WO2025212639A1 - Soy protein product and process of preparing the same - Google Patents

Abstract

The present disclosure relates to a soy protein product and a process for preparing the same. The process comprises the steps of providing a soy protein containing material; humidifying the soy protein containing material at a relative humidity and a humidifying temperature of less than 100°C to obtain a humidified material; and drying the humidified material to obtain the soy protein product. The soy protein product has content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product.

Description

SOY PROTEIN PRODUCT AND PROCESS OF PREPARING THE SAME

CROSS REFERENCE

[0001] This application claims the benefit of United States Provisional Application No. 63/572,963, filed April 2, 2024, which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

[0002] This invention relates to the field of plant protein products, in particular soy protein products.

BACKGROUND

[0003] Many ingredients refined from plants, such as plant proteins and plant fibers, have undesirable flavor characteristics due to the volatile and relatively small organic compounds bound to the surfaces. The perceived “off-flavor” often limits the application of such ingredients in making food products like meat substitute products, cheese substitutes, ready-to-eat cereals, nutrition bars, conventional processed meats, and confectionary coatings.

[0004] Many of these ingredients have been through prior aqueous, alkane, or aqueous alcohol processing steps followed by high temperature evaporation processes; however, such ingredients still retain these compounds with undesirable flavors. Proteins derived from plants are especially prone to this problem, but some relatively unrefined plant fibers and some animal-derived proteins experience off-flavors as well. Removal of these compounds results in an ingredient that is much less intensely flavored and thus more suitable for use in common foods.

[0005] Therefore, a plant protein product (e.g., soy protein product) having a reduced flavor intensity and an improved process for preparing such product are needed.

SUMMARY

[0006] The present disclosure provides a process for preparing a soy protein product comprising the steps of providing a soy protein containing material; humidifying the soy protein containing material at a relative humidity and a humidifying temperature of less than 100°C to obtain a humidified material; and drying the humidified material to obtain the soy protein product. The resulting soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

[0007] The present disclosure also provides a process for reducing volatile compound content of a soy protein product comprising the steps of humidifying a soy protein containing material at a relative humidity from 50 to 100% and a humidifying temperature of less than 100°C to obtain a humidified material; and drying the humidified material at a drying temperature from 50 to 90°C to obtain the soy protein product. The resulting soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

[0008] The present disclosure also provides a soy protein product having content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product.

BRIEF DESCRIPTION OF THE FIGURES

[0009] The drawings illustrate generally, by way of example, but not by way of limitation, various aspects discussed in the present document.

[0010] Figure 1 shows the overall flavor intensity of treated and untreated textured soy flour (TSF) samples. All test samples were prepared at a concentration of 3.0% but symbols have been moved slightly to improve visibility.

[0011] Figure 2 is a log-log plot (log2(treated/untreated) against loglO(treated)) that shows changes in concentrations of volatile compounds, as a function of initial concentration, in the samples that are humidified but not dried. Numbers in the upper left of each panel represent the treatment condition. Treatments 2 and 8 are replicates that are plotted together; treatment 2 is represented by the lighter symbols while treatment 8 is represented by the darker symbols. The top part of each panel shows that volatile compounds whose relative concentrations are increased because of the treatment, and the bottom part shows that concentrations of volatile compounds are decreased due to the treatment.

[0012] Figure 3 is a log-log plot (log2(treated/untreated) against loglO(treated)) that shows changes in concentrations of volatile compounds, as a function of initial concentration, in the samples that are humidified and dried. Numbers in the upper left of each panel represent the treatment condition. Treatments 2 and 8 are replicates that are plotted together; treatment 2 is represented by the lighter symbols while treatment 8 represented by is the darker symbols. The top part of each panel shows that volatile compounds whose relative concentrations are increased because of the treatment, and the bottom part shows that concentrations of volatile compounds are decreased due to the treatment.

[0013] Figure 4 is a log-log plot (log2(treated/untreated) against loglO(treated)) that shows changes in concentrations of volatile compounds, as a function of initial concentration, in the samples. Numbers in the upper left of each panel represent the treatment condition. Treatments 2 and 13 are replicates that are plotted together; treatment 2 is represented by the lighter symbols while treatment 8 is represented by the darker symbols. The top part of each panel shows that volatile compounds whose relative concentrations are increased because of the treatment, and the bottom part shows that concentrations of volatile compounds are decreased due to the treatment. [0014] Figure 5 shows the distribution of volatile compounds (in the calibration set) in untreated samples.

[0015] Figure 6 shows the distribution of volatile compounds (in the calibration set) in treated samples.

DETAILED DESCRIPTION

[0016] Reference will now be made in detail to certain aspects of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention belongs. As used herein, each of the following terms has the meaning associated with it as defined below.

[0018] Unless expressly stated, ppm (parts per million), percentage, and ratios are based on a dry weight basis. Percentage based on a dry weight basis is also referred to as wt% below.

[0019] The term "for example," "for instance," "such as," or "including" as used herein is meant to introduce examples that further clarify more general subject matter. Unless otherwise specified, these examples are provided only as an aid for understanding the applications illustrated in the present disclosure and are not meant to be limiting in any fashion.

[0020] As used herein, “room temperature” or “RT” refers to a temperature between 20°C to 25°C. [0021] In the processes described herein, the acts can be carried out in any order without departing from the principles of the disclosure, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0022] Described herein is a soy protein product and a process of preparing the soy protein product. The soy protein product has less flavor intensity and is suitable for use as a protein source for incorporation into foods for human and/or animal consumption.

Process for preparing a soy protein product

[0023] The present disclosure provides a process for preparing a soy protein product. The process comprises the steps of humidifying a soy protein containing material at a relative humidity and a humidifying temperature of less than 100°C to obtain a humidified material; and drying the humidified material to obtain the soy protein product. The resulting soy protein product has one or more improved attributes as compared to an equivalent untreated soy protein product; preferably, the one or more improved attributes may include, but may not be limited to, a reduced volatile compound content.

[0024] As described herein, an “equivalent untreated soy protein product” refers to an equivalent soy protein product that has not been subjected to any process of the instant invention as described in the present disclosure. An “equivalent soy protein product” refers to a soy protein product prepared from the same starting material used in the instant invention (e.g., a soy protein isolate from the same batch).

[0025] The soy protein containing material serves as a starting material to the process and may include, but may not be limited to, textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, or any combinations thereof. A soy protein isolate comprises a protein concentration of at least 90 wt% on a dry basis. A soy protein concentrate comprises a protein concentration between 65 and 90 wt% on a dry basis.

[0026] In one aspect, the soy protein containing material can have a protein concentration in a range from 10 to 90 wt% on a dry basis; preferably, the soy protein containing material can have a protein concentration of at least 50 wt% on a dry basis.

[0027] In the humidifying step, the soy protein containing material can be exposed to an atmosphere comprising, preferably a high relative humidity, more preferably a high relative humidity and a high humidifying temperature, to liberate and remove a substantial fraction of compounds (e.g., organic compounds, volatile compounds), which are responsible for causing flavor perceptions. The removed compounds may include, but may not be limited to, organic compounds, volatile compounds, or any combinations thereof. Preferably, moisture content of the resulting humidified material is not increased by the humidifying step.

[0028] In one aspect, the humidifying step at high relative humidity is more effective at elevated humidifying temperatures, but the humidifying temperature is not desirably to exceed 100°C. Preferably, steam is not to be used in the humidifying step to avoid degradation of the starting material.

[0029] Preferably, the atmosphere contacting the soy protein containing material should be exchanged so that the liberated compounds can be swept away, but air velocity should be kept low enough to prevent the soy protein containing material itself from being swept away. In other words, the air velocity should be maintained low enough to only remove the liberated compounds but not the soy protein containing material itself.

[0030] The relative humidity at the humidifying step can be 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100%. In one aspect, the relative humidity can be at least 50% or at most 100%. Examples of the relative humidity may include, but may not be limited to, a range from 50 to 100%, from 60 to 100%, from 60 to 99%, from 60 to 90%, from 60 to 80%, from 70 to 100%, from 70 to 99%, from 70 to 90%, or from 75 to 100%.

[0031] The humidifying temperature at the humidifying step can be 55°C, 60°C, 70°C, 80°C, 90°C, or 95°C. In one aspect, the humidifying temperature can be at least 55°C or at most 95°C. Examples of the humidifying temperature may include, but may not be limited to, a range from 55 to 95°C, from 55 to 90°C, from 60 to 95°C, from 60 to 90°C, from 70 to 95 °C, from 70 to 90°C, from 70 to 85°C, or from 70 to 80°C.

[0032] In one aspect, the humidifying step is carried out by passing humidified or warmed air to deliver water to the soy protein containing material over one or more static beds, or one or more fluid beds. A fluid bed system that can improve air-particle contact and mass transfer may be desired. Preferably, water is uniformly delivered and distributed over the soy protein containing material; more preferably, water is delivered in a form of a vapor; even more preferably, water delivered is not in a form of liquid water or not in a form of steam.

[0033] The humidifying period for humidifying the soy protein containing material is a function of humidifying temperature, relative humidity, surface area of the starting material, particle size of the starting material, or any combinations thereof. In one aspect, the humidifying period can be 10 minutes, 15 minutes, 30 minutes, 45 minutes, 60 minutes, 75 minutes, or 90 minutes. For example, the humidifying period can be in a range from 10 to 90 minutes, from 15 to 75 minutes, or from 30 to 60 minutes. In one aspect, the humidifying period can be at most 90 minutes.

[0034] The humidified material can be de-humidified in the drying step to obtain the final soy protein product. The drying step can be carried out at a drying temperature for a drying period to obtain the soy protein product. If excess moisture is absorbed by the humidified material, gentle drying can remove the excess moisture and restore and/or establish the desired moisture content in the soy protein product.

[0035] The drying temperature can be less than 100°C and can be 50°C, 55°C, 60°C, 70°C, 75°C, 85°C, or 90°C. In one aspect, the drying temperature can be at least 50°C or at most 90°C. Examples of the drying temperature may include, but may not be limited to, a range from 50 to 90°C, from 50 to 85°C, from 60 to 90°C, from 60 to 85°C, from 70 to 95°C, from 70 to 90°C, or from 70 to 85°C.

[0036] The drying period can be 5 minutes, 8 minutes, 10 minutes, 15 minutes, 20 minutes, or 25 minutes. For example, the drying period can be in a range from 5 to 25 minutes, from 8 to 20 minutes, from 10 to 15 minutes. In one aspect, the drying period can be at least 5 minutes. In another aspect, the drying period can be at most 25 minutes.

[0037] The relative humidity at the drying step can be 0%, from 0 to 0.5%, from 0.5% to 1%, or at least 1%. [0038] In one aspect, each of the humidifying step and the drying step can be performed for one or more than one time, preferably for at least two times, more preferably for two times. Preferably, the humidifying step and the drying step can be carried out as a cycle and the cycle can be performed for one or more than one time, preferably for at least two times, more preferably for two times.

[0039] The soy protein product obtained from the process as described above has content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product. Preferably, the content of one or more volatile compounds in the soy protein product can be reduced by at least 1%, at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, at least 95%, or at least 98% as compared to an equivalent untreated soy protein product. More preferably, the soy protein product has content of one or more volatile compounds reduced by 100% as compared to an equivalent untreated soy protein product.

[0040] Preferably, the content of one or more volatile compounds in the soy protein product can be reduced by a range from 20 to 100%, more preferably from 55 to 100%, or even more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

Process for reducing volatile compound content of a soy protein product

[0041] The present disclosure provides a process for reducing volatile compound content of a soy protein product. Preferably, off-notes of the soy protein product are reduced by the process of the instant invention.

[0042] As described herein, an “off-note”, “off-taste”, or “off-flavor” is an undesirable and/or unwanted flavor (e.g., taste, odor) present in food products. An “off-note” can be originated from raw materials and/or derived from chemical changes during food processing and storage. Examples of compounds generating “off-note” may include, but may not be limited to, aldehydes, ketones, alcohols, carboxylic acids, sulfur-containing compounds, heterocyclic compounds, or other small volatile compounds.

[0043] The process comprises a step of humidifying a soy protein containing material at a relative humidity from 50 to 100% and a humidifying temperature of less than 100°C to obtain a humidified material. The humidified material is then dried at a drying temperature from 50 to 90°C to obtain the soy protein product. The resulting soy protein product has content of one or more volatile compounds reduced by at least 1%, at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, at least 95%, or at least 98% as compared to an equivalent untreated soy protein product. Preferably, the resulting soy protein product has content of one or more volatile compounds reduced by 100% as compared to an equivalent untreated soy protein product; in other words, the resulting soy protein product can be completely free of one or more volatile compounds.

[0044] Preferably, the soy protein product has content of one or more volatile compounds reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

[0045] The soy protein containing material may include, but may not be limited to, textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, or any combinations thereof. A soy protein isolate comprises a protein concentration of at least 90 wt% on a dry basis. A soy protein concentrate comprises a protein concentration between 65 and 90 wt% on a dry basis.

[0046] In one aspect, the soy plant protein containing material can have a protein content in a range from 10 to 90 wt% on a dry basis; preferably, the soy plant protein containing material can have a protein concentration of at least 50 wt% on a dry basis.

[0047] During the humidifying step, the soy protein containing material is humidified at a relative humidity in a range from 50 to 100%, from 60 to 99%, or from 70 to 99%, and at a humidifying temperature in a range from 55 to 95°C, from 60 to 95°C, or from 70 to 95°C. The soy protein containing material is humidified for a humidifying period in a range from 10 to 90 minutes, from 15 to 75 minutes, or from 30 to 60 minutes.

[0048] The humidified material is dried at a drying temperature in a range from 50 to 90°C, from 60 to 90°C, or from 70 to 90°C, for a drying period in a range from 5 to 25 minutes, from 8 to 20 minutes, or from 10 to 15 minutes to obtain the soy protein product.

[0049] In one aspect, each of the humidifying step and the drying step can be performed for one or more than one time, preferably for at least two times, more preferably for two times. Preferably, the humidifying step and the drying step can be carried out as a cycle and the cycle can be performed for one or more than one time, preferably for at least two times, more preferably for two times.

[0050] In one aspect, no purification step may be required to separate fibers out from the soy protein containing material before the material is fed to the process. In another aspect, no enzymatic step may be required in any process of the instant invention described in the present disclosure.

[0051] In another aspect, no alcohol washing step may be required in any process of the instant invention described in the present disclosure.

Soy protein product [0052] The soy protein product of the present invention has content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product. Thus, the soy protein product may have one or more off-notes partially or completely removed. In other words, the content of one or more volatile compounds in the soy protein product described in this disclosure is reduced, preferably completely eliminated, as compared to an equivalent untreated soy protein product. Volatile compounds are substances present in a soy protein product that may impart a flavor (e.g., an earthy flavor, a savory flavor, a meaty flavor, a brothy flavor, a grainy flavor, a cereal flavor, a malty flavor, a toasted flavor, a beany flavor, a green flavor, or any combinations thereof) to the product. Examples of the volatile compounds may include, but may not be limited to, furan, pyran, organic acid, aldehyde, alcohol, ketone, pyrazine, lactone, thiol, sulfide, or any combinations thereof.

[0053] Preferably, the volatile compounds may include, but may not be limited to, hexanal, heptanal, 2-heptenal, 2-pentyl-furan, benzaldehyde, l-octen-3-ol, octanal, 2-ethyl-l -hexanol, 4- ethyl-benzaledhyde, 2-pentyl-furan, 2-heptanone, or any combinations thereof.

[0054] In one aspect, the soy protein product of the present invention has content of one or more volatile compounds reduced by at least 1%, at least 5%, at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, at least 95%, or at least 98% as compared to an equivalent untreated soy protein product. Preferably, the soy protein product has content of one or more volatile compounds reduced by 100% as compared to an equivalent untreated soy protein product.

[0055] Preferably, the content of one or more volatile compounds in the soy protein product can be reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

[0056] Preferably, the soy protein product of the present invention may be prepared by any process described in the present disclosure.

[0057] In one aspect, attributes other than the volatile compound content of the soy protein product prepared by any process of the instant invention described in the present disclosure may be improved as compared to an equivalent untreated soy protein product.

Examples

[0058] The invention is further described in detail by reference to the following experimental examples. These examples are provided for purposes of illustration only and are not intended to be limiting unless otherwise specified. Thus, the invention should in no way be construed as being limited to the following examples, but rather should be construed to encompass any and all variations which become evident as a result of the teaching provided herein. Example 1

1.1. Materials and Method

[0059] Approximately 5g samples of textured soy flour (TSF) (Cargill Incorporated) was weighed and placed in shallow aluminum weigh boats. Then, the samples were treated by a humidifying step and a drying step. Boats were placed in an Unox combi oven set for the humidification conditions described in Table 1. Six samples were prepared for each humidification treatment condition (“treatment condition”). At the end of the humidification phase, three samples were removed, exactly weighed, transferred to vials and frozen. The remaining three samples were heated in the oven for 12 minutes at 70°C and 0% relative humidity to remove water. After the drying step, the treated samples were exactly weighed, placed in vials and frozen until analysis.

[0060] Initial moisture content was estimated using quadruplicate measurements with a moisture balance.

Table 1

[0061] For sensory analysis, single samples of about 40g TSF were placed in larger aluminum pans and exposed to the same treatment conditions described in Table 1. At the end of the humidification phase, samples were transferred to mylar bags and frozen without any drying treatment.

[0062] A reference curve was created by suspending untreated material at a ratio of 5g material with 95g water and allowing the suspension to steep at room temperature for about 10 minutes. The solution was centrifuged and the supernatant was pulled through a 0.2-micron polyethersulfone (PES) membrane in a sterile vessel. Similar solutions were also prepared at concentrations of 0.25, 0.5, 0.75, 1.0, 3.0, and 5.0%. These samples were tasted blindly and independently by a trained panel (6 people) who were asked to place the reference standards on a line scale. The panel did not specifically know what the standards represented. The panel leader then reviewed the data of the composite samples for panel agreement of sample intensity rank order and the software assigned numerical values of 0 to 100. Panelists that were deemed outliers were removed and an average of their numerical values was taken for the remaining panelists. Those average values became the scale values of 0 to 100 for the reference standards and were anchored on the line accordingly for the remainder of the tests.

[0063] They were then presented with the treated and untreated materials at 3.0% concentration and asked to place each of the samples on the line scale using the standards which were already anchored on the line based on the initial values from the establishment testing. This resulted in an intensity measurement that is an overall flavor intensity value. The response curve (Figure 1) can be used to compute an equivalent concentration (by rearrangement of the regression equation) that reflects the degree of dilution of the untreated material required to match intensity. Because of the non-linear response of intensity to concentration, the apparent concentration may decrease disproportionately compared to the direct intensity.

1.2. Results and Discussion

1.2,1 Moisture Gain

[0064] The moisture after the humidification was a function of the humidifying temperature, relative humidity (RH), and humidification period(overall analysis of variance using backward elimination in a 2-factor interaction analysis, p<0.0001).

Table 2

[0065] As observed in in Table 2, which shows the mean moisture (%) before and after humidifying, there was a significant difference in moisture after the humidifying step. Subsequent analyses were adjusted to a moisture-free basis using the observed moistures for individual samples.

1.2,2 Sensory Analysis

[0066] The panel successfully placed blind references at the appropriate flavor intensity relative to the established scale. Table 3 below shows the relationship between treatment conditions, perceived flavor intensity, and equivalent concentration of treated solutions of TSF. Some treatments had a significant effect on the overall flavor intensity values (in a scale of 0 to 100 - with 0 being the least intense and 100 being the most intense) measured by the sensory panel. For example, treatment conditions 2, 5, and 8 all achieved a decrease in flavor intensity equivalent to a 60% dilution of the untreated sample.

Table 3

1.2,3 Untargeted GC/MS Analysis [0067] General effects of treatments on volatile compounds in the samples can be detected using untargeted GC/MS methods. For example, general changes to the population of volatile compounds can be detected by the untargeted GC/MS methods. Such volatile compounds may be responsible for carrying flavors (e.g., off-note flavors). This approach is based on the fingerprinting of volatile compounds via gas chromatography (GC) and mass spectrometric (MS) identification. The overall purpose is to look at the volatile composition of the various samples and compare the different experimental treatments to look for differences and patterns.

[0068] Though untargeted GC/MS does not provide exact quantitative data, it does provide relative comparative potential. Every compound identified has an associated area count, which is the mass abundance of the fragment ions from the compounds, which can be a relative proxy for concentration. Since different compounds have different sensitivities, one compound cannot be compared to another, but one compound can be compared to itself provided a similar mass fragmentation process was conducted across the samples. Even in this case, the responsiveness may not be perfectly linear, but it is approximately linear.

[0069] Principal Component Analysis (PCA) was performed on both pre-drying and post-drying samples in order to investigate the impact of treatment conditions on the concentration of unidentified compounds. The results showed that the high temperature and high humidity treatment caused the samples to be distinctly different from the other treatment conditions, leading to a different fingerprint of volatile compounds. Further analysis revealed that a larger number of volatiles that were decreased in relative concentration caused the high temperature and high humidity samples to cluster differently.

[0070] Figure 2 shows the effect of humidification alone (before drying) on the profile of volatile compounds, in which compounds that showed less than 2-fold change were excluded from the visualization. Clearly, different treatment conditions had significant effects on the changes in concentrations. For example, treatments conditions 1 and 5 showed a much greater depletion than increase, while treatment condition 6 involved more increase than depletion. In most cases, the volatile compounds increasing in concentration tended to have initially low concentrations. The same visualization after drying looks very similar (Figure 3).

[0071] The effects of treatment conditions can be illustrated by the number of volatile compounds were increased or decreased by at least 2-fold (Table 4). In six of the ten treatments, more volatile compounds decreased in concentration than increased whether before or after drying, but in three of the treatments more compounds increased than decreased.

Table 4

[0072] Overall, the untargeted analysis showed that TSF responded to different treatment conditions quite differently. Under some conditions hundreds of compounds decreased in concentration along with increases in a couple of dozen. Other treatments seemed to increase concentrations of more volatile compounds than were decreased. Most of the changes in concentration were driven by humidification (and presumably moisture uptake by the material), with subsequent drying being a relatively minor influence.

1.2,4 Targeted GC/FID Analysis

[0073] Treated and untreated samples collected before and after drying were analyzed for about 30 analytes using a calibrated GC/FID method. Not all compounds in the calibration set appear in the samples.

[0074] A study on the distribution of calibrated compounds in the untreated samples shows that about 83% of the mass of these compounds are associated with hexanal, 2-pentyl furan, and benzaldehyde. The overall flavor intensity observed in Table 3 may correlate to one or more of the above compounds. Some of the flavor intensity may arise from compounds that are not part of the standard set. In any event, it may be important to understand that overall flavor intensity may be dominated by a subset of the compounds present and analyzed and include influences from compounds that were present but not analyzed.

[0075] Modeling of the effect of treatment conditions resulted in significant relationships for many of the compounds detected. Concentrations of most compounds responded to humidification conditions; 2-ethyl-6-pyrazine, 2,4-nonadienal, and o-tolualdehyde were exceptions. Before drying, concentrations of most compounds were sensitive to humidifying temperature alone, but drying eliminated most of that main effect sensitivity. Before and after drying, there were strong interactions between humidifying temperature and relative humidity. Time of treatments (i.e., humidifying period) was apparently less significant in these samples.

[0076] A study on the response of the concentrations of volatile compounds to humidifying temperature and relative humidity showed that high humidity generally decreased concentrations relative to the untreated material. In those cases where there was apparent increased concentration at high temperature and low humidity, that effect was increased by drying.

[0077] Table 5 summarizes the effect of different treatment conditions on the number of compounds that have changed significantly in concentration. Columns 1 to 3 represent number of compounds having significant changes in concentration between untreated samples and humidified-only samples, between untreated samples and humidified and dried samples, and between humidified-only samples and humidified and dried samples, respectively. For each treatment condition, the number represents the number of compounds (out of 21) that showed a significant difference in concentration between the treated materials and the untreated material (assuming no variation in the untreated sample). For example, treatment condition 5 was associated with a significant change in eighteen and nineteen compounds. In contrast, treatment condition 1 caused changes in only five and fourteen compounds. A comparison of the effect of drying showed that in seven of ten cases, the concentrations of compounds were not significantly changed by drying; in treatment condition 6, the majority of compounds were significantly different before and after drying.

Table 5

1.2.5 Conclusion

[0078] The following observations can be drawn from the above studies:

[0079] - The overall flavor intensity of TSF can be decreased by treatments that combine humidification and drying. The largest effects were observed at high relative humidity and high humidifying temperature.

[0080] - A decrease in flavor intensity was associated with an increase in water absorption during hydration.

[0081] - The absolute concentrations of many volatile compounds changed in response to relative humidity and humidifying temperature. In general, high relative humidity was associated with decreases in concentration. In the presence of high relative humidity, high humidifying temperature promoted decreasing concentrations. At low relative humidity, high humidifying temperature may promote increases in concentration.

Example 2

2.1 Materials and Method

[0082] Materials being treated by a humidifying step and a drying step in this study are summarized in Table 6.

Table 6

[0083] About 5g of material was weighed into a pre-weighed aluminum weighing dish. Triplicate samples were placed in a Combi-oven for 60 minutes at 40°C or 90°C and 100% relative humidity (humidified samples). A matching set of samples was prepared (reference samples), and both the humidified samples and reference samples were placed in the Combi-oven for 20 minutes at 80°C and 0% relative humidity to obtain treated samples and dried-only samples, respectively. One untreated sample, three treated samples, and three dried-only samples were placed in gas-tight vials and stored in the dark at room temperature until analysis. 2.2 Results and Discussion

[0084] Humidification treatment at 90°C and 100% relative humidity caused a large fraction of the observed peaks to decrease by 2-fold of greater as measured by untargeted GC/MS method. This effect was not visible at lower temperature in this time frame (60 minutes). Tables 7 and 8 below show the number of compounds that were increased or decreased at least 2-fold in concentration by humidification and drying or drying alone (with a<0.05). Column “Total” refers to the total number of compounds detected in the untreated samples. H&D indicates humidified and dried treatment (i.e., treated samples). OD indicates dried only treatment (i.e., dried-only samples).

Table 7

Table 8

Example 3

3.1 Materials and Method

[0085] Approximately 5g samples of soy protein isolate (SPI) (Cargill Incorporated) were weighed and placed in shallow aluminum weigh boats. Then, the samples were treated by a humidifying step and a drying step. Boats were placed in an Cheftop combi oven set for the humidification conditions described in Table 9. The samples were heated in the oven for 20 minutes at 75°C and 0% relative humidity to remove water. After the drying step, the treated samples were exactly weighed, placed in vials and frozen until analysis.

Table 9

3.2 Results and Discussion

3,2,1 Untargeted GC/MS analysis

[0086] General effects of treatments on volatile compounds can be detected using untargeted GC/MS methods. For example, general changes to the population of volatile compounds can be detected by the untargeted GC/MS methods. Such volatile compounds may be responsible for carrying flavors (e.g., off-note flavors). This approach is based on the fingerprinting of volatile compounds via gas chromatography (GC) and mass spectrometric (MS) identification. The overall purpose is to look at the volatile composition of the various samples and compare the different experimental treatments to look for differences and patterns.

[0087] Though untargeted GC/MS does not provide exact quantitative data, it does provide relative comparative potential. Every compound identified has an associated area count, which is the mass abundance of the fragment ions from the compounds, which can be a relative proxy for concentration. Since different compounds have different sensitivities, one compound cannot be compared to another, but one compound can be compared to itself provided a similar mass fragmentation process was conducted across the samples. Even in this case, the responsiveness may not be perfectly linear, but it is approximately linear.

[0088] Principal Component Analysis (PCA) was performed on both pre-drying and post-drying samples in order to investigate the impact of treatment conditions on the concentration of unidentified compounds. The results showed that the high temperature and high humidity treatment caused the samples to be distinctly different from the other treatment conditions, leading to a different fingerprint of volatile compounds. Further analysis revealed that a larger number of volatiles that were decreased in relative concentration caused the high temperature and high humidity samples to cluster differently.

[0089] Figure 4 shows the effect of treatment on the profile of volatile compounds, in which compounds that showed less than 2-fold change were excluded from the visualization. A total of about 587 compounds were identified in the samples. Generally, many more compounds were decreased in concentration than increased. Increased concentrations were more likely to arise from compounds that were in low concentration in the untreated sample. As observed, treatments 7 and 10 seem to affect more compounds than treatments 1 and 12.

[0090] One further way to understand the effect of treatment is to count the number of volatile compounds that show two-fold concentration decreases (down) or increases (up). Table 10 shows how most treatment conditions favor decreasing concentrations.

Table 10

3,2.2 Targeted GC/FID analysis

[0091] Samples of treated and untreated samples were analyzed for about 25 analytes using a calibrated GC/FID method. Not all compounds in the calibration set appear in the samples. Figure 5 shows the distribution of calibrated compounds in the untreated samples. About 98% of the mass of these compounds are associated with hexanal, 2-pentyl furan, benzaldehyde, and 2-heptanone. Because different compounds have quite different flavor and aroma potencies, this does not mean that the sensory experience depends on just these compounds. An integrated flavor perception might be more dependent on the combination and concentrations of compounds than concentration of any single compound. In any event, it may be important to understand that overall chemical response may be dominated by a subset of the compounds present and analyzed.

[0092] The treatment process drastically reduces volatile compounds and can change the overall composition of these individual volatile compounds. Figure 6 shows the SPI volatile composition (of tracked compounds) after humidifying at 90°C at 100% RH for 90 minutes. The dominance of hexanal in the composition has diminished and other minor compounds are more resistant to removal and have increased comparatively, such as benzaldehyde and octanal. Table 11 shows the percentage reduction of major volatile compounds after treatment as compared to the untreated samples. For the treatment producing Figure 6, hexanal was removed at 97.2%, while benzaldehyde and octanal were removed at 53.9% and 42.2%, respectively.

[0093] The “All Peaks” column refers to the sum of all detected volatile species in the sample, both calibrated and uncalibrated. This is indicative of the total volatile composition change, regardless of individual compounds decreasing or increasing at a given processing condition.

Table 11

[0094] Table 12 shows the simple correlation coefficients between the humidifying temperature, relative humidity (RH), and humidifying period and the observed concentrations of compounds after the treatment. “All peaks” is a sum of all peaks detected, both calibrated and not, including the entire volatile composition of the sample. Correlations show that relative humidity has the largest impact on reduction in volatile species. Effects of both humidifying temperature and humidifying period are more dependent on the relative humidity of the treatment. For example, higher humidifying temperature, lower relative humidity conditions tended to increase certain volatile concentrations, while high humidifying temperature, high relative humidity conditions were the best at reducing volatile concentrations.

Table 12

3,2,3 Conclusion

[0095] The following observations can be drawn from the above studies:

[0096] - A large number of volatile compounds decreased in concentration as indicated by untargeted GC/MS. A relatively small number of compounds increased in concentration.

[0097] - The changes in concentration found in untargeted analyses were dominated by the change in concentration of the more prominent compounds.

[0098] - Most volatile compounds tracked in quantitative analysis showed sensitivity to conditions during humidification. Generally, high humidity favored decreased concentrations after treatment.

[0099] - The highest degree of removal of most volatile compounds was under high relative humidity and high humidifying temperature conditions.

[0100] - Some volatile compound concentrations were increased under high humidifying temperature, low relative humidity conditions.

Clauses describing the invention

[0101] Clause 1. A process for preparing a soy protein product, comprising the steps of: a. providing a soy protein containing material; b. humidifying the soy protein containing material at a relative humidity and a humidifying temperature of less than 100°C to obtain a humidified material; and c. drying the humidified material to obtain the soy protein product; wherein the soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product. [0102] Clause 2. The process of clause 1, wherein the soy protein containing material is selected from the group consisting of textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, and any combinations thereof.

[0103] Clause 3. The process of any of the preceding clauses, wherein the relative humidity in the humidifying step is in a range from 50 to 100%.

[0104] Clause 4. The process of any of the preceding clauses, wherein the humidifying temperature is in a range from 55 to 95°C.

[0105] Clause 5. The process of any of the preceding clauses, wherein the humidifying temperature is less than 100°C.

[0106] Clause 6. The process of any of the preceding clauses, wherein the soy protein containing material is humidified for a humidifying period in a range from 10 to 90 minutes, from 15 to 75 minutes, or 30 to 60 minutes.

[0107] Clause 7. The process of any of the preceding clauses, wherein in the humidifying step, the relative humidity is in a range from 60 to 100%, the humidifying temperature is in a range from 60 to 90°C; and the humidifying period is in a range from 30 to 90 minutes.

[0108] Clause 8. The process of any of the preceding clauses, wherein water is uniformly delivered and distributed over the soy protein containing material in the humidifying step.

[0109] Clause 9. The process of any of the preceding clauses, water delivered in the humidifying step is in a form of a liquid water or a vapor.

[0110] Clause 10. The process of any of the preceding clauses, water delivered in the humidifying step is not in a form of steam.

[OHl] Clause 11. The process of any of the preceding clauses, wherein the humidified material is dried at a drying temperature in a range from 50 to 90°C.

[0112] Clause 12. The process of any of the preceding clauses, wherein the humidified material is dried for a drying period in a range from 5 to 25 minutes, from 8 to 20 minutes, or from 10 to 15 minutes.

[0113] Clause 13. The process of any of the preceding clauses, wherein each of the humidifying step and the drying step is performed for one or more than one time, preferably for at least two times, more preferably for two times.

[0114] Clause 14. A process for reducing volatile compound content of a soy protein product, comprising the steps of: a. humidifying a soy protein containing material at a relative humidity from 50 to 100% and a humidifying temperature of less than 100°C to obtain a humidified material; and b. drying the humidified material at a drying temperature from 50 to 90°C to obtain the soy protein product; wherein the soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

[0115] Clause 15. A process for reducing volatile compound content of a soy protein product, consisting of the steps of: a. humidifying a soy protein containing material at a relative humidity from 50 to 100% and a humidifying temperature of less than 100°C to obtain a humidified material; and b. drying the humidified material at a drying temperature from 50 to 90°C to obtain the soy protein product; wherein the soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

[0116] Clause 16. The process of any of clauses 14 to 15, wherein the soy protein containing material is selected from the group consisting of textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, and any combinations thereof.

[0117] Clause 17. The process of any of clauses 14 to 16, wherein the humidifying step is performed at a humidifying temperature in a range from 55 to 95°C.

[0118] Clause 18. The process of any of the clauses 14 to 17, wherein the soy protein containing material is humidified for a humidifying period in a range from 10 to 90 minutes, from 15 to 75 minutes, or 30 to 60 minutes.

[0119] Clause 19. The process of any of the clauses 14 to 18, wherein in the humidifying step, the relative humidity is in a range from 60 to 100%, the humidifying temperature is in a range from 60 to 90°C; and the humidifying period is in a range from 30 to 90 minutes.

[0120] Clause 20. The process of any of clauses 14 to 19, wherein water is uniformly delivered and distributed over the soy protein containing material in the humidifying step.

[0121] Clause 21. The process of any of clauses 14 to 20, water delivered in the humidifying step is in a form of a liquid water or a vapor.

[0122] Clause 22. The process of any of clauses 14 to 21, water delivered in the humidifying step is not in a form of steam.

[0123] Clause 23. The process of any of clauses 14 to 22, wherein the humidified material is dried at a drying temperature in a range from 50 to 90°C.

[0124] Clause 24. The process of any of clauses 14 to 23, wherein the humidified material is dried for a drying period in a range from 5 to 25 minutes, from 8 to 20 minutes, or from 10 to 15 minutes. [0125] Clause 25. The process of any of clauses 14 to 24, wherein each of the humidifying step and the drying step is performed for one or more than one time, preferably for at least two times, more preferably for two times. [0126] Clause 26. The process of any of the preceding clauses, wherein the soy protein product has content of one or more volatile compounds reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

[0127] Clause 27. A soy protein product prepared by the process of any of the preceding clauses. [0128] Clause 28. A soy protein product having content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product.

[0129] Clause 29. The soy protein product of any of clauses 27 to 28, having content of one or more volatile compounds reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

[0130] Clause 30. The soy protein product of any of clauses 27 to 29, wherein the one or more volatile compounds are selected from the group consisting of aldehyde, furan, and alcohol.

[0131] Clause 31. The soy protein product of any of clauses 27 to 30, wherein the one or more volatile compounds are selected from the group consisting of hexanal, heptanal, 2-heptenal, 2- pentyl-furan, benzaldehyde, l-octen-3-ol, octanal, 2-ethyl-l-hexanol, 4-ethyl-benzaledhyde, 2- pentyl-furan, 2-heptanone, and any combinations thereof.

[0132] Clause 32. The soy protein product of any of clauses 27 to 31, wherein the one or more volatile compounds are selected from the group consisting of hexanal, heptanal, benzaldehyde, octanal, 2-pentyl-furan, 2-heptanone, and any combinations thereof.

[0133] Clause 33. The soy protein product of any of clauses 27 to 32, having content of hexanal reduced by a range from 70 to 99%, preferably from 80 to 99%, more preferably from 90 to 99%, as compared to an equivalent untreated soy protein product.

[0134] Clause 34. The soy protein product of any of clauses 27 to 33, having content of hexanal reduced by at least 90%, preferably at least 94%, or more preferably at least 97%, as compared to an equivalent untreated soy protein product.

[0135] Clause 35. The soy protein product of any of clauses 27 to 34, having content of heptanal reduced by a range from 30 to 75%, preferably from 40 to 75%, more preferably from 45 to 75%, as compared to an equivalent untreated soy protein product.

[0136] Clause 36. The soy protein product of any of clauses 27 to 35, having content of heptanal reduced by at least 45%, preferably at least 50%, or more preferably at least 70%, as compared to an equivalent untreated soy protein product.

[0137] Clause 37. The soy protein product of any of clauses 27 to 36, having content of benzaldehyde reduced by a range from 25 to 55%, preferably from 30 to 55%, more preferably from 45 to 55%, as compared to an equivalent untreated soy protein product. [0138] Clause 38. The soy protein product of any of clauses 27 to 37, having content of benzaldehyde reduced by at least 40%, preferably at least 45%, or more preferably at least 50%, as compared to an equivalent untreated soy protein product.

[0139] Clause 39. The soy protein product of any of clauses 27 to 38, having content of octanal reduced by a range from 20 to 45%, preferably from 30 to 45%, more preferably from 40 to 45%, as compared to an equivalent untreated soy protein product.

[0140] Clause 40. The soy protein product of any of clauses 27 to 39, having content of octanal reduced by at least 30%, preferably at least 35%, or more preferably at least 40%, as compared to an equivalent untreated soy protein product.

[0141] Clause 41. The soy protein product of any of clauses 27 to 40, having content of 2-pentyl- furan reduced by a range from 40 to 95%, preferably from 60 to 95%, more preferably from 75 to 95%, as compared to an equivalent untreated soy protein product.

[0142] Clause 42. The soy protein product of any of clauses 27 to 41, having content of 2-pentyl- furan reduced by at least 75%, preferably at least 80%, or more preferably at least 90%, as compared to an equivalent untreated soy protein product.

[0143] Clause 43. The soy protein product of any of clauses 27 to 42, having content of 2- heptanone reduced by a range from 70 to 99%, preferably from 80 to 99%, more preferably from 90 to 99%, as compared to an equivalent untreated soy protein product.

[0144] Clause 44. The soy protein product of any of clauses 27 to 43, having content of 2-pentyl- furan reduced by at least 90%, preferably at least 94%, or more preferably at least 96%, as compared to an equivalent untreated soy protein product.

Claims

CLAIMS What is claimed is:

1. A process for preparing a soy protein product, comprising the steps of: a. providing a soy protein containing material; b. humidifying the soy protein containing material at a relative humidity and a humidifying temperature of less than 100°C to obtain a humidified material; and c. drying the humidified material to obtain the soy protein product; wherein the soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

2. The process of claim 1, wherein the soy protein containing material is selected from the group consisting of textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, and any combinations thereof.

3. The process of any of the preceding claims, wherein the relative humidity in the humidifying step is in a range from 50 to 100%.

4. The process of any of the preceding claims, wherein the humidifying temperature is in a range from 55 to 95°C.

5. The process of any of the preceding claims, wherein the soy protein containing material is humidified for a humidifying period in a range from 10 to 90 minutes, from 15 to 75 minutes, or 30 to 60 minutes.

6. The process of any of the preceding claims, wherein the humidified material is dried at a drying temperature in a range from 50 to 90°C.

7. The process of any of the preceding claims, wherein the humidified material is dried for a drying period in a range from 5 to 25 minutes, from 8 to 20 minutes, or from 10 to 15 minutes.

8. The process of any of the preceding claims, wherein each of the humidifying step and the drying step is performed for one or more than one time, preferably for at least two times, more preferably for two times.

9. A process for reducing volatile compound content of a soy protein product, comprising the steps of: a. humidifying a soy protein containing material at a relative humidity from 50 to 100% and a humidifying temperature of less than 100°C to obtain a humidified material; and b. drying the humidified material at a drying temperature from 50 to 90°C to obtain the soy protein product; wherein the soy protein product has a reduced volatile compound content as compared to an equivalent untreated soy protein product.

10. The process of claim 9, wherein the soy protein containing material is selected from the group consisting of textured soy flour, textured soy protein concentrate, soy protein isolate, soy protein concentrate, and any combinations thereof.

11. The process of any of claims 9 to 10, wherein the humidifying step is performed at a humidifying temperature in a range from 55 to 95°C.

12. The process of any of claims 9 to 11, wherein the soy protein product has content of one or more volatile compounds reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

13. The process of any of claims 9 to 12, wherein each of the humidifying step and the drying step is performed for one or more than one time, preferably for at least two times, more preferably for two times.

14. A soy protein product prepared by the process of any of the preceding claims.

15. A soy protein product having content of one or more volatile compounds reduced as compared to an equivalent untreated soy protein product.

16. The soy protein product of any of claims 14 to 15, having content of one or more volatile compounds reduced by a range from 20 to 100%, preferably from 55 to 100%, more preferably from 70 to 100%, as compared to an equivalent untreated soy protein product.

17. The soy protein product of any of claims 14 to 16, wherein the one or more volatile compounds are selected from the group consisting of aldehyde, furan, and alcohol.

18. The soy protein product of any of claims 14 to 17, wherein the one or more volatile compounds are selected from the group consisting of hexanal, heptanal, 2-heptenal, 2- pentyl-furan, benzaldehyde, l-octen-3-ol, octanal, 2-ethyl-l -hexanol, 4-ethyl-benzaledhyde, 2-pentyl-furan, 2-heptanone, and any combinations thereof.