RU2835946C1 - Inner coated drinking straw - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: disclosed is a drinking straw comprising an elongated tubular body made from an insoluble material having an inner coating containing a matrix and one or more active agents which are dispersed throughout the matrix. Said housing is sized to draw carrier fluid there through so that passage of said carrier fluid results in release from the matrix of said one or more active agents into said carrier fluid to be consumed by the drinker. Matrix contains 65–80% of partially hydrolysed guar gum (PHGG), 15–30% of acid and 3–10% of modified cellulose.

EFFECT: invention enables to obtain an alternative drinking straw which contains a material which dissolves in a liquid drawn through the straw during use.

12 cl, 4 ex

Description

AREA OF TECHNOLOGY

The present invention relates to drinking straws having an internal coating that quickly dissolves, disintegrates or dissolves in liquid drawn through the straw during use. The coating may typically include vitamins, stimulants, probiotics and/or pharmaceutical products, and may additionally or alternatively include other agents such as sweeteners and flavoring agents.

PRIOR ART

Pre-filled straws for flavouring drinks are available in supermarkets around the world. Most often, the straws are filled with granules containing sweeteners and flavourings, such as strawberry or chocolate. The straws can be used to drink milk, with the granules gradually dissolving in the milk as it passes through the straw, adding flavour and sweetness to the milk. The advantage of these straws is that the flavourings take up less space, the straws have a longer shelf life than flavoured milk products, and they are easier to use and control than powdered milk flavouring, which must be dissolved in milk to make a drink. The straws can also be used to flavour water.

In addition, other types of filled straws have been proposed, including straws that have a soluble coating bonded to the inner surface. During use, as liquid is drawn through the straw, the coating dissolves into the liquid.

U.S. Patent No. 4,921,713 issued to Fowler describes a straw for imparting flavor to generally neutral liquids such as water or milk. Various methods for producing a material that dissolves in the liquid are described. Such methods include a separate chamber containing a flavor material, a granular material retained within the body of the straw by a pair of spongy members, and the flavor material adhered to the interior surface of the straw.

US 2003/168772 to Palaniappan describes a method for producing a straw with an internal coating, wherein the internal coating is applied to the internal surface of the straw as it exits the extruder in which the molding takes place. The coating material includes a matrix agent, which can be maltodextrin or alginate, with the addition of a flavoring agent.

US 2011/143005 to Gaonkar also describes a drinking straw having an inner surface coated with a material that imparts flavor and sweetens a beverage drawn through the straw. The coating comprises an adhesion agent and a powdered agent. The adhesion agent includes lipids, medium chain triglyceride oils, emulsifiers, and mixtures thereof. The powder may include food acids, food bases, sweeteners, flavors, vitamins, minerals, colors, sensory agents, carotenoids, antioxidants, polyphenols, phytoadditives, and mixtures thereof.

The problem with all these coatings is that the flavor and aroma they impart to the drink is weak enough that it simply doesn't make economic sense to produce them as a commercial product.

US 2006/0286214 to Sanford Weiss et al describes an edible drinking straw comprising layers of a fruit film twisted into a spiral. The layers may be held together by a zein solution. The straw may be used to draw liquid into the user's mouth, and as the liquid passes through the straw, some of the liquid dissolves, imparting flavor and aroma to the liquid. This results in a loss of structural integrity of the straw, and after this occurs, the remaining straw material may be dissolved in the liquid or eaten directly.

US 2005/0106188 to Kerdar et al describes a filled drinking straw where the filler is retained within the straw by barrier devices, which may be in the form of a plug or a mesh. The barrier devices allow liquid to pass through the straw, dissolving the filler, but retain any undissolved filler within the straw. Other types of filled straws are known, such as those described in EP 1 509 096, where the filler is in the form of granules and retained in the straw by filters.

The need for barriers or filters adds additional steps to the manufacturing process, increasing time and cost. Additionally, barriers or filters, unless they are an integral part of the straw, can become dislodged and create a choking hazard. Additionally, a filter failure, i.e., a larger-than-intended hole, can result in the straw contents being released into the user’s mouth undissolved, creating another choking hazard.

One of the objectives of the invention is to obtain a filled straw without the use of barrier or filtering means.

US 2004/0109932 to Chen et al discloses a coated straw wherein the coating comprises 40 to 99.99% of a food grade acid. The composition may also include a surface tension reducing agent, a plasticizer, a bulking agent, and water. The coating may be produced by co-extrusion, spraying, or dipping. The second coating may be in the form of a powder further comprising a food grade acid, sugar, effervescent agents, colorants, probiotics, vitamins, herbs, and flavoring agents. This powder may adhere to the adhesive surface of the acid coating.

More recently, the patent document WO 2016/198515 describes the use of a modified cellulose matrix. This material is very effective in producing a drinking straw with an inner coating that imparts flavor and aroma to a beverage drawn through the straw and gradually dissolves in the beverage during the time required to consume the beverage. Typically, such straws are used for iced beverages, beverages containing small ice crystals, and other beverages that are quite thick and viscous. Such beverages are typically consumed within approximately 10 to 15 minutes and have a volume of 600 to 1000 ml. Drinking straws with an inner lining containing a modified cellulose matrix can impart flavor and aroma to the beverage throughout the entire drinking process. In fact, the rate of dissolution of the inner coating is such that it cannot dissolve in a beverage that is consumed quickly. It is also believed that ice crystals present in iced drinks, for which such straws are commonly used, touch the coating during drinking, causing it to dissolve. Examples of modified cellulose matrix include hydroxypropyl methylcellulose, hydroxypropyl cellulose or methylcellulose, but other cellulose matrices, including mixtures, may also be used. Although the use of modified cellulose matrices is quite effective for beverages that are consumed slowly and with a sufficient volume of liquid, especially liquid containing particles, it is not effective in imparting flavor and aroma to beverages that are consumed quickly and with a smaller volume of liquid.

A thirsty consumer, for example after physical activity or on a hot day, may want to drink a beverage quickly and directly from the refrigerator. The volume of such a beverage may be between 100 and 500 ml, and it may take approximately 2 minutes to consume it. A drinking straw having an inner coating based on modified cellulose will not dissolve in the beverage quickly enough to impart sufficient flavor and aroma to it and will essentially be completely consumed at the same speed as the beverage. This is especially important in the case where the inner coating contains a drug or a supplement or probiotic, such as a vitamin or mineral, or a combination thereof. In this case, the consumer will also want to consume the active ingredient quickly and, as a rule, with a cold beverage from the refrigerator, such as water.

There are a number of challenges to overcome when finding a coating agent that will adhere to the inside surface of a drinking straw. First, aqueous materials typically shrink when dried. This is a significant advantage when used as an external coating, such as on the outside of a granule or tablet, because the shrinkage will pull the coating more tightly onto the granule or tablet. However, it is a significant disadvantage when used to coat the inside surface of anything, including a drinking straw, because the shrinkage will pull the coating material away from the surface of the straw. This will result in insufficient adhesion of the coating material to the drinking straw, which will result in damage to the straw. Second, drinking straws are typically made of hydrophobic materials, to which aqueous materials typically do not adhere, which exacerbates the problem. Most drinking straws are most often made of polypropylene, which is hydrophobic, or other materials that are hydrophobic or have a hydrophobic coating. Nowadays, more and more drinking straws are made from biodegradable materials, including polylactic acid (PLA) or polybutylene succinate (PBS). They are also hydrophobic materials, which means that water does not stick well to them.

It would be desirable to create a straw with an inner coating that can release the active ingredient into a quickly consumed beverage.

It would also be desirable to create a straw with an improved inner coating.

The aim of the invention is to provide alternative drinking straws containing a material that dissolves in a liquid drawn through the straw during use, and methods for producing such straws.

BRIEF DESCRIPTION OF THE ESSENCE OF THE INVENTION

A drinking straw is proposed, comprising an elongated body having an internal coating containing partially hydrolyzed guar gum, which adheres to the internal surface of the body and retains one or more agents consumed by the user.

DETAILED DESCRIPTION OF THE INVENTION

Thus, the present invention provides a drinking straw comprising an elongated tubular body of insoluble material having an inner coating containing a matrix and an active agent, wherein the active agent is dispersed throughout the matrix, the body being sized to draw a carrier liquid through it in such a way that passage of the carrier liquid results in the release of the active agent from the matrix into the carrier liquid for consumption by the drinker, wherein the matrix comprises partially hydrolyzed guar gum (PHGG), an acid and modified cellulose.

During use, the user places one end of the straw into a beverage container and sucks the beverage through the straw, releasing the active agent from the gum matrix into the beverage being consumed.

Gums for use in the invention are preferably cold water soluble, i.e., water at a temperature of 5°C or below.

Gums are mass-produced commercial products available from many sources. Suitable gums are water-soluble branched polysaccharides and, as such, are structurally and functionally distinct from cellulose and cellulose derivatives, as cellulose is a linear polysaccharide. Gums are also distinct from inulins, which are unstable at low pH and are not suitable for the invention. Gums may also be referred to as dietary fibres and are often used as such.

Partially hydrolyzed guar gum is a known, mass-produced commercial product available from many sources. It is a water-soluble, branched polysaccharide and is supplied in varying degrees of hydrolysis, typically being at least 5% hydrolyzed, preferably at least 10%. Typically, gums for use in the invention are hydrolyzed to 40%, more preferably to 30%, and suitably to 20%. The degree of hydrolysis is measured in a standard manner and is usually reported as a fiber content in %.

The examples below use PHGG (Partially hydrolysed guar gum) with a fibre content of approximately 85% or more; this PHGG has been found to be stable at low pH and soluble in cold water.

More specifically, gums are naturally occurring polysaccharides that can cause a significant increase in solution viscosity even at low concentrations. Some gums are soluble or partially soluble in water at ambient temperatures, while others are insoluble but swell in water. In the food industry, gums are used as thickeners, clarifiers, gelling agents, emulsifiers, and stabilizers.

The most common uses of gums are as thickeners and stabilizers in food and beverages. Gums can be used, for example, in meat products, ice cream, salad dressings, confectionery, beverages, jams, cheeses, cosmetics, and toothpastes.

Guar gum is widely used in the food industry as a stabilizer in frozen fruit products, glazes, frostings, and fruit drinks. It is also used as a binder in meat products, baked goods, cream cheese, and ice cream. Guar gum is also sometimes used to add bulk and texture to cosmetics and toothpaste. Guar gum, also known as guaran, is a galactomannan from the endosperm of the guar seed.

Partially hydrolyzed guar gum (PHGG) is typically produced by partial enzymatic hydrolysis of guar gum. The gum is a neutral polysaccharide consisting of a mannose backbone with single galactose pendant units present on nearly two out of every three mannose units. The average molecular weight is approximately 25,000 Daltons. Hydrolyzed guar gum is used as a soluble fiber in many fiber supplements and prebiotic food supplements. PHGG is used in food products for thorough suspension, emulsification, anti-staling, ice crystal control, and reduced fat baked goods, and as mentioned, is commercially available from a variety of sources.

The gum matrix of the invention is prepared in the form of a thick aqueous paste or syrup that can adhere to the inner surface of the straw. After the matrix is applied to the inner wall of the straw, it is dried to remove excess moisture. More preferably, the gum matrix is made non-drip; after application, such a matrix adheres to the inner wall of the straw without dripping or spreading, and therefore does not drip or flow so much as to accumulate in lower vertical parts of the straw.

It has also been found that the inclusion of acid in the matrix increases the adhesion to the inner wall of the straw. The amount of acid can be up to 50 wt.%, suitably from 10 to 45 wt.%, preferably from 20 to 40%. The preferred amount of acid in the matrix used in the examples below is about 20 to 25%.

The acid prevents the coating from drying out, maintaining its plasticity. However, the presence of too much acid can be harmful to the coating. Firstly, too much acid may not dry the coating sufficiently for storage. Toxic moulds can grow on food products with a water activity of 0.66 or higher. It is therefore important to ensure that the water activity in the dried coating is below this level. Another factor is that high acid levels, i.e. low pH, can lead to the decomposition of some active agents. Thus, the amount of acid depends partly on the matrix and partly on the active agent(s) in the coating.

The acid used in the inner-coated drinking straw may be a food-grade acid. Preferred examples of suitable acids include citric acid, malic acid, tartaric acid, ascorbic acid. The preferred acid is citric acid or ascorbic acid, most preferably citric acid. Other acids, such as acetic acid, may be used, but they are likely to produce an unpleasant taste and should therefore be avoided.

Modified cellulose provides greater ease of handling. Preferably, the modified cellulose is selected from hydroxypropyl methylcellulose, hydroxypropyl cellulose, methylethyl cellulose, methylcellulose and carboxymethylcellulose or a combination thereof. All of these modified celluloses are approved for use in foodstuffs, and are therefore assigned food additive numbers E464, E463, E465, E461 and E466. The preferred modified cellulose is hydroxypropyl methylcellulose or methylcellulose, most preferably hydroxypropyl methylcellulose.

The use of modified cellulose as a matrix in a straw with an inner coating has been described in patent document WO 2016/198515, as discussed above. Although effective, the active agent is released from the coating over a long period of time, meaning that such a coating is not suitable for drinks that need to be consumed quickly. This is especially true for drinks from a refrigerator or drinks with ice.

A combination of modified cellulose and PHGG can be used to produce inner-coated drinking straws in which the coatings release their active agent over different periods of time and at different temperatures. Typically, by varying the ratio of these elements, a coating can be produced that has a release time of between 2 and 20 minutes. The thickness of the coating also affects the release time. However, very thick coatings, typically more than 2 mm, should be avoided because drying such coatings is difficult and time-consuming.

In the case where the matrix is exclusively or almost exclusively modified cellulose, the release time may be from 8 to 20 minutes. When using a combination of modified cellulose and PHGG in combination with an acid, a release time of 1 to 10 minutes can be obtained, depending on the ratios of the components.

The proportions of components in the matrix can be as follows:

from 65 to 80% PHGG,

from 15 to 30% acid,

from 3 to 10% modified cellulose.

Preferably, the proportions of the components are as follows:

from 65 to 75% PHGG,

from 20 to 30% acid,

from 3 to 8% modified cellulose.

Most preferably, the proportions of the components are as follows:

from 70 to 75% PHGG,

from 20 to 25% acid,

from 3 to 8% modified cellulose.

The ratio of modified cellulose:PHGG may be from 1:5 to 1:25, preferably from 1:10 to 1:20, and more preferably from 1:15 to 1:20.

To achieve a fast release time, a high proportion of PHGG can be used. For example, with a modified cellulose to PHGG ratio of 1:6, the release time is approximately 3 to 5 minutes. Typically, a modified cellulose to PHGG ratio of 1:15 produces a straw with an inner coating having a release time of 1 to 3 minutes.

When using a combination of PHGG and modified cellulose in a ratio of 15:1, the proportion of acid is typically 30%.

Typically, the active agent will include a food additive including plant extracts, vitamins, minerals, amino acids, fatty acids, probiotics and/or pharmaceuticals. Additionally or alternatively, sweeteners and flavors may also be included, and coloring agents may also be included. As a further alternative, the active agent may be formulated to produce an energy drink, typically containing a stimulant such as caffeine and B vitamins. In such compositions, it is important that the water content is low, since some vitamins, and in particular B vitamins, may degrade in the presence of water. Amino acids also typically require low water content, since these compounds may degrade in the presence of high levels of humidity.

Flavoring agents may include additional acids, including fumaric acid.

Typically, the ratio of active substances to matrix will be between 2:1 and 1:4. This ratio will depend, among other things, on the nature of the active substances. If the addition of active substances results in a thicker mixture, less matrix is required. If the addition of active substances results in a thinner mixture, more matrix is required.

The water content of the coating can affect the stability of the active agent. Typically, the coated straw is dried to remove additional water and reduce the water content. Typically, the straws have a water content of less than 5%, preferably less than 3%, and most preferably less than 1% by weight. Advantageously, the composition after drying will have a water activity of less than 0.6, and preferably less than 0.5, and more preferably less than 0.4.

Many pharmaceutical compounds can be formulated to be retained within a matrix and released into the liquid as the matrix rapidly disintegrates or dissolves as the liquid passes through a straw. The compounds can be dissolved in the liquid or suspended, but will be drawn into the user's mouth for swallowing. This may provide some patients with a more convenient form of administration of certain medications as an alternative to swallowing tablets. Such compositions may also include sweetening or flavoring agents.

Additionally, the active agent may include nutritional compounds that are also capable of being dissolved or suspended in the liquid as the matrix rapidly dissolves in the liquid drawn through the straw. Again, this allows for a convenient method of administering such compounds.

Typically, the active agent will include at least one sweetening or flavoring agent.

Once dried on the inside surface of the straw, the matrix also functions as a protective coating for the active ingredients. It helps protect some of the more sensitive active ingredients from atmospheric moisture and oxygen, even if the atmosphere around the finished and packaged straw is not an artificial or controlled atmosphere.

The ratios of matrix to active agent may vary depending on the active agent and the volume of liquid in which it is desired to dissolve the coating. Typically, the coating may have a matrix:active agent ratio (dry weight) of approximately 65:35. For example, the matrix:active agent ratio may be from 80:20 to 20:80 or from 80:20 to 40:60. In embodiments, the ratio is from 70:30 to 30:70. In embodiments, the ratio is from 70:30 to 45:55. In embodiments, the range is from 60:40 to 50:50.

The coating may contain (by dry weight) from 50 to 80% matrix and from 50 to 20% active agent. Preferably, the matrix will contain from 60 to 70% matrix and from 40 to 30% active agent.

The coatings can quickly release the active agent in a given volume of liquid, which will depend on the active agent and the user. Typically, the coating is designed to release the active agent or disperse it in 100 to 1000 ml of liquid. Preferably, the coating is designed to disperse in 100 to 500 ml of liquid and, most preferably, in 100 to 300 ml of beverage.

In some examples, in particular, the coating may be designed to release the active agent or disperse it in a relatively small volume of liquid, typically from 100 to 150 ml, so that the active agents can be easily and quickly consumed by a user who may be ill or may want to quickly take the active substance.

The thickness of the coating will also affect the dissolution of the coating. Thicker coatings generally take longer to dissolve (at the same degree of drying). The coatings are typically applied in thicknesses of up to 1 mm, such as from 0.01 to 1 mm, more preferably up to 0.7 mm, such as from 0.05 to 0.7 mm. Typically, the coating will have a thickness of up to 0.5 mm, preferably up to 0.25 mm. The most preferred coating thickness used in the specific example below is essentially from 0.05 to 0.2 mm.

The combination of coating thickness, component ratio, and matrix composition can be altered to change the dissolution time and concentration of the active agent in the consumed beverage, as discussed above.

The present invention also provides a method for producing a drinking straw having an at least partially coated interior, the method comprising the steps of:

take a drinking straw made of insoluble material;

taking the matrix defined in the first aspect, with the addition of the active agent(s) to be dispersed therein, and mixing with water to form a syrup or paste;

apply the syrup or paste as a coating to the inside surface of the drinking straw; and

dry the coating.

As described below in embodiments, the method includes obtaining a matrix and one or more active agents, wherein the matrix comprises a partially hydrolyzed gum, and mixing them with water to form a syrup or paste, wherein the syrup or paste is used to form a coating on the inner surface of a straw. The matrix material and one or more active agents can be mixed together, then the resulting mixture is combined with water, or all components can all be combined and mixed in more or less one step.

According to some embodiments, the coating is suitably prepared in the form of a syrup, which allows it to be processed on the processing equipment and to adhere to the inner surface of the straw. According to other embodiments, the coating is prepared in the form of a paste, usually a thick paste. It is also preferable that the coating is made without the possibility of dripping, remaining in place during drying and not dripping. The matrix is usually dissolved in water, as are some active agents, depending on their composition. In this case, depending on the amount of water used, the mixture will be a paste or a syrupy solution.

The coating can be produced by mixing the coating with water and heating the mixture to form a paste or syrup. The active agent can be added at high temperature, or the paste/syrup can be cooled before adding the active agent. Alternatively, the coating can be produced by mixing the gum with water at ambient temperature and stirring to form a syrup or paste. Sometimes the syrup or paste can have the consistency of a thick cream, so that it can support its own weight and thus will not drip or run, particularly when applied to a surface. The working thickness depends to some extent on the thickness of the coating being applied. A thinner coating will be less fluid, even if the syrup flows well in large quantities.

However, to automate the process, the coating is most often prepared in the form of a syrup, which has properties that meet the requirements of fluidity in large quantities, but at the same time is relatively non-dripping and has limited fluidity after application to the inner surface of the straw.

Typically, a weight of water approximately equal to the dry weight of the matrix is used. For example, the coating (dry weight) : water ratio may be from 20:80 to 80:20 or from 30:70 to 70:30, preferably from 45:55 to 60:40, and most preferably from 50:50 to 60:40.

A particularly suitable matrix for rapid dissolution would include 7.5 g PHGG, 0.5 g modified cellulose and 3 g acid in 15 g water.

Depending on the active agent and the volume of liquid in which the coating is intended to be dissolved, 1 to 10 g, preferably 3 to 9 g, and more preferably 5 to 8 g, of the active agent is typically added to the syrup.

As discussed above, the matrix will preferably include a food grade acid. It has also been found that the inclusion of an acid in the active agent increases the adhesion between the PHGG (and modified cellulose) and the hydrophobic wall of the drinking straw. The amount of acid may be from 20 to 40 w/w%.

As explained elsewhere, acid prevents the coating from drying out while maintaining plasticity, and various acids can be used.

In addition, the active agent will often include a sweetener, such as stevole glycosides (stevia) or sugars, including glucose and/or fructose, and may also include flavoring agents, such as fruit flavors, chocolate flavors, vanilla flavors. Coloring agents may also be included. Typically, the active agent will also include pharmaceutical compounds and/or nutritional compounds, including vitamins and minerals, and possibly fatty acids, amino acids, and/or phytochemicals. Additional or alternative agents may include plant extracts.

The ratios of matrix to active agent may vary depending on the active agent and the volume of liquid in which it is desired that the coating be suspended or dissolved to form a suitable syrup or paste. Typically, the coating may have a matrix:active agent ratio (dry weight) of approximately 60:40. For example, the matrix:active agent ratio may be from 80:20 to 20:80, or from 75:25 to 25:75, or from 75:25 to 40:60, preferably from 70:30 to 45:55, and most preferably in the range from 65:35 to 50:50.

The coating may contain (by dry weight) from 40 to 75% matrix together with from 60 to 25% active agent. Preferably, the matrix will contain from 45 to 65% matrix and from 55 to 35% active agent.

Once the coating has been formed, it is used to at least partially coat the interior surface of a straw. Typically, the straw is made of a plastic material, typically polypropylene, polylactic acid (PLA) or polybutylene succinate (PBS), although other types of plastic materials such as polyethylene or PET (Poly Ethylene Terephthalate) may be used. Metal or glass may also be used. Preferably, the straw may be recyclable or biodegradable.

The coating may be applied by spraying the coating onto the inside of the straw. Alternatively, the coating may be produced by dipping the straw into the coating and then wiping off any excess from the outside.

Preferably, the coating is applied using a core with a head from 0.01 mm to 1 mm smaller than the inner diameter of the straw. A predetermined amount of coating is placed on the end of the core that passes through the straw, applying the coating in the form of a thin layer along the inner perimeter of the straw. Alternatively, the core can be provided with a hollow body with an outlet on the head having a larger diameter than the body. A predetermined amount of coating can be pumped through the body into the head as the core passes through the straw. As the core is removed from the straw, the head evenly distributes the coating along the inner surface of the straw. The relative size of the inner diameter of the straw and the diameter of the head of the core determines the thickness of the coating applied.

The coating may be applied over the entire length of the straw. Alternatively, the coating may be applied to only part of the length of the straw. For example, the coating may be applied only to the middle of the straw, with no coating applied near one or both ends of the straw. A section of 10 to 30 mm at the end of the straw may be uncoated. When applying the coating by spraying, both ends of the straw may be uncoated. When using a core, typically only one end is uncoated. Alternatively, the coating may be applied over the entire length of the straw and then removed from one or both ends, for example by washing or wiping.

The coating may also be applied to a portion of the straw to achieve a particular geometric shape for use with the beverage being consumed. This may mean application to the top half of the straw in the case of a coating that is not in the beverage being consumed, or alternatively application to the bottom half of the straw in the case of a coating that provides an improved result when immersed in the beverage being consumed. Straws that are coated unevenly, i.e. mainly on one half, are usually marked in some way to indicate to the user which end of the straw should be placed in the beverage and which should be used for drinking. The marking may consist of providing the straw with a flat end, perhaps a flattened end, for drinking through it, and an angled end for placement in the beverage. Alternatively, the end to be placed in the beverage may be flared. As a further alternative, an indication, such as an inscription or a colour marking, may be applied to the outside of the straw.

The more of the inner surface of the straw that is coated, the greater the chance that the straw will contain a higher level of active substances. Typically, the coating is applied to at least 50%, preferably at least 70% of the inner surface area of the drinking straw, preferably 70 to 90% of the surface, and most preferably 75 to 85% of the inner surface.

Once the coating has been applied, it is typically dried before the straw is packaged. Drying is typically accomplished by passing a stream of relatively cool, dry air, such as dry air at room temperature, through the straw. Alternatively, the coated straws may be passed through a moderately heated medium, or a stream of moderately heated air may be used to dry the coating. It is important that the air is not so hot as to cause melting of the straw or decomposition of the active agent. Alternatively, the coating may be dried by passing a stream of cool, dry air through the straws. The drying process may be carried out at refrigeration temperatures. This method of drying may be advantageous when working with heat-sensitive active substances.

It may be preferable to rotate the straw during coating application and/or while the coating is drying. Rotation may help to achieve an even coating and to achieve uniform and complete drying of the coating.

The water content of the coating after drying will typically be less than 5%, preferably less than 3%, and most preferably less than 1% by weight. Typically, the dry coating will have a water activity of 0.6 or less, preferably 0.5 or less, and more preferably 0.4 or less.

Once dried, the straws are usually packaged individually or in small quantities, typically 1 to 5, in moisture-proof packaging material to prevent the coating from absorbing atmospheric moisture. In some cases, the atmosphere inside such packaging is artificially controlled to prevent moisture and/or oxygen from being present in the packaging to extend the shelf life of the active ingredient.

DESCRIPTION OF EXAMPLES OF IMPLEMENTING THE INVENTION

During the development of the invention, many attempts were made to obtain a suitable coating or lining of the inner surface of a drinking straw using a wide range of ingredients commonly used in the food industry, the properties of which were found to be advantageous and suitable for forming such a coating or lining. In particular, various combinations of food grade ingredients were used that were expected to have the necessary film-forming and adhesive properties, including vegetable gums (carrageenan, acacia, locust bean gum, xanthan gum), sodium alginate, agars, certain pregelatinized starches and other simple food compounds, including in various combinations. However, none of these attempts were successful; these ingredients either did not form a syrup that could be used to coat the inner surface of the straw, or when dried, they separated from the straw or returned to powder form. Additionally, the compounds were tested in combination with a previously identified hydroxypropyl methylcellulose composition including polysorbate 80, croscarmellose, glycerin, sorbitol, mannitol, acacia, pullulan, xanthan gum, locust bean gum, and carrageenan. These compositions failed to maintain adhesion upon drying, becoming instead powdery or flaky and separating from the straw.

Below the invention will be illustrated with specific examples.

Example 1

Drinking straw with energy composition

7.5 g PHGG and 0.5 g hydroxypropyl methylcellulose were mixed with 15.0 g water to form a paste. 3.0 g citric acid and 6.0 g caffeine were added to the resulting mixture.

The drinking straws were coated over their entire length with 0.6 g of the coating, 125 μm thick, as described above. The straws were then dried in a low-temperature oven to a water activity of 0.4, after which the coating weighed 0.34 g. The coating formed an even layer over the entire inner surface of the drinking straw and appeared to adhere tightly to it.

The finished straws could be used to drink 450 ml of cold water from the refrigerator (4-5°C) within 2 to 2.5 minutes. After consumption, no traces were left on the inside of the straw or on the drink container.

Example 2

Drinking straw with energy composition and cherry flavor

To prepare the coating, 7.5 g of partially hydrolyzed guar gum was mixed with 0.5 g of hydroxypropyl methylcellulose in 15.0 g of water at ambient temperature. To the resulting mixture were added 6.0 g of caffeine, 3.0 g of L-theanine (an extract of green tea and some other plants), 2.0 g of cherry flavoring, 2.0 g of citric acid, 1.0 g of stevia sweetener, and 0.2 g of red dye, and the mixture was thoroughly mixed.

Drinking straws made of white polylactic acid were coated with 0.53 g of the prepared mixture to obtain a coating thickness of 50 μm. Thus, each straw contained 100 mg of caffeine and 50 mg of L-theanine. The straws were then dried in a low-temperature drying chamber to obtain a film weighing 0.41 g, which firmly adhered to the straw.

The straws were used to consume 170 ml of chilled water (4-5°C) for 2 minutes. At this stage, no traces were left on either the straw or the beverage container. The white colour of the straws concealed any potential coating defects due to the dispersed nature of the active ingredients.

Example 3

Drinking straw with a coating containing black cohosh extract

7.5 g partially hydrolyzed guar gum and 0.5 g methylcellulose were mixed with 15.0 g water at ambient temperature to form a thick syrup. 5.1 g black cohosh extract (a herbal remedy for menopause-related symptoms that has a bitter taste), 2.0 g lemon flavor, 2.0 g citric acid, 1.0 g stevia sweetener, and 0.2 g yellow dye were added to the resulting paste and mixed thoroughly.

Polypropylene drinking straws were prepared and 0.45 g of syrup was applied to the inner surface of each drinking straw, resulting in a coating thickness of 50 μm. After drying in a low-temperature drying chamber, the straws contained a coating weighing 0.31 g uniformly attached to them. The finished straw contained 80 mg of black cohosh extract.

These straws were used to consume 160 ml of chilled water (4-5°C) for approximately 2 minutes. After this time, there was no residue left on either the straw or the beverage container. The composition and delivery method masked the bitter taste of the black cohosh extract, resulting in a beverage with a pleasant taste.

Example 4

Drinking straw with probiotic coating

15.0 g partially hydrolyzed guar gum and 1.0 g methylcellulose were mixed with 30.0 g water at ambient temperature. To the resulting mixture were added 3.0 g spray-dried Bacillus Coagulans powder, 3.0 g grape flavor, 4.0 g citric acid, 2.0 g stevia sweetener, 0.5 g red dye, and 0.1 g blue dye. The coating was thoroughly mixed until uniform.

0.38 g of the resulting syrup was applied to polypropylene drinking straws, forming a coating 50 μm thick. After drying with stirring at low temperatures, the film weight was 0.27 g, and the film adhered firmly and uniformly to the straw. Each straw contained 2 billion CFU (colony-forming unit) of probiotic material.

The straw was completely used to consume approximately 180 ml of chilled water (4-5°C) in approximately 2 minutes. After consuming this volume, no traces remained on either the straw or the glass.

Thus, the invention provides drinking straws with an internal coating, where the coating contains a camidium matrix and an active agent, and methods for producing them.

Claims (25)

1. A drinking straw comprising an elongated tubular body of insoluble material having an internal coating comprising a matrix and one or more active agents, wherein said one or more active agents are dispersed throughout the matrix, wherein said body is sized to draw a carrier liquid therethrough such that passage of said carrier liquid results in the release of said one or more active agents from the matrix into said carrier liquid consumed by the drinker, wherein said matrix comprises: (a) 65 to 80% partially hydrolyzed guar gum (PHGG), (b) from 15 to 30% acid, (c) from 3 to 10% modified cellulose. 2. A drinking straw according to claim 1, wherein the acid is selected from citric acid, malic acid, tartaric acid, ascorbic acid, or a combination thereof. 3. The drinking straw of claim 1, wherein the modified cellulose is selected from hydroxypropyl methylcellulose, hydroxypropyl cellulose, methylethylcellulose, methylcellulose and carboxymethylcellulose, or a combination thereof. 4. A drinking straw according to any of the preceding claims, wherein the matrix comprises: (a) 65 to 75% PHGG, (b) 20 to 30% acid, (c) from 3 to 8% modified cellulose. 5. A drinking straw according to any one of the preceding claims, wherein said coating has a water activity of 0.6 or less. 6. A drinking straw according to any one of the preceding claims, wherein the active agent comprises a food additive including plant extracts, vitamins, minerals, amino acids, fatty acids, probiotics, a pharmaceutical substance, a sweetener, a flavouring agent or a colouring agent, or a combination of two or more of them. 7. A method for producing a drinking straw having an at least partially coated interior, said method comprising the steps of: (a) take a drinking straw made of insoluble material; (b) taking a matrix and one or more active agents, said matrix comprising 65 to 80% PHGG, 15 to 30% acid and 3 to 10% modified cellulose, and mixing them with water to form a coating in the form of a syrup or paste; (c) applying said coating to the inner surface of said drinking straw; and (d) dry the said coating. 8. The method according to claim 7, wherein the acid is a food acid. 9. The method according to claim 7 or 8, wherein the acid is selected from citric acid, malic acid, tartaric acid, ascorbic acid, or a combination thereof. 10. The method according to claims 7, 8 or 9, wherein the modified cellulose is selected from hydroxypropyl methylcellulose, hydroxypropyl cellulose, methylethylcellulose, methylcellulose and carboxymethylcellulose or a combination thereof. 11. The method according to any one of claims 7-10, wherein the coating is dried to obtain a water activity of less than 0.6. 12. A drinking straw comprising an elongated tubular body of an insoluble material having an internal coating comprising a matrix and one or more active agents, wherein said one or more active agents are dispersed throughout the matrix, wherein said body is sized to draw a carrier liquid therethrough such that passage of said carrier liquid results in the release of said one or more active agents from the matrix into said carrier liquid consumed by the drinker, wherein said matrix comprises: (a) from 70 to 75% by weight of hydrolyzed gum, (b) from 3 to 8% by weight of modified cellulose, and (c) from 20 to 25% by weight of acid.