GB1559989A - Edible products the use of certain sugar alcohols in combination as sweetener and a method of preparing such sweetener - Google Patents

Description

(54) ED1BLE PRODUCTS, THE USE OF CERTAIN SUGAR ALCOHOLS IN COMBINATION AS SWEETENER, AND A METHOD OF PREPARING SUCH SWEETENER (71) We, BARNANGEN AB ,a Swedish Joint stock company, of Gustavslundsvagen 145-163, Bromma, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to edible products containing as a principal sweetener a combination of certain sugar alcohols, and to a method of preparing the sweetener.

From scientific research it has become clear that ordinary sugar, i.e. saccharose, has a decisive influence on the presence of caries. In this connection it is known that ordinary sugar in its decomposition results in the formation of acid in the plaque layer of the teeth. This results in decrease of pH and calcium hydrogen phosphate is dissolved from the enamel if pH decreases below about 5.5. The result of this is the creation of holes in the teeth. On the other hand, it is a fact that increased pH, namely a pH exceeding about 5.5, results in precipitation of calcium hydrogen phosphate on the surface of the teeth resulting in a possible remineralization where cavities have already formed as a result of acid attack. The higher the pH, at any rate up to about 8, the larger the precipitation of calcium hydrogen phosphate. Thus, at a pH of about 8 remineralization of the tooth enamel takes place at a maximum rate.

It must be noted, however, that a pH of about 5.5 in the dental plaque is in no way a specific limit, since, as is well known, raising of pH above said limit does not immediately eliminate all hydrogen phosphate ions to result in a positive effect in the form of remineralization. As is clear from the titration curve of phosphoric acid (see, for example, Latimer, Hildebrand, Reference Book of inorganic Chemistry, third edition, New York, p. 231) there is always around said pH-value an equilibrium between dihydrogen phosphate ions and hydrogen phosphate ions. This also, of course, means that all measures bringing about an increase in pH will have a positive effect on the dental enamel even if well above the pH-value about 5.5.

Against the background of the above finding it has been desirable to look for other naturally occurring sugar types and to investigate their odontological effects. In organic chemistry, different types of sugars have been known for decades, inter alia fructose, and also sugar alcohols, such as sorbitol and xylitol. However, a substitute for saccharose should, as far as possible, have a similar sweetness, the same agreeable taste and should be practically odourless. It is also, of course, essential that the substitute has normal metabolic reaction routes in the organism and thus, when taken in great amounts, must not result in abnormal blood and urinary values.

It is known, particularly from certain Finnish investigations carried out at the Odontologic Institution in Turku that the sugar alcohol xylitol is a highly preferred non-cariogenic sweetener. It seems that the use of xylitol as a sweetener instead of saccharose reduces the caries frequency significantly. When compared to the result of using sorbitol as a sweetener it has been found that xylitol is less cariogenic than sorbitol. However, in view of the fact that xylitol is an expensive sugar alcohol due to high manufacturing costs, it has not been possible to replace the cheaper sugars to the extent desirable.

In British Patent Specification No.

1,401,590, there is disclosed a humectant sweetener for use in oral hygiene composi tions characterized by containing at least about 5% by weight of xylitol. In Example I there is described a composition containing inter alice xylitol and sorbitol in a weight ratio of 5:11.9. In Example II the weight proportions are 10:7. The composition disclosed in said patent specification is said to prevent caries and to keep moisture so that clogging of the opening of an open tooth paste tube will be prevented.

I-Iowe-,-er, there is no discussion of the effect of the composition on the dental plaque pH. This is, of course, to be expected, since an oral hygiene composition is in the first place not expected to have any decisive influence on the dental plaque pH due to the fact that the duration of contact is always very short. As isl clear to all versed in the art, the impact of the characteristics of a sweetener on the dental plaque conditions will be much more significant in connection with the administration of edible products which will be contacted by the saliva for a longer period of time. In particular, this is the case with regard to socalled stimulants, i.e. sweets of different kinds.

In connection with studies performed on compositions containing both xylitol and sorbitol on behaviour in contact with human saliva, a highly surprising discovery has been made. It has thus been found according to the present invention that the content of xylitol may be reduced significantly while maintaining a high pH in the dental plaque under prolonged contact of the composition with the teeth. It is known that the hexol sorbitol, when contacted by the saliva is decomposed resulting in some acid formation, which will be shown in more detail below, thereby unfavourably affecting the teeth when orally administered.

The surprising discovery in connection with experiments carried out is the fact that only a small proportion of xylitol in relation to the sorbitol will eliminate this unfavourable effect of the sorbitol.

The present invention provides edible product containing as a principal sweetener sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol.

Although the invention is not to be bound to any theory, it seems that xylitol hampers the decomposition of sorbitol by the cariogeneous bacteria strain streptococcus mutans. The inhibiting effect of the xylitol seems to be due to inhibition of inducement of sorbitol-decomposing enzyme(s) rather than direct inhibition on induced enzyme(s).

With regard to the lower limit of the per- centage of xylitol a practical minimum amount is 1% by weight and a particularly preferred weight ratio of xylitol : sorbitol is 1:30 to 1:6.

The edible products of the invention are preferably so-called stimulants such as certain sweets, especially chewing gums.

Furthermore, the invention provides a method for preparing a sweetening noncariogenic composition, comprising mixing sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol. The amount of xylitol is suitably at least 1% by weight.

The invention thus provides edible products comprising as a principal sweetener a mixture of sorbitol and xylitol in the given proportions. In this disclosure, the expression "edible products" is intended to cover all types of products intended for oral administration and containing a sweetener, i.e. having a sweet taste. Among such products there may be mentioned desserts, bakery products, sweets, artificial juices and safts. Products of particular interest are so-called stimulants, such as different kinds of sweets; examples include lollypops, lozenges, chocolate, candies, marmalade and chewing gums. The chewing gum type of products are of particular interest, from obvious reasons, since such products are in contact with the saliva for a long time and have an extended retention time in the mouth. It is to be noted that although chewing gums are not normally swallowed they are considered to be of the edible type and thus covered by the invention.

In the products of this invention, the amount of xylitol present should suitably be sufficient to prevent significant decomposition of the sorbitol when contacted by the saliva.

This minimum amount providing sorbitol stabilization may be easily estimated from case to case by practical experiments and no absolute lower limit for the amount of xylitol can thus be given. Generally, the xylitol content based on the combined weight of sorbitol and xylitol should be at least 1% by weight, preferably at least 3% by weight.

As has been indicated already, this invention is particularly applicable to edible products which have a long retention period in the oral cavity when administered. Chewing gums are a good example of such products and other examples are tablets of different kinds. Among products where this invention is applicable there may be mentioned also different kinds of so-called quasi-medicinal products, for instance cough drops and cough elixirs or syrups.

Such products are frequently taken at bed time, i.e. after the teeth have been brushed, and will thus have a long time to act on the dental plaque. Generally, in this disclosure periods of at least a few minutes are con sidered to be long contact times in the oral cavity for products which are administered orally. It will be understood by those skilled in the art that the time of contact of the product in question is not the sole factor governing the resulting effect on the dental plaque; the physical character of the product will also govern the effect to some extent. Thus, when eating for example a tough and sticky caramel or toffee the deleterious effect of the product will be present much longer than the time it takes to consume the product as such The invention will now be described in more detail by the following Examples which are given by way of illustration. Some of the Examples are described in connec tion with the accompanying Drawings wherein: Fig. 1 shows pH as a function of time during influence of human saliva by different types of sugars and sugar combinations; Fig. 2 shows the pH of the dental plaque before and after chewing a chewing gum in accordance with this invention and a comparison chewing gum; and Fig. 3 shows pH as a function of the percentage of xylitol in a sorbitol-xylitol mixture when used in chewing gum.

In the Examples below all percentages are by weight if not otherwise indicated.

EXAMPLE 1.

The experiments are carried out by cultivation in vitro in a test tube containing a conventional meat extract (DIFCO-bouillon) not resulting in acid formation and human saliva, in the form of a mixture from three persons, containing the cariogeneous bacteria strain Streptococcus mutans. The test solutions are incubated at 37"C and sterilized, whereafter the pH is measured after varying times.

In the experiments, 1 ml of a 70-per cent sorbitol solution and a 1 ml of a 50-per cent sucrose solution are used, and to 10 ml of bouillon containing 0.1 ml human saliva (90. 103 organisms per ml) together with the sorbitol and sucrose, respectively, there are added varying amounts of a 50-per cent xylitol solution. pH is measured after 16 hours and the results are given in the diagram of Fig. 1 where the xylitol fraction in per cent is also given.

As is clear from Fig. 1, addition of 3.5% of xylitol already results in essentially inhibited acid formation as compared to the acid formation resulting when using only sorbitol. For comparison, the result is shown when using pure sugar, i.e. sucrose, and as seen from the diagram of Fig. 1, the pH in this case is reduced to about 4.5.

E \ ANIPLE 2.

Preparation of ice chocolate.

An iced chocolate composition is made up from the following ingredients: 2 eggs 360 g sorbitol (100% pure) 40 g xylitol 60 g cacao 1 piece of vanilla bar, ground 350 g coco fat These ingredients are intimately mixed to form a heterogeneous mixture which is distributed in suitable plastic containers for storage in refrigerator. The product obtained has a favourable appearance and a good taste.

EXAMPLE 3.

Sweet sponge cake.

A mixture is prepared from the following constituents: 3 eggs 112 g sorbitol (100% pure) 13 g xylitol 4 g lemon juice 225 g wheat flour 12 g baking powder 100 g water The ingredients are intimately mixed to form a mass having a thick but flowing consistency. The mixture is poured into a baking mould and baked in an oven to form the cake. The cake obtained has a favour able consistency and a good taste.

EXAMPLE 4.

Black currant syrup.

The following ingredients are intimately mixed: 1 kg black currants 1 kg water 200 g sorbitol (100% pure) 10 g xylitol 0.5 g sodium benzoate The syrup obtained, in use, is diluted with water (about 1:4 by volume) to form a good-tasting black currant drink.

EXAMPLE 5.

Chewy Toffee.

The following ingredients are intimately mixed to form a sticky mass: 200 g sorbitol (100% pure) 10 g xylitol 125 g double cream 20 g cocoa 10 g butter 50 g chopped almonds After setting, the composition is cut into suitable pieces having a sticky consistency when chewed and a favourable taste.

EXAMPLE 6.

Hard candy.

The following ingredients are intimately mixed: 90% sorbitol (100% solid basis) in the form of a 70% aqueous solution 9% xylitol 1% flavouring agents The mixture is heated to boiling forming a sticky mass, which is formed into pieces of candy, for example by pouring into moulds. The hard candy obtained has a good taste.

EXAMPLE 7.

Tablets.

A tablet composition is prepared from the following ingredients: Gummi Arabicum 50 O Sorbitol 40% (100% solids basis) in the form of a 70% aqueous solu tion Xylitol 8 % Flavouring agents 2% The mixture obtained is poured into starch moulds to form tablets having a good taste and a favourable consistency.

EXAMPLE 8.

Chewing glut.

A chewing gum composition is prepared starting from the following ingredients: Gum base 30.0 % Sorbitol (70% aqueous solution) 15.0 SO Sorbitol (100% pure powder) 44.55% Xylitol 7.5 % Glycerine 1.60% Flavouring agents 1.35% The ingredients are intimately mixed by kneading at about 50"C and are then extruded and rolled into bands which are severed into suitable pieces, The chewing gum obtained has a good taste and has a favourable consistency whell chewed.

The chewing gum prepared by Example 9 is subjected to tests and is compared to a conventional chewing gum not containing xy.itol. This conventional chewing gum is made in the same manner as described above, except that no xylitol is added, and the amount of sorbitol powder is increased correspondingly to 52%. Moreover, in order to establish the minimum amount of xylitol in chewing gum resulting in the desired pHincrease, different chewing gum compositions were made wherein the ratio of xylitol to sorbitol was varied.

In Fig. 3, the plaque pH as a function of percentage of xylitol (based on the combined weight of xylitol and sorbitol) is shown. The diagram is obtained by measuring the plaque pH after chewing 10 pieces of chewing gum of the invention, the measurements being made about 10 minutes after chewing the final gum piece. As is seen from the diagram the plaque pH starts to increase at a percentage of xylitol of about 3.5 and that, after a fairly rapid increase, the pH reaches a constant level which is largely independent of further increase of the xylitol percentage. This is a highly surprising discovery which was not at all anticipated by those skilled in the art.

In practice, this finding means that the substantially cheaper sugar alcohol sorbitol may replace a large fraction of xylitol without resulting in any substantial change in plaque pH as compared to the use of xylitol alone.

In Fig. 2 there is shown comparison between chewing gums containing xylitol as per Example 9 and chewing gums excluding xylitol while correspondingly increasing the amount of sorbitol. To the left in the diagram there is shown the plaque pH before starting chewing, whereas to the right in the diagram there is shown the plaque pH 10 minutes after chewing the last piece of gum out of 10 pieces chewed in one day.

In Fig. 2 the dashed lines relate to xylitol-containing chewing gum, whereas the uninterrupted lines relate to xylitolfree chewing gum. The reason why the initial plaque pHs vary is that different individuals show different plaque pHs in dependence of different oral bacterial conditions.

It is seen from the diagram that those indi viduals having a high initial plaque pH will be subject to a larger decrease in plaque pH when using xylitol-free chewing gum whereas those individuals having a lower initial plaque pH are not significantly affected with regard to plaque pH when chewing xylitol-free chewing gum. However. irrespective of initial plaque pH chewing of a xyli tol-containing gum always results in an improvement in that the final pH of the plaque is always higher than that obtained after chewing a gum not containing xylitol.

The sweetening strength of the composition according to this invention when based solely on the combination xylitol-sorbitol seems to be of the same order of magnitude as that of ordinary sugar. Thus, the composition can be used to completely replace ordinary sugar in conventional sweet products, such as the above-identified types of sweets. The amount used is in no way critical and is only dependent on the degree of sweetness desired in the product in question. In other respects the composition may be used mainly in the same manner as ordinary sugar.

WHAT WE CLAIM IS:- 1. Edible product containing as a principal sweetener sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol.

2. Product according to claim 1 which contains at least 1% by weight of xylitol.

3. Product according to claim 1 or 2, wherein the weight ratio of xylitol : sorbitol is 1:30 to 1:6.

4. Product according to any one of the preceding claims, in the form of a stimulant.

5. Product according to claim 4, wherein the stimulant is a chewing gum.

6. Product according to any one of claims 1 to 4, in the form of a sweet.

7. Edible product according to claim 1 substantially as hereinbefore described with reference to any one of the Examples.

8. A method for preparing a sweetening non-cariogenic composition, comprising mixing sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol.

9. A method according to claim 8 for preparing a composition as claimed in any one of claims 1 to 3 and 5 to 7.

10. A method according to claim 9 substantially as hereinbefore described with reference to any one of the Examples.

11. A sweetening non-cariogenic composition when prepared by a method as claimed in any one of claims 8 to 10.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. tol-containing gum always results in an improvement in that the final pH of the plaque is always higher than that obtained after chewing a gum not containing xylitol. The sweetening strength of the composition according to this invention when based solely on the combination xylitol-sorbitol seems to be of the same order of magnitude as that of ordinary sugar. Thus, the composition can be used to completely replace ordinary sugar in conventional sweet products, such as the above-identified types of sweets. The amount used is in no way critical and is only dependent on the degree of sweetness desired in the product in question. In other respects the composition may be used mainly in the same manner as ordinary sugar. WHAT WE CLAIM IS:-

1. Edible product containing as a principal sweetener sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol.

2. Product according to claim 1 which contains at least 1% by weight of xylitol.

3. Product according to claim 1 or 2, wherein the weight ratio of xylitol : sorbitol is 1:30 to 1:6.

4. Product according to any one of the preceding claims, in the form of a stimulant.

5. Product according to claim 4, wherein the stimulant is a chewing gum.

6. Product according to any one of claims 1 to 4, in the form of a sweet.

7. Edible product according to claim 1 substantially as hereinbefore described with reference to any one of the Examples.

8. A method for preparing a sweetening non-cariogenic composition, comprising mixing sorbitol and up to 25% by weight of xylitol based on the combined weight of sorbitol and xylitol.

9. A method according to claim 8 for preparing a composition as claimed in any one of claims 1 to 3 and 5 to 7.

10. A method according to claim 9 substantially as hereinbefore described with reference to any one of the Examples.

11. A sweetening non-cariogenic composition when prepared by a method as claimed in any one of claims 8 to 10.