Patent Publication Number: US-2009220664-A1

Title: Methods and apparatus for the production of sweeteners

Description:
PRIORITY 
     This application claims the benefit and priority of U.S. Provisional Application No. 61/011,612 filed on Jan. 18, 2008, U.S. patent application Ser. No. 12/215,214, filed on Jun. 25, 2008, and U.S. patent application Ser. No. 12/243,435 filed on Oct. 1, 2008, all of which are incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present inventions relate to sweeteners and, in particular, to methods and apparatus for the production of dried sweeteners. 
     BACKGROUND OF THE INVENTION 
     Trehalose is a disaccharide composed of two glucose molecules bound by an alpha, alpha-1, 1 linkage. Trehalose may be produced from starch by enzymatic cleavage of the starch molecules using the enzymes maltooligosyl trehalose synthase (MTSase) and maltooligosyl trehalose trehalohydrolase (MTHase), which act on amylose or starch to produce trehalose. Trehalose is a generally recognized as safe [GRAS] compound, so that trehalose may be readily used in the food industry, and the particular physical features of trehalose make it an extremely attractive substance for use in the food industry. 
     Trehalose may be mixed with a high intensity sweetener in water and the resulting mixture dried in order to produce a dry sweetener with a desired sweetness. However, various problems may occur in drying the trehalose—high intensity sweetener mixture. For example, in a crystallization process such as freeze drying, the trehalose crystals tend to exclude the high intensity sweetener. This results in non-uniform distribution of the high intensity sweetener in the dried product. Spray drying of the trehalose-high intensity sweetener mixture may result in at least some thermal degradation of the trehalose and/or the high intensity sweetener. Spray drying as well as freeze drying may also exhibit limited control of particle sizes, densities, morphologies, and flow properties. 
     Therefore, a need exists for apparatus and methods for the production of dry sweeteners that include trehalose and a high intensity sweetener. 
     SUMMARY OF THE INVENTION 
     Methods and compositions in accordance with the present inventions may resolve many of the needs and shortcomings discussed above and will provide additional improvements and advantages that may be recognized by those of ordinary skill in the art upon review of the present disclosure. 
     The present inventions may provide methods for producing a sweetener. The methods may include forming a sweetener in a liquid form by combining trehalose with a high intensity sweetener in water, introducing the sweetener in the liquid form into a gas stream, and recovering the sweetener in a dried form from the gas stream. The gas stream may be a pulsed gas stream. In some embodiments the pulsed gas stream has a first temperature, which may be an inlet temperature and a second temperature, which may be an outlet temperature. In some embodiments, the first temperature of the gas stream may range from about 700° F. to about 1300° F., or from about 900° F. to about 1100° F. In these or other embodiments, the second temperature of the gas stream may range from about 150° F. to about 250° F. In some embodiments, the frequency of pulses may range from about 30 to 1000 Hertz. 
     In these or other embodiments, the method includes a high intensity sweetener comprising aspartame and/or acesulfame potassium. The sweetener in the liquid state may comprise about 50% solids. 
     The present inventions may provide a sweetener in a dried form. The sweetener may include trehalose and a high intensity sweetener and may have the following properties:
         a substantially uniform distribution of trehalose and one or more high intensity sweeteners within the particles,   particle size between about 1 and about 100 microns,   moisture content between about 0.5% and about 10%, and   generally spherical shape.       

     In some embodiments the particle size is between about 1 and 60 microns. In some embodiments the high intensity sweetener comprises aspartame and/or acesulfame potassium. 
     Another aspect of the inventions provides a sweetener in dried form, prepared by a process comprising forming a sweetener in a liquid form by combining trehalose with a high intensity sweetener in water, introducing the sweetener in the liquid form into a gas stream; and recovering the sweetener in a dried form from the gas stream. In some embodiments, the first temperature of the gas stream may range from about 700° F. to about 1300° F., or from about 900° F. to about 1100° F. In these or other embodiments, the second temperature of the gas stream may range from about 150° F. to about 250° F. In some embodiments, the frequency of pulses may range from about 30 to 1000 Hertz. 
     In these or other embodiments, the high intensity sweetener may comprise aspartame and/or acesulfame potassium. The sweetener in the liquid state may comprise about 50% solids. 
     Other features and advantages of the inventions will become apparent from the following detailed description and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates by schematic diagram an example of the drying of sweetener in the liquid form; 
         FIG. 2A  illustrates by schematic diagram an embodiment of the pulse combustion dryer; 
         FIG. 2B  illustrates by schematic diagram a cross-section of an embodiment of the drying chamber. 
     
    
    
     All Figures are illustrated for ease of explanation of the basic teachings of the present inventions only; the extensions of the Figures with respect to number, position, order, relationship and dimensions will be explained or will be within the skill of the art after the following description has been read and understood. Further, the apparatus, materials and other operational parameters to conform to specific size, dimension, force, weight, strength, velocity, temperatures, flow and similar requirements will likewise be within the skill of the art after the following description has been read and understood. 
     Where used to describe the drawings, the terms “top,” “bottom,” “right,” “left,” “forward,” “rear,” “first,” “second,” “inside,” “outside,” and similar terms may be used, the terms should be understood to reference the structure and methods described in the specification and illustrated in the drawings as they generally correspond to their with the apparatus and methods in accordance with the present inventions as will be recognized by those skilled in the art upon review of the present disclosure. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present inventions provide a composition in the form of a sweetener  73  in a dried form  77  that as well as apparatus and associated methods for use in the production of the sweetener  73  in the dried form  77 . The sweetener  73  includes trehalose and one or more high intensity sweeteners. The trehalose and the one or more high intensity sweeteners may be combined generally in the desired proportions in water to form the sweetener  73  in a liquid form  75 . The apparatus may include a dryer configured to produce a gas stream  20  to remove the water from the sweetener in order to dry the sweetener  73  in the liquid form  75  into the sweetener  73  in the dried form dried form  77 . In one aspect, the water is vaporized by the gas stream  20  to produce the sweetener  73  in the dried form  77 . The gas stream  20  may be heated and/or pulsed in various aspects. Methods include drying the sweetener  73  in the liquid form  75  into sweetener  73  in the dried form  77 . Surprisingly, the trehalose and high intensity sweetener do not degrade or disintegrate at these high temperatures. The resulting sweetener  73  in the dried form  77  includes trehalose and one or more high intensity sweeteners substantially intermixed generally in the desired proportions. The resulting dried sweetener  77  comprises spherical particles of between about 1 and 100 microns, or between about 0.1 and 300 microns, with a substantially uniform distribution of the two or more sweeteners within the particles. The particles also may be substantially free-flowing and non-aggregating or non-cohesive. 
     The Figures generally illustrate various exemplary embodiments of apparatus and methods including aspects of the present inventions. The particular exemplary embodiments illustrated in the Figures have been chosen for ease of explanation and understanding of various aspects of the present inventions. These illustrated embodiments are not meant to limit the scope of coverage, but, instead, to assist in understanding the context of the language used in this specification and in the claims. Accordingly, variations of the apparatus, methods, and compositions of matter from the illustrated embodiments may be encompassed by the appended claims. 
     By certain accepted measures, trehalose has about 45% the sweetness of sucrose. The trehalose may have the α,α-1 linkage between the two glucose moieties. Iso-trehalose (β,β-1 linkage) or neo-trehalose (α, β-1 linkage) may also be used. The sweetener  73  may be formed by adding one or more high intensity sweeteners to the trehalose in proportions such that the resulting sweetener  73  generally matches a desired multiple of the sweetness of sucrose. The sweetness of the sweetener  73  may range from about ½ the sweetness of sucrose to about 12 times the sweetness of sucrose. The high intensity sweeteners added to the trehalose to form the sweetener  73  may include one or more of acesulfame potassium, alitame, aspartame, cyclamate, neohesperidin dihydrochalcone, neotame, saccharin, stevia, sucralose, lohan guo, and similar sweeteners, and combinations thereof, as would be recognized by those of ordinary skill in the art upon review of this disclosure. 
     In various aspects, trehalose may be combined with the one or more high intensity sweeteners in water to form the sweetener  73  in the liquid form  75 . Water, as used herein, may include, for example, water, water in combination with various acids, bases, and buffers, and water in combination with other solvents and additives, and other solvents and/or volatiles. The sweetener  73  may include additional materials such as buffers, acids and bases for the adjustment of the pH, fillers, binding agents, and preservatives. The sweetener  73  in the liquid form  75  may be substantially liquid or may be in the form of slurry, paste, or other viscous or non-Newtonian form. The sweetener  73  in the liquid form  75  may include various agglomerations, aggregations, non-homogeneities, and/or clumps. 
     The sweetener  73  may be dried from the liquid form  75  to the dried form  77  by contacting the sweetener  73  in the liquid form  75  with a gas stream  20 . The sweetener  73  is dried as the sweetener  73  is transported by the gas stream  20 . The sweetener  73  in the dried form  77  is drier than, and may be substantially drier than, the sweetener  73  in the liquid form  75 . In some aspects, substantially all of the water may be removed from the sweetener  73  in the dried form  77 , while, in other aspects, the sweetener  73  in the dried form  77  may retain some residual amount of water. The water content of the sweetener  73  in the dried state  77  may be between 1% and 10% and in some embodiments may be approximately about 6% to about 8%. The sweetener  73  in the liquid form  75  may be continuously introduced into the gas stream  20  and sweetener  73  in the dried form  75  may be continuously recovered from the gas stream  20  over a period of time in a continuous process as opposed to a batch process. 
     In some aspects, the gas stream  20  may consist generally of air and combustion products produced by the combustion of various solid, liquid, or gaseous fuels or combinations thereof. Examples of fuels would include propane, natural gas, and kerosene. In other aspects, the gas stream  20  may consist of heated air propelled by the release of compression. In various aspects, the gas stream  20  may include other gases or combinations of gases, which may be heated in various ways and configured to form the flowing gas stream  20 , as would be recognized by those of ordinary skill in the art upon review of this disclosure. 
     In some aspects, the gas stream  20  may be characterized by a generally continuous flow. In other aspects, the gas stream  20  may be pulsed, and the pulses may have a frequency that may range from about 30 Hz to about 1,000 Hz. In various aspects, the gas stream  20  may include regions of high velocity flow, turbulence, and may include supersonic flows and shock waves. The gas stream typically has a maximum velocity of between around 10 m/s and 200 m/s and, in certain preferred aspects, is between 50 m/s and 160 m/s but may range upward into the supersonic velocity. When the flow is pulsed, the gas stream  20  may oscillate between a lower value and the maximum velocity as will be recognized by those skilled in the art. When the gas stream is continuous, the maximum velocity may be maintained within a range or at a desired velocity within these ranges. Pressures in the gas stream  20  may be about 2×10 4  Pa (gage) or more in various aspects. Sound pressures in the gas stream  20  may fall in the range of about 100 dB to about 200 dB in various aspects. In various aspects, a swirl component may be induced into the flow of the gas stream  20 . 
     The flow of the gas stream  20  defines a flow path  90  having a first end  94  and a second end  96  with the gas stream  20  flowing generally from the first end  94  to the second end  96 . The first end  94  of the flow path  90  may be generally coincident with the location at which the gas stream  20  is generated. The second end  96  of the flow path  90  may be generally coincident with the region from which the sweetener  73  in the dried form  77  is recovered from the gas stream  20  and may be defined by various structures configured to recover the sweetener  73 . The sweetener  73  in the liquid form  75  may be contacted with the gas stream  20  by being introduced into the gas stream  20  at an introduction location  110 , with the introduction location  100  disposed along the flow path  90  generally between the first end  94  and the second end  96 . 
     One or more passages  120 , which may be defined by tubes, channels, pipes, or other structures, with each passage  120  having one or more passage outlets  122  adapted for the introduction of sweetener  73  into the gas stream  20  may be located in the flow path  90  between the first end  94  and the second end  96 , and the location of the passage(s)  120  in the flow path  90  defines the introduction location  110 . Sweetener  73  may be introduced into the gas stream  20  at the introduction location  110  through the passage(s)  120 . Pumps, piping, valves, and other such structures may be provided in various aspects to convey the sweetener  73  to the passage(s)  120  for introduction into the gas stream  20  at the introduction location  110  as would be recognized by those of ordinary skill in the art upon review of this disclosure. 
     The temperature of the gas stream  20  may be 2,300° F. or more generally proximate the first end  94  of the gas stream  20 , which may be excessive for drying sweetener  73 . Accordingly, the temperature of the gas stream  20  may be controlled, in various aspects, to provide a first temperature  104  generally proximate the introduction location  110  and/or a second temperature  106  generally proximate the second end  96  of the flow path  90 . The temperature of the gas stream  20  may be controlled in various aspects proximate the first end  94  of the flow path  90  in order to control the first temperature  104  of the gas stream  20  generally proximate the introduction location  110 . The temperature of the gas stream  20  may be controlled in various aspects to control the second temperature  106  of the gas stream  20  generally proximate the second end  96  of the flow path  90  where the sweetener  73  in the dried form  77  may be recovered from the gas stream  20 . 
     For example, one or more gas flows may be combined with the gas stream  20  as the gas stream  20  flows along the flow path  90  to control, at least in part, the first temperature  104  of the gas stream  20  at introduction location  110 . The one or more gas flows combined with the gas stream  20  may control, at least in part, the temperature at the second end  96  of the flow path  90 . The one or more gas flows combined with the gas stream  20  may control, at least in part, the temperature variation of the gas stream  20  between the first temperature  104  and the second temperature  106 . In various aspects, one or more gas flows may be combined with the gas stream  20  to provide for the uptake of water vapor and/or for other purposes as would be recognized by those of ordinary skill in the art upon review of this disclosure. In various aspects, conditions at the first end  94  of the flow path  90  may be adjusted in order to achieve a specific first temperature  104  and/or specific second temperature  106 . 
     The first temperature  104  and/or the second temperature  106  may be chosen depending upon the nature of the sweetener  73  to be introduced into the gas stream  20  in order to be dried into the dried form  77 . For example, in various aspects, the first temperature  104  may be about 1,000° F. while the second temperature  106  may be about 150° F. 
     The sweetener  73  may be introduced into the gas stream  20  at the introduction location  110  to be exposed to the temperature of the gas stream  20  while being conveyed by the gas stream  20  from the introduction location  110  to the second end  96  of the flow path  90 . The sweetener  73  may be in contact with the gas stream  20  for an exposure time that may be on the order of fractions of a second, and, in some aspects, on the order of a millisecond or less. The temperature of the gas stream  20  may cause water associated with the sweetener  73  to flash into the vapor phase, while the latent heat of vaporization of the water in combination with the exposure time may keep the sweetener  73  generally cool thereby protecting the sweetener  73  from the temperature of gas stream  20 . Turbulence, high velocities, and/or shock waves in the gas stream  20  may strip water from the sweetener  73  and may otherwise increase the rate of evaporation of water from the sweetener  73  by various mechanisms. The latent heat of evaporation of the water may also cool the gas stream  20 , at least in part, from the first temperature  104  to the second temperature  106 , so that the water content of the sweetener  73  in the liquid form  75  may, in some aspects, control the second temperature  106  and may control the temperature variation between the first temperature  104  and the second temperature  106 , at least in part. The rate at which sweetener  73  in the liquid form  75  is fed into the gas stream  20  may control the first temperature  94 , may control the second temperature  96 , and may control the form of the temperature gradient between the first temperature  94  and the second temperature  96  by controlling the rate at which liquid is evaporated. 
     A collector  60  may be positioned about the second end  96  of the flow path  90  to recover the sweetener  73  generally in the dried form  77  from the gas stream  20 , and the collector  60  may generally define the second end  96  of the flow path  90 . The collector  60  may be a cyclone, baghouse, screen or series of screens, filter(s), or similar, or combinations thereof configured to capture the sweetener  73  generally in the dried form  77  from the gas stream  20  as would be recognized by those of ordinary skill in the art upon review of this disclosure. The collector  60  may be configured to cooperate with various material handling and storage mechanisms for the manipulation and/or storage of sweetener  73  in the dried form  77 , as would be recognized by those of ordinary skill in the art upon review of this disclosure. 
     In some aspects, the gas stream  20  may be generated by a pulse combustion dryer  30 . Examples of pulse combustion dryers  30  are described in U.S. Pat. Nos. 3,462,995, 4,708,159, 4819,873, and 4,941,820 to Lockwood the disclosures of which are hereby incorporated by reference in their entireties. The pulse combustion dryer  30  may include a combustor  31  that defines a combustion chamber  32 , and a tailpipe  40  that defines a tailpipe passage  42  having a first tailpipe passage end  44  and a second tailpipe passage end  46 . The tailpipe passage  42  is in fluid communication with the combustion chamber  32  through the first tailpipe passage end  44 . 
     The pulse combustion dryer  30 , in some aspects, may include a drying chamber  50  that defines a drying chamber passage  52  having a first drying chamber passage end  54 , a second drying chamber passage end  56 , and centerline  153 . The first drying chamber passage end  54  of the drying chamber  50  may be disposed with respect to the second tailpipe passage end  46  of the tailpipe  40  so that the drying chamber passage  52  is in fluid communication with the tailpipe passage  42 , and, thence, in fluid communication with the combustion chamber  32 . The combustor  31 , tailpipe  40 , and drying chamber  50  may be disposed with respect to one another in a variety of ways and may assume a variety of orientations with respect to the vertical that would be readily recognized by those of ordinary skill in the art upon review of this disclosure. 
     Combustion air  86  and fuel  84  may be admitted into the combustion chamber  32 , and the resulting fuel-air mixture ignited periodically to provide the gas stream  20  in the form of a series of pulses of air mixed with heated combustion products. Combustion of the fuel-air mixture may be generally complete so that the heated combustion products would consist largely of carbon dioxide and water vapor. The gas stream  20  may flow from the combustion chamber  32  through the tailpipe passage  42  from the first tailpipe passage end  44  to the second tailpipe passage end  46 . In aspects that include the drying chamber  50 , the gas stream  20  may be communicated from the tailpipe passage  42  into the drying chamber passage  52  generally proximate the first drying chamber passage end  54 , and the gas stream  20  may flow through the drying chamber passage  52  generally from the first drying chamber passage end  54  to the second drying chamber passage end  56 . Thus, the flow path  90  of the gas stream  20  includes the combustion chamber  32 , the tailpipe passage  42 , and, in aspects that include drying chamber  50 , the flow path  90  also generally includes the drying chamber passage  52 . The first end  94  of the flow path  90  may be generally coincident with the combustion chamber  32 . 
     In aspects wherein the gas stream  20  is generated by the pulse combustion dryer  30 , the collector  60  may be disposed generally proximate the tailpipe passage second end  96  or, in aspects that include the drying chamber  50 , generally proximate the second drying chamber passage end  56  to recover the sweetener  73  in the dried form  77 . As would be understood by those of ordinary skill in the art upon review of this disclosure, the collector  60  may be disposed in other ways with respect to the drying chamber  50  to recover the sweetener  73  in the dried form  77  from the second end  96  of the flow path  90  of the gas stream  20 . 
     The sweetener  73  generally in the liquid form  75  may be introduced into the flow path  90  of the gas stream  20  at the introduction location  110 . In various aspects, the introduction location  110  may be within the tailpipe passage  42  or within the drying chamber passage  52 . The sweetener  73  may be entrained in the gas stream  20  generally at the introduction location  110  and dried while being conveyed by the gas stream  20  along the portion of the flow path  90  from the introduction location  110  to the second end  96  of the flow path  90 . The sweetener  73  in the dried form  77  may be recovered at the second end  96  of the flow path  90  of the gas stream  20  by the collector  60 . 
     The sweetener  73  in the liquid form  75  may be introduced into the gas stream  20  at the introduction location  110  from one or more passages  120  through one or more passage outlets  122  defined by the one or more passages  120  disposed about the gas stream  20  at the introduction location  110  for that purpose. The sweetener  73  may pass through the one or more passages  120  into the gas stream  20  by gravity feed and/or by the application of pressures, which may be quite minimal. Pressure pulses in the gas stream  20  may aid in drawing the sweetener  73  through the passage  120  and into the gas stream  20 . Accordingly, the shear forces that the sweetener  73  is subjected to while passing through the passage  120  may be generally small or negligible. In various aspects, the rate at which sweetener  73  is fed into the gas stream  20  may be controllable. 
     In some aspects, nozzles, sprayers, or similar may be appended to the passage  120  to disperse the sweetener  73  from the passage outlet  122  into the gas stream  20 . However, this may not be necessary, as the violence of the flow of the gas stream  20  may be sufficient to disperse the sweetener  73  including the dispersal of any agglomerations, aggregations, non-homogeneities and/or clumps of materials. The shock waves and/or turbulence in the gas stream  20  may disperse the sweetener. Sound waves in the gas stream  20  may sonicate the sweetener  73 , which may aid in the dispersal of the sweetener  73  into the gas stream  20 . Pressure pulses in the gas stream  20  may also aid in the dispersal of the sweetener  73  into the gas stream  20 . 
       FIG. 1  illustrates by schematic diagram the methods of drying the sweetener  73  in the liquid form  75  into sweetener  73  in the dried form  75  using the gas stream  20 . This Figure depicts the gas stream  20  flowing along flow path  90  from the first end  94  to the second end  96 . The sweetener  73  in the liquid form  75  is introduced into the gas stream  20  at introduction location  110 , as illustrated. The sweetener  73  is dried by the gas stream  20  while being convected by the gas stream  20  from the introduction location  110  to the second end  96  of the flow path  90 . The sweetener  73  in the dried form  77  is recovered from the gas stream  20  proximate the second end  96  of the flow path  90 , the location or locations at which the sweetener  73  in the dried form  77  is recovered from the gas stream  20  generally defining the second end  94 . 
     An embodiment of the pulse combustion drier  30  is generally illustrated in  FIG. 2A . The embodiment of  FIG. 2A  includes the combustor  31 , the tailpipe  40 , and the drying chamber  50 . The combustion chamber  31  fluidly communicates with the tailpipe passage  42  through the first tailpipe passage end  44 . The tailpipe  40  is disposed with respect to the drying chamber  50  such that the tailpipe passage  42  fluidly communicates through the second tailpipe passage end  46  into the drying chamber passage  52  generally proximate the first drying chamber passage end  54 , as illustrated. The drying chamber passage  52  fluidly communicates with the collector  60  through the second drying chamber passage end  56 , in this embodiment. In other embodiments, the collector  60  could be otherwise disposed with respect to the drying chamber  50 . For example, at least a portion of the collector  60  could be positioned within a portion of the drying chamber passage  52  generally proximate the second drying chamber passage end  56 . 
     In the embodiment illustrated in  FIG. 2A , the gas stream  20  is generated within the pulse combustion dryer  30  and the sweetener  73  in the liquid form  75  is introduced into the gas stream  20  to be dried into the sweetener in the dry state  75 . Fuel  84  and combustion air  86  are admitted into the combustion chamber  32  defined by the combustor  31  to be ignited periodically in order to produce the gas stream  20 . An air valve  88  may be disposed in the path of the combustion air  88  to admit combustion air  88  into the combustion chamber  32  while generally preventing backflows of the gas stream  20 , as illustrated. As illustrate in  FIG. 2A , the flow of the gas stream  20  from the combustion chamber  32 , through the tailpipe passage  42 , through the drying chamber passage  52  and into the collector  69  defines the flow path  90 . The first end  94  of the flow path  90  is generally within the combustion chamber  32 , and the second end  96  of the flow path  90  is generally proximate the collector  60  which is disposed about the second drying chamber passage end  56  of the drying chamber  50  in the embodiment illustrated in  FIG. 2A . 
     Sweetener  73  generally in the liquid form  75  may be introduced into the gas stream  20  at the introduction location  110  through the passage outlet  122  defined by passage  120  in the embodiment illustrated in  FIG. 2A . In this embodiment, a portion of the tailpipe  40  extends into the drying chamber passage  52  of the drying chamber  50 . The introduction location  110 , in this embodiment, is within the drying chamber passage  52  generally proximate the tailpipe passage second end  46  and generally proximate the first drying chamber passage end  54 . The passage  120  is disposed within the drying chamber passage  52  to introduce the sweetener into the gas stream  20  generally proximate the centerline  153  of the drying chamber passage  52  in the embodiment of  FIG. 2A . 
     In other embodiments, a plurality of passages  120  may be provided. One or more passages  120  may be disposed within the drying chamber passage  42 , in some embodiments, to introduce the sweetener  73  into the gas stream  20  at an off-set from the centerline  153 . For example, a plurality of passages  120  may be disposed circumferentially within the drying chamber passage  42  with each passage  120  of the plurality of passages  120  positioned to introduce the sweetener  73  into the gas stream  20  at a constant radial location with respect to the centerline  153 . 
     As illustrated in  FIG. 2A , the sweetener  73  may be introduced into the gas stream  20  through the passage outlet(s)  122  to be entrained into the gas stream  20  and dried from the liquid form  75  to the dried form  77 . The collector  60  is positioned proximate the second drying chamber passage end  56  and generally defines the second end  96  of the flow path  90 , in this illustrated embodiment. The sweetener  73  generally in the dried form  77  may then be recovered from the gas stream  20  by the collector  60 . 
     As illustrated in  FIG. 2A , one or more additional airflows may be admitted into the drying chamber passage  52  in various embodiments of the pulse combustion dryer  30 . In the embodiment of  FIG. 2A , quench air  22  may be admitted into the drying chamber passage  52  generally proximate the first drying chamber end  54  to control the temperature of the gas stream  20  within the drying chamber passage  52 . The quantity of quench air  22  admitted into the drying chamber passage  52  may be regulated in order to control the temperature of the gas stream  20  including the first temperature  104  and the second temperature  106 . In this embodiment, dilution air  24  may also introduced into the drying chamber passage  52  generally proximate the first drying chamber passage end  54  to provide thermodynamic space for the uptake of water evaporated from the sweetener  73  in order to prevent water condensation and/or saturation conditions in the drying chamber passage  52  and/or in the collector  60 . The quantity of dilution air  24  admitted into the drying chamber passage  52  may be regulated in various embodiments. 
     In the embodiment illustrated in  FIG. 2A , the gas stream  20  may pass through a core region  155  generally proximate the centerline  153  of the drying chamber passage  52 . The dilution air  24  may pass through the wall region  159  of the drying chamber passage  52  which is the portion of the drying chamber passage  52  generally proximate the inner wall  53  of the drying chamber  50 . The quench air  22  may pass through an intermediate region  157  which is intermediate between the wall region  159  and the core region  155 . 
     Sweetener  73  may be introduced into the gas stream  20  passing though the core region  155 . The quench air  22  and/or the dilution air  24  may prevent or at least diminish contact between the sweetener  73  and the inner wall  53  of the drying chamber  50  as the sweetener  73  is convected through the drying chamber passage  42  by the gas stream  20  in order to generally reduce or eliminate deposition of sweetener  73  onto the inner wall  53 . 
       FIG. 2B  illustrates a cross-section of the drying chamber  50 . As illustrated, the drying chamber  50  defines a drying chamber passage  52  having a substantially circular cross-section. In this embodiment, the flows of the gas stream  20 , the quench air  22 , and the dilution air  24  through the drying chamber passage  52  generally define three regions within the drying chamber passage. These regions include the core region  155  generally proximate the centerline  153  through which the gas stream  20  generally passes, the intermediate region  155  through which the quench air  22  generally passes, and the wall region  159  through which the dilution air  24  generally passes. The pulse combustion dryer  30  may be configured to regulate the amount of quench air  22  and/or the amount of dilution air  24  admitted into the drying chamber passage  52  in order to regulate temperature and other conditions within the drying chamber passage  52 . In other embodiments, one or more airstreams could be introduced into the drying chamber passage  52  at various locations about the drying chamber passage  52  to cool the gas stream  20 , provide thermodynamic space for evaporation, or for other purposes as would be understood by those of ordinary skill in the art upon review of this disclosure. 
     The gas stream  20  has a first temperature  104  generally proximate the introduction location  110 , as illustrated in  FIG. 2A . The gas stream  20  has a second temperature  106  generally proximate the second end  96  of the flow path  90  of the gas stream  20 , as illustrated. In various embodiments, the pulse combustion dryer  30  may be configured to regulate the amount of additional gas flows such as the quench air  22  and the dilution air  24  admitted into the gas stream  20  to regulate the temperature. In various embodiments, the fuel admitted into the combustion chamber  32  may be controlled, the pulse rate of the pulse combustion dryer  30  may be regulated, and/or the pulse combustion dryer  30  may be configured and/or controlled in other ways to regulate the temperature of the gas stream  20  including the first temperature  104  and the second temperature  106  as would be recognized by those of ordinary skill in the art upon review of this disclosure. 
     Methods may include introducing the sweetener  73  in the liquid form  75  into the gas stream  20  and recovering the sweetener  73  in the dried form  77  from the gas stream  20 . Various aspects may include continuously introducing the sweetener  73  in the liquid form  75  into the gas stream  20  and continuously recovering the sweetener  73  in the dried form  77  from the gas stream  20  in a continuous process. Some aspects include pulsing the gas stream  20 . Some aspects include generating the gas stream  20  using a pulse combustion dryer  30 . 
     The sweetener produced by this process may have a number of distinctive characteristics. The dried particles of the sweetener may be generally spherical in shape with particle sizes between about 1 and 100 microns. The particles may have a substantially uniform distribution of trehalose and one or more high intensity sweeteners within the particles. The moisture content of the dried sweetener may be between about 0.5% and about 10% or between about 0.1% and about 25%. The dried sweetener may also be free-flowing and non-aggregating or non-agglomerating. The generally spherical particles may be relatively smooth compared to particles obtained from spray drying. The dried sweetener particles of this invention may also have a more uniform particle diameter than those obtained by other drying methods such as spray drying, including having a narrower size distribution and lower polydispersity index. 
     EXAMPLES 
     A further understanding may be obtained by reference to certain specific examples, which are provided herein for the purpose of illustration only and are not intended to be limiting unless otherwise specified. 
     Example 1 
     Trehalose and high intensity sweeteners are combined with water according in the proportions given in Table 1 to produce the sweetener in the liquid form. The sweetener may have about 4 times the sweetness of sucrose. 
                     TABLE 1               4 × Sucrose                                                    Trehalose   10.0   kg           Aspartame   54.0   g           acesulfame   23.2   g           potassium                        
Water is added such that the sweetener in the liquid form is approximately 50% solids by weight. The sweetener in the liquid form is dried into the sweetener in the dried form using the pulse combustion dryer Model P-0.1 manufactured by Pulse Combustion Systems, Inc. of Payson, Ariz. A peristaltic pump is used to introduce the sweetener in the liquid form into the drying chamber through a turbo cone nozzle positioned within a ⅜″ venturi. The pulse combustion dryer settings in this example are given in Table 2.
 
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Pulse Combustion Dryer Settings - Example 1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Heat Release 
                 84,000 ± 1,000 BTUH 
               
               
                   
                 Turbo Air 
                 90 ± 5 psi 
               
               
                   
                 Exhaust Air 
                 60% 
               
               
                   
                 Combustion Air 
                 65% 
               
               
                   
                 Quench Air 
                 40% 
               
               
                   
                 Transportation Air 
                  5% 
               
               
                   
                 Contact Temperature 
                 900° F. 
               
               
                   
                 Exit Temperature 
                 200° F. 
               
               
                   
                   
               
            
           
         
       
     
     The resulting sweetener in the dried form may have the properties given in Table 3. 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Properties Of Sweetener In The Dried form - Example 1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 mean particle size 
                 30 μm 
               
               
                   
                 d 90   
                 60 μm 
               
               
                   
                 d 10   
                  1 μm 
               
               
                   
                   
               
            
           
         
       
     
     Example 2 
     Trehalose and high intensity sweetener are combined with water according in the proportions given in Table 4 to produce the sweetener in the liquid form. The sweetener may have about ½ the sweetness of sucrose. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 0.5 × Sucrose 
               
            
           
           
               
               
               
            
               
                   
                 Ingredient 
                 Spec. Amount 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Trehalose 
                 10.0 
                 kg 
               
               
                   
                 Water 
                 8.18 
                 kg 
               
               
                   
                 Aspartame 
                 0.50 
                 g 
               
               
                   
                 acesulfame 
                 0.25 
                 g 
               
               
                   
                 potassium 
               
               
                   
                   
               
            
           
         
       
     
     Example 3 
     Trehalose and high intensity sweetener are combined with water according in the proportions given in Table 5 to produce the sweetener in the liquid form. The sweetener may have about the same sweetness as sucrose. 
                     TABLE 5                  1 × Sucrose                             Ingredient   Spec. Amount                                             Trehalose   10.0   kg           Water   8.18   kg           Aspartame   13.5   g           acesulfame   5.8   g           potassium                        
Water is added such that the sweetener in the liquid form is approximately 33% solids. The sweetener in the liquid form is dried into the sweetener in the dried form using the pulse combustion dryer Model P-0.1 manufactured by Pulse Combustion Systems, Inc. of Payson, Ariz. A peristaltic pump is used to introduce the sweetener in the liquid form into the drying chamber through a turbo cone nozzle positioned within a ⅜″ venturi. The pulse combustion dryer settings in this example are given in Table 6.
 
     
       
         
           
               
             
               
                 TABLE 6 
               
               
                   
               
               
                 Pulse Combustion Dryer Settings - Example 1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Heat Release 
                 84,000 ± 1,000 BTUH 
               
               
                   
                 Turbo Air 
                 90 ± 5 psi 
               
               
                   
                 Exhaust Air 
                 60% 
               
               
                   
                 Combustion Air 
                 65% 
               
               
                   
                 Quench Air 
                 40% 
               
               
                   
                 Transportation Air 
                  5% 
               
               
                   
                 Contact Temperature 
                 900° F. 
               
               
                   
                 Exit Temp 
                 200° F. 
               
               
                   
                   
               
            
           
         
       
     
     The resulting sweetener in the dried form may have the properties given in Table 7. 
     
       
         
           
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Properties Of Sweetener In The Dried form - Example 1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 mean particle size 
                 30 μm 
               
               
                   
                 d 90   
                 60 μm 
               
               
                   
                 d 10   
                  1 μm 
               
               
                   
                   
               
            
           
         
       
     
     Example 4 
     Trehalose and high intensity sweetener are combined with water according in the proportions given in Table 8 to produce the sweetener in the liquid form. The sweetener may have about 12 times the sweetness of sucrose. 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 12 × Sucrose 
               
            
           
           
               
               
               
            
               
                   
                 Ingredient 
                 Spec. Amount 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Trehalose 
                 10.0 
                 kg 
               
               
                   
                 Water 
                 8.18 
                 kg 
               
               
                   
                 Aspartame 
                 162.0 
                 g 
               
               
                   
                 acesulfame 
                 69.6 
                 g 
               
               
                   
                 potassium 
               
               
                   
                   
               
            
           
         
       
     
     The foregoing discussion discloses and describes merely exemplary embodiments. Upon review of the specification, one of ordinary skill in the art will readily recognize from such discussion, and from the accompanying figures and claims, that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.