WO2006112607A1

WO2006112607A1 - Manufacturing method of old red platycodon, old red platycodon therefrom and functional food containing the same

Info

Publication number: WO2006112607A1
Application number: PCT/KR2006/000826
Authority: WO
Inventors: Young-Chul Chung; So-Young Kim; Shin-Kwon Kang; Seong-Hwan Roh
Original assignee: Jangsaeng Doraji Co., Ltd.
Priority date: 2005-04-22
Filing date: 2006-03-09
Publication date: 2006-10-26
Also published as: CN1988813A; KR20060111093A; JP2007517528A; CN100531597C; KR100644239B1; JP4372820B2

Abstract

The present invention relates to a method for preparing red old platycodon useful as a functional food material by steaming and dying old platycodon (cultivated over 20 years), as well as old red platycodon prepared thereby and a functional food material comprising the same. The method comprises the steps of: steaming old platycodon at a temperature of 90-120 °C for 1-2 hours; cooling the steamed platycodon; and drying the cooled platycodon at a temperature of 55-75 °C for 60-96 hours. The old red platycodon according to the present invention has an increased saponin content compared to general old platycodon, and thus can have increased pharmacological effects. Also, because it has a decreased number of microorganisms, the storage stability can be improved. Furthermore, because it has improved palatability with respect to taste and flavor, it can be used as a functional food material without needing to other sweeteners.

Description

[DESCRIPTION]

[Invention Title]

MANUFACTURING METHOD OF OLD RED PLATYCODON, OLD RED PLATYCODON THEREFROM AND FUNCTIONAL FOOD CONTAINING THE SAME

[Technical Field]

<i> The present invention relates to a method for preparing old red platycodon, old red platycodon prepared thereby and a functional food comprising the same, and more particularly to a method for preparing red old platycodon useful as a functional food material by steaming and drying old platycodon (cultivated over 20 years), as well as old red platycodon prepared thereby and a functional food material comprising the same.

[Background Art]

<2> Platycodon grandiflorum A. DC, which is a plant belonging to Campanulaceae, is about 10-15 cm in tap root length and 1-3 cm in diameter, has irregular stem sites, is grayish brown through milky in color, and has deep wrinkles in a longitudinal direction, and lenticels and wrinkles in a transversal direction. It is hard in quality, but non-fibrous so as to be easily broken. Also, it has a little smell and a biting taste (Yook, CS et al . , Modern Pharmacognosy, Seoul, Hakchangsa, 460-461, 1993).

<3> The main pharmacological components of Platycodon grandiflorum are triterpenic saponins (platycodin A, C, D, D2 and D₃), which forms about 3% of the root. It has been proved through animal tests that these pharmacological components have cough-relieving and phlegm-discharge effects, central nerve inhibitory effects (sedative, pain-relieving and fever-alleviating effects), anti-inflammatory effects against acute and chronic inflammations, anti-ulcer and gastric juice secretion inhibitory action, anti-choline action of lowering blood pressure by vasodilatation, blood glucose lowering action, cholesterol metabolism-improving action, and the like (Chew. Pharm. Bull., 20, 1952 (1972), Chem. Pharm. Bull., 23, 2965 (1975), /. Chen. Soc, Perkin trans I, 661 (1984), Sogoigaku, 3, 1 (1951), /. Pharm. Soc. XOr., 19, 164 (1975)). In addition, other pharmacological components isolated from Platycodon grandiflorum include steroid compounds, such as α-spinasterol, stigmast-7-en-ol and α-spinasterolglucoside, and polysaccharides, such as inulin and betulin.

<4> Old platycodon (Jang Saeng Doraji) refers to platycodon {Platycodon grandiflorum) cultivated over 20 years. In the past, Platycodon grandiflorum was difficult to cultivate for a long period, even though it has various pharmacological effects. However, the technology allowing the cultivation over-20-years-old platycodon was recently developed (Sung-ho Lee, Korean Patent Registration No. 045971, entitled cultivation method of perennial platycodon), and as a result, the mass production of old platycodon became possible. Such old platycodon has excellent pharmacological action and physiological activity compared to general platycodon cultivated over 2 to 4 years.

<5> Studies on old platycodon, which have been known so far, include a test on anti-diabetic effect (J. Korean Soc. Food Sci. Nutr., 25, 986(1996)), a test on hyperlipidemia (J. Pharmaceutical Society of Japan 93(1973) 1188- 1194), and the like. Also, studies on liver injury suppression and protection are ongoing. [Disclosure] [Technical Problem]

<6> The present inventors have conducted studies on old platycodon and, as a result, developed a method for preparing old red platycodon, which can be used for the production of various foods and has improved storage stability and pharmacological effects, as well as long platycodon prepared thereby and a functional food material comprising the same.

<7> Accordingly, it is an object of the present invention to provide a method for preparing old red platycodon having improved storage stability and pharmacological effects compared to those of old platycodon, as well as red old platycodon prepared thereby and a functional food material comprising the same. [Technical Solution] <8> To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing red old platycodon, comprising the steps of: steaming old platycodon at a temperature of 90-120 °C for 1-2 hours; cooling the steamed platycodon; and drying the cooled platycodon at a temperature of 55-75 °C for 60-96 hours. The above steaming conditions cause the saponin content of the old red platycodon to be maximized while minimizing the breakdown of intrinsic components of the old platycodon, and the drying conditions do not cause the decomposition of the old red platycodon while inducing the suitable browning of the old red platycodon. Herein, the drying step is preferably performed by drying the cooled platycodon in hot air at 75 °C for 24 hours, followed by drying at 60 ⁰C for 36-72 hours. This is because, if the old platycodon is continuously dried at an excessively high temperature for a long time, the browning of the old red platycodon can be accelerated, thus deteriorating the appearance of the old red platycodon. [Description of Drawings]

<9> FIG. 1 shows a process of analyzing the free sugar content of old red platycodon.

<io> FIG.2 shows the free amino acid content of old red platycodon.

<π> FIG.3 shows a sensory test method for old red platycodon.

<i2> FIGS.4 and 5 show the appearance of old red platycodon.

<13> FIG.6 is a graphic diagram showing the crude saponin content of old red platycodon at varying steaming conditions.

<i4> FIG. 7 is a photograph showing the TLC pattern of old red platycodon at varying steaming conditions.

<i5> FIG. 8 is a photograph showing the colors of old red platycodon powder according to steaming conditions.

<16> FIG. 9 is a graphic diagram showing the change in the pH of water extracts of old red platycodon as a function of steaming conditions.

<i7> FIG. 10 is a graphic diagram showing measurement results for the change in the brownness of water extracts of old red platycodon at varying steaming conditions.

<18> FIG. 11 is a graphic diagram showing analysis results for colony forming units in old red platycodon at varying steaming conditions. [Best Mode]

<)9> Hereinafter, the present invention will be described in detail with reference to Example.

<20> *1. Materials

<2i> For use in test, old platycodon produced in Jirisan Mountain, Korea, was selected, washed with water and then used as samples for preparing old red platycodon.

<22> 2. Preparation of old red platycodon

<23> Old platycodon samples which have been washed clean with tap water were steamed in a temperature-controllable autoclave at 100 °C and 120 ⁰C for 1 hour and 2 hour, respectively, cooled and then dried in hot air at 75 ⁰C for 24 hours, followed by drying at 60 ⁰C for 72 hours, thus preparing old red platycodon samples.

<24> For the preparation of analysis samples, the body and root of the prepared old red platycodon were crushed in a mill (Thomas Wiley Laboratory Mill 4-arthur, Thomas. P.A. , U.S.A) and sieved through a 50 mesh sieve, and the powder samples were stored in a freezer.

<25> 3. Saponin

<26> To measure the saponin content of the prepared old red platycodon, 3 g of the powder sample was added to 100 ml of 80% methanol and extracted four times at 75 "C for 2 hours, followed by filtration. The filtrate was concentrated in vacuum at a temperature of less than 70 °C , and the concentrate was dissolved in 50 ml of distilled water and shaken two times with 50 ml of diethyl ether so as to remove oil soluble substances transferred to the ether layer. The aqueous layer was added to 50 ml of water-saturated butanol and extracted four times. The extract was washed two times with 50 ml of distilled water, concentrated in vacuum at 70 "C and dried at 105 ⁰C for 2 hours. The weight of the remaining sample was expressed as crude saponin (rrbutanol extract).

<27> *The analysis of saponin patterns was performed using a TLC method. The samples were comparatively analyzed by dropping 10 ≠ of 5% methanol solution onto a silica gel 60 F254 TLC plate each time, developing the sample solution with chloroform/methanol/water (65:30:10, lower layer), spraying the sample solution with 30% sulfuric acid and heating and color-developing the sample solution at 110 °C for 10 minutes.

<28> 4. Preparation of water extract of old red platycodon

<29> To prepare water extract samples, 3g of each of the steamed old red platycodon powder samples was added to 200 ml of distilled water and extracted in a constant-temperature water bath equipped with a cooling bath, at 80 °C for 3 hours, followed by cooling to 20 °C . The cooled extract was filtered through filter paper (Whatman No.41), and the filtrate was adjusted to a volume of 200 ml .

<30> 5. Color, pH and brownness

<3i> The color of the powder was measured with Chroma meter (Minolta, CR-200, Japan), D₆5 was used as a standard light source, and the measured value was expressed as Hunter's color value, L ranging from 100 (white) to 0 (black), b ranging from +60 (yellow) to -60(blue), a ranging from +60 (red) to -60(green), and overall difference being expressed as ΔE. Herein, standard values were 97.67 for L, -0.57 for a, and 2.70 for b.

<32> The color measurement for the water extract of old red platycodon was performed using a Chroma meter (Minolta, CT-210, Japan), standard values for distilled water were 100 for L, -0.01 for a, and 0.03 for b. The brownness of the water extract was determined by measuring the absorbance of the water extract at 420 nm with an UV/Visible spectrophotometer (Shimadzu, UV-1201, Japan), and distilled water was used as control. The pH of the water extract was measured with a pH meter (691 pH meter Metrohn, Switzerland).

<33> 6. Free sugars

<34> To analyze free sugar contents, as shown in FIG. 1, 3 g of the sample was added to 100 ml of 80% methanol, and the solution was extracted three times in a water bath at 80 °C for 2 hours using a reflux process. The extract was concentrated with a rotary evaporator at less than 80 °C under vacuum, and the concentrate was dissolved in 50 ml of distilled water, and defatted by extraction with diethyl ether. Then, the aqueous layer was extracted two times with n-butanol, and the butanol layer was removed. Then, the aqueous layer was concentrated and dissolved in 5 ml of 50% methanol, and the solution was filtered through a 0.45μm membrane filter (Millipore). The filtrate was analyzed using HPLC (Waters 600, U.S.A).

<35> The HPLC analysis was performed in the following conditions. Column: Lichrosorb NH2 column (Merck Co., 5/an, 25 x 0.4 cm I.D); mobile phase: acetonitrile/water (80:20); flow rate: 1.5 ml/min; chart speed: 0.5 cm; detector: RI-410 Differential Refractometer; and attenuation and injection volume: x64 and 20/^, respectively.

<36> 7. Amino acids

<37> 1) Free amino acids

<38> To measure the content of free amino acids, as shown in FIG. 2, 5 g of the sample was added to 50 ml of 75% ethanol and homogenized two times with a homogenizer, and the supernatant was concentrated in vacuum. After removing ethanol, the concentrate was dissolved in 25 ml of distilled water, and then 10 ml of the solution was taken and added to 50 mg/ml of SSA (5- sulfosalycilic acid). The mixture was left to stand at room temperature for 30 minutes, centrifuged and then filtered through a 0.22μm membrane filter, and the filtrate was analyzed with an amino acid automatic analyzer (Pharmacia Biochrom. 20, U.S.A).

<39> The amino acid analysis was performed in the following conditions. Column: ultrapac 11 cation exchange resin (llμm±2μm) ; flow rate: 25m^/hr ; buffer: ninhydrin; pH: 3.0-10.0; column temperature and reaction temperature: 46 °C and 88 ^°C , respectively; and analysis time: 44 min.

<40> 2) Total amino acids

<4i> To analyze total amino acids, 250 mg of the old red platycodon powder was placed in an ampoule, to which 10 ml of 6N HCl was then added. The ampoule was charged with nitrogen gas and sealed in vacuum. Then, the content in the ampoule was hydrolyzed at 110 ± 1 ^°C for 22 hours. The hydrolyzed material was concentrated in vacuum , and dissolved 3 ml of sodium citrate buffer at pH 2.2, and then filtered through a 0.2//m millipore filter. 1 ml of the filtrate was taken, passed through a pre-activated sep pak C₁₈ cartridge, and analyzed using the amino acid automatic analyzer in the same conditions as in the analysis of the free amino acids.

<42> 8. Microorganisms

<43> *To measure the total number of microorganisms, 1 g of the platycodon powder was diluted stepwise in a 10-fold volume of distilled water, and the sample solution was inoculated into plate count agar (Difco Laboratorues, Detroit, U.S.A) and cultured at 30 °C for 48 hours. Then, the number of produced colonies was measured as the number of bacteria.

<44> 9. Flavor components

<45> 40 g of the old red platycodon powder was taken and placed in a 2-liter flask, to which 500 ml of distilled water was added. Then, the volatile components of the platycodon powder were extracted using SDE (Likens Nikerson type simultaneous steam distillation and extraction apparatus) according to the method of Schultz et al . for 2 hours.

<46> As the extraction solvent, 50 ml of a mixture of redistilled n- pentane:diethyl ether (1:1, v/v) was used. After completion of the extraction, the extract was dehydrated over anhydrous sodium sulfate and concentrated at less than 30 °C to remove the solvent. Then, 300 ml of ? terpene as an internal standard was added to the concentrate, and volatile components in the concentrate were analyzed using GC/MS. The GC/MS analysis was performed in conditions shown in Table 1 below. <47> [Table 1]

The conditions of GC/MS for analysis of volatile flavor compounds in steam-dried Platycodon grandiflorum powder.

<48> <49> 10. Evaluation of preference for powder flavors

<50> 10 sensory panels that have experienced flavor tests and have been trained were selected. The sensory panels were provided with the dried old red platycodon samples and permitted to describe expressions and terms which are reminded of sensible flavors. Among the test results, overlapping terms and similar expressions were arranged, and the test results were expressed as the following terms which can represent flavors: scorched rice flavor, sweet flavor, dry grass flavor, burnt flavor and palatability.

<51> After providing the samples to the 10 sensory panels, an evaluation table as shown in FIG. 3 was presented to each of the sensory panels, and the sensory panels were permitted to evaluate the samples on a 9-point hedonic scale. The sensory test of the sample was performed by placing about 20 g of the powder into a lidded cup, closing the lid and opening the lid for each sensory test. In the sensory test, each of the sensory panels evaluated one sample two times, and the results were averaged. The samples were presented in a random order.

<52> Test Example <53> 1. Appearance <54> Raw old platycodons were washed with tap water and steamed in a temperature-controllable autoclave at 100 ⁰C and 120 ^°C for each of 1 hour and 2 hours and cooled. The cooled platycodons were dried in a hot air dryer at 75 "C for 24 hours and further dried at 60 "C for 72 hours. The prepared old red platycodons are shown in FIGS. 4 and 5.

<55> In the steaming conditions at 100 °C for 1 hr, the old red platycodon smelled fragrant just after steaming and showed a yellow-brown color after 72 hours of drying. In the steaming conditions at 100 ^°C for 2 hr, and at 120 °C for 1 hr and 2 hr, the old red platycodon gradually turned brown as steaming time increased, and the appearance thereof after drying was significantly shrunk without showing the circular body shape. This shrinkage is believed to be because the platycodon comprises inulin. Accordingly, it is considered that, in order for the old red platycodon to be used as commercial products, it is preferable that the old red platycodon be powdered.

<56> 2. Saponin (crude saponin, TLC pattern)

<57> Analysis results for the crude saponin content of platycodon as a function of steaming conditions are shown in FIG. 6. As shown in FIG. 6, unsteamed platycodon showed a crude saponin content of 1.73%, and steamed platycodons showed crude saponin contents of 1.86% for the group steamed at 100 ⁰C for 1 hr, and 1.99% for the group steamed at 100 °C for 2 hr. Also, steamed platycodons showed crude saponin contents of 2.81% for the group steamed at 120 "C for 1 hr, and 3.17% for the group steamed at 120 for 2 hr.

<58> Accordingly, as the steaming time and temperature increased, the content of crude saponin in platycodon increased. This is believed to be because, as the steaming temperature and time increase, the tissue (e.g., cell wall) of platycodon become weak and is easily dissolved out. The TLC patterns of platycodon at varying steaming conditions are shown in FIG. 7. As shown in FIG. 7, unsteamed platycodon showed a weak TLC plattern, but platycodons steamed at 100 °C for 1 hr and 2 hr, and platycodons steamed at 120 ⁰C for 1 hr and 2 hr showed strong patterns compared to the unsteamed platycodon.

<59> 3. Colors of powder (Lab, photographs)

<6o> Analysis results for the colors of old red platycodon powder at varying steaming conditions are shown in Table 2 and FIG.8. <6i> [Table 2]

Changes in Hunter color values of Platycodon grandiflorum powder steamed at different condition.

<62>

<63> As shown in Table 2 and FIG. 8, L values representing lightness were as high as 77.61 for the unsteamed control group and were 71.29 for the group steamed at 100 ⁰C for 1 hr, 70.75 for the group steamed at 100 ⁰C for 2 hr, 68.19 for the group steamed at 120 °C for 1 hr, and 55.30 for the group steamed at 120 °C for 2 hr. This suggests that, as the steaming time and temperature increase, the lightness decreases. This tendency indicates that, as the steaming temperature and time increase, the browning reaction of platycodon is promoted to increase the production of brown pigments.

<64> a values representing values ranging from green to blue were 0.80 for the unsteamed control group, 1.48 for the group steamed at 100 ⁰C for 1 hr, 1.34 for the group steamed at 100 °C for 2 hr, 1.95 for the group steamed at 120 °C for 1 hr, and a red value of 5.04 for the group steamed at 120 ^°C for 2 hr.

<65> b values representing values ranging from blue to yellow were 17.86 for the unsteamed control group, 19.70 for the group steamed at 100 ⁰C for 2 hr, 17.92 for the group steamed at 100 ^°C for 1 hr, and 20.82 for the group steamed at 120 °C for 2 hr.

<66> 4. Properties of water extract <67> 1) Color values <68> Measurement results for the color values of water extracts of old red platycodon at varying steaming conditions are shown in Table 3 below. <69> [Table 3]

Changes in Hunter color values of water extracts in Platycodon grandiflorum steamed at different condition.

<70>

<71> As shown in Table 3, L values representing the lightness values of water extracts of old red platycodon were 92.64 (the highest) for the unsteamed control group, 91.81 for the group steamed at 100 °C for 1 hr, 91.33 for the group steamed at 100 ⁰C for 2 hr, and 91.34 and 90.54 for the groups steamed at 120 ⁰C for 1 hr and 2 hr, respectively. This indicates that L values slightly decreased, as the steaming time and temperature increased, a values representing values ranging from green to red were as low as -0.53 for the unsteamed control group, -0.52 for the group steamed at 100 °C for 1 hr, -0.67 for the group steamed at 100 °C for 2 hr, and -1.08 and -0.93 (green colors) for the groups steamed at 120 "C for 1 hr and 2 hr, respectively.

<72> On the other hand, b values representing values ranging from blue to yellow were 8.69 for the unsteamed control group, and 8.70 and 28.64 (yellow colors) for the groups steamed at 100 °C for 2 hr and at 120 °C for 2 hr, respectively. Accordingly, it can be seen that, as the steaming temperature and time increase, raw old platycodon turns yellow due to a browning phenomenon.

<73> 2) Change in pH <74> Measurement results for the change in the pH of water extracts of platycodon at varying steaming conditions are shown in FIG.9.

<75> As shown in FIG. 9, the pH values of water extracts of old platycodon were 5.82 for the control group, 5.78 for the group steamed at 100 "C for 1 hr, 5.68 for the group steamed at 100⁰C for 2 hr, 5.34 for the group steamed at 120 ^°C for 1 hr, and 4.98 for the group steamed at 120 "C for 2 hr. As can be seen from these results, as the steaming time and temperature increased, the pH of water extracts of old red platycodon gradually decreased. This is believed to be because, as the steaming temperature and time of platycodon increase, the saccharides of platycodon are decomposed to produce acids, resulting in a decrease in pH.

<76> 3) Brownness

<77> Measurement results for the change in the brownness of water extracts of old red platycodon as a function of steaming conditions are shown in Table 10.

<78> As shown in Table 10, the brownness values of water extracts of red old platycodon were 0.35 for the unsteamed control group, and 0.40 for the group steamed at 100 ^°C for 1 hr, and 0.45 for the group steamed at 100 ⁰C for 2 hr, indicating an increase in brownness compared to the control group. However, steaming at 120 "C for 1 hr showed a brownness of 0.47, and steaming at 120 ^°C for 2 hr showed a brownness of 0.63 which is about two times higher than that of the control group. These results suggest that, as the steaming temperature and time of platycodon increased, the browning reaction of platycodon was promoted.

<79> 5. Free sugars <80> Analysis results for the free sugar contents of platycodon at varying steaming conditions are shown in Table 4 below.

<81> [Table 4]

Contents of free sugars in Platycodon grandiflorum

<82>

1) <83> Not detected <84> As shown in Table 4, the control group had a rhamnose content of 0.68%, a fructose content of 1.05%, a glucose content of 0.14% and a sucrose content of 0.02%. The fructose content was decreased to 0.25% for the group steamed at 100⁰C for 1 hr, 0.23% for the group steamed at 100 °C for 2 hr, 0.21% for the group steamed at 120 °C for 1 hr, and 0.11% for the group steamed at 120 ⁰C for 2 hr. These results suggest that, as the steaming temperature and time increased, the contents of free sugars gradually decreased. In steaming at 120 °C for 2 hr, rhamnose, glucose and sucrose completely disappeared. That the content of fructose was 0.11% even when steamed at 120 °C for 2 hr is because the main component of platycodon is inulin.

<85> Among the free sugars of platycodon, reducing sugars such as glucose and fructose were greatly reduced, as the steaming temperature and time increased. It is believed that these reducing sugars are consumed, because they are greatly involved in maillard reaction with amino compounds. The content of sucrose, as non-reducing sugar, was greatly reduced, as the steaming temperature and time increased. This is believed to be because glucosidic bonds are hydrolyzed by thermal decomposition into glucose and fructose which are then involved in maillard reaction, thus producing browning substances and flavors.

<86> 6. Amino acids

<87> 1) Free amino acids

<88> Analysis results for the free amino acid contents of platycodon at varying steaming conditions are shown in Table 5 below.

<89> [Table 5]

<90>

1) <91> Not detected <92> As shown in Table 5, from the unsteamed platycodon, a total of 34 free amino acids were isolated and identified. The contents of these free amino acids were higher in the order of urea 8.61 mg%, L-arginine 7.10 mg%, L- asparagine 2.39 mg%, L-alanine 1.91 mg%, O-phospho-L-serine 1.55 mg% and L- citrull ine 1.48 mg%.

<93> Compared to the control group, upon steaming at 100 °C for 1 hr, L- aspartic acid and D,L-β-aminoisobutyric acid completely disappeared. Upon steaming at 120 °C for 2 hr, L- α-aminoadipic acid, L-cystine, cystathionine and 1-methyl-L-histidine completely disappeared. These results suggest that, as the steaming temperature and time increased, the contents of free amino acids gradually decreased. Furthermore, the total contents of free amino acids were 34.22 mg% for the control group, 23.67 mg% for the group steamed at 100 °C for 1 hr, 17.86 mg% for the group steamed at 100 °C for 2 hr, 18.18 mg% for the group steamed at 120 ^°C for 1 hr, and 12.42 mg% for the group steamed at 120°C for 2 hr. These results suggest that, as the steaming temperature and time increased, the total content of free amino acid in platycodon was reduced. Also, it can be seen that, as the steaming temperature and time increased, the content of free amino acid rapidly decreased and the extent of a decrease in the free amino acid content varied depending on the kind of amino acid.

<94> It is reported that these free amino acids have a high mail lard reaction rate compared to proteins, peptides, constituent amino acids, free sugars and the like, and interact with reducing sugars to cause maillard reactions, thus producing brown substances and flavor components.

<95> 2) Constituent amino acids

<96> Analysis results for the constituent amino acid contents of platycodon at varying steaming conditions are shown in Table 6.

<97> [Table 6]

<98>

<99> Not detected

<100> As shown in Table 6, from the unsteamed platycodon, a total of 17 amino acids were isolated and identified. The contents of these amino acids were higher in the order of glutamic acid 36.14 mg%, arginine 32.18 mg%, aspartic acid 11.86 mg%, alanine 8.69 mg%, tyrosine 8.58 mg% and leucine 8.32 mg%. The content of methionine was the lowest content of 1.27 mg%.

<101> When platycodon was steamed at 100 "C for 2 hr, the contents of the amino acids were decreased as follows: glutamic acid 31.82 mg%, arginine 30.57 mg%, aspartic acid 10.61 mg%, alanine 7.36 mg%, tyrosine 5.35 mg% and leucine 6.94 mg%. When it was steamed at 120 "C for 2 hr, the contents of the amino acids were decreased as follows: glutamic acid 27.88 mg%, arginine 17.09 mg%, aspartic acid 10.12 mg%, alanine 7.22 mg%, tyrosine 3.81 mg% and leucine 6.60 mg%. Among these amino acids, tyrosine showed the highest decrease rate.

<102> Also, the total contents of the constituent amino acids were 158.85 for the unstearned group, 137.77mg% for the group steamed at 100 °C for 1 hr, and 105.4 mg% for the group steamed at 120 ⁰C for 2 hr. These results suggest that, the steaming temperature and time increased, the contents of the constituent amino acids decreased compared to the unsteamed group. The extent of a decrease in the constituent amino acid contents was much lower than that of the free amino acid contents in Table 5. This is believed to be because the free amino acids of platycodon more easily interact with reducing sugars during steaming compared to the total amino acids, and thus are involved in mail Hard reactions.

<1O3> 7. Microorganisms

<iO4> Analysis results for the number of microorganisms in platycodon at varying steaming conditions are shown in FIG. 11.

<iO5> As shown in FIG. 11, the unsteamed platycodon group showed the presence of a large amount of soil microorganisms (9.3x10 CFU/g) . Meanwhile, the numbers of soil microorganisms in the steamed platycodons were

5X10⁵ CFU/g for the group steamed at 100 ⁰C for 1 hr, 12,900 CFU/g for the group steamed at 100 °C for 2 hr, 3,100 CFU/g for the group steamed at 120⁰C for 1 hr, and 200 CFU/g for the group steamed at 120 t for 2 hr. These results suggest that, as the steaming time and temperature increased, the number of microorganisms in platycodon gradually decreased.

<i06> 8. Flavor compounds

<iO7> Analysis results for the contents of flavor compounds in platycodon at varying steaming conditions are shown in Table 7 below. <1O8> [Table 7]

<109>

<110> As shown in Table 7, from the unsteamed platycodon, a total of 22 flavor compounds were isolated and identified. Also, 20 flavor compounds were isolated and identified for the group steamed at 100 ⁰C for 1 hr, 13 flavor compounds for the group steamed at 100 °C for 2 hr, 13 flavor compounds for the group steamed at 120 °C for 1 hr, and 13 flavor compounds for the group steamed at 120 ^°C for 2 hr. The main flavor compounds in platycon were pyrizines, furans, alcohols, aldehydes and acids. Among them, the contents of 2-acetyl furan, 2,6-dimethyl pyrazine, 2,3-dimethyl pyrazine, 5-methyl furan, trimethyl pyrazine, tetramethyl pyrazine, 2,3,5-trimethyl-β- ethyl pyrazine, α-ylangene, 2,6-di-tert-butyl-p-benzo-quinone and dibutyl phthalate were gradually increased, as the steaming temperature and time increased. However, 2,3-dimethyl pyrizine, l-octen-3-ol , 2-pentyl furan and benzyl alcohol were gradually decreased, as the steaming temperature and time increased. The contents of myristic acid and palmitic acid were high at 120 °C; this is believed to be sugars are thermally decomposed to produce acids, reducing pH.

<ni> Pyrazine derivatives, which are the key flavors of steamed platycodon, are produced in maillard reactions between sugars and amino acids by heating in a process of roasting food raw materials and include about 100 kinds or more of known compounds. Also, these derivatives are reported to be similar to the roasted or nutty notes which are generally known to have savory flavor, such as scorched rice flavor, pop corn flavor or roast chestnut f1avor.

<ii2> As the steaming temperature and time increase, the contents of furan derivatives such as 5-methyl furfural increase. These furan derivatives show flavor properties varying depending on reactive groups, and are known to have soybean flavor, grass flavor, burnt flavor, and caramel flavor. These furans do not belong to good flavors, but show unique flavors in a mixture with other flavor compounds and are reported to be very important as the flavor components of food.

<ii3> 9. Sensory evaluation

<ii4> To select the optimum steaming conditions of platycodon, the sensory characteristics of platycodon powder were evaluated varying steaming conditions, and the results are shown in Table 8. <I 15> [Table 8]

Sensory evaluation for flavor intensity of powders in Platycodon grandiflorum steamed at different condition.

<116> <1 17> Means of 10 panel tests by 9-ρoint hedonic scale, the higher score being the stronger flavor.

<1 18> As shown in Table 8, the unsteamed control group powder showed dry glass odor as high as 6.4. As the steaming temperature and time increased, scorched rice flavor, sweet flavor and palatability increased.

<119> Particularly, in steaming at 100 ^°C for 2 hr, the highest palatability of 7.1 was shown, but, in steaming at 120 °C for 2 hr, palatability was rather decreased. [Industrial Applicability]

<120> As described above, the old red platycodon according to the present invention has an increased saponin content compared to general old platycodon, and thus can have increased pharmacological effects. Also, because it has a decreased number of microorganisms, the storage stability can be improved.

<121> Furthermore, because it has improved palatability with respect to taste and flavor, it can be used as a functional food material without needing to other sweeteners.

Claims

[CLAIMS] [Claim 1]

<i23> A method for prepar ing red old platycodon, compr ising the steps of :

<124> steaming old platycodon at a temperature of 90-120 ^°C for 1-2 hours ;

<125> cool ing the steamed pl atycodon; and

<i26> drying the cooled pl atycodon at a temperature of 55-75 ⁰C for 60-96 hours .

[Claim 2]

<i27> The method of Claim 1, wherein the drying step is performed by drying the cooled platycodon in hot air at 75 "C for 24 hours, followed by drying at 60⁰C for 72 hours.

[Claim 3]

<128> An old red platycodon prepared according to a method set forth in Claim 1 or 2. [Claim 4]

<129> A functional food material comprising the old red platycodon of Claim 3.