Caramel color and its preparation method

Abstract

This invention discloses a caramel color and its preparation method, comprising the following steps: 1) Pretreatment: removing gum and ash from sugarcane waste molasses; 2) Evaporating and concentrating the pretreated molasses to a molasses solution with a total sugar content of 50%; 3) Adding ammonia water to the molasses solution to form a reaction system, wherein the NH4+ of the ammonia water is added. + The total sugar content in the molasses solution is 5-7%; 4) Add one of ferric sulfate, sodium sulfite, or cysteine ​​to the reaction system and stir until homogeneous, the amount added being 1% of the total sugar content in the molasses solution; 5) Heat the reaction solution obtained in step 4) to 130-140°C and maintain the temperature for 55-70 minutes; 6) Immediately cool the reaction solution obtained in step 5) to room temperature, and concentrate the cooled reaction product to a concentration of 68%-75% soluble solids to obtain caramel color. This invention aims to develop high-quality, high-safety, and high-economical caramel color through additive research.

Description

Technical Field

[0001] This invention relates to the field of caramel color production technology. More specifically, this invention relates to a caramel color and a method for preparing the same. Background Technology

[0002] Caramel color is mainly used as a food coloring agent, found in beverages, alcoholic beverages, soy sauce, pastries, candies, and other food flavorings, as well as pharmaceutical extracts. The formation of caramel color primarily involves two types of reactions: the Maillard reaction and the caramelization reaction, a collective term for a series of complex changes. Caramel color is obtained from sugar through a high-temperature reaction. Based on the reactants used in the production process, caramel color is classified into the following four categories:

[0003] The first type of caramel coloring is ordinary caramel, produced by directly heating sugars during the production process to cause a caramelization reaction, without using ammonia or sulfite compounds; the caramelization reaction is the dominant process. It is generally used for coloring spirits such as brandy.

[0004] The second type of caramel color is caustic sulfite caramel, which is produced by using sulfurous acid as a catalyst and heating. The resulting compound has a very limited range of applications.

[0005] The third type of caramel color is ammonia-based caramel, which uses ammonia as a catalyst in its production process, and the color formation mainly relies on the Maillard reaction pathway. Because this type of caramel carries a relatively strong positive charge, it can maintain good stability in salt solutions. Due to this property, this type of caramel is often used in brewed products, especially in commonly used condiments such as soy sauce.

[0006] The fourth type of caramel color is produced using the ammonium sulfite process, where ammonium sulfite is used in the reaction. This type of caramel color is also known as acid-resistant caramel color because it carries a relatively strong negative charge, allowing it to maintain good stability in acidic environments. It is commonly used in the soft drink industry.

[0007] Currently, caramel color production in my country is primarily classified as Category III and IV. However, the production processes of caramel color using ammonia-based and ammonium sulfite-based methods easily generate 4-methylimidazole during the Maillard reaction and caramelization. 4-Methylimidazole is readily soluble in water and ethanol, is corrosive, and is a byproduct of ammonia-based caramel color production, posing a risk of tumor development in animals. Therefore, the brewing industry urgently needs to research a manufacturing method for caramel color produced using ammonia-based methods that yields high color yield, high red index, and low 4-methylimidazole content, in order to obtain high-quality, safe, and economical caramel color. Summary of the Invention

[0008] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0009] This invention provides a caramel color and its preparation method, aiming to develop a high-quality, safe, and economical caramel color production process through the research of additives.

[0010] To achieve these objectives and other advantages of the present invention, a method for preparing caramel coloring is provided, comprising the following steps:

[0011] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0012] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0013] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + The content of sugar in the molasses solution is 5-7% by mass.

[0014] 4) Add one of ferric sulfate, sodium sulfite or cysteine ​​to the reaction system and stir until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0015] 5) Heat the reaction solution obtained in step 4) to 130-140℃ and keep it at that temperature for 55-70 minutes;

[0016] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 68% to 75% soluble solids to obtain caramel coloring.

[0017] Preferably, in step 3), the ammonia water is added in the form of NH4. + It is 5% of the total sugar mass in the molasses solution;

[0018] In step 4), cysteine ​​is added to the reaction system and stirred until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0019] In step 5), the reaction solution is heated to 135°C and kept at that temperature for 55 minutes.

[0020] Preferably, the preprocessing specifically includes:

[0021] 1.1) Dilute the sugarcane waste molasses to a Baume degree of 30–31°Bé;

[0022] 1.2) Use a 20% sulfuric acid solution as a pH adjuster to adjust the pH of the material to 2.3–3.5;

[0023] 1.3) The material is heated to 105℃ for hydrolysis, and the hydrolysis rate is measured during the hydrolysis process;

[0024] 1.4) When the hydrolysis rate is ≥85%, centrifuge or filter to remove insoluble colloids and ash from the material to obtain pretreated molasses.

[0025] Preferably, the reaction system also includes mannitol, tea polyphenols, and chitosan.

[0026] Preferably, step 4) is: adding mannitol, tea polyphenols, chitosan and cysteine ​​to the reaction system and stirring until homogeneous, with the addition amounts being 1%, 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively, and then preheating to 50°C and maintaining for 10 min.

[0027] The present invention also provides a caramel color, which is a caramel color prepared by the above method.

[0028] The present invention has at least the following beneficial effects:

[0029] First, the present invention uses sugarcane waste molasses to prepare caramel color after removing colloids and ash, which has high economic efficiency.

[0030] Secondly, this invention utilizes ferric sulfate, sodium sulfite, or cysteine ​​as additives to produce caramel coloring with higher color rate and red index, and reduces 4-methylimidazole content, within a set reaction temperature, holding time, and ammonia addition range, after processing pretreated sucrose molasses.

[0031] Third, this invention utilizes the combination of mannitol, tea polyphenols, and chitosan to facilitate interaction with degradation products of sugars (such as α-dicarbonyl groups), reducing the production of methylglyoxal and affecting the formation of 4-methylimidazole. Simultaneously, it promotes the condensation between sugars, intermediates, and cysteine, allowing the products of the Maillard reaction and caramelization reaction to interact and generate more abundant large molecules, thus improving the coloring power of the product, further enhancing the red index and color rate, and exhibiting good salt resistance. This provides a framework for developing high-quality, high-safety, and high-economic-value caramel color.

[0032] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0033] Figure 1 This is a trend graph showing the influence of the changes in the levels of four factors—additives, reaction temperature, holding time, and the mass fraction of ammonia added—on the color rate and red index of caramel pigments. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0035] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0036] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the preparation process of the embodiments and comparative examples of this invention, the pretreatment method for removing gum and ash from sugarcane waste molasses is as follows:

[0037] 1.1) Dilute the sugarcane waste molasses to a Baume degree of 30–31°Bé;

[0038] 1.2) Use a 20% sulfuric acid solution as a pH adjuster to adjust the pH of the material to 2.3–3.5;

[0039] 1.3) The material is heated to 105℃ for hydrolysis. The hydrolysis rate is measured during the hydrolysis process. The hydrolysis rate is calculated as follows:

[0040]

[0041] 1.4) When the hydrolysis rate is 85%, centrifuge or filter to remove insoluble colloids and ash from the material to obtain pretreated molasses.

[0042] Example 1

[0043] (The additive is ferric sulfate)

[0044] The preparation method of caramel color includes the following steps:

[0045] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0046] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0047] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + The content of sugar in the molasses solution is 5-7% by mass.

[0048] 4) Add ferric sulfate to the reaction system and stir until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0049] 5) Heat the reaction solution obtained in step 4) to 130-140°C and maintain the temperature for 55-70 minutes.

[0050] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0051] Example 2

[0052] (The additive is sodium sulfite)

[0053] The preparation method of caramel color includes the following steps:

[0054] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0055] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0056] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + The content of sugar in the molasses solution is 5-7% by mass.

[0057] 4) Add sodium sulfite to the reaction system and stir until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0058] 5) Heat the reaction solution obtained in step 4) to 130-140°C and maintain the temperature for 55-70 minutes.

[0059] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0060] Example 3

[0061] (The additive is cysteine)

[0062] The preparation method of caramel color includes the following steps:

[0063] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0064] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0065] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + The content of sugar in the molasses solution is 5-7% by mass.

[0066] 4) Add cysteine ​​to the reaction system and stir until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0067] 5) Heat the reaction solution obtained in step 4) to 130-140°C and maintain the temperature for 55-70 minutes.

[0068] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0069] I. Orthogonal Experiment

[0070] Four factors were considered: the selection of additives, reaction temperature, heat preservation time, and ammonia mass fraction. For each factor, three optimal levels were selected for orthogonal experiments.

[0071] Table 1: Factors and Levels of Orthogonal Experiments

[0072]

[0073] II. Orthogonal Experiment

[0074] Caramel coloring was prepared according to the preparation methods of Examples 1-3, and orthogonal experiments were conducted according to Table 1. The experimental results are shown in Table 2.

[0075] Table 2: Results of the orthogonal experiment

[0076]

[0077]

[0078] III. Range Analysis of Orthogonal Experiment Results

[0079] Range analysis of the orthogonal experiment results for caramel coloring is shown in Table 3.

[0080] Table 3: Range Analysis of Orthogonal Experiment Results for Caramel Pigments

[0081]

[0082]

[0083] Table 3 shows that the order of influence of each factor on the color rate is: A > B > D > C, i.e., additives > reaction temperature > ammonia mass fraction > holding time. The order of influence of each factor on the red index is: A > C > B > D, i.e., additives > holding time > reaction temperature > ammonia mass fraction. This demonstrates that the order of influence of the four factors is different.

[0084] In this experiment, since higher values ​​for both the color rate and the red index indicate better product quality, the optimal solution for the color rate is A1B3D3C2, where the reaction additive is ferric sulfate, the reaction temperature is 140℃, the ammonia concentration is 7%, and the reaction holding time is 60 min. The optimal solution for the red index is A2C2B1D1, where the reaction additive is sodium sulfite, the reaction holding time is 60 min, the reaction temperature is 130℃, and the ammonia concentration is 5%. It is evident that this solution is good for the color rate but not for the red index. To find a better solution for both, the results are comprehensively analyzed. For ease of observation, the trend graphs of each index changing with factors (additive, reaction temperature, holding time, and ammonia concentration) are presented. Figure 1 As shown.

[0085] Additives (Factor A) are the most important influencing factor for both indicators. Figure 1 It can be seen that the additives have opposite effects on the two indicators. For color rate, A1 is better, while for red index, A2 is better. However, although A1 yields a higher color rate, the red index is relatively low, which does not meet the optimization requirements, so A1 is not chosen. Between A2 and A3, choosing A3 can significantly improve the color rate, and the red indexes of both are almost identical. Therefore, based on comprehensive analysis, A3 can be chosen, i.e., the additive is cysteine.

[0086] Reaction temperature (factor B) is a relatively important influencing factor for both indicators. Figure 1 It can be seen that the reaction temperature has different effects on the two indicators. For the color rate, B3 (140℃) is better, while for the red index, B2 is better. However, although B3 yields a higher color rate, the red index is relatively low, which does not meet the optimization requirements, so B3 is not chosen. Between B1 and B2 (135℃), choosing B2 significantly improves the red index, and the color rate is also better than B1. Therefore, based on comprehensive analysis, B2, i.e., a reaction temperature of 135℃, is the best choice.

[0087] Insulation time (factor C) has a significant impact on the red index, but a minor impact on the color rate. Furthermore, from... Figure 1 It can be seen that factor C has different trends in its influence on the two indicators. When C2 is selected, the color rate is the highest, but the red index is already relatively low, so C2 is not chosen. When C3 is selected, the color rate does not change much, but the red index increases. When C1 is selected, the decrease in color rate is not significant, and C1 has a larger red index. Therefore, based on comprehensive analysis, C1 can be selected, i.e., the heat preservation time is 60 minutes.

[0088] The effect of ammonia dosage (factor D) on color rate and red index is relatively minor, and from... Figure 1It can be seen that the effect of ammonia dosage on the two indicators is relatively stable, with small increases and decreases. When D3 is selected, the increase in color rate is not significant, while the red index decreases considerably. Furthermore, increasing the ammonia dosage inhibits the reaction, and excessively high ammonium content can easily produce harmful substances such as 4-methylimidazole, which can cause convulsions. Therefore, D3 is not selected. Selecting D1 can increase the red index more, and D1 also has a relatively high color rate. Therefore, based on comprehensive analysis, D1, i.e., an ammonia dosage of 0.05, can be selected.

[0089] The optimal preparation process was determined through the above analysis. Theoretically, the process with the best color rate is A1B3C2D3, where the reaction additive is ferric sulfate, the reaction temperature is 140℃, the reaction holding time is 60 min, and the mass fraction of ammonia is 7%. The process with the best red index is A3B2C1D1, where the reaction additive is cysteine, the reaction temperature is 135℃, the reaction holding time is 55 min, and the mass fraction of ammonia is 5%. Using a comprehensive balance method, the possible combination for a product with high color rate and high red index is A3B2C1D1, where the reaction additive is cysteine, the reaction temperature is 135℃, the reaction holding time is 55 min, and the mass fraction of ammonia is 5%. Since the theoretically optimal process conditions are not in the orthogonal table, three parallel experiments were conducted under each of the above conditions for verification. The results show that a good color rate of 7.4 × 10⁻⁶ is achieved. 4 BEC, with a good red index of 5.498. A better product combination for high color rate and high red index is A3B2C1D1, where the reaction additive is cysteine, the reaction temperature is 135℃, the reaction holding time is 55 min, and the mass fraction of ammonia is 5%. The color rate of the molasses caramelization oxidation product is 6.3 × 10⁻⁶. 4 With a BEC and a red index of 5.34, preferred embodiment 4 was obtained.

[0090] Example 4

[0091] The preparation method of caramel color includes the following steps:

[0092] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0093] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0094] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + It is 5% of the total sugar mass in the molasses solution;

[0095] 4) Add cysteine ​​to the reaction system and stir until homogeneous. The amount added is 1% of the total sugar mass in the molasses solution.

[0096] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0097] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0098] Although the caramel color prepared in the preferred embodiment 4 has a low 4-methylimidazole content, color rate and red index are important indicators of caramel color. The preferred embodiment 5, which improves color rate and red index while ensuring a low 4-methylimidazole content, is as follows:

[0099] Example 5

[0100] The preparation method of caramel color includes the following steps:

[0101] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0102] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0103] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + It is 5% of the total sugar mass in the molasses solution;

[0104] 4) Add mannitol, tea polyphenols, chitosan and cysteine ​​to the reaction system and stir until homogeneous. The amounts added are 1%, 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min.

[0105] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0106] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0107] Comparative Example 1

[0108] The method for preparing caramel color differs from Example 5 only in that it does not include mannitol and tea polyphenols. The specific steps are as follows:

[0109] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0110] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0111] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + It is 5% of the total sugar mass in the molasses solution;

[0112] 4) Add chitosan and cysteine ​​to the reaction system and stir until homogeneous. The amounts added are 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min.

[0113] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0114] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0115] Comparative Example 2

[0116] The method for preparing caramel color differs from Example 5 only in that it does not include mannitol. The specific steps are as follows:

[0117] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0118] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0119] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + It is 5% of the total sugar mass in the molasses solution;

[0120] 4) Add tea polyphenols, chitosan and cysteine ​​to the reaction system and stir until homogeneous. The amounts added are 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min.

[0121] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0122] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0123] Comparative Example 3

[0124] The method for preparing caramel color differs from Example 5 only in that it does not include tea polyphenols. The specific steps are as follows:

[0125] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0126] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0127] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. +It is 5% of the total sugar mass in the molasses solution;

[0128] 4) Add mannitol, chitosan and cysteine ​​to the reaction system and stir until homogeneous. The amounts added are 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min.

[0129] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0130] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0131] Comparative Example 4

[0132] The method for preparing caramel color differs from Example 5 only in that cysteine ​​is replaced with sodium sulfite. The specific steps are as follows:

[0133] 1) Pretreatment: Remove the gum and ash from the sugarcane waste molasses;

[0134] 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%;

[0135] 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + It is 5% of the total sugar mass in the molasses solution;

[0136] 4) Add mannitol, tea polyphenols, chitosan and sodium sulfite to the reaction system and stir until homogeneous. The amounts added are 1%, 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min.

[0137] 5) Heat the reaction solution obtained in step 4) to 135℃ and keep it at that temperature for 55 minutes;

[0138] 6) Immediately cool the reaction obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 75% soluble solids to obtain caramel coloring.

[0139] The color rate, red index, 4-methylimidazole content, and salt tolerance of caramel pigment samples prepared in Examples 4, 5, and Comparative Examples 1-4 are shown in Table 4.

[0140] Table 4: Color rate, red index, 4-methylimidazole content and salt tolerance

[0141]

[0142] As shown in Table 4, in Comparative Example 1, the addition of chitosan to the reaction system resulted in a decrease in both the red index and color rate, while the 4-methylimidazole content increased significantly. In Comparative Example 2, the addition of tea polyphenols and chitosan improved the red index, but the color rate decreased significantly, affecting the quality. In Comparative Example 3, the addition of mannitol and chitosan resulted in a higher color rate than Comparative Example 2, but the red index was lower. In Example 5, the combination of mannitol, tea polyphenols, and chitosan with cysteine ​​significantly and simultaneously improved both the red index and color rate, while also resulting in a lower 4-methylimidazole content and better salt resistance. This provides a framework for developing high-quality, safe, and economical caramel color.

[0143] The methods for determining the color rate, red index, 4-methylimidazole content, and salt tolerance as described above are as follows:

[0144] 1. Determination of the color index of caramel pigment

[0145] Color index is a physicochemical indicator representing the depth of color in a caramel pigment sample. To calculate the color index of a sample, the absorbance of a 1000-fold diluted sample solution needs to be measured at wavelengths of 510 nm and 610 nm. The dilution method is as follows: Accurately weigh 1 g of sample using an analytical balance and dissolve it. Pour the solution into a volumetric flask, rinse three times to prevent any sample residue from the beaker or glass rod, and make up to volume to obtain a 100-fold diluted sample solution. Accurately measure 10 mL of the 100-fold diluted sample solution prepared by the above method into a volumetric flask, add pure water to make up to 100 mL, and finally, hold the stopper and shake the sample solution well to obtain a 1000-fold diluted solution. Pour the diluted sample solution into a 1 cm cuvette. Turn on the spectrophotometer and wait 15 minutes for the instrument to warm up, then adjust the wavelength to 610 nm. Place the cuvette in the instrument and measure the absorbance after 1 minute when the value stabilizes. Measured every 1 minute, repeated 3 times, and the average of the three readings is A. 610 The EBC chromaticity is calculated according to the formula:

[0146] X1 = A 610 ×20000 / 0.076

[0147] Note: In the formula, A 610 --- Absorbance at 610 nm

[0148] 2. Determination of the red index of caramel color

[0149] The red index indicates the intensity of the red hue in the caramel color sample. Obtain the diluted sample solution using the method described above. Pour the 1000-fold diluted sample solution into a 1cm cuvette for the UV-Vis spectrophotometer. Turn on the instrument and wait 15 minutes for it to warm up. Adjust the wavelength to 510nm. Place the cuvette in the instrument and measure the absorbance. After 1 minute of stabilization, read the absorbance. Measure every 1 minute, repeating the measurement three times. The average of the three readings is taken as A. 510 Combined with the A obtained from the color index measurement above 610 The data is used to calculate the red index according to the formula:

[0150] X2 = 10lg A 510 / A 610

[0151] Note: In the formula, A 510 A 610 --- Absorption values ​​at 510nm and 610nm

[0152] 3. Determination of 4-methylimidazole content in caramel color

[0153] 4-Methylimidazole was extracted from caramel samples using a method previously described by Fernandes and Ferreira, later developed by Cunha et al., based on ion-pair extraction of bis(2-ethylhexyl) phosphate (BEHPA) and derivatization with isobutyl chloroformate (IBCF). A stock solution of 4-methylimidazole (100 mg / L) and an internal standard (2-EI, 1 g / L) were prepared by dissolving the compound in 0.1 mol·L⁻¹ hydrochloric acid. To compensate for matrix effects, the caramel solution was supplemented with the internal standard, using 4-MeI as a standard, to yield 0 μg / mL. -1 2μg mL -1 4μg mL -1 10 μg mL -1 20μg mL -1 and 40 μg mL -1 Calibration curves were generated for six concentrations. The internal standard 2-ethylimidazole (2-EI) was added to all calibration solutions and analytical samples. The analytes were then extracted using ion-pair extraction and derivatized according to the described procedure. Finally, the content of 4-methylimidazole in the samples was determined by GC-MS.

[0154] 3-1. Ion-pair extraction

[0155] Weigh 3g of ammoniacal caramel, dilute with 10mL of phosphate buffer, and then titrate with potassium hydroxide to reach pH 6.0. Next, transfer the entire mixture to a 25mL flask and fill to 25mL with water. Transfer 1mL of this solution to a second vial and extract with 2mL of 0.1% bis(2-ethylhexyl)phosphoric acid (BEHPA) in chloroform. Mix the mixture for 10 minutes. After centrifuging at 1500g for 10 minutes, transfer the bottom layer (1.8mL) to a third tube and aspirate with 1.5mL of HCl. After centrifugation, the upper layer is ready for derivatization.

[0156] 3-2. Derivatization

[0157] Add 50 μL of 2-EI (used as an internal standard) to the aqueous phase of 500 μL of the aliquot sample, then mix with an equal volume (500 μL) of acetonitrile:isobutanol:pyridine (5:3:2 v / v) and 60 μL of isobutyl chloroformate (IBCF). After shaking by hand for 10 seconds, add 1 mL of saturated NaHCO3 to the sample and stir for 1 minute. Then, add 1 mL of n-hexane and stir for 10 minutes. After centrifugation, inject 2 μL of the supernatant into the GC-MS system.

[0158] 3-3. GC-MS System Measurement Conditions

[0159] GC-MS / MS analysis was performed using a gas chromatograph and a triple quadrupole mass spectrometer. Samples were injected into an RTX-5MS column (10m × 0.18mm × 0.1mm) in non-split mode. The column oven temperature program during analysis was as follows: initial temperature 70℃ for 1 minute, with temperature ramped up at a minimum of 20℃ to a maximum of 280℃. The syringe and mass spectrometer ion source temperatures were 280℃ and 230℃, respectively. Analyzed compounds and internal standards were first analyzed in scan mode, then in SIM, and finally in MS / MS. Product ion determination was performed in product ion mode, with their origin examined in precursor ion mode, and multiple reaction monitoring (MRM) used for quantification. Helium was used as the carrier gas at a flow rate of 1 mL / min. -1. Nitrogen gas was used as the collision gas, and its flow rate was set to 1.5 mL / min. -1The collision energies tested ranged from 5 to 50 V, resulting in product ions of varying intensities. The optimal collision-induced dissociation (CID) value occurred at 10 V. During this process, the product ion spectrum with the minimum precursor ion abundance and the maximum selected product ion was selected for further method development. The mass spectrometer was operated in electron ionization (EI) mode at 70 eV. The precursor ions used for MRM quantification were 182 for 4-MeI and 196 for 2-EI (internal standard). The precursor ions of both compounds underwent secondary fragmentation, resulting in product ions of 82 for 4-MeI and 96 for 2-EI. Data acquisition and analysis were performed using Agilent Technologies MassHunter workstation software.

[0160] 4. Salt tolerance testing methods

[0161] ① Measure 30 ml of the sample to be tested using a 100 ml measuring cup and pour it into the prepared beaker;

[0162] ② Measure 200ml of 20.5% saline solution, and rinse the sample residue in the measuring cup into the beaker in small amounts several times. Heat the mixture of saline solution and sample solution until it boils. At the beginning, you should pay attention to stirring while heating to make the liquid uniform.

[0163] ③ After heating to just boiling, pour the boiling mixed solution into a 250ml reagent bottle and let it stand.

[0164] ④ Shine a flashlight on the bottom of the conical flask and observe for 24 hours to see if any sediment is produced. If sediment is produced, the flask is considered unqualified.

[0165] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0166] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A method for preparing caramel color, characterized in that, Includes the following steps: 1) Pretreatment: Dilute sugarcane waste molasses to 30-31°Bé Baumé, adjust the pH to 2.3-3.5 with 20% sulfuric acid solution, heat to 105℃ to hydrolyze until the hydrolysis rate is ≥85%, centrifuge to remove gum and ash to obtain pretreated molasses; 2) Evaporate and concentrate the pretreated molasses to a molasses solution with a total sugar content of 50%; 3) Add ammonia to the molasses solution to form a reaction system, and add the NH4+ of the ammonia. + The content of sugar in the molasses solution is 5-7% by mass. 4) Add mannitol, tea polyphenols, chitosan and cysteine ​​to the reaction system and stir until homogeneous. The amounts added are 1%, 1%, 1% and 2% of the total sugar mass in the molasses solution, respectively. Then preheat to 50°C and maintain for 10 min. 5) Heat the reaction solution obtained in step 4) to 130-140℃ and keep it at that temperature for 55-70 minutes; 6) Immediately cool the reaction solution obtained in step 5) to room temperature, and concentrate the cooled reaction product to contain 68% to 75% soluble solids to obtain caramel coloring.

2. A caramel coloring, characterized in that, It is a caramel color prepared by the method described in claim 1.

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