example 3

After 2 liters of the water-soluble bean extract solution was obtained by the method of example 1, it was lyophilized for 2 days at-85 ℃ and 10mm Torr using a lyophilizer manufactured by Bertis Corp, to obtain 350 g of pale yellow dry cake. The dry cake contained 70 g of isoflavone derivative and had a solubility of about 200 mg/ml. Solubility was determined by first stirring 1 g of the dried extract in 1ml of pure water at 25 ℃ for 5 minutes, then observing whether the mixture was completely dissolved, and if not, adding 1ml of water and stirring at 25 ℃ for 5 minutes. Further, whether or not the solution was completely dissolved was observed, and if not, 1ml of water was added thereto and the mixture was stirred at 25 ℃ for 5 minutes until complete dissolution was observed.

OTHER EMBODIMENTS

All of the features disclosed in this specification may be combined in any suitable manner. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

And from the foregoing, it will be readily apparent to those skilled in the art that various changes and modifications can be made in the invention to adapt it to various usages and conditions without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (29)

1. A water-soluble bean extract comprising one or more isoflavone derivatives of the formula:

in the formula R₁Is hydrogen or hydroxy, R₂Is hydrogen or methoxy, R₃Is hydrogen or CO-R₄，R₄Is methyl or carboxymethyl, and the water-soluble bean extract comprises5-50 parts by weight of an isoflavone derivative having a solubility in water at 25 ℃ of 10 to 1000 mg/ml; and the water-soluble bean extract is prepared by the following method: mixing 1 to 50 parts by weight of the powdered crude bean extract with 100 parts by weight of water; heating the mixture to a temperature of between 60 and 100 ℃ for a period of between 10 and 120 minutes; adding a coagulant to this mixture at 0.001 to 3 parts by weight per 100 parts by weight of water to form a suspension; heating the suspension to a temperature of between 30 and 100 ℃ for a period of between 1 and 120 minutes; and collecting the supernatant by filtration or centrifugation to obtain a water-soluble bean extract.

2. The water-soluble bean extract according to claim 1, wherein the bean extract is based on soybean, mung bean, black bean, or kidney bean.

3. The water-soluble bean extract according to claim 1, wherein the bean extract is based on soybean.

4. The water-soluble bean extract according to claim 1, wherein the water-soluble bean extract comprises 10 to 20 parts by weight of isoflavone derivative in a dry state and has a solubility in water at 25 ℃ of 30 to 300 mg/ml.

5. The water-soluble bean extract according to claim 1, wherein the water-soluble bean extract comprises 10 to 20 parts by weight of isoflavone derivative in a dry state and has a solubility of 50 to 200mg/ml in water at 25 ℃.

6. The water-soluble bean extract according to claim 1, wherein the isoflavone derivative is soybean isoflavone glycoside, genistin, daidzin, 6 "-O-acetyl soybean isoflavone glycoside, 6" -O-acetyl genistin, 6 "-O-acetyl daidzin, 6" -O-malonyl soybean isoflavone glycoside, 6 "-O-malonyl genistin or 6" -O-malonyl daidzin.

7. The water-soluble bean extract according to claim 6, wherein the bean extract is based on soybean.

8. The water-soluble bean extract according to claim 6, wherein the water-soluble bean extract comprises 10 to 20 parts by weight of isoflavone derivative in a dry state and has a solubility in water at 25 ℃ of 30 to 300 mg/ml.

9. The water-soluble bean extract according to claim 6, wherein the water-soluble bean extract comprises 10 to 20 parts by weight of isoflavone derivative in a dry state and has a solubility of 50 to 200mg/ml in water at 25 ℃.

10. A method for preparing a water-soluble bean extract, comprising:

mixing 1 to 50 parts by weight of the powdered crude bean extract with 100 parts by weight of water;

heating the mixture to a temperature of between 60 and 100 ℃ for a period of between 10 and 120 minutes;

adding a coagulant to this mixture at 0.001 to 3 parts by weight per 100 parts by weight of water to form a suspension;

heating the suspension to a temperature of between 30 and 100 ℃ for a period of between 1 and 120 minutes; and

collecting the supernatant by filtration or centrifugation to obtain a water-soluble bean extract.

11. The method of claim 10, wherein the bean extract is based on soybean, mung bean, black bean, or kidney bean.

12. The method of claim 10, wherein the bean extract is based on soy.

13. The method of claim 10, wherein the coagulating agent is citric acid.

14. The method of claim 10, wherein the supernatant is collected by filtering the suspension.

15. The method of claim 10, further comprising drying the supernatant to obtain a dried water-soluble bean extract.

16. The method of claim 10, wherein the coagulating agent is an acid.

17. The method of claim 16, wherein the coagulating agent is an organic acid.

18. The method of claim 17, wherein the coagulating agent is citric acid, fumaric acid, lactic acid, malic acid, or tartaric acid.

19. The method of claim 18, wherein the coagulating agent is citric acid.

20. The method of claim 16, wherein the coagulating agent is an inorganic acid.

21. The method of claim 20, wherein the coagulating agent is HCl or H₂SO₄Or H₃PO₄。

22. A food product comprising the water-soluble bean extract of claim 1.

23. The food product of claim 22, wherein the bean extract is based on soy, mung bean, black bean, or kidney bean.

24. The food product of claim 23, wherein the legume extract is soy-based.

25. The food product of claim 22, wherein the food product is cow's milk, tea, soft drinks, fruit juices, coffee, sauces, cereals, water, beer, crackers, chewing gum, chocolate, or soup.

26. The food product of claim 23, wherein the food product is cow's milk, tea, soft drinks, fruit juices, coffee, sauces, cereals, water, beer, crackers, chewing gum, chocolate, or soup.

27. The food product of claim 24, wherein the food product is cow's milk, tea, soft drinks, fruit juices, coffee, sauces, cereals, water, beer, crackers, chewing gum, chocolate, or soup.

28. A food product comprising the water-soluble bean extract of claim 9.

29. The food product of claim 28, wherein the food product is cow's milk, tea, soft drinks, fruit juices, coffee, sauces, cereals, water, beer, crackers, chewing gum, chocolate, or soup.