A method of controlling PCO2 in a patient at a predetermined desired level(s) comprising a breathing circuit which is capable of organizing exhaled gas so as to be preferentially inhaled during re-breathing when necessary by providing alveolar gas for re-breathing in preference to dead space gas.

This Application claims priority to Canadian Application Serial No. 2304292 filed Mar. 31, 2000.
[Not Applicable]
Venous blood returns to the heart from the muscles and organs depleted of oxygen (O2) and full of carbon dioxide (CO2). Blood from various parts of the body is mixed in the heart (mixed venous blood) and pumped to the lungs. In the lungs the blood vessels break up into a net of small vessels surrounding tiny lung sacs (alveoli). The net sum of vessels surrounding the alveoli provides a large surface area for the exchange of gases by diffusion along their concentration gradients. A concentration gradient exists between the partial pressure of CO2 (PCO2) in the mixed venous blood (PvCO2) and the alveolar PCO2. The CO2 diffuses into the alveoli from the mixed venous blood from the beginning of inspiration until an equilibrium is reached between the PvCO2 and the alveolar PCO2 at some time during the breath. When the subject exhales, the first gas that is exhaled comes from the trachea and major bronchi which do not allow gas exchange and therefore will have a gas composition similar to the inhaled gas. The gas at the end of this exhalation is considered to have come from the alveoli and reflects the equilibrium CO2 concentration between the capillaries and the alveoli; the PCO2 in this gas is called end-tidal PCO2 (PetCO2).
When the blood passes the alveoli and is pumped by the heart to the arteries it is known as the arterial PCO2 (PaCO2). The arterial blood has a PCO2 equal to the PCO2 at equilibrium between the capillaries and the alveoli. With each breath some CO2 is eliminated from the lung and fresh air containing little or no CO2 (CO2 concentration is assumed to be 0) is inhaled and dilutes the residual alveolar PCO2, establishing a new gradient for CO2 to diffuse out of the mixed venous blood into the alveoli. The rate of breathing, or ventilation (V), usually expressed in L/min, is exactly that required to eliminate the CO2 brought to the lungs and maintain an equilibrium PCO2 (and PaCO2) of approximately 40 mmHg (in normal humans). When one produces more CO2 (e.g., as a result of fever or exercise), more CO2 is produced and carried to the lungs. One then has to breathe harder (hyperventilate) to wash out the extra CO2 from the alveoli, and thus maintain the same equilibrium PaCO2. But if the CO2 production stays normal, and one hyperventilates, then the PaCO2 falls. Conversely, if CO2 production stays constant and ventilation falls, arterial PCO2 rises.
It is important to note that not all V contributes to blowing off CO2. Some V goes to the air passages (trachea and major bronchi) and alveoli with little blood perfusing them, and thus doesn""t contribute to blowing off CO2. This V is termed xe2x80x9cdead spacexe2x80x9d ventilation and gas in the lung that has not participated in gas exchange with the blood is called xe2x80x9cdead spacexe2x80x9d gas. That portion of V that goes to well perfused alveoli and participates in gas exchange is called the alveolar ventilation (VA) and exhaled gas that had participated in gas exchange in the alveoli is termed xe2x80x9calveolar gasxe2x80x9d.
Referring to the PCT Application No. WO98/41266 filed by Joe Fisher (WO98/41266), there is taught a method of accelerating the resuscitation of a patient having been anaesthetized by providing the patient with a source of fresh gas and a source of reserve gas. When the patient breathes at a rate less than or equal to the fresh gas flowing into the circuit, all of the inhaled gas is made up of fresh gas. When the patient""s minute ventilation exceeds the fresh gas flow, the inhaled gas is made up of all of the fresh gas and the additional gas is provided by xe2x80x9creserve gasxe2x80x9d consisting of a composition similar to the fresh gas plus CO2 such that the concentration of CO2 in the reserve gas of about 6% is such that its partial pressure is equal to the partial pressure of CO2 in the mixed venous blood. At no time while using this method will the patient rebreathe gas containing anaesthetic. In order to accelerate the resuscitation of the patient, a source of fresh gas is provided for normal levels of minute ventilation, typically 5 L per minute and a supply of reserve gas is provided for levels of ventilation above 5 L per minute wherein the source of reserve gas includes approximately 6% carbon dioxide having a PCO2 level substantially equal to that of mixed venous blood. It has been found that this method and various circuits and processes for implementing the method are advantageous not only for resuscitating individuals from surgery, but also to deal with carbon monoxide poisoning or the like as taught in the application. By allowing increased ventilation yet maintaining the PCO2 level substantially equal to that prior to the increased ventilation, it has been found that in utilizing the method, maximum benefits of gas elimination are achieved without changing the CO2 levels in the patient. However, one limitation is that a source of reserve gas and its delivery apparatus must be supplied to pursue the method and that the reserve gas must be at about 6% CO2 concentration substantially having a PCO2 equal to that of mixed venous blood or about 46 mmHg.
To simplify the circuit taught by Fisher (WO98/41266), the reserve gas can be replaced by previously exhaled gas. The gas at the end of exhalation has substantially equilibrated with mixed venous gas and thus has a PCO2 substantially equal to it. However, if rebreathed gas is used instead of separately constituted reserve gas to prevent the decrease in PCO2 with increased ventilation, the anesthetic and CO will also be rebreathed and their elimination will not be enhanced. There are other applications for a circuit that maintains PCO2 constant with increased ventilation which are not invalidated by using exhaled gas as the reserved gas which are listed hereinafter.
Discussion of Prior Art Circuits Used for Rebreathing
Prior art circuits used to prevent decreased in PCO2 resulting from increased ventilation, by means of rebreathing of previously exhaled gas are described according to the location of the fresh gas inlet, reservoir and pressure relief valve with respect to the patient. They have been classified by Mapleson and are described in Dorsch and Dorsch pg 168.
1. Maintenance of constant CO2 with increased minute ventilation.
Mapleson A
The circuit comprises a pressure relief valve nearest the patient, a tubular reservoir and fresh gas inlet distal to the patient. In this circuit, on expiration, dead space gas is retained in the circuit, and after the reservoir becomes full, alveolar gas is lost through the relief valve. Dead space gas is therefore preferentially rebreathed. Dead space gas has a PCO2 much less than mixed venous PCO2. This is less effective in maintaining PCO2 than rebreathing alveolar gas, as occurs with the circuit of the present invention.
Mapleson B, C
The circuit includes a relief valve nearest the patient, and a reservoir with a fresh gas inlet at the near patient port. As with Mapleson A, dead space gas is preferentially rebreathed when minute ventilation exceeds fresh gas flow. In addition, if minute ventilation is temporarily less than fresh gas flow, fresh gas is lost from the circuit due to the proximity of the fresh gas inlet to the relief valve. Under these conditions, when ventilation once again increases there is no compensation for transient decrease in ventilation as the loss of fresh gas will prevent a compensatory decrease in PCO2.
With the present invention circuit, when minute ventilation temporarily is less than fresh gas flow, no fresh gas is lost from the circuit. Instead, the reservoir acts as a buffer, storing the extra fresh gas, and when ventilation increases once more, breathing the accumulated fresh gas allows PCO2 to return to the previous level.
Mapleson D and E
Mapleson D consists of a circuit where fresh gas flow enters near the patient port, and gas exits from a pressure relief valve separated from the patient port by a length of reservoir tubing. Mapleson E is similar except it has no pressure relief valve allowing the gas to simply exit from an opening in the reservoir tubing. In both circuits, fresh gas is lost without being first breathed. The volume of gas lost without being breathed at a given fresh gas flow is dependent on the minute ventilation such that only at infinite ventilation is all the fresh gas used for alveolar ventilation. Thus the alveolar ventilation and the PCO2 level are also dependent on the minute ventilation. Fresh gas is lost because during expiration, fresh gas mixes with expired gas and escapes with it from the exit port of the circuit. Furthermore, the amount of fresh gas lost is a function of expiratory time, and hence by changing the pattern of breathing, one can increase or decrease the proportion of fresh gas breathed. With our circuit, all of the fresh gas is breathed by the subject.
Circle anaesthetic circuit with CO2 absorber removed.
There are many different possible configurations of fresh gas inlet, relief valve, reservoir bag and CO2 absorber (see Dorsch and Dorsch, pg. 205-207). In all configurations, a mixture of expired gases enters the reservoir bag, and therefore rebreathed gas consists of combined dead space gas and alveolar gas. This is less efficient in maintaining PCO2 constant than rebreathing alveolar gas preferentially as occurs with our circuit, especially at small increments of V above the fresh gas flow.
Circuit previously described by Fisher (WO98/41266)
Fisher (WO98/41266) has previously described a circuit that maintains PCO2 independent of minute ventilation. Instead of making up the difference between fresh gas flow and minute ventilation with gas expired from a previous breath, Fisher (WO98/41266) requires an external source of CO2. The circuit of the present invention exploits the same principle in maintaining PCO2 constant, however it uses the patient""s own previously expired CO2 instead of externally provided CO2. Thus the circuit is must less expensive to operate, more compact and portable and thus would be more practical for applications where the maintenance of CO2 is desired but the elimination of other gases such as anesthetics and carbon monoxide is not required.
2. Changes in CO2 or other gas
For other applications such as a) maintaining a constant PCO2 or instituting two or more levels of arterial PCO2 during nuclear magnetic resonance imaging, b) raising PCO2 i) during pregnancy to improve placental blood flow, ii) to prevent shivering, iii) to increase tissue perfusion, and iv) protect tissues from oxidative damage, preventing rebreathing of exhaled gases is not necessary.
However, it would therefore be advantageous to reap the benefits of controlling the PCO2 at a constant level and not having to incur the expense of supplying reserve gas. It has been determined that traumatized patients may be assisted in certain circumstances by maintaining the PCO2 level substantially constant or increased. It has also been determined that various diagnostic procedures can be enhanced by pursuing the same. This heretofore was not contemplated in the prior art nor in the prior disclosure of Joseph Fisher (WO98/41266) discussed above.
It is therefore a primary objective of the present invention to provide a simplified method of controlling PCO2 at a predetermined desired level. It is a further objective of the present invention to provide a simplified method of changing the PCO2 of a patient by changing the fresh gas flow in the circuit.
It is a further objective of the present invention to provide a circuit to affect the method that prevents loss of fresh gas and that ensures that a patient breathing at a rate greater than the fresh gas flow receives all the fresh gas independent of the rate of pattern of breathing.
It is a further objective of the present invention to provide a breathing circuit that prevents rebreathing unless the minute ventilation exceeds the fresh gas flow.
It is yet a further objective of the present invention to provide a circuit where alveolar gas is rebreathed in preference to dead space gas.
It is a further objective of the present invention to provide an improved breathing circuit to be used to assist patients who have been traumatized or run the risk of being traumatized, or alternatively to enhance the results of diagnostic procedures, or the benefits of medical procedures.
It is a further object of the present invention to provide methods of treatment using the said circuit and the use of the said circuit to assist patients who have been traumatized or run the risk of being traumatized or alternatively to enhance the results of diagnostic procedures, or the benefits of medical procedures.
Further and other objectives of the present invention will become apparent to those skilled in the art when considering the following summary of the invention and the more detailed description of the preferred embodiments illustrated therein.
According to a primary aspect of the invention there is provided a method of controlling PCO2 in a patient at a predetermined desired level(s) comprising a breathing circuit which is capable of organizing exhaled gas so as to be preferentially inhaled during rebreathing when necessary by providing alveolar gas for rebreathing in preference to dead space gas. The preferred circuit in effecting the above-mentioned method includes a breathing port for inhaling and exhaling gas; a bifurcated conduit adjacent said port; preferably being substantially Y-shaped, and including a first and second conduit branch, with the first conduit branch including a fresh gas inlet, preferably oxygen, and a check valve disposed proximate the port. The check valve allows the passage of inhaled fresh gas to the port but closes during exhalation. The second conduit includes a check valve which allows passage of exhaled gas through the check valve but prevents flow back to the breathing port once the gas passes through the check valve. The first conduit branch has located proximate the terminus thereof, a fresh gas reservoir of predetermined size and preferably a flexible bag. The second conduit branch has located proximate the terminus thereof, an exhaled gas reservoir, preferably being a rigid tube having an open end and being preferably approximately 3 L in capacity. The terminus of said first and second conduit branches have extending there between an interconnecting conduit and has a check valve located therein. When minute ventilation for the patient is equal to the fresh gas flow, for example 5 liters/minute, fresh gas enters the breathing port from the first conduit branch at a predetermined rate and preferably 5 L per minute and is exhaled through the second conduit branch at a rate of preferably 5 L per minute; wherein the exhaled gas travels down the exhaled gas reservoir which preferentially provides that dead space gas be disposed nearest the open end of the reservoir and that alveolar gas would be located proximate the end of the reservoir nearest the terminus of the second conduit branch. When it is desirable for the minute ventilation to exceed the fresh gas flow, for example 5 L per minute, the patient will inhale expired gas retained in the expired gas reservoir which will pass through the check valve in the interconnecting conduit at a rate making up the shortfall in the fresh gas flow of, for example, 5 L per minute, wherein the shortfall differential is made up of rebreathed gas of which alveolar gas is preferentially rebreathed, thereby preventing a change in the PCO2 level of alveolar gas despite the increased minute ventilation.
When setting the fresh gas flow to maintain a desired PCO2 it is important that the fresh gas reservoir be allowed to first be depleted of gas until it just empties at the end of the inhalation cycle. In this way once it is desired to increase the minute ventilation, a slight negative pressure will exist in the interconnecting conduit during inhalation, opening its check valve and allowing further breathing gas beyond the normal level of ventilation to be supplied by previously exhaled gas.
There are many uses for this particular circuit which will be described hereinafter. There may be situations which exist when treating a patient wherein it is desirable to prevent hypocapnia in the patient. For example, in the case of a pregnant woman having great anxiety due to the pain during delivery, it is desirable not to have her hyperventilate so as to contract the blood vessels in the placenta causing potential insufficient blood flow to the baby. By using the above-mentioned circuit during labor, this can be avoided. It also may be advantageous to induce hypercapnea during diagnostic procedures to enhance the diagnostic procedure or alternatively when a patient undergoes treatment as in treatment with ionizing radiation, to increase the sensitivity of tissue to the treatment. This, for example, would occur during radiation treatment for cancerous cells.
According to yet another aspect of the invention, there is provided a method of enhancing the results of a diagnostic procedure or medical treatment comprising the steps of:
providing a circuit which is capable of organizing exhaled gas so as to provide to the patient preferential rebreathing of alveolar gas in preference to dead space gas (for example the circuit described above), when the patient is ventilating at a rate greater than the fresh gas flow, and when inducing hypercapnea is desired, by decreasing the fresh gas flow and passively providing a corresponding increase in rebreathed gas so as to prevent the PCO2 level of arterial blood from dropping despite increases in minute ventilation;
continuing inducing hypercapnia until such time as the diagnostic or medical procedure is completed, wherein the results of said diagnostic or medical procedure are enhanced by carrying out the method in relation to the results of the procedure had the method not been carried out. Examples of such procedures would be MRI or radiation treatments or the like.
A method of treating or assisting a patient, preferably human, during a traumatic event characterized by hyperventilation comprising the steps of:
providing a circuit in which alveolar ventilation is equal to the fresh gas flow and increases in alveolar ventilation with increases in minute ventilation is prevented by a circuit (for example the preferred circuit described above) which is capable of organizing exhaled gas so as to provide to the patient preferential rebreathing alveolar gas in preference to dead space gas;
following ventilating the patient at a rate of normal minute ventilation, preferably approximately 5 L per minute, and when desired inducing hypercapnea so as to increase arterial PCO2 and prevent the PCO2 level of arterial blood from subsequently dropping below that achieved as a result of decreasing the fresh gas flow;
continuing maintaining normocapnia despite the ventilation at an increased rate until such time as the traumatic event and concomitant hyperventilation is completed, wherein the effects of hyperventilation experienced during the traumatic event are minimized, for example, the mother during labor becoming light headed or the baby during the delivery also being effected with the oxygen delivery to its brain being decreased as a result of contraction of the blood vessels in the placenta and fetal brain.
A list of circumstances in which the method enhancing the diagnostic procedure results or the experience of the traumatic event are listed below.
Applications of this method and circuit:
1. Maintenance of constant PCO2 and inducing changes in PCO2 during MRI;
2. Inducing and/or maintaining increased PCO2
a) to prevent or treat shivering and tremors during labor, post-anesthesia, hypothermia, and certain other pathological states;
b) to treat fetal distress due to asphyxia;
c) to induce cerebral vasodilatation, prevent cerebral vasospasm, and provide cerebral protection following subarachnoid hemorrhage, cerebral trauma and other pathological states;
d) to increase tissue perfusion in tissues containing cancerous cells to increase their sensitivity to ionizing radiation and delivery of chemotherapeutic agents;
e) to aid in radiodiagnostic procedures by providing contrast between tissues with normal and abnormal vascular response;
f) protection of various organs such as the lung, kidney and brain during states of multi-organ failure.
3. Prevention of hypocapnia with O2 therapy, especially in pregnant patients.
4. Other applications where O2 therapy is desired and it is important to prevent the accompanying drop in PCO2.
It has been found in carrying out the above-mentioned method and preferably with the preferred circuit described that by maintaining a constant PCO2 level and inducing changes in PCO2 during a diagnostic procedure such as an MRI, better quality pictures can be obtained. It is therefore provided, according to another aspect of the invention, that an improved method of creating MRI images is disclosed by following the above-mentioned method and particularly comprising the steps of maintaining a constant PCO2 and inducing changes in that PCO2 level during the MRI procedure in order to facilitate improvement in the quality of the pictures being taken. The method for inducing the changes in the PCO2 include preferably using the above-mentioned circuit or any circuit known in the prior art and described in the background of the invention which might provide a substantial part or most of the benefits described herein. For example, the Mapleson D and E circuits predictably may work as might a standard circle circuit with the carbon dioxide filter by-passed or removed; however fresh gas will be wasted and the efficiency would be reduced.
When minute ventilation is greater than or equal to fresh gas flow, the above-mentioned preferred circuit prevents loss of fresh gas and ensures that the patient receives all the fresh gas independent of the pattern of breathing since fresh gas alone enters the fresh gas reservoir, and exhaled gas enters its own separate reservoir. The fresh gas reservoir bag is large enough to store fresh gas for 5-10 seconds or more of reduced ventilation or total apnea, ensuring that even under these circumstances fresh gas will not be lost. The preferred circuit prevents rebreathing at a minute ventilation equal to the fresh gas flow because the check valve in the interconnecting conduit does not open to allow rebreathing of previously exhaled gas unless a negative pressure exists on the inspiratory side of the conduit of the circuit. Also, when minute ventilation exceeds the fresh gas flow, a negative pressure occurs in the inspiratory conduit, opening the conduit""s check valve. The circuit provides that after the check valve opens, alveolar gas is rebreathed in preference to dead space gas because the interconnecting conduit is located such that exhaled alveolar gas will be closest to it and dead space gas will be furthest from it. The exhaled gas reservoir is preferably sized at 3 L which is well in excess of the volume of an individual""s breath, therefore it is unlikely that the patient shall be able to breathe any room air entering via the opening at the end of the exhaled gas reservoir.
The basic approach of preventing a decrease in PCO2 with increased ventilation is similar as that taught by Fisher (WO98/41266). In brief, only breathing the fresh gas contributes to alveolar ventilation (VA) which establishes a gradient for CO2 elimination. All gas breathed in excess of the fresh gas entering the circuit, or the fresh gas flow, is rebreathed gas. Fisher (WO98/41266) has in his prior application taught that the closer the partial pressure of CO2 in the inhaled gas to that of mixed venous blood (PvCO2), the less the effect on CO2 elimination. Fisher (WO98/41266) expressed the relationship of alveolar ventilation, minute ventilation (V) and PCO2 of rebreathed gas as follows:
VA=FGF+(Vxe2x88x92FGF)(PvCO2xe2x80x94PCO2 of exhaled gas)/PvCO2
(Where FGF stands for the fresh gas flow, and other terms as described previously)
It is clear from this equation that as the PCO2 of the exhaled gas approaches that of the mixed venous blood, the alveolar ventilation is determined only by the fresh gas flow and not the minute ventilation.
As one exhales, the first gas to exit the mouth comes from the trachea where little gas exchange has occurred. The PCO2 of this gas is close to that of the inhaled gas and is termed xe2x80x9cdead space gasxe2x80x9d. The last gas to exit the mouth has had the most time to equilibrate with mixed venous blood, has a PCO2 closest to that of mixed venous blood and is termed xe2x80x9calveolar gasxe2x80x9d. Gas exhaled between these two periods has a PCO2 intermediate between the two concentrations. The equation cited above explains why rebreathing alveolar gas would be the most effective in maintaining the PCO2 at a constant level when minute ventilation increases.
Accordingly, in the circuit of the present invention:
1. All of the fresh gas is inhaled by the subject when minute ventilation is equal to or exceeds fresh gas flow;
2. The xe2x80x9calveolar gasxe2x80x9d is preferentially rebreathed when minute ventilation exceeds the fresh gas flow;
3. When minute ventilation is equal to or greater than fresh gas flow, all the fresh gas contributes to alveolar ventilation.

Rebreathing circuit to set and stabilize end tidal and arterial PCO2 despite varying levels of minute ventilation


An edible acid mixture, products containing same, and methods of making same are provided. At least two acidulants are encapsulated by a polyvinyl acetate matrix. An encapsulated acid mixture is thereby produced. Preferably the acid mixture includes at least fumaric and malic acid. The mixture can be used in ingestible products including confectionery products, such as chewing gum.

The present invention generally relates to edible products. More specifically, the present invention relates to food products, including confectionery products, that include edible acids.
It is known to add food acids, edible acids, or acidulants as they are known, to food products. These acidulants are used to provide a pleasant, refreshing, acidic taste to foods, drinks, confectionery products and beverages. If desired, they can also serve as a preservative by lowering the pH of the foodstuff to which they are added thereby reducing the activity of possibly harmful microorganisms. An example of such a food acid is citric acid.
Typically, the acid taste profile of a food acid can be described as a rapid burst of tartness. Usually, food acids reach their peak acid taste fairly early, with the taste falling off and disappearing quite rapidly thereafter. The rapid burst can create issues as the strong acid taste tends to overpower the flavor of sweeteners and flavorants in the foodstuff to which the food acid has been added. The relatively rapid loss of tartness also can result in a bitter aftertaste if certain synthetic high-intensity sweeteners are used in the foodstuff in conjunction with the food acid. Not only do food acids suffer disadvantages in view of their strong sharp taste and short-lived tartness flavor, they can suffer some additional disadvantages. These disadvantages may impair their use in certain manufacturing processes.
It is known to use food acids in confectionery products such as chewing gum and other chewable candies to provide a tartness or sour taste to the product. Numerous attempts have been made to extend the tartness of food acids in confectionery products and other foods. Such attempts include trying to encapsulate the food acids. However, many of these acids destroy the encapsulant matrices that have been used.
With respect to chewing gum compositions, food grade acids have been added to same in order to achieve, for example, a sourness effect. Particularly citrus fruit flavors have been added to chewing gum. Generally, the acids are added directly to the water-soluble gum portion of the chewing gum to ensure the release of the acid during the chew. See, for example, U.S. Pat. Nos. 4,088,788 and 4,151,270. U.S. Pat. No. 4,085,227 also discloses the addition of food acids directly in their free form to a chewing gum composition. In the patent, food acids are added to the gum base portion of the chewing gum composition. U.S. Pat. No. 4,800,191 also discloses the addition of free acids to a chewing gum composition.
It is known in the food science art to encapsulate certain products that are added to food products. U.S. Pat. No. 3,795,744 discloses various seasonings that are coated or encapsulated. It is also known to encapsulate food grade acids in chewing gum. EP 0446170 discloses a food acid delivery system that effects a controlled release of an acid.
Despite the various attempts to provide food products including food grade acids, there is a need for an improved method and food products including food grade acid having an extended period of tartness perception, increased salivation, and overall enjoyment of the food products.
The present invention provides improved food acid mixtures. Moreover, the present invention provides improved consumables such as confectionery products, e.g., chewing gums, including food acid mixtures. Additionally, the present invention provides improved methods for making food products including edible acids. Although in the preferred embodiment set forth in detail below, the present invention relates to confectionery products and specifically chewing gums, the present invention can be utilized to produce a variety of edible products, including foodstuffs, nutrients, pharmaceuticals, nutraceuticals, confectionery products including chewing gum and chewable candies, and other products that are designed to be ingested by a consumer.
In an embodiment, the present invention provides a chewing gum comprising a water-soluble portion, a water-insoluble portion, and an encapsulated acid mixture comprising a mixture of at least two acidulants that are encapsulated in polyvinylacetate.
In an embodiment, the mixture of acidulants includes at least one acid selected from the group consisting of fumaric, malic, and tartaric acid.
In an embodiment, the mixture of acidulants comprises approximately 0.1 to about 10% by weight of the chewing gum.
In an embodiment, the mixture of acidulants comprises 10% to about 40% by weight of the encapsulated acid mixture.
In an embodiment, the mixture of acidulants comprises, by total weight percent: approximately 25% to about 65% fumaric acid; approximately 10% to about 50% malic acid; and approximately 0% to about 25% tartaric acid.
In an embodiment, the polyvinyl acetate has a molecular weight range of 20,000 to about 120,000.
In another embodiment of the present invention, a confectionery product is provided comprising an acid mixture including at least fumaric acid and malic acid encapsulated by a coating of a hydrophobic polymer.
In an embodiment, the acid mixture comprises, by total weight percent: approximately 25% to about 65% fumaric acid; approximately 10% to about 50% malic acid; and approximately 0% to about 25% tartaric acid.
In an embodiment, the acid mixture comprises approximately 10% to about 40% by weight of the encapsulated acid mixture.
In an embodiment, the confectionery product is a chewing gum product.
In yet another embodiment of the present invention, an acid mixture is provided comprising: at least one particle of a mixture of acidulants including fumaric and malic acid, and polyvinyl acetate encapsulating the particle.
In a still further embodiment of the present invention, a method of producing an edible product including an acidulant is provided comprising encapsulating at least fumaric and malic acid in a hydrophobic polymer.
In an embodiment, the method includes the step of adding the encapsulated acidulant to a chewing gum.
In an embodiment, the method includes the step of preparing particles that include the acidulant and coating the particles with the hydrophobic polymer. In a further embodiment, the particles are coated by being extruded with the hydrophobic polymer.
It is an advantage of the present invention to provide improved food products including an edible acid.
Another advantage of the present invention is to provide improved confectionery products.
Moreover, an advantage of the present invention is to provide improved chewing gum products.
Still further, an advantage of the present invention is to provide improved products including food acids that can be added to products that are designed to be consumed.
Further, an advantage of the present invention is to provide improved methods for making food products including a food acid.
Furthermore, an advantage of the present invention is to provide confectionery products including a food acid that has prolonged tartness and salivation characteristics.
Another advantage of the present invention is to provide food acids in a food product that have an improved acid taste profile.
Still, an advantage of the present invention is to provide a food acid delivery system for delayed or prolonged release of tartness from the food acids.
Additional features and advantages of the present invention will be described in and apparent from the detailed description of the presently preferred embodiments.
The present invention provides improved food acid mixtures, products containing same, and methods of manufacturing such products.
To this end, the present invention provides encapsulated acidulants. By encapsulating the acidulants, it has been found that one is able to extend or delay the release of acids. Further, the encapsulated acidulants are in a form that is suitable for incorporation in food products such as confectionery products, e.g., chewing gum. The encapsulated acidulants produced by the present invention reduce degradation of the encapsulated material during extrusion, resulting in longer lasting tartness and/or longer lasting flavor in food products containing same.
Pursuant to the present invention, the acidulants are coated by polyvinyl acetate. It has been found that the coating of polyvinyl acetate on the acid mixture provides a material that will not degrade during processing. Moreover, when added to a confectionery product, such as chewing gum, the encapsulated acid mixture provides a longer lasting tartness duration. Because the polyvinyl acetate coating is substantially water insoluble, it protects the food acid from hydrolytic degradation and/or neutralization. Yet, when chewed, the acid core material will slowly be released from the polyvinyl acetate into the oral cavity.
Pursuant to the present invention, the composite acid mixture is in the form of a particle. In an embodiment, generally, the particle is prepared by first making a slurry including a slow release edible acid that has low water solubility, e.g., fumaric acid, and mixing it with an aqueous acid solution of edible acids having high water solubilities, e.g., malic and tartaric acids. The slurry is then granulated and dried.
The encapsulated composite acid matrix is generally prepared by blending ground polyvinyl acetate and the powder composite acid and adding them together into an extruder. The outer layer components are maintained at a temperature of approximately 200xc2x0 F. The resultant mixture after existing the extruder is cooled to about 32xc2x0 F. The solid mixture of this invention can then be milled or ground into a powder or granulated form.
It has been found that particle size is not critical to the delivery system. Accordingly, the size of the particles can be adjusted to accommodate a particular desired release rate and mouth feel, depending on the vehicle, e.g., chewing gum compositions, pharmaceutical preparations, denture products, confection and the like, in which it is incorporated.
The food acids, also commonly known as acidulants in the food industry, may be present in amounts of approximately 0.1% to about 10% by weight of the total chewing gum composition. Acidulants may also be present in amounts of approximately 0.5% to about 7.5% or, in an embodiment, approximately 1% to about 2.5% by weight of the total chewing gum composition. With respect to their presence in the encapsulant, the acids are present in amounts of approximately 10% to about 40%, by weight or, in an embodiment, approximately 20% to about 30%, and in a further embodiment, about 25% of the complete encapsulation system.
The particular amount of acids present and the type of acids used in the composite acid mixture should be balanced in order to achieve a stable encapsulant as well as attaining the desired amount of tartness. Too much or too little of any of the participating acids can challenge the integrity of the encapsulating matrix. This may not achieve the effect of extended tartness and pleasant taste. Preferably, the acid mixture includes at least two acidulants. The acidulants can be selected from the group consisting of fumaric acid, malic acid, tartaric acid, citric acid, lactic acid, ascorbic acid, or mixtures of same. Preferably the composite acid form comprises fumaric acid in an amount of approximately 25% to about 65%, malic acid in an amount of approximately 10% to about 50% and tartaric acid in an amount of approximately 0% to about 25%, all by weight percent of the total acid. The fumaric acid may be cold water soluble fumaric acid. Generally, cold water soluble fumaric acid refers to finely ground fumaric acid that includes a small amount of a wetting agent.
In a preferred embodiment the encapsulated acidulant is an acid composite as set forth in PCT WO 98/53705, the disclosure of which is incorporated herein by reference.
The polyvinyl acetate (PVAc) coatings of the present invention result in an improved sustained release of food acids to the sensory system. Preferably the PVAc used for encapsulation has a medium range molecular weight of approximately 20,000 to about 50,000 or, in an embodiment, approximately 30,000 to about 40,000. Low molecular weight PVAc having a range of approximately 15,000 to about 25,000 or a high molecular weight PVAc having a range of approximately 50,000 to about 80,000 may also be used. Very high molecular weight PVAc having a range of approximately 80,000 to 120,000 may also give extended release of acids. It is believed that lower molecular weight PVAc provides faster release, whereas higher molecular weight PVAc would extend acid release.
In an embodiment of the invention, a chewing gum having extended acid release is provided. The chewing gum comprises a chewing gum base and an extended release acid composition that comprises a composite acid mixture encapsulated by a coating material of a hydrophobic polymer. The polymer is characterized by: (a) being water insoluble; (b) having form filming capability; and (c) being compatible with the composite acid mixture, wherein the amount of coating material to composite acid mixture is from approximately 55% to about 85% by weight.
The present invention, it is believed, can be used with a variety of processes for manufacturing chewing gum. It may also be used for sugar gum, sugarless gum and bubble gum.
Chewing gum products of the present invention may be and include a variety of different compositions that are typically used in chewing gum compositions. In general, a chewing gum composition typically contains a chewable gum base portion which is essentially free of water and is water soluble, a water soluble bulk portion and flavors which are typically water insoluble.
The water soluble portion dissipates with a portion of the flavor over a period of time during chewing. The gum base portion is retained in the mouth throughout the chew. The gum base portion is retained in the mouth throughout the chew. The insoluble gum base generally comprises elastomers, elastomer solvents, plasticizers, waxes, emulsifiers, and inorganic fillers. Plastic polymers such as polyvinyl acetate, which behave somewhat as plasticizers, are also included. Other plastic polymers that may be used include polyvinyl laurate, polyvinyl alcohol, and polyvinyl pyrrolidone.
Elastomers may include polyisobutylene, butyl rubber, isobutylene-isoprene copolymer, and styrene butadiene rubber, as well as natural latexes such as chicle. Elastomer solvents are often resins such as terpene resins. Plasticizers, sometimes referred to as softeners, are typically fats and oils, including tallow, hydrogenated vegetable oils, and cocoa butter. Commonly employed waxes include paraffin, microcrystalline waxes, especially those with a high degree of crystallinity, may be considered bodying agents or texture modifiers.
Gum base typically also includes a filler component. The filler component may be calcium carbonate, magnesium carbonate, talc, dicalcium phosphate or the like. The filler may constitute between approximately 5% to about 50% of the gum base.
Emulsifiers, which sometimes also have plasticizing properties, include glycerol monosterate, lecithin, and glycerol triacetate. Further, gum bases may also contain optional ingredients such as antioxidants, colors, and flavors.
The insoluble gum base may constitute between approximately 5% to about 95% of the gum. Typically, the insoluble gum base may comprise between approximately 10% and 50% of the gum, or from approximately 20% to about 40% of the gum. The water soluble portion of the chewing gum may further comprise softeners, sweeteners, flavoring agents, and combinations thereof. The sweeteners often fulfill the role of bulking agents in the gum. The bulking agents typically comprise approximately 5% to about 95% of the gum composition.
Softeners are added to the chewing gum in order to optimize the chewability and mouth feel of the gum. Softeners, also known in the art as plasticizers or plasticizing agents, generally constitute between approximately 0.5% to about 15% of the chewing gum. Softeners contemplated by the present invention include, for example, lecithin. Further, aqueous sweetener solutions such as those containing sorbitol, hydrogenated starch hydrolysate, corn syrup, and combinations thereof may be used as softeners and binding agents in the gum.
In an embodiment, the gum formulation of the present invention is a sugar-free gum formulation. However, sugar-gum formulations also may be manufactured pursuant to the present invention. Sugar sweeteners generally include saccharide-containing components commonly known in the chewing gum art which comprise, but are not limited to, sucrose, fructose, levulose, galactose, corn syrup solids and the like, alone or in any combination. Generally, sugarless sweeteners include components with sweetening characteristics, but which are devoid of the commonly know sugars. Such sugarless sweeteners are sorbitol, mannitol, xylitol, hydrogenated isomaltulose, maltitol, erythritol, and the like, alone or in any combination.
Depending on the particular sweetness release profile and shelf stability required, coated or uncoated high intensity sweeteners may be used in chewing gum composition. High intensity sweeteners, such as aspartame, may be used at levels from approximately 0.01% to about 3.0%. Encapsulated aspartame is a high intensity sweetener with improved stability and release characteristics, as compared to free aspartame. Free aspartame can also be added, and a combination of some free and encapsulated aspartame can be used.
Combinations of sugar and sugarless sweeteners may be used in chewing gum. Additionally, the softener may also provide additional sweetness such as with aqueous sugar or alditol solutions.
Flavors may be present in the chewing gum in an amount within the range from approximately 0.1% to about 10% and typically from approximately 0.5% to about 3.0% of the gum. Flavors contemplated by the present invention include any liquid flavoring that is of food acceptable quality. The flavor may comprise essential oils, synthetic flavors, or mixtures thereof, including but not limited to, oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil, clove oil of wintergreen, anise and the like. Artificial flavoring components are also contemplated by the present invention. Those of ordinary skill in the art will recognize that natural and artificial flavors may be combined in any sensorally acceptable blend. All such flavors and blenders are contemplated by the present invention.
Optional ingredients such as colors, emulsifiers, and pharmaceutical agents may also be added as separate components of the chewing gum composition, or added as part of the gum base.
A method of manufacturing chewing gum according to the present invention is by sequentially adding the various chewing gum ingredients to any commercially available mixer known in the art. After the ingredients have been thoroughly mixed, the gum base is discharged from the mixer and shaped into the desired form such as by rolling into sheets and cutting into sticks, extruding into chunks, or casing into pellets.
Generally, the ingredients are mixed by first melting the gum base and adding it to the running mixer. The base may also be melted into the mixer itself. Colors or emulsifiers may also be added at this time. A softener may be added to the mixer at this time, along with syrup and a portion of the bulking agent. Further parts of the bulking agent are then added to the mixer. Flavoring agents are typically added with the final portion of the bulking agent. Other optional ingredients are added in the batch in a typical fashion, well known to those of ordinary skill in the art.
The entire mixing procedure typically takes from five to fifteen minutes, but longer mixing times may sometimes be required. Those skilled in the art will recognize that many variations of the above-described procedure may be follows.
After the ingredients are mixed, the gum mass may be formed into a variety of shapes and products. For example, the ingredients may be formed into pellets or balls and used as cores to make a coated chewing gum product. However, any type of chewing gum product can be utilized with the present invention.
If a coated product is desired, the coating may contain ingredients such as flavoring agents, artificial sweeteners and dispersing agents, coloring agents, film formers and binding agents. Flavoring agents contemplated by the present invention, include those commonly known in the art such as essential oils, synthetic flavors, or mixtures thereof, including but are not limited to, oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil, other mint oils, clove oil, oil of wintergreen, anise and the like. The flavoring agents may also be added to the coating syrup in an amount such that the coating will contain from approximately 0.2% to about 1.2% flavoring agent, and typically constitute from approximately 0.7% to about 1.0% flavoring agent.
Artificial sweeteners, particularly high intensity sweeteners, contemplated for use in the coating include, but are not limited to, synthetic substances, saccharin, thaumatin, alitame, saccharin salts, aspartame, sucralose, and acesulfame K. The artificial sweetener may be added to the coating syrup in an amount such that coating will contain from approximately 0.05% to about 1.0% and typically from approximately 0.10% to about 0.5%, artificial sweetener.
Dispersing agents are often added to syrup coatings for the purpose of whitening and tack reduction. Dispersing agents contemplated by the present invention to be employed in the coating syrup include titanium dioxide, talc, or any other antistick compound. The dispersing agent may be added to the coating syrup in an amount such that the coating syrup in an amount such that the coating will contain approximately 0.1% to about 1.0% and typically from approximately 0.3% to about 0.6% of the agent.
Coloring agents may be added directly to the coating syrup in dye or lake form. Coloring agents contemplated by the present invention include food quality dyes. Film formers may be added to the coating syrup include methylcellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and the like or combinations thereof
Binding agents may be added either as an initial coating on the chewing gum center or may be added directly to the coating syrup. Binding agents contemplated by the present invention include gum arabic, gum talha, gelatin, vegetable gums, and the like. The binding agents, when added to the coating syrup, are typically added at a level of between approximately 0.5% to about 10%.
By way of example and not limitation, an example of the food grade composite acid mixture is as follows:

Chewing gum including encapsulated acid mixtures