PROCESS FOR THE MANUFACTURE OF A LEAVENED FOODSTUFF AND AN APPARATUS THEREFOR

Abstract

The present invention provides a process for the manufacture of a leavened foodstuff, such as a leavened or heat treated leavened foodstuff, and apparatus for the same, wherein in said process an ingredient composition comprising a food structurant, water and a leavening agent is treated with ultrasound from an ultrasound source during at least a part of a leavening step, and/or an ingredient composition comprising a food structurant, water and a leavening agent or a leavened ingredient composition, typically obtained therefrom, is treated with ultrasound from an ultrasound source during at least a part of a heat treating step.

Claims

1. A process for the manufacture of a leavened foodstuff, comprising the steps of: treating an ingredient composition comprising food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid, water and a leavening agent, and combinations thereof, said ingredient composition being a dough or batter, with ultrasound from an ultrasound source to modify the gas cell structure developing in the ingredient composition during at least a part of a leavening step to provide a leavened ingredient composition as the leavened foodstuff, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW and wherein when the leavening agent is a biological leavening agent, the leavening step further comprises the step of controlling the relative humidity of the environment surrounding the ingredient composition such that it is greater than 30%, and/or treating an ingredient composition comprising food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid, water and a leavening agent, and combinations thereof, said ingredient composition being a dough or batter or a leavened ingredient composition having a gas cell structure and comprising a food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid and water, and combinations thereof, said leavened ingredient composition being a dough or batter, with ultrasound from an ultrasound source to modify the gas cell structure developing in the ingredient composition or to modify the gas cell structure of the leavened ingredient composition during at least a part of a heat treating step to provide a heat treated leavened foodstuff, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW.

2. The process of claim 1 wherein the leavening agent is selected from one or both of a chemical leavening agent and a biological leavening agent.

3. A process for the manufacture of a heat treated leavened foodstuff, comprising the steps of: providing an ingredient composition comprising food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid, water and a leavening agent, and combinations thereof, said ingredient composition being a dough or batter, or a leavened ingredient composition having a gas cell structure and comprising a food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid and water, and combinations thereof, said leavened ingredient composition being a dough or batter; heat treating the ingredient composition to develop a gas cell structure in the ingredient composition and provide a heat treated leavened ingredient composition as the heat treated leavened foodstuff and/or heat treating the leavened ingredient composition to provide a heat treated leavened ingredient composition as the heat treated leavened foodstuff; wherein the ingredient composition or the leavened ingredient composition is subjected to ultrasound treatment during at least a part of the heat treating step to modify the gas cell structure of the composition, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW.

4. The process of claim 3, wherein the leavened ingredient composition is provided by the steps of: providing an ingredient composition comprising food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid, water and a leavening agent, and combinations thereof, wherein said ingredient composition is a dough or batter; and leavening the ingredient composition to develop a gas cell structure in the ingredient composition to provide the leavened ingredient composition having a gas cell structure and comprising food structurant, water and optionally any remaining leavening agent.

5. The process of claim 4, wherein the ingredient composition is subjected to ultrasound treatment during at least a part of the leavening step.

6. The process of claim 5 wherein the ingredient composition is subjected to ultrasound treatment during at least the final 25%, by duration, of the leavening step.

7. The process of claim 3 wherein the leavening agent in the ingredient composition is heat activated such that the ingredient composition will undergo leavening during the heat treating step to provide a heat treated leavened foodstuff.

8. A process for the manufacture of a leavened foodstuff, comprising the steps of: providing an ingredient composition comprising food structurant selected from the group consisting of protein, polymeric carbohydrate and hydrocolloid, water and a leavening agent, and combinations thereof, wherein said ingredient composition is a dough or batter; leavening the ingredient composition to develop a gas cell structure to provide a leavened ingredient composition having a gas cell structure as the leavened foodstuff, and wherein when the leavening agent is a biological leavening agent, leavening further comprises controlling the relative humidity of the environment surrounding the ingredient composition such that it is greater than 30%; wherein the ingredient composition is subjected to ultrasound treatment from an ultrasound source during at least a part of the leavening step to modify the gas cell structure of the ingredient composition, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW.

9. The process of claim 8 wherein the ingredient composition is subjected to ultrasound treatment during at least the final 25%, by time, of the leavening step.

10. The process of claim 8 further comprising the step of: heat treating the leavened ingredient composition to provide a heat treated leavened composition.

11. The process of claim 10, wherein the leavened ingredient composition is subjected to ultrasound treatment during at least a part of the heat treating step.

12. The process of claim 8 wherein the leavening agent comprises one or both of a biological leavening agent and a chemical leavening agent.

13. The process of claim 12 wherein the leavening agent comprises a biological leavening agent and the step of controlling the relative humidity of the environment surrounding the ingredient composition controls the relative humidity in a range of from 70% to 90%.

14. The process of claim 13 wherein the biological leavening agent is selected from the group consisting of a yeast, a yeast of the genus Saccharomyces, a bacterium, a lactic acid bacteria, an acetic acid bacteria and combinations thereof.

15. The process of claim 14 wherein the leavening agent comprises a chemical leavening agent comprising a compound selected from the group consisting of ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, potassium bitartrate, potassium carbonate, monocalcium phosphate, sodium acid pyrophosphate, sodium aluminium pyrophosphate, di-calcium dihydro phosphate and hydrogen peroxide.

16. The process of claim 15 wherein the chemical leavening agent further comprises an acidic compound.

17. The process of claim 1 wherein the ingredient composition does not comprise gluten such that the ingredient composition is a gluten-free ingredient composition.

18. The process of claim 1 in which the process is carried out without any mechanical manipulation to alter the developing gas cell structure or cell structure.

19. The process of claim 1 wherein the food structurant is selected from the group consisting of protein selected from albumin, casein, gluten or gelatin, polymeric carbohydrate selected from starch or cellulose, and hydrocolloid selected from a gum.

20. The process of claim 1, wherein the modification of the gas cell structure comprises increasing the homogeneity of the gas cell structure.

21. A heat treating apparatus to carry out the method of claim 1 for the manufacture of a foodstuff comprising at least a chamber for an ingredient composition, means for heating the chamber, means for controlling the temperature of the chamber, an ultrasound source for transmitting ultrasound to the chamber, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW, and a control system, said control system configured to transmit ultrasound to the chamber from the ultrasound source during at least a portion of the heating of the chamber by said means for heating the chamber.

22. A proofing apparatus for an ingredient composition to carry out the method of claim 1 comprising at least a chamber for an ingredient composition, means for controlling the temperature of the chamber, means for controlling the humidity in the chamber to a relative humidity of greater than 30% and an ultrasound source for transmitting ultrasound to the chamber, wherein said ultrasound has a frequency in the range of from 20 kHz to 200 kHz and a power in the range of greater than 50 W to 1 kW.

23. The process of claim 15 wherein the chemical leavening agent further comprises an organic acid.

24. The process of claim 1 wherein said dough is not a laminated structure.

25. A leavened foodstuff made by the process of claim 1.

Description

[0071] Embodiments of the present invention will now be described by way of example only and with reference to the accompanying non-limited drawings in which:

[0072] FIG. 1 is a diagrammatic scheme of a leavening apparatus for the manufacture of a leavened foodstuff as described herein.

[0073] FIG. 2 is a diagrammatic scheme of a frying apparatus for the manufacture of a fried leavened foodstuff as described herein.

[0074] FIG. 3 is a diagrammatic scheme of a baking apparatus for the manufacture of a baked leavened foodstuff as described herein.

[0075] FIG. 4 shows graphs of the cell count results for cross-sections of bread loaves, made from a conventional ingredient composition, subjected to different durations and powers of ultrasound during leavening and/or baking versus a control which was not subjected to any ultrasound treatment.

[0076] FIG. 5 shows graphs of the results of granulometry analyses for cross-sections of bread loaves, made from a conventional ingredient composition, subjected to different durations and powers of ultrasound during leavening and/or baking versus a control which was not subjected to any ultrasound treatment.

[0077] FIG. 6 shows graphs of the cell count results for cross-sections of bread loaves, made from a conventional ingredient composition (100% water) and an ingredient composition with 10 wt. % less water, subjected to different powers of ultrasound during leavening and baking versus a control which was not subjected to any ultrasound treatment.

[0078] FIG. 7 shows graphs of the results of granulometry analyses for cross-sections of bread loaves, made from a conventional ingredient composition (100% water) and an ingredient composition with 10 wt. % less water, subjected to different powers of ultrasound during leavening and baking versus a control which was not subjected to any ultrasound treatment.

[0079] FIG. 8 shows graphs of the results of granulometry analyses for cross-sections of bread loaves, made from a gluten-free ingredient composition, subjected to different durations and powers of ultrasound during leavening and/or baking versus a control which was not subjected to any ultrasound treatment.

[0080] FIG. 9 shows graphs the cell count results for cross-sections of scones, made from a conventional ingredient composition having a chemical leavening agent, subjected to ultrasound during baking versus a control which was not subjected to an ultrasound treatment.

[0081] FIG. 10 shows graphs of the results of granulometry analyses for cross-sections of scones, made from a conventional ingredient composition having a chemical leavening agent, subjected to ultrasound during baking versus a control which was not subjected to any ultrasound treatment.

[0082] As used herein, the term ultrasound refers to sound pressure, particularly cyclic sound pressure, preferably with a frequency in the range of from 18 kHz to 300 MHz, more preferably in the range of from 20 kHz to 200 kHz. A composition which has undergone an ultrasound treatment can be referred to as sonicated, while the application of ultrasound can be referred to as sonication.

[0083] If the ingredient composition is not in direct contact with the ultrasound source, the ultrasound may have to pass through one or more media, termed herein ultrasound coupling agents to reach the composition. The ultrasound coupling agent may be a gas, a liquid medium fit for human consumption or a solid. Examples of gaseous media include air. Examples of solid media include plastics, ceramics, metals and alloys, for instance in the form of trays and tins. By fit for human consumption it is meant a liquid medium which is not injurious for health. Examples of liquid media fit for human consumption include water, cooking oils such as vegetable oils and glycerine. Liquid media unfit for human consumption, which should therefore not be used as coupling agents, for example due to toxicity or for other reasons include alkanes such as paraffin oil.

[0084] As used herein, the term foodstuff means a substance or composition that can be used, or prepared for use, as food.

[0085] The ingredient composition comprises a food structurant. As used herein, the term food structurant means an edible ingredient which, after heat treating, changes form to provide the ingredient composition with a more fixed cell structure. In the baking process, the change in form may occur as a result of one or more of denaturing, cross-linking, gelatinisation, dehydration and hydrogen bonding. One well known example is the denaturisation of gluten upon baking to provide a rigid and viscous matrix around gas cells. The food structurant may be part of another ingredient in the ingredient composition, for instance starch food structurants may be part of a flour component of an ingredient composition.

[0086] As used herein, the term flour is intended to mean a powder obtained from grinding one or more of cereal grain, other seed or root. Typical cereal grains include wheat, maize, rice and rye.

[0087] As used herein, the term leavening refers to a step in the manufacture of a foodstuff during which the ingredient composition is left for a period of time for gas generation and cell expansion to take place. Typically one or more of gas formation and release, aeration and foaming occurs in the ingredient composition as a result of the action of the leavening agent. Leavening can be carried out under conditions appropriate to enable the leavening agent to generate gas within the ingredient composition, typically to provide a foam. Leavening does not typically involve any mechanical manipulation of the ingredient composition, for instance such that there is no mixing, kneading, folding and/or extrusion etc. which would disrupt the gas cell formation. As used herein, leavening can refer to the period of time when the ingredient composition is left, e.g. after shaping, but prior, particularly immediately prior, to heat processing.

[0088] Leavening can be carried out before, or as part of the heat treating step. For instance, in the manufacture of bagels, the ingredient composition in the form of a dough may be boiled during leavening to provide a crust. Furthermore, when a heat activated chemical leavening agent is present, gas generation and cell expansion can occur during the heating of the ingredient composition.

[0089] As used herein, a leavened ingredient composition or a leavened foodstuff is one which has undergone the leavening process. Thus, a leavened ingredient composition obtained from an ingredient composition comprising a food structurant, water and a leavening agent is the result of leavening the ingredient composition.

[0090] As already discussed, the leavening agent may be a biological leavening agent or a chemical leavening agent. Without wishing to be bound by theory, it is thought that the application of ultrasound during the leavening of an ingredient composition is optimal during the final stages of leavening, such as during at least the final 25%, by duration, of the leavening step, because this is when the gas cell structure is most developed. Application of ultrasound during the early stages of leavening is less efficient because the gas cell structure is less developed and gas is continually being generated.

[0091] When the leavening agent is a biological agent, this leavening process is also known as proofing. Biological leavening agents are microorganisms that can release gases, typically carbon dioxide, to leaven ingredient compositions. For instance, types of yeast, such as baker's yeast can act on the ingredient composition through fermentation, thereby biologically changing the chemistry of the composition.

[0092] Chemical leavening agents can be compounds or compositions which release gases, such as carbon dioxide upon activation. Activation typically occurs upon contact with moisture and/or heat. For instance, carbon dioxide gas can be generated by the action of an acid, such as a low molecular weight organic acid, and an alkali which can liberate carbon dioxide upon neutralisation. Alternatively, the chemical leavening agent may be a compound which undergoes thermal decomposition, typically at those temperatures used in the heat treating step. Without activation by the appropriate stimulus, such as contact with moisture and/or heat, the rate of generation of gas by a chemical leavening agent is negligibly small. It is only upon activation during the leavening step that the rate of generation of gas is sufficient to develop the gas cell structure in the ingredient composition. Once a gas cell structure begins to develop during leavening, this can then be modified by the application of ultrasound.

[0093] When the leavening agent is a chemical leavening agent, it may or may not be entirely consumed in the leavening step. Consequently, leavening agent may be present during subsequent processing steps, such as during a heat treating step. Thus, the generation of gas by the leavening agent may continue in a subsequent processing step, such as during heat treating.

[0094] It is preferred that the ingredient composition, particularly the leavened ingredient composition, is not a laminated structure. For instance laminated structures comprising dough and fat, such as in puff pastry, croissants and Danish pastries, achieve expansion upon baking largely due to the effect of heat on gas trapped by the interlayering of fat and dough rather than from the generation of gas during leavening and optionally heat treating.

[0095] The term heat treating is intended to encompass any treatment resulting in an increase in temperature which can bring about a change in the food structurant to retain a cell structure, typically a matrix holding gas bubbles, in the ingredient composition or leavened ingredient composition. The heat treating may, for example, comprise one or more of baking, either fully or partially, boiling, poaching, steaming, frying and grilling. The heat treatment can affect the structurant in the ingredient or leavened ingredient composition to maintain a particular cell structure upon cooling to room temperature. This can be achieved by, for instance, the denaturing or cross-linking of the structurant to retain a particular gas cell structure, and can be associated with a loss of fluidity and/or elasticity of the matrix.

[0096] Heat treating of an ingredient composition comprising a chemical leavening agent or a leavened ingredient composition, even without the application of ultrasound, retains the gas cell structure generated upon heating or present in the leavened ingredient composition. However, heating alone is unable to redistribute the gas between the gas cells in the matrix, which would modify the gas cell structure during the heat treatment. In order to control the modification of the gas cell structure, the application of ultrasound is required. Without wishing to be bound by theory, it is thought that the application of ultrasound during the heat treating of a leavened ingredient composition, which already comprises a gas cell structure, can redistribute the gas to provide a more homogeneous structure. In this case, the gas cells are competing for a constant amount of gas because leavening has already occurred.

[0097] FIG. 1 shows a schematic diagram of a proofing apparatus, particularly an industrial proofing apparatus 10. Such a proofing apparatus can be used when the leavening agent in the ingredient composition is a biological leavening agent. The proofing apparatus provides the conditions, typically the optimal conditions, necessary for the biological leavening agent to generate gas which forms the cell structure in the composition.

[0098] The proofing apparatus 10 comprises a proofing chamber 15 including an insulating layer 35, a combined heat and humidity source 25, and an ingredient composition container 55. The proofing chamber 15 further comprises a door (not shown) allowing the removal of the ingredient composition container 55 and may optionally further comprise a separator 30 between the combined heat and humidity source 25 and ingredient composition container 55. If present, the separator 30 may be a heat and humidity permeable wall, such as a grille, mesh or the like, which allows the transmission of the humidity from the combined heat and humidity source 25 to the ingredient composition container. Although a combined heat and humidity source 25 is shown in FIG. 1, these functions can be provided as separate units, namely independent heat and humidity generation sources. The combined source or independent sources have associated temperature and humidity sensors within the proofing chamber and can be connected to a control system to allow the control of the temperature and humidity within the chamber in pre-set ranges.

[0099] The ingredient composition container 55 may be provided on wheels 40, to allow easy removal from the proofing chamber 15. The ingredient composition container 55 can contain a number of shelves 45, typically removable shelves, on which the ingredient composition 50 can be placed. In FIG. 1, the ingredient composition 50 is shown as multiple lozenge-shaped rolls.

[0100] The ingredient composition container 55 allows free transmission of the heat and humidity generated by the combined heat and humidity source 25 to the ingredient composition 50 held within. For instance, the ingredient composition container 55 may be open sided, or have mesh, perforated or grille walls. The ingredient composition container 55 further comprises an ultrasound source 20 for transmitting ultrasound to the ingredient composition 50. In the embodiment shown in FIG. 1, the ultrasound source 20 is shown on one side of the ingredient composition container 55. However, multiple ultrasound sources may be provided, for instance on two, three or four sides of the ingredient composition container 55 to ensure that the ultrasound reaches the ingredient composition. Further ultrasound sources may be provided on one or both of the ceiling and floor of the ingredient composition container 55. In a further embodiment, the ultrasound source 20 may be directly connected to the shelves 45, to ensure efficient transmission of the ultrasound to the ingredient composition.

[0101] FIG. 2 shows a schematic diagram of one heat treating apparatus 100, particularly a fryer or steamer, described herein. The fryer or steamer comprises a liquid chamber 115 for an ingredient composition. The liquid chamber 115 may be filled with a liquid heat transfer medium such as water or cooking oil, particularly a vegetable oil. When the liquid chamber 115 comprises water, the apparatus 100 may be a steamer, such as a bagel steamer. When the liquid chamber 115 comprises cooking oil, the apparatus 100 may be a fryer, such as a doughnut fryer.

[0102] One or more ultrasound sources 120 may be placed on one or both of the walls and floor of the liquid chamber 115. In the embodiment shown in FIG. 2, the ultrasound source 120 is shown in the rear wall of the liquid chamber 115. It will be apparent that the liquid heat transfer medium also functions as an ultrasound coupling agent, to transmit ultrasound from the ultrasound source 120 in the chamber wall to ingredient composition suspended in the liquid chamber 115.

[0103] The heat treating apparatus 100 further comprises one or more heating elements 125, located to transmit heat to the liquid heat transfer medium in the liquid chamber 115. Control dials 130 are provided to set the temperature of the liquid chamber 115 and the power of the ultrasound generated by the ultrasound source 120. The control dials 130 can be connected to a controller (not shown) which determines the power provided to the heating element 125 and ultrasound source 120 and is configured to activate the ultrasound source 120 to transmit ultrasound to the chamber during at least a portion of the time when the heating element 125 is activated. A temperature sensor (not shown) may also be provided to measure the temperature of the liquid heat transfer medium and provide a feed-back signal to the controller.

[0104] An insulating layer 135 can be provided between the heating elements 125 and the external cladding 140 of the heating apparatus 100. One or more support legs 145 may also be provided to raise the liquid chamber 115.

[0105] FIG. 3 shows a diagrammatic scheme of a further heating apparatus 200, particularly a tunnel or travelling oven, as described herein. An insulating layer 235 defines an oven chamber 215 within. The insulating layer 235 may be covered with external cladding 240. An oven entrance 260 and an oven exit 270 are provided through the insulating layer 235 and external cladding 240. The oven chamber 235 may be supported on one or more legs 245.

[0106] The oven entrance 260 and oven exit 270 are aligned with an endless belt 280 on which the ingredient composition 250 can be placed. The endless belt is supported by a plurality of rollers 290, at least one of which is driven by a motor to convey the ingredient composition 250 from the oven entrance 260 to oven exit 270 on the endless belt 280. A heating source (not shown) is provided to heat the oven chamber. The heating source may comprise one or more heating elements. In one embodiment, the heating elements may be placed in one or more of the ceiling, floor or sides of the oven chamber 215. Typically, one or more fans are provided (not shown in FIG. 3) to distribute the hot air produced by the heating elements throughout the oven chamber 215. An exhaust flue 295 is provided through the insulating layer 235 and external cladding 240 on the upper surface of the oven to allow exit of exhaust air from the oven chamber 215.

[0107] One or more ultrasound sources 220 are provided in the oven chamber 215. In the embodiment shown in FIG. 3, these are provided on the sides of the oven chamber 215 (only the near-side ultrasound source is shown). The ultrasound is transmitted to the ingredient composition during at least a portion of the time heating source is activated. This may be achieved by a controller (not shown). The ultrasound can be transmitted to the ingredient composition through the air in the oven chamber 215, with the air acting as an ultrasound coupling medium. In an alternative embodiment, the ultrasound source may be provided on the ceiling of the oven chamber 215, above the endless belt 280 and/or within the endless belt 280 itself, for instance positioned between adjacent pairs of rollers 290.

[0108] It will be apparent that the process described herein can be carried out in a variety of other heating apparatus, such as deck ovens, rack ovens and reel ovens.

[0109] The following non-limiting Examples provide embodiments of the process and apparatus disclosed herein. The effect of ultrasound was tested in the manufacture of bread. Example 1 examines the application of ultrasound during different stages in the manufacture of bread from a standard ingredient composition. Example 2 examines the application of ultrasound during different stages in the manufacture of bread from a low water ingredient composition. Example 3 examines the application of ultrasound during different stages in the manufacture of bread from a gluten-free ingredient composition. A biological leavening agent is used in Examples 1-3. Example 4 examines the application of ultrasound during different stages in the manufacture of bread from an ingredient composition comprising a chemical leavening agent.

[0110] The Examples show that the application of ultrasound improved the porosity and volume of loaves, making them more aerated with a higher lift. In addition, the texture of the sonicated bread was much improved in comparison to the control loaf. Whilst not wishing to be bound by theory, it appears that ultrasound enhances the nucleation, formation and growth of bubbles in the dough matrix.

[0111] In addition, the application of ultrasound was found to improve the crumb of a low water content bread with 90% (wt.) water content (called herein 10 wt. % less water) as discussed above. Ultrasound was also found to improve the crumb of gluten-free bread. However, in contrast to the effect on regular bread, the ultrasound expands the size of existing pores rather than generating new pores.

[0112] The benefits of the application of ultrasound are also shown to be applicable to ingredient compositions comprising a chemical leavening agent, as well as those compositions comprising a biological leavening agent.

Experimental Procedure

[0113] A Russell Hobbs breadmaker (Model 18036) was used to make bread. Ingredients were loaded into a removable tin, which was then inserted into the breadmaker. Any preheating, mixing, kneading, leavening, baking and sonication occurred within this container.

[0114] Various ingredient compositions were prepared in accordance with the recipes shown in Tables 1-3 in the Examples below. The experiments of the Examples show the effect of ultrasound on ordinary, gluten and wheat free and reduced water loaves using the timing of the regular and gluten-free pre-set programs of the breadmaker as templates. The durations of the pre-set programs are discussed in the relevant Examples.

[0115] The effects of ultrasound with respect to the duration of sonication, the stage in bread production during which sonication occurred and the ultrasound power were investigated. In particular, the effect of ultrasound on the leavening and early baking stages of the dough was examined. The late-baking stage during which the dough reaches temperatures exceeding 60 C., in particular from 60 to 100 C., was not investigated in this study.

[0116] The gluten-free cycle is much longer, so its 54 minute proof was divided into four 12 minute blocks with an additional 10 possible minutes at the start of baking. Loaves were sonicated in different combinations of these blocks, with the particular timings provided in the relevant Example. The experiments were replicated under three ultrasound powers. An unsonicated loaf of each description was also baked to allow comparison between a control loaf and the experimental loaves.

[0117] To sonicate the bread dough during a biological leavening step (proofing), the loaf tin was removed from the bread maker at the time when sonication was supposed to begin. The tin, containing dough, was covered with cling film and placed into an 25 kHz ultrasonic bath (Pulsation KS.310, Kenny's Ultrasonics Ltd.) filled with water at 40 C. A temperature controller including a temperature sensor and heating element was added to the ultrasound bath contained to allow the temperature to be maintained at 40 C. A weight placed on top of the tin kept its sides submerged. At the end of sonication the tin was reinserted into the breadmaker for the remainder of the cycle.

[0118] In these experiments, the proofing step was not carried out under control of the humidity of the environment surrounding the ingredient composition. However, the results below in which there is no control of humidity when sonication was applied during proofing show the benefits of the application of ultrasound during this step, even without humidity control, such that corresponding benefits would be observed when ultrasound is applied during proofing under humidity control.

[0119] To sonicate the bread dough during the early stages of baking, the 25 kHz ultrasound bath was used to replicate the baking conditions in the breadmaker. A temperature controller including a temperature sensor and heating element was added to the ultrasound bath, allowing temperature control of the water present. The requisite breadmaker temperature program was monitored over time with a thermocouple to provide a temperature profile which was then applied to the ultrasound bath via the temperature sensor and heating element.

[0120] Once the loaves were cooked they were removed from the breadmaker to cool. Loaves were then cut into thirds with a band saw and the crumb of each slice scanned by placing the open side facedown onto a scanner. An open sourced image-processing program called ImageJ (W. Rasband, 1997, National Institutes of Health, USA, http://rsbweb.nih.gov/ij/) was used to analyze the bread crumb by performing two analytical tests.

[0121] The cell analysis test counts and measures objects in binary or thresholded images. Scanned bread images were first converted from colour to greyscale, and the threshold level adjusted to highlight the darker pixels in a marker colour, such as red. As the darker pixels were normally present in the pores of the bread, this process accurately highlighted the holes within the crumb. For each ingredient composition (e.g. the regular, low water and gluten-free compositions), once adjusted to highlight the darker pixels, the threshold level was fixed for the remainder of the analysis. This meant that the data from different batches of foodstuff prepared from a particular ingredient composition were directly comparable. The cell analysis tool was then used to count and measure the red objects in the image, which gave a value of the number of pores in each slice.

[0122] A granulometry test was used to measure the distribution of pore sizes in each bread image. In order to perform this test the scanned bread image was converted into greyscale. The program was then used to produce a graph showing the density distribution of pores sizes in the picture as a plot of relative density versus radius of opening. A minimum radius of opening was set so that pores that were smaller than minimum radius value were considered to be outside the accuracy range (i.e. noise) of the analysis, and therefore were excluded to avoid errors. Four (4) pixels were used for all cases, with the exception of gluten-free loaves, which used eight (8) pixels. The guidelines used for interpreting the results of the granulometry test are as follows.

[0123] A maximum or high relative density value for a given radius on a curve indicates that most pores in the loaf are of that size. The steeper the fall from this maximum on the curve, the less of a presence of other pore sizes in the loaf. A curve that is more of an arc shape (i.e. multiple radii are present at densities that are close to the maximum) shows that that the there is a greater distribution of pores over a number of sizes in that loaf. A curve that is flat indicates that the loaf has an equal number of pores of all sizes. In terms of height, if one graph has consistently higher values in comparison to another graph this means it has greater density values for all its pores such that more of the loaf's area is composed of pores, regardless of size.

[0124] It can be undesirable to have a small maximum pore size. This is shown by a peak to the left of a density distribution plot. It is also undesirable to have an equal number of pores of every size because this indicates that there are similar amounts of very small as well as very large pores in the loaf. Improved porosity occurs if the maximum pore size is larger and this is indicated by a shift in the peak to the right in a density distribution plot. A loaf with an even, homogenous texture would have all pores of a similar size and this is indicated by a plot having a single, sharp peak.

EXAMPLE 1

[0125] This experiment shows the effect of ultrasound on the proofing and baking steps of a regular loaf. The ingredient composition was prepared according to a conventional recipe shown in Table 1.

[0126] The bread was produced on the machine's regular program. This cycle lasts 55 minutes. The setting begins with 8 minutes of kneading during which the temperature is raised to the range of from 40 to 60 C., followed by a 19 minute leavening (proof) at this temperature. Baking takes place in the last 28 minutes of the cycle when the temperature is raised to 130 to 150 C. over a period of 5 minutes. The temperature is then maintained in this range for the remaining 23 minutes.

TABLE-US-00001 TABLE 1 Regular bread recipe for a 750 g loaf Ingredient Mass or volume Water 300 g Olive oil 20 ml Salt 11 g Sugar 20.5 g Strong white flour 470 g Dried milk powder 11.5 g Yeast 9.5 g

[0127] The regular ingredient compositions were sonicated for (i) the last 15-minutes of the proof, (ii) the first 10 minutes of baking or both (i) and (ii), at either 100, 200 or 300 watts as shown in Table 2.

TABLE-US-00002 TABLE 2 Sonication duration and power for regular ingredient composition Power/W 0 100 200 300 (Control) Bread stage Proof/ Bake/ Proof/ Bake/ Proof/ Bake/ Bake/ Proof/ min min min min min min min min Loaf 15 0 15 0 15 0 0 0 0 10 0 10 0 10 15 10 15 10 15 10

[0128] In the following discussion, the loaves are identified as control or by the duration and power of sonication in their proof and bake periods (power, sonication duration during proof, sonication duration during bake) e.g. 100 W, 15, 10.

[0129] FIG. 4 graphs the cell count results for cross-sections of the bread loaves, made from a conventional regular ingredient composition, subjected to different durations and powers of ultrasound during leavening and/or baking versus a control which was not subjected to any ultrasound treatment. These results show that ultrasound increases the porosity of bread, which is an effect which can improve the texture and appeal of the product. There is a correlation between the duration of ultrasound and loaf porosity: the 15, 10 sonication block most significantly affected the porosity of the bread, followed by 0, 10 and then 15, 0. This suggests that the combination of sonication through proof and early baking yields the best results. In addition, sonication later in bread production is evidently preferable to sonication during leavening (proof). There is also a correlation between ultrasound power and the porosity of the loaves. Sonication at 200 watts generates the greatest change in porosity for the 0, 10 and 15, 10 loaves, followed by 300 watts and then 100 watts. In summary, the combination of ultrasound timing and power that produces the greatest porosity is the 15, 10 block at 200 watts.

[0130] FIG. 5 shows the results of the granulometry analyses for cross-sections of bread loaves, made from a conventional regular ingredient composition, subjected to different durations and powers of ultrasound during leavening and/or baking versus a control which was not subjected to any ultrasound treatment. The shape of the control and 15, 0 curves are similar. They have a sharp peak followed by a steep fall in density values. This indicates that the size distribution of pores in these loaves is minimal. This contrasts with the 15, 10 and 0, 10 loaves at powers of 100, 200 and 300 watts. The curves of these loaves are more rounded. Therefore, the spread of pore sizes in those loaves is greater.

[0131] The control and 15, 0 curves have a density maximum at 5 pixels at all powers, which means that this is the most commonly sized pore in both loaves regardless of sonication. Meanwhile, the 0, 10 and 15, 10 loaves sonicated at 100, 200 and 300 watts have a maximum density around a radius of 7 pixels. This means that the 0, 10 and 15, 10 loaves have larger pores on average.

[0132] As ultrasound power increases the heights of the loaves' granulometry curves become greater. Thus, an increase in ultrasound power corresponds to an increase of pore area in the resulting loaves. Additionally, the 0, 10 and 15, 10 loaves' curves become more parabolic as ultrasound power increases. This means that the distribution of pore sizes becomes slightly more constrained with a higher power. This higher density of pores of a few similar sizes indicates fewer unwanted large pores and very small pores.

[0133] A visual inspection of the loaves indicates that the sonicated loaf is spongier and less dense than the control. Its pores are larger and the pore size distribution is more homogeneous.

[0134] These results affirm the conclusions drawn from the cell analysis that ultrasound has a clear effect on the size and size distribution of pores in bread loaves, particularly at powers of 200 and 300 watts, and for the 15, 10 and 0, 10 blocks of sonication.

EXAMPLE 2

[0135] This experiment shows the effect of ultrasound on the proofing and early baking steps of reduced water content loaves. A low water ingredient composition was prepared by reducing the water content of the conventional composition shown in Table 1 by 10% by weight. The 10 wt. % less water ingredient composition is shown in Table 3. The 10 wt. % less water ingredient composition provided a 720 g loaf.

TABLE-US-00003 TABLE 3 Low water content bread ingredient composition Ingredient Mass or volume Water 270 g Olive oil 20 ml Salt 11 g Sugar 20.5 g Strong white flour 470 g Dried milk powder 11.5 g Yeast 9.5 g

[0136] The bread was produced from the 10 wt. % less water ingredient composition on the machine's regular setting in a similar manner to Example 1.

[0137] These loaves were sonicated at 300 watts for 25 minutes, comprising 15 minutes of the leavening (proofing) step and the first 10 minutes of the baking step. The corresponding control 10 wt. % less water loafs were made from identical an ingredient composition but did not undergo any sonication.

[0138] FIG. 6 shows graphs of the cell count results for cross-sections of bread loaves, made from a conventional ingredient composition (100% water) and an ingredient composition with 10 wt. % less water, subjected to ultrasound (300 W) during leavening and baking versus a control which was not subjected to any ultrasound treatment. The cell analysis shows that ultrasound successfully increases the porosity of loaves with 10 wt. % less water content.

[0139] FIG. 7 shows graphs of the results of granulometry analyses for cross-sections of bread loaves, made from a conventional ingredient composition (100% water) and an ingredient composition with 10 wt. % less water, subjected to different powers of ultrasound during leavening and baking versus a control which was not subjected to any ultrasound treatment. The results of the granulometry test show that the size distribution of pores is different between the control and sonicated loaves with 90% water. Additionally, the curve of the low water content sonicated loaf is very different to that of the non-sonicated loaf. The former informs of a more homogeneous distribution of pore sizes. This suggests that sonication is able to repair the effects of water deprivation on pore size distribution in a loaf to some extent.

EXAMPLE 3

[0140] This experiment shows the effect of ultrasound on the proofing and early baking steps of gluten-free loaves. The gluten-free ingredient composition was prepared according to a conventional recipe shown in Table 4.

TABLE-US-00004 TABLE 4 Gluten-free bread ingredient composition Ingredient Mass or volume Water 350 g Olive oil 17.5 ml Salt 11 g Sugar 15.4 g Gluten and wheat free white 400 g bread flour mix (Doves farm) Yeast 4.8 g

[0141] The loaves were baked using the machine's gluten-free program. This program lasts 174 minutes. The cycle begins with an 8 minute pre-heating period, after which the temperature is raised to about 40 C. The pre-heating period is followed by 4 minutes of light kneading and 19 minutes of intense kneading, again at a temperature of about 40 C. Kneading is succeeded by a 48 minute leavening (proof) at 40 C. After leavening, a 95 minute bake is carried out. The baking stage comprises raising the temperature to about 110 C. over the first 6 to 8 minutes of the bake and subsequently increasing the temperature to about 140 to 150 C. over the remaining 87 to 89 minutes.

[0142] For the purposes of the ultrasound application, the 48 minute leavening (proofing) step was split into four equal segments1, 2, 3 and 4and the ultrasound applied during different combinations of these segments optionally in combination with the first 10 minutes of the baking period. The various combinations of the application of ultrasound is shown in Table 5.

TABLE-US-00005 TABLE 5 Sonication duration and power for gluten-free ingredient composition Power/W 0 Control 100 200 300 Bread stage Proof Proof Proof Proof 1, 2, 3, 4 Bake 1, 2, 3, 4 Bake 1, 2, 3, 4 Bake 1, 2, 3, 4 Bake Loaf 0, 0, 0, 0 0 0, 0, 0, 12 10 0, 0, 0, 12 10 0, 0, 0, 12 10 0, 12, 12, 12 10 0, 12, 12, 12 10 0, 12, 12, 12 10 12, 12, 12, 12 0 12, 12, 12, 12 0 12, 12, 12, 12 0 0, 0, 0, 0 10 0, 0, 0, 0 10 0, 0, 0, 0 10

[0143] FIG. 8 shows graphs of the results of granulometry analyses for cross-sections of bread loaves, made from the gluten-free ingredient composition, subjected to the different durations and powers of ultrasound during shown in Table 5. The graphs show that as ultrasound duration increases, the fraction of the loaf made up of pores increases. This is apparent because the graphs of those loaves sonicated for longer, namely the 0, 12, 12, 12, 10 and 12, 12, 12, 12, 0 samples, are placed higher than those sonicated for less time. This is accompanied by an increase in pore size apparent because the density values for larger radii increase as ultrasound duration increases.

[0144] The granulometry test also shows that an ultrasound power of 200 watts yielded loaves with the greatest fraction of porosity and largest pores. Gluten-free ingredient compositions appear to respond to ultrasound in a similar manner to regular bread; 200 watts appears to be the optimal power for improving porosity. In addition, the longer period of ultrasound application, the better the results obtained.

EXAMPLE 4

[0145] This experiment shows the effect of ultrasound on the early baking of ingredient compositions having a chemical leavening agent. Instead of the bread ingredient compositions of Examples 1-3, a scone mixture having the ingredient composition shown in Table 6 was used.

[0146] The leavening agent is a composition comprising sodium bicarbonate and sodium acid pyrophosphate. Sodium bicarbonate generates carbon dioxide gas within the ingredient composition upon heating and by reaction with an acid source provided by the sodium acid pyrophosphate in the presence of water. No biological leavening agent, such as yeast, was present in the composition.

TABLE-US-00006 TABLE 6 Scone ingredient composition Ingredient Amount (wt. %) Wheat flour 55 Water 22 Sugar 8 Vegetable oil 6 Milk proteins 4 Leavening agents 3 Modified starch 1.5 Emulsifier <1

[0147] The scones were baked using the machine's cake program. This program lasts 60 minutes. The cycle begins with a 5 minute mixing period, followed by 10 minutes resting. This is succeeded by a 45 minute baking stage during which the temperature is raised to between 140 to 160 C. over the first 5 minutes of the bake. The temperature is then maintained within this range for the next 40 minutes.

[0148] The ingredient composition was subjected to ultrasound at a power of 300 W for the first 10 minutes of the baking step. A control scone of identical composition was prepared under the same bread maker program except no ultrasound was applied.

[0149] Both the volume and texture of the scone is significantly improved with the application of ultrasound at a power of 300 W for the first 10 minutes of the baking step. The sonicated scone presents a rounder outer shape. The non-sonicated scone presented zones of higher density when slicing the samples which lumped up on the 2-D plane.

[0150] FIG. 9 shows graphs of the cell count results for cross-sections of scones, made from a conventional ingredient composition having a chemical leavening agent, subjected to ultrasound during baking versus a control which was not subjected to an ultrasound treatment. The cell count is remarkably larger in the sonicated samples. This confirms that the sonicated samples have more pores. In practical terms, the sonicated scone is less collapsed and has a better formed structure of larger cells. A visual inspection of the sonicated scone confirms these results.

[0151] FIG. 10 shows graphs of the results of granulometry analyses for cross-sections of scones, made from a conventional ingredient composition having a chemical leavening agent, subjected to ultrasound during baking versus a control which was not subjected to any ultrasound treatment. As in the previous study, the granulometry analysis was performed on the same binary samples used for the cell count analysis. The distribution of relative density versus radius of opening (in pixels) for both the control sample (four different slices), and the sonicated sample (four different slices) are shown. The minimum radius of opening considered was 4 pixels, in agreement with the previous Examples on ingredient compositions for bread loaves comprising yeast as the biological leavening agent.

[0152] Average values for those two series were obtained. This allows a clearer comparison of both distributions of pore sizes, which can be seen in FIG. 10. The sonicated scone presents a distribution of pores with a larger relative density than that of the control scone. Consequently, the sonicated samples have larger pores which influences the texture of the scone. The scone has an increased height, as it expanded more and the structure is improved, compared to that of the non-sonicated samples. The sonicated scone also presents a larger density of smaller pores, when compared to the non-sonicated scone. This also indicates a less collapsed structure of pores, or more pores of a smaller size more noticeable to the eye and detected by the image analysis process. Therefore, chemical leavening ingredient compositions respond to ultrasound in a similar manner to those compositions presented in the previous Examples.

[0153] The person skilled in the art will understand that the present invention can be carried out in many various ways without departing from the scope of the appended claims.