Technical Field The present invention relates to a chewing gum base comprising a protein complex, which is prepared by mixing a protein and a polyphenol, and chewing gum comprising the same.

Background Art Chewing gum typically comprises 20-30% of a gum base, 60-80% of sugars (or sugar alcohols in the case of sugarless chewing gum), 1-2% of a flavoring agent and other nutrients, and further includes food additives, such as a sweetener and an acidulant. Thus, most ingredients of chewing gum are water-soluble. A gum base, as one ingredient of chewing gum, is water-insoluble and binds to a portion of flavor molecules so that it is not dissolved by saliva and remains in the mouth after being chewed. In contrast, other ingredients, including sucrose, starch syrup and most flavors, are water-soluble and thus dissolved by saliva. The gum base is prepared using a natural or synthetic resin as a major component. The natural resin includes chicle, jelutong and sorva, and the synthetic resin includes polyvinylester, polyisobutylene and polyvinylacetate. Inmost cases, the natural and synthetic resins are used in combination. In 1890, gum bases were mostly prepared with 100% chicle. At present, gum bases are prepared with natural or synthetic polymers using a softening agent, such as glycerin, to soften gum and facilitate the chewing of gum. Ingredients suitable for use in chewing gum should meet several requirements, including suitable elasticity and affinity to saliva, the ability to be softened by body temperature, non-stickiness to teeth, tastelessness, odorlessness, transient stability, and affinity to flavors or sugars added upon gum preparation. Also, since a chewing gum base is not dissolved by saliva and thus remains in the mouth after being chewed, the base decisively affects the quality of the finished gum. Thus, a chewing gumbase is preferably made of non- harmful natural materials to ensure its safety to the body. Among materials commonly used in gum bases, paraffin-containing ingredients, such as liquid paraffin or microcrystalline paraffin waxes, are somewhat slowly biodegraded, and thus, can harm the environment and affect the health of people (Smith JH et al., Toxicol Pathol, 24:214-30, 1996; HoglenNC et al., Toxicol Sci., 46:176-84, 1998). In 1986, American Nabisco Company developed a chewing gum base comprising 5- 30 wt% of aqueous hydrogenated starch hydrolysate, 0-30 wt% of glycerine, and carboxymethyl cellulose, but failed to commercialize the gum base (U.S. Pat. No. 4,582,707). Japanese Kanebo Company developed a non-adhesive gum base comprising lactose, calcium carbonate and a saturated fatty acid to reduce the stickiness of chewing gum (U.S. Pat. No.4,208,432). In addition, many studies have involved chewing gum that naturally degrades as time goes by, that is, biodegradable chewing gum. For example, some efforts have been made to make gum bases using biodegradable polymers having enhanced water solubility, such as hemicellulose, polyester andpolyhydroxyalkanoates (U.S. Pat. Nos. 6,280,526 and 6,004,616). Korean Pat. Laid-open Publication No. 1995-28628 discloses a chewing gum base prepared using biologically-active vegetable proteins extracted from wheat. U.S. Pat. No. 5,580,590 discloses an environmentally friendly chewing gum composition comprising a water- soluble gum portion and a water-insoluble gum base portion including an elastic protein-based polymer. Also, U.S. Pat. No. 5,424,081 describes a non-adhesive chewing gum base comprising gluten and a protein condensing agent. The present inventors found that a biodegradable chewing gum having good texture and antimicrobial activity can be prepared by mixing a biodegradable protein, safe to the body, with a polyphenol and using the resulting protein complex as a gum base, thereby leading to the present invention. Disclosure of Invention Technical Solution Accordingly, the present invention intends to provide a chewing gum base comprising a protein complex that is prepared by mixing a protein and a polyphenol, and a chewing gum comprising the same. The present invention provides a chewing gum base comprising a protein complex that is prepared by mixing a protein and a polyphenol, and a chewing gum comprising the same. The chewing gum base of the present invention includes a protein complex, which is prepared by mixing a protein and a polyphenol at a weight ratio of 1:0.1-3, dissolving the mixture in a solvent, allowing the mixture to react and collecting formed precipitates. The chewing gumbase of the present invention is prepared by mixing a protein and a polyphenol at a weight ratio of 1 :0.1-3, and preferably at a weight ratio of 1.0.5-1.5, dissolving the mixture in water, a lower alcohol or a solvent mixture thereof of about 0.5-100 times the weight (g) of the mixture at 10-1000C for 0.01-10 hours, forming precipitates at 0-40°C for 0.1-48 hours, and recovering the precipitated protein complex. When the protein and the polyphenol are mixed at a ratio below 1 :0.1 or exceeding 1 :3, the yield of the protein complex is remarkably reduced. The protein used in the present invention is one or more selected from the group consisting of water-soluble proteins derived from animals, plants or microorganisms. Preferably, the protein may be selected from among structural proteins, such as gelatin, collagen, elastin and keratin; fibrous proteins, such as fibrinogen; serum proteins, such as albumin; storage proteins, such as milk proteins and egg proteins; vegetable proteins, such as soybean proteins; and yeast proteins. In addition, the polyphenol used in the present invention may be a polyphenol extracted, isolated and purified from green tea leaves, grapes or onions. Preferably, the polyphenol may be one or more selected from the group consisting of green tea polyphenols, such as epigallocatechin gallate (EGCG)5 epigallocatechin (EGC), epicatechin (EC) and epicatechin gallate (ECG); grape polyphenols, such as anthocyanin, proanthocyanin and tannin; anion polyphenols, such as quercetin; and tannin from GallaRhois. The protein or polyphenol of the present invention may be contained in an amount of 0.01-80.0 wt% in the mixture, and may be used in its original powder form or after being dissolved in water, a lower alcohol or a solvent mixture thereof at a concentration of 0.01-80%. Polyphenols extracted from green tea leaves may be used as the polyphenol in the present invention. Green tea polyphenols may be extracted and purified, for example, according to a method of preparing a green tea extract, described in Korean Pat. Registration No. 10-377313. A preferred method is as follows. 5-20 wt% of water is added to 1.0 wt% of hot air-dried green tea leaf powder, and heating is carried out for 15 minutes to 2 hours. After the green tea leaf powder is removed, the remaining solution is cooled, and precipitates are removed. The primary extract is heated again and cooled. After precipitates are removed, the secondary extract is dried, thus generating a final extract. The heating ispreferablycarried out at 60-110°C, andthe drying is preferably carried out by means of spray-drying. The final extract contains 50.0-90.0 wt% of polyphenols. The chewing gum base of the present invention contains 5.0-95.0 wt% of the protein complex precipitate prepared as described above. In addition, the present invention provides a chewing gum prepared by adding food additives acceptable in processed foods to the chewing gum base containing a protein complex. The chewing gum of the present invention contains the chewing gum base containing a protein complex in an amount of 10.0-90.0 wt% based on the total weight of the chewing gum. The present chewing gum contains suitable amounts of food additives acceptable in processed foods, including a sweetener, a softening agent, a moisturizing agent, an emulsifier, a flavoring agent and a natural colorant. The sweetener gives a sweet taste, and is exemplified by sucrose, starch syrup and glucose. The sweetener is typically contained in an amount of 20.0-80.0 wt% in chewing gum. The softening agent gives bulk texture, and is exemplified by glycerin, animal proteins and water. The softening agent is typically contained in an amount of 0.1-1.0 wt% in chewing gum. The moisturizing agent prevents gum from separating and enhances the rolling effect on the gum. Examples of the moisturizing agent include a sorbitol solution and glycerin. It is typicallycontainedinanamountof0.1-1.0wt% inchewinggum. The emulsifying agent prevents the gum from sticking to tooth surface and controls the physical properties of the gum. Sucrose esters of fatty acids are mainly used as emulsifying agents. The emulsifying agent is typically contained in an amount of 0.1-1.0 wt%in chewing gum. The flavoring agent imparts flavor. A fruit flavoring agent having grape flavor or strawberry flavor or a peppermint flavoring agent is mainly used. The flavoring agent is typically contained in an amount of 0.5-5.0 wt% in chewing gum. The natural colorant imparts a desired color. It is typically contained in an amount of 0.01-0.1 wt% in chewing gum. The present chewing gum may be prepared according to the aforementioned composition within a range not deviating from typical preparation temperature and time. The preparation method of chewing gum willbe described in detail, below. First, the aforementioned ingredients except for the flavoring agent are added to a pre-heated blender. While the internal temperature of the blender is maintained at 30-70°C, a flavoring agent is added to the blender, blended with other ingredients, and the molten mass is extruded from the blender, rolled and maturated for several days. Herein, the mixture is pre¬ heated to help the ingredients blend well with each other and to reduce the load on the blender. The addition of a flavoring agent after the blender is pre-heated allows gum to maintain flavor for a prolonged period of time. After the molten mass is rolled and maturated, it is cut to a desired size and packaged, thus generating the chewing gum of the present invention. The chewing gum of the present invention, comprising a chewing gum base containing a protein complex, unlike general gum, does not generate a synthetic rubber odor and maintains the unique flavor of green tea even when being chewed for over five minutes, so that it has excellent taste and flavor.

Description of Drawings FIG. 1 is a photograph of a protein complex for preparing a gum base, which is preparedusinggelatinandgreenteapolyphenols; FIG. 2 is a photograph of a protein complex for preparing a gum base, which is prepared using egg proteins and green tea polyphenols; FIG. 3 is a photograph of a protein complex for preparing a gum base, which is prepared using wheat proteins and green tea polyphenols; and FIG. 4 is a photograph of a chewing gum prepared using gelatin and green tea polyphenols, wherein the chewing gumis stretched by hand.

Modefor Invention A better understanding of the present invention may be obtained through the following examples which are set forth to illustrate, but are not to be construed as the limit of the present invention.

EXAMPLE 1 : Preparation Iof a chewing gumbase according to the present invention 1) Preparation of polyphenol powder In order to prepare the composition of the present invention, polyphenol powder was obtained from green tea leaves. The green tea polyphenol powder contained in the present composition was prepared by extracting, isolating and purifying polyphenols according to a method of preparing a green tea extract, described in Korean Pat. Registration No. 10-377313. Ih order to determine whether the purified extract contains large amounts of green tea polyphenols, it was subjected to component analysis, as follows. Each polyphenol and caffeine were measured by HPLC (high performance liquid chromatography), and the entire polyphenol content was measured by a spectrophotometric redox assay based on a Prussian blue method. As a result, the green tea polyphenol powder obtained in this Example was found to contain more than 83% of polyphenols. This purity is sufficient for displaying thephysicochemical properties ofpure polyphenols. 2) Preparation of a chewing gumbase according to the present invention A chewing gum base according to the present invention was prepared by mixing a protein, gelatin, andthe polyphenol powder. 100 g of gelatin (gelatin type a from porcine skin, Cat. No. G2500, Sigma Co. USA) was dissolved in 2000 ml of water to generate a protein solution, and 100 g of the polyphenol powder was added to the protein solution. The mixture of the protein solution and the polyphenol powder was well stirred for 20 min at 25-32°C. Then, the mixture was allowed to cool to 0-15°C and stand for 30 min to 4 hrs, and precipitates were recovered. The precipitates were thoroughly rubbed against each other, thus yielding 190 g of a protein complex. The protein complex thus obtained was used as a chewing gum base according to the present invention. FIG. 1 is a photograph of the protein complex prepared as described above, the photograph being taken with a digital camera (CAMEDIA C-3020 ZOOM, Olympus, Japan).

EXAMPLE 2: Preparation Hof a chewing gumbase according to the present invention A chewing gum base was prepared using 100 g of egg proteins (egg whites dried, Cat. No. E0500, Sigma Co. USA) and 70 g of green tea polyphenols according to the same method as in Example 1. FIG. 2 is a photograph of a protein complex prepared using egg proteins and green tea polyphenols, the photograph being taken with a digital camera (CAMEDIAC-3020 ZOOM, Olympus, Japan).

EXAMPLE 3: Preparation IE of a chewing gumbase according to the present invention A chewing gum base was prepared using 100 g of wheat proteins (gluten crude, Cat. No. G5004, Sigma Co. USA) and 15O g of green tea polyphenols according to the same method as in Example 1. FIG. 3 is a photograph of a protein complex prepared using wheat proteins and green tea polyphenols, the photograph being taken with a digital camera (CAMEDIA C-3020 ZOOM, Olympus, Japan).

EXAMPLE 4: Preparation of chewing gum containing the chewing gum base of the present invention 19O g of the protein complex prepared in Example 1, 454 g of sucrose, 80 g of starch syrup, 140 g of glucose, 3 g of a softening agent, glycerin (Glycerol, Cat. No. G2025, Sigma. USA), 21 g of a peppermint flavor, and 1 g of an emulsifying agent, sucrose esters of fatty acids (S170, Nam- Young Co. Ltd., Korea) were added to a pre-heated blender, and blended for about 30 minwhile the internal temperature ofthe blender was maintained at 55°C. The resultant homogeneously molten mass was extruded from the blender, rolled and maturated for 24-48 hrs. Then, themass was cut to a desired size and packaged.

COMPARATIVE EXAMPLE: Preparation of chewing gum containing a conventional chewing gumbase 19O g of a gum base (natural chicle, Bolak Co. Ltd., Korea), 454 g of sucrose, 80 g of starch syrup, 140 g of glucose, 3 g of a softening agent, glycerin (Glycerol, Cat. No. G2025, Sigma. USA), 21 g of a peppermint flavor, and 1 g of an emulsifying agent, sucrose esters of fatty acids (S170, Nam- Young Co. Ltd., Korea) were added to a pre-heated blender, and blended for about 30 min while the internal temperature of the blender was maintained at 55°C. The resultant homogeneous molten mass was extruded from the blender, rolled and maturated for 24-48 hrs. Then, themasswas cutto a desired size and packaged.

TEST EXAMPLE 1 : Sensory evaluation of the chewing gum containing the protein complex gumbase of the present invention Chewing gum, prepared in Example 4 and Comparative Example, was evaluated for taste, flavor and texture. A total of fifty people ranging in age from teenage to fifties, ten people in each age group, were selected as panelists, and performed sensory evaluation of the chewing gum. Five panelists per age group chewed the chewing gum prepared in Example 4 according to the present invention, and the remaining five panelists chewed the chewing gum prepared in Comparative Example. Then, panelists evaluated the taste, flavor and texture of the chewing gum, as follows. Sensory evaluation was carried out 1 , 5 and 10 min after the gum was chewed. The texture, taste and flavor of gum were scored on a five-point scale of 1 to 5 (1: excellent, 2: good, 3: ordinary, 4: bad, and 5: very bad). The cases in each score point were counted, and the results are given in Tables 1, 2 and 3, below.

TABLE l Results of sensory evaluation carried out 1 min after gum is chewed Evaluation Example 4 Comparative Example results Very Very Excellent Good Ordinary Bad Excellent Good Ordinary Bad bad bad Texture 1 3 1 - - 1 3 1 - - Taste 3 2 - - - 2 3 - - - Flavor 3 2 - - - 2 3 - - - TABLE 2

Results of sensory evaluation carried out 5 min after gumis chewed Evaluation Example 4 Comparative Example results Very Very Excellent Good Ordinary Bad Excellent Good Ordinary Bad bad bad Texture 2 3 - - - 1 4 - - - Taste 2 3 - - - 1 3 1 - - Flavor 2 3 - - - - 2 1 2 -

TABLE 3 Results of sensory evaluation carried out 10 min after gumis chewed Evaluation Example 4 Comparative Example results Very Very Excellent Good Ordinary Bad Excellent Good Ordinary Bad bad bad Texture 1 3 1 - - - 2 3 - - Taste 1 3 1 - - - 1 3 1 - Flavor 1 3 1 - - - 1 1 3 -

As shown in Tables 1, 2 and 3, compared to the chewing gum prepared using the

conventional gum base, the chewing gum prepared using the protein complex gum base of the

present invention had similar texture, taste and flavor 1 min after being chewed, but was found

to be excellent in these characteristics 5 min and 10 min after being chewed. In particular, the

chewing gum of the present invention did not generate a synthetic rubber odor, which is

generally generated when conventional chewing gum is chewed for over five minutes, and

maintained the unique flavor of green tea for a prolonged period of time, indicating that the

present chewing gumis excellent with respect to taste and flavor.

TEST EXAMPLE 2: Antibacterial test against tooth decay-causing bacteria

The green tea polyphenol powder prepared in Example 1 and tannic acid were

evaluated for their antibacterial activity.

The antibacterial activity was determined by measuring minimal inhibitory

concentrations (MIC) using Streptococcus mutans, which is found in 80% of Korean people with decayed teeth, according to a method described by Murray et al. (Murray, PR. and

Jorgensen, JH.; Antimicrob. Agents Chemother. 20:66-70, 1981). Streptococcus mutans

(KCTC 3065) was obtained from the Korean Collection for Type Cultures (KCTC, Daejon,

Korea), and cultured on a selective MSB (Mitis Salivalis-Bacitracin) agar plate (containing 0.5

μg/ml of bacitracin) at 37°C for 48 hrs. One colony emerging on the MSB agar plate was

picked, inoculated in Todd Hewitt broth (TH broth, Difco, Lab., USA), and incubated in an

incubator at 37°C for 24 hrs. The resulting bacterial culture was usedin the antibacterial test.

The cultured bacterial cells were resuspended to have an absorbance value of 0.1 at

450 nm using a Microplate Reader (Model; EL311SX, BIO-TEX Instruments Inc., USA).

0.1 ml of the bacterial suspension was then inoculated in 0.1 ml of a liquid medium containing

the green tea polyphenol powder or tannic acid (Cat. No. T0125, Sigma Chemical Co. USA)

in amounts of 2000, 1000, 500, 250, 125, 62.5, 31.25 and 0 μg/ml, and was cultured in an

incubator at 37°C for 36 hrs. Absorbance was measured at 450 nm, and MIC values were

calculated from the absorbance values. 100 μg/ml of ampicillin was used as a negative

control. The results are given in Table 4, below.

TABLE 4 Effects of polyphenols onthe growth ofS. mutans KCTC 3065 Polyphenol or tannin Cone, Absorbance at450 nm (μg/ml) #^3|fe *)e) ^E Green tea polyphenols Tannin tøgtøβ) 2000 0.016+0.013 0.012+0.017 1000 0.015+0.030 0.011+0.010 500 0.025+0.021 0.015+0.014 250 0.023±0.014 0.127+0.028 125 0.184+0.032 0.234+0.041 62.5 0.256+0.012 0.275+0.025 31.25 0.284+0.023 0.324+0.032 0 0.295+0.022 0.312+0.028 Note: Data are expressed as meaniSD. As shown in Table 4, the growth ofS. mutans KCTC 3065 was remarkably inhibited when treated with the green tea polyphenols of more than 125 μg/ml and tannin of more than 250 μg/ml. Thus, the MtCs against the S. mutatis strain were below 125 μg/ml for the green tea polyphenols and below 250 μg/ml for tannin.

Industrial Applicability As described hereinbefore, the chewing gum base and the gum containing the base according to the present invention have good biodegradability and good texture, as well as effectively preventing foul breath and tooth decay due to their antibacterial action.