阅读说明：本技术 降低糖羰基物水溶液中的甲醛的浓度的方法 (Method for reducing the concentration of formaldehyde in aqueous solutions of sugar carbonyls ) 是由 J·皮斯科兹 P·马杰尔斯基 于 2018-06-19 设计创作，主要内容包括：提供了一种降低含有甲醛、羟乙醛和其它糖羰基物的水溶液中的甲醛的浓度的方法。所述方法包括将氨基酸加入所述水溶液中,并维持所述水溶液处于一定温度下一定持续时间,所述温度和所述持续时间足够使所述甲醛和所述氨基酸根据美拉德反应进行反应,从而在所述水溶液中产生最终浓度的甲醛和最终浓度的羟乙醛。甲醛的所述最终浓度明显低于甲醛的初始浓度,且所述羟乙醛的最终浓度不明显低于羟乙醛的初始浓度。还提供了一种使食品褐变的水溶液和方法。(A method of reducing the concentration of formaldehyde in an aqueous solution containing formaldehyde, glycolaldehyde, and other sugar carbonyls is provided. The method includes adding an amino acid to the aqueous solution and maintaining the aqueous solution at a temperature and for a duration sufficient to cause the formaldehyde and the amino acid to react according to a maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in the aqueous solution. The final concentration of formaldehyde is significantly lower than the initial concentration of formaldehyde, and the final concentration of glycolaldehyde is not significantly lower than the initial concentration of glycolaldehyde. An aqueous solution and method for browning food products is also provided.)

1. A method of reducing the concentration of formaldehyde in an aqueous solution containing formaldehyde, glycolaldehyde, and other sugar carbonyls, the method comprising:

a) adding an amino acid to the aqueous solution; and

b) maintaining said aqueous solution at a temperature and for a time sufficient to allow said formaldehyde and said amino acid to react according to a Maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in said aqueous solution;

c) wherein said final concentration of formaldehyde is substantially less than the initial concentration of formaldehyde in said aqueous solution and said final concentration of glycolaldehyde is not substantially less than the initial concentration of glycolaldehyde in said aqueous solution.

2. The method of claim 1, wherein the final concentration of formaldehyde is less than 50% of the initial concentration of formaldehyde.

3. The method of claim 2, wherein the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

4. The method of claim 1, wherein the final concentration of glycolaldehyde is greater than 50% of the initial concentration of glycolaldehyde.

5. The method of claim 4, wherein the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

6. The method of claim 1, wherein the amino acid is one of glycine and cysteine.

7. The method of claim 6, wherein the amino acid is cysteine.

8. The method of claim 1, wherein the aqueous solution has an initial amount of formaldehyde and an amount of amino acid is added to the aqueous solution, wherein the molar ratio of the amount of amino acid added to the solution to the initial amount of formaldehyde is in the range of 1:2 to 1: 10.

9. The method of claim 8, wherein the molar ratio is in the range of 1:3 to 1: 5.

10. The method of claim 1, wherein the other glycocarbonyls further comprise one or more of glyoxal, methylglyoxal and acetol.

11. The method of claim 10, wherein the aqueous solution has an initial concentration of glyoxal, an initial concentration of methylglyoxal, an initial concentration of acetol, a final concentration of glyoxal, a final concentration of methylglyoxal, and a final concentration of acetol; wherein said final concentration of glyoxal is not substantially lower than said initial concentration of glyoxal, said final concentration of methylglyoxal is not substantially lower than said initial concentration of methylglyoxal, and said final concentration of methylglyol is not substantially lower than said initial concentration of methylglyoxal.

12. A method of browning a food product, the method comprising:

a) preparing an aqueous solution of a sugar carbonyl comprising formaldehyde and glycolaldehyde by pyrolysis of a sugar, the aqueous solution having an initial concentration of formaldehyde and an initial concentration of glycolaldehyde;

b) adding an amino acid to the aqueous solution;

c) maintaining said aqueous solution at a temperature and for a time sufficient for said formaldehyde and said amino acid to react according to a Maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in said aqueous solution, wherein said final concentration of formaldehyde is substantially less than said initial concentration of formaldehyde and said final concentration of glycolaldehyde is not substantially less than said initial concentration of glycolaldehyde; and

d) heating the aqueous solution having the final concentration of formaldehyde in the presence of the food product to brown the food product.

13. The method of claim 12, wherein the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

14. The method of claim 12, wherein the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

15. The method of claim 12, wherein the amino acid is one of glycine and cysteine.

16. The method of claim 15, wherein the amino acid is cysteine.

17. An aqueous solution of sugar carbonyls prepared by pyrolysis of sugars, said sugar carbonyls comprising formaldehyde and glycolaldehyde, said aqueous solution having a final concentration of formaldehyde that is significantly lower than the initial concentration of formaldehyde and a final concentration of glycolaldehyde that is not significantly lower than the initial concentration of glycolaldehyde, said final concentrations of formaldehyde and glycolaldehyde being produced by:

a) adding an amino acid to the aqueous solution; and

b) maintaining said aqueous solution at a temperature and for a time sufficient to cause said formaldehyde and said amino acid to react according to a Maillard reaction to produce said final concentration of formaldehyde and said final concentration of glycolaldehyde in said aqueous solution.

18. The method of claim 17, wherein the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

19. The method of claim 17, wherein the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

20. The method of claim 17, wherein the amino acid is cysteine.

Technical Field

Embodiments disclosed herein relate to methods of providing aqueous solutions with reduced formaldehyde concentrations, and more particularly, to methods of providing aqueous solutions with reduced formaldehyde concentrations that include glycolaldehyde and other sugar carbonyl compounds.

Background

Pyrolysis of sugars, such as glucose, is a known reaction that has proven useful for producing solutions containing glycolaldehyde (also known as glycolaldehyde). For example, as shown in U.S. patent No.7,094,932, pyrolysis of glucose can provide commercially useful yields of aqueous solutions containing glycolaldehyde. These aqueous solutions can be used in the food industry as natural browning agents (e.g. for meat, fish and bakery products), as flavour precursors, as protein cross-linking agents and as antimicrobial solutions.

During the pyrolysis of glucose, formaldehyde is produced as an undesirable by-product. Formaldehyde is particularly undesirable in aqueous solutions containing glycolaldehyde intended for use in the food industry, as it is well known that gaseous formaldehyde is a hazardous substance to humans.

U.S. patent application No.2016/0002137 teaches a method of removing formaldehyde from a solution containing glycolaldehyde. The process uses reactive distillation in the presence of an alcohol and a catalyst to remove formaldehyde from a solution comprising glycolaldehyde, wherein the formaldehyde is selectively acetylated. Although the product of the reactive distillation is essentially free of formaldehyde, the formaldehyde acetal formed during the reactive distillation must be removed separately from the product solution before the product solution is used for the subsequent catalytic hydrogenation of glycolaldehyde to ethylene glycol.

Accordingly, there is a need for an improved method of reducing the concentration of formaldehyde in an aqueous solution comprising a sugar carbonyl.

Disclosure of Invention

According to one aspect, a method of reducing the concentration of formaldehyde in an aqueous solution containing formaldehyde, glycolaldehyde, and other sugar carbonyls is provided. The method includes adding an amino acid to the aqueous solution and maintaining the aqueous solution at a temperature and for a duration sufficient to react the formaldehyde and the amino acid according to the Maillard reaction (Maillard reaction) to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in the aqueous solution. The final concentration of formaldehyde is significantly lower than the initial concentration of formaldehyde in the aqueous solution, and the final concentration of glycolaldehyde is not significantly lower than the initial concentration of glycolaldehyde in the aqueous solution.

In another aspect of the method, the final concentration of formaldehyde is less than 50% of the initial concentration of formaldehyde.

In another aspect of the method, the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

In another aspect of the process, the final concentration of glycolaldehyde is greater than 50% of the initial concentration of glycolaldehyde.

In another aspect of the process, the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

In another aspect of the method, the amino acid is one of glycine and cysteine.

In another aspect of the method, the amino acid is cysteine.

In another aspect of the method, the aqueous solution has an initial amount of formaldehyde and an amount of the amino acid is added to the aqueous solution, wherein the molar ratio of the amount of the amino acid added to the solution to the initial amount of formaldehyde is in the range of 1:2 to 1: 10.

In another aspect of the process, the molar ratio is in the range of 1:3 to 1: 5.

In another aspect of the method, the other sugar carbonyls further comprise one or more of glyoxal, methylglyoxal and acetol.

In another aspect of the method, the aqueous solution has an initial concentration of glyoxal, an initial concentration of methylglyoxal, an initial concentration of acetol, a final concentration of glyoxal, a final concentration of methylglyoxal, and a final concentration of acetol; wherein the final concentration of glyoxal is not substantially lower than the initial concentration of glyoxal, the final concentration of methylglyoxal is not substantially lower than the initial concentration of methylglyoxal, and the final concentration of methylglyol is not substantially lower than the initial concentration of methylglyoxal.

In another aspect, a method of browning a food product is provided. The method comprises the following steps: preparing an aqueous solution of a sugar carbonyl comprising formaldehyde and glycolaldehyde by pyrolysis of a sugar, the aqueous solution having an initial concentration of formaldehyde and an initial concentration of glycolaldehyde; adding an amino acid to the aqueous solution; maintaining said aqueous solution at a temperature and for a time sufficient to allow said formaldehyde and said amino acid to react according to a Maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in said aqueous solution, wherein the final concentration of formaldehyde is substantially less than the initial concentration of formaldehyde and the final concentration of glycolaldehyde is not substantially less than the initial concentration of glycolaldehyde; and heating an aqueous solution having a final concentration of formaldehyde in the presence of the food product to brown the food product.

In another aspect of the method, the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

In another aspect of the process, the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

In another aspect of the method, the amino acid is one of glycine and cysteine.

In another aspect of the method, the amino acid is cysteine.

In another aspect, there is provided an aqueous solution of sugar carbonyls, prepared by pyrolysis of sugars. The sugar carbonyls include formaldehyde and glycolaldehyde. The aqueous solution has a final concentration of formaldehyde that is significantly lower than the initial concentration of formaldehyde and a final concentration of glycolaldehyde that is not significantly lower than the initial concentration of glycolaldehyde. The final concentration of formaldehyde and the final concentration of glycolaldehyde are produced by: adding an amino acid to the aqueous solution; and maintaining the aqueous solution at a temperature and for a duration sufficient to cause the formaldehyde and the amino acid to react according to a maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in the aqueous solution.

In another aspect of the method, the final concentration of formaldehyde is less than 10% of the initial concentration of formaldehyde.

In another aspect of the process, the final concentration of glycolaldehyde is greater than 80% of the initial concentration of glycolaldehyde.

In another aspect of the method, the amino acid is cysteine.

Other aspects will be apparent in view of the following description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications will become apparent to those skilled in the art from this detailed description.

Detailed Description

Various methods will be described below, providing examples of one or more embodiments. The following embodiments do not limit any claimed embodiments, and any claimed embodiments may encompass processes that differ from the processes described below. The claimed embodiments are not limited to processes having all of the features of any one of the processes described below or features common to many or all of the processes described below. Any embodiments disclosed below that are not claimed in this document may be subject to further patent documentation, for example, continuing patent application, and the applicant, inventor, or owner do not intend to disclaim, or dedicate any such embodiments to the public by virtue of the disclosure in this document.

As used herein, the term "Maillard reaction" refers to the chemical reaction that occurs between an amino acid and a reducing sugar. In the food industry, the maillard reaction is used as a form of non-enzymatic browning in which the carbonyl group of sugar carbonyl compounds reacts with the nucleophilic amino group of amino acids in proteins to form a complex mixture of poorly characterized molecules. In food processing applications, complex mixtures of poorly characterized molecules may contribute to a range of aromas, colors and flavors. The maillard reaction may include a series of consecutive reactions involving a number of compounds that affect food and biopharmaceutical products. In this process, hundreds of different flavor compounds can be established. These compounds in turn decompose to form more new flavor compounds, and the like. Each type of food has a very unique set of flavor compounds formed during the maillard reaction. It has been the use of these compounds by flavor scientists for many years to produce a variety of flavors.

In one example, the maillard reaction begins with the reaction of the carbonyl group of a sugar with the amino group of an amino acid to produce an N-substituted glycosylamine and water. The labile glycosylamine may then undergo an Amadori rearrangement (Amadori rearrangement) to form an Amadori compound (e.g., a ketoamine). The amadori rearrangement is an organic reaction that describes the isomerization or rearrangement of the N-glycoside of an aldose or glycosylamine to the corresponding 1-amino 1-deoxy-ketose, catalyzed by an acid or a base. Returning to the Maillard reaction mechanism, once the Amadori rearrangement is performed, the ketoamine reacts further in several ways. For example, a ketoamine can produce two water molecules and a reduced ketone. Alternatively, diacetyl, aspirin, methylglyoxal and other short chain sugar carbonyl hydrolysis fission products may be formed. Alternatively, brown nitrogenous polymers and melanoidins can be produced. Melanoidins are complex, poorly characterized, nitrogen-containing water-soluble copolymers that cause browning of foods. In particular, melanoidin pigments cause different shades of browning in foods that are smoked, baked, roasted and/or broiled, for example. Each type of food has a very unique set of flavor compounds, and during the maillard reaction, a different set of melanoidins is formed based on the type of food.

As used herein, the term "glycocarbonyl" or "glycocarbonyl" refers to a low molecular weight carbonyl compound such as, but not limited to, formaldehyde, glycolaldehyde, glyoxal, methylglyoxal (also known as methylglyoxal), and acetol.

A method of reducing the concentration of formaldehyde in an aqueous solution having a sugar carbonyl using a maillard reaction is described.

In one embodiment, the aqueous solution has an initial concentration of formaldehyde. For reference, formaldehyde is represented by the following formula I:

the initial concentration of formaldehyde in the aqueous solution may be in the range of 1 to 6 wt%. In one embodiment, the initial concentration of formaldehyde is in the range of 2 to 6 weight percent and more specifically, in the range of 3 to 6 weight percent of the total weight of the aqueous solution.

The initial concentration of formaldehyde is reduced by: the amino acid is added to the solution and the solution is maintained at a temperature and for a duration such that the maillard reaction occurs and a final concentration of formaldehyde and a final concentration of glycolaldehyde are produced in the aqueous solution.

The final concentration of formaldehyde in the aqueous solution is significantly lower than the initial concentration of formaldehyde in the aqueous solution. Herein, a final concentration of a solute that is "significantly lower" than an initial concentration of the solute means that the final concentration of the solute is 50% or less of the initial concentration of the solute.

In one embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 50% of the initial concentration of formaldehyde in the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 40% of the initial concentration of formaldehyde in the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 30% of the initial concentration of formaldehyde in the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 20% of the initial concentration of formaldehyde in the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 10% of the initial concentration of formaldehyde in the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 5% of the initial concentration of formaldehyde in the aqueous solution.

In one embodiment, the final concentration of formaldehyde in the aqueous solution may be in the range of 0 to 2 wt% and more specifically, in the range of 0 to 1 wt% of the total weight of the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 0.5 wt% of the total weight of the aqueous solution. In another embodiment, the final concentration of formaldehyde in the aqueous solution may be less than 0.2 wt% of the total weight of the aqueous solution.

The aqueous solution also includes sugar carbonyls, such as glycolaldehyde. For reference, glycolaldehyde is represented by the following formula II:

the initial concentration of glycolaldehyde in the aqueous solution may be in the range of 4 to 50 wt%. In one embodiment, the initial concentration of glycolaldehyde in the aqueous solution may be in the range of 20 to 30 wt% and more specifically, in the range of 24 to 26 wt% of the total weight of the aqueous solution.

The initial concentration of glycolaldehyde in the aqueous solution is not significantly reduced by: the amino acid is added to the aqueous solution and the aqueous solution is maintained at a temperature and for a duration such that a maillard reaction occurs and a final concentration of glycolaldehyde is produced in the aqueous solution.

The final concentration of glycolaldehyde in the aqueous solution is not significantly less than the initial concentration of glycolaldehyde in the aqueous solution. Herein, the final concentration of the solute is "not significantly lower than" the initial concentration of the solute means that the final concentration of the solute is 50% or more of the initial concentration of the solute.

In one embodiment, the final concentration of glycolaldehyde in the aqueous solution may be in excess of 50% of the initial concentration of glycolaldehyde in the aqueous solution. In another embodiment, the final concentration of glycolaldehyde in the aqueous solution may exceed 60% of the initial concentration of glycolaldehyde in the aqueous solution. In another embodiment, the final concentration of glycolaldehyde in the aqueous solution may be in excess of 70% of the initial concentration of glycolaldehyde in the aqueous solution. In another embodiment, the final concentration of glycolaldehyde in the aqueous solution may be in excess of 80% of the initial concentration of formaldehyde in the aqueous solution.

In one embodiment, the final concentration of glycolaldehyde in the aqueous solution may be in the range of from 4 to 50 wt%, more specifically in the range of from 18 to 30 wt%, and more specifically in the range of from 20 to 25 wt% of the total weight of the aqueous solution.

In one embodiment, the molar ratio of the initial amount of glycolaldehyde in the aqueous solution to the initial amount of formaldehyde in the aqueous solution may be in the range of 10:1 to 2:1, and more specifically, in the range of 5:1 to 3: 1. In another embodiment, the molar ratio of the final amount of glycolaldehyde in the aqueous solution to the final amount of formaldehyde in the aqueous solution may be at least 50: 1.

In one embodiment, the sugar carbonyls may include sugar carbonyls other than formaldehyde and glycolaldehyde. For example, the sugar carbonyl may further comprise one or more of glyoxal, methylglyoxal and acetol. The initial concentration of glyoxal in the aqueous solution can be in the range of 0.5 to 5 wt% and, more specifically, in the range of 1 to 5 wt% of the total weight of the aqueous solution. The initial concentration of methylglyoxal in the aqueous solution may be in the range of 0 to 5 wt% and more specifically in the range of 0 to 2 wt% of the total weight of the aqueous solution. The initial concentration of acetol in the aqueous solution can be in the range of 0 to 5 wt% and more specifically, in the range of 0 to 3 wt% of the total weight of the aqueous solution. Glyoxal, methylglyoxal, and acetol may be combined such that the initial concentration of the combination in the aqueous solution is in the range of 1 to 20 weight percent, more specifically in the range of 1 to 15 weight percent, and more specifically in the range of 1 to 10 weight percent of the total weight of the aqueous solution.

In one embodiment, each of the initial concentrations of glyoxal, methylglyoxal and acetol in the aqueous solution is not significantly reduced by: the amino acid is added to the aqueous solution and the aqueous solution is maintained at a temperature and for a duration to allow the maillard reaction to occur and to produce a final concentration of each of glyoxal, methylglyoxal, and acetol in the aqueous solution.

In one embodiment, the final concentration of glyoxal in the aqueous solution can be in the range of 1 to 5 wt% and, more specifically, in the range of 2 to 5 wt% of the total weight of the aqueous solution. The final concentration of methylglyoxal in the aqueous solution may be in the range of 0 to 5 wt% and more specifically in the range of 0 to 2 wt% of the total weight of the aqueous solution. The final concentration of acetol in the aqueous solution can be in the range of 0 to 5 wt% and more specifically, in the range of 0 to 3 wt% of the total weight of the aqueous solution. Glyoxal, methylglyoxal and acetol may be combined such that the final concentration of the combination in the aqueous solution is in the range of 1 to 10 wt%, and more specifically, in the range of 2 to 8 wt%, of the total weight of the aqueous solution.

In one embodiment, the aqueous solution may further comprise water at an initial concentration in the range of 10 to 90 wt%, and more specifically, in the range of 50 to 70 wt%, and a final concentration in the range of 10 to 90 wt%, and more specifically, in the range of 50 to 70 wt%, of the total weight of the aqueous solution.

As previously described, to reduce the initial concentration of formaldehyde in the aqueous solution, an amino acid is added to the aqueous solution.

The amino acid added to the aqueous solution may be selected from the group consisting of: alanine, arginine, asparagine, cysteine, glutamine, glycine, histidine, lysine, methionine, proline, serine, tryptophan, tyrosine and valine. In one embodiment, the amino acid is selected from the group consisting of glycine and cysteine. In another embodiment, the amino acid may be one of glycine and cysteine. In another embodiment, the amino acid may be cysteine.

In one embodiment, the amino acid is added to the aqueous solution in an amount sufficient to produce a maillard reaction between the amino acid and formaldehyde. In one example, the amount of amino acid added to the aqueous solution is in the range of 1 to 5 wt% and more specifically, in the range of 2 to 4 wt% of the total weight of the aqueous solution. In another example, the amount of amino acid added to the aqueous solution is such that the molar ratio of the amount of amino acid added to the aqueous solution to the amount of formaldehyde in the aqueous solution is in the range of 1:2 to 1: 10. In another example, the amount of amino acid added to the aqueous solution is such that the molar ratio of amino acid added to the aqueous solution to formaldehyde in the aqueous solution is in the range of 1:3 to 1: 5.

After the amino acid is added to the aqueous solution, the aqueous solution is maintained at a temperature and for a duration sufficient to reduce the concentration of formaldehyde in the aqueous solution as a result of a maillard reaction between the amino acid and formaldehyde. After mixing, the amino acid may be dissolved in an aqueous solution.

In one embodiment, the temperature of the aqueous solution may be maintained in the range of about 15 ℃ to 30 ℃ (e.g., room temperature), and more specifically, in the range of about 18 ℃ to 22 ℃, to reduce the concentration of formaldehyde in the aqueous solution as a result of the maillard reaction between the amino acid and formaldehyde.

In another embodiment, the temperature of the aqueous solution may be maintained for a duration in the range of 0 to 96 hours, and more specifically, in the range of 48 to 96 hours, to reduce the concentration of formaldehyde in the aqueous solution as a result of the maillard reaction between the amino acid and formaldehyde.

In one embodiment, the amount of amino acid added to the aqueous solution is such that the molar ratio of the amount of amino acid added to the aqueous solution to the initial amount of formaldehyde in the aqueous solution is in the range of 1:2 to 1:10, and more specifically, in the range of 1:3 to 1: 5.

In one embodiment, the aqueous solution may further comprise melanoidins after the maillard reaction. Melanoidins are the product of the maillard reaction. The structure of melanoidins is poorly defined because these heterogeneous macromolecular compounds cannot be characterized individually. Melanoidins include polymers of the maillard reaction and colored end products. Melanoidins may include copolymers containing furan rings and nitrogen, the structure of which varies depending on the reactants and conditions of preparation. Melanoidins can cause the brown or red color of baked, roasted, coked, or browned foods and are common in many edible liquids such as soy sauce, honey, wine, beer, and coffee. Melanoidins can be formed by cyclization, dehydration, aldol condensation, rearrangement, isomerization and condensation that occur during the maillard reaction.

In one example, after the maillard reaction, the aqueous solution may contain melanoidins at a concentration in the range of 0-20 wt% and more specifically in the range of about 8-15 wt%. In another embodiment, when the initial concentration of formaldehyde in the aqueous solution is about 4 wt% and the initial concentration of glycolaldehyde in the aqueous solution is about 25 wt%, the aqueous solution may contain melanoidins at a concentration in the range of about 8-15 wt% after the maillard reaction.

In another embodiment, the aqueous solution may have a red color after the maillard reaction. Optionally, the red color of the aqueous solution may be removed by known techniques such as, but not limited to, activated carbon or ion exchange resin application, membrane separation, nanofiltration, or reverse osmosis.

In another embodiment, the aqueous solution may be used to brown food after the aqueous solution is provided with a reduced concentration of formaldehyde. Herein, the term food product refers to a substance suitable for consumption as a food.

In one embodiment, the food product may be browned by heating the food product in the presence of the aqueous solution at a temperature and for a duration sufficient to brown the food product.

In one embodiment of the method of browning a food product, the aqueous solution of sugar carbonyls may be prepared by pyrolysis of sugar. The sugar carbonyls comprise formaldehyde and glycolaldehyde and the aqueous solution has an initial concentration of formaldehyde and an initial concentration of glycolaldehyde as previously described. As previously described, the amino acid is added to the aqueous solution and the aqueous solution is maintained at a temperature and for a duration sufficient to allow the formaldehyde and the amino acid to react according to the maillard reaction to produce a final concentration of formaldehyde and a final concentration of glycolaldehyde in the aqueous solution. The final concentration of formaldehyde is significantly lower than the initial concentration of formaldehyde and the final concentration of glycolaldehyde is not significantly lower than the initial concentration of glycolaldehyde.

In one embodiment, the aqueous solution having the final concentration of formaldehyde may be heated in the presence of food at a temperature in the range of 60-150 ℃. In another embodiment, the food product may be added to the hot aqueous solution while maintaining the aqueous solution at a temperature and for a duration sufficient to cook the food product. In one embodiment, the duration may be in the range of 2 to 5 minutes.

In one embodiment, heating the food product in an aqueous solution having a final concentration of formaldehyde can produce a brownish color on the exterior surface of the food product, or by other means, apply a browning solution on the exterior.

In one embodiment, the food product may be selected from: meat (e.g. sausage, bacon, etc.), fish or baked goods (e.g. bakery or pastry).