Method for detecting wax content in baking mold oil

Abstract

The invention relates to a method for detecting the content of wax in baking mold oil, and belongs to the technical field of analytical chemistry. According to the method, the reaction principle that fatty acid and alkali in the natural wax are subjected to saponification reaction, and generated fatty acid salt is separated out at normal temperature is utilized, the wax content in the baking mold-releasing oil is quantified by combining a standard addition method, and a standard curve of the natural wax content and turbidity in the baking mold-releasing oil is established; and determining the content of the natural wax in the baking mold oil according to the turbidity change. According to the method, the influence of emulsifiers such as phospholipid or other auxiliary materials in the mold oil can be eliminated, the accuracy of detecting the wax content in the baking mold oil is improved, the applicability in the baking mold oil is relatively high, the operation is simple and easy to implement, and the method has important significance on development and quality control of baking mold oil products; and the method also has guiding significance on detection and quantification of a certain component or substance in substances containing complex components.

Description

Technical Field

[0001] The invention belongs to the field of analytical chemistry, and particularly relates to a method for detecting wax content in baking demoulding oil. Background Art

[0002] Baking mold release oil is made of vegetable oil and natural wax as the base material, with phospholipids added and other ingredients through emulsification reaction. Its viscosity is higher than that of general vegetable oils, and it can form a complete, tough and tight film on the surface of the mold, effectively isolating the baked product from the mold, ensuring that the baked product is taken out of the mold intact. Natural waxes such as beeswax and carnauba wax have good emulsification and adhesion, and excellent frying resistance. They can make up for the defects of palm oil such as low viscosity and difficulty in hanging on the wall, and greatly improve the effect of mold release oil. Therefore, it is often used as one of the raw materials for preparing baking mold release oil.

[0003] The amount of wax added to baking mold release oil affects the use effect of the product. In order to obtain a mold release oil with high emulsification stability and excellent mold release, it is necessary to reduce the emulsification stratification index and increase the viscosity as much as possible. When the wax content gradually increases, the emulsification stratification index shows a trend of first decreasing and then increasing, and the viscosity first increases significantly and then tends to stabilize. Generally, it is more appropriate to keep the wax content in baking mold release oil between 2% and 6%. Therefore, the wax content in baking mold release oil is an important indicator of product quality. At present, the detection methods of natural wax in the market are mainly concentrated on the detection of wax content in vegetable oils, including insoluble matter measurement method, turbidity meter determination method, chromatography, etc. The insoluble matter method has also become the gravimetric method, which is the wax content determination method commonly used at home and abroad at first, including the acetone insoluble matter determination method and the butanone insoluble matter determination method, that is, by obtaining a crystal insoluble in acetone or butanone, filtering and accurately weighing to determine the wax content in the vegetable oil (CARELLI AA. FRIZZREAL M, FORBITO PR, et al. Wax composition of sunflower seed oils [J]. J Am Oil Chem Soc, 2002, 79 (8): 763-768.). Since the demoulding oil contains phospholipids, which are insoluble in acetone, and the errors in the filtering and weighing processes are large, the use of a large amount of acetone will also threaten human health, so this method is not suitable for baking demoulding oil. Turbidimeter determination is a wax content determination method with a wide range of applications. For example, Chinese patent CN103994983B discloses a rapid detection method for wax content in edible plants, which cools the edible plants at 0-6°C to precipitate crystals, and then uses a spectrophotometer to detect turbidity to determine the wax content; Chinese patent CN104198444A discloses a device and method for rapid determination of wax content in oil products, which calculates turbidity through the different light transmittances of the refrigerant and the oil to be tested after low-temperature treatment, and finally determines the wax content in the oil product. However, the phospholipids in baking demoulding oil will also precipitate in an ice water bath, so this method is not suitable for demoulding oil. Chromatography can also be used for wax content determination and wax composition analysis. For example, Chinese patent CN115389686A discloses a method for detecting carnauba wax in fruit, which obtains a liquid by homogenizing the fruit and extracting it with toluene, and then purifies the liquid through a solid phase extraction column, and finally detects it by gas chromatography to obtain the carnauba wax content; Mariani et al. used a silica gel column containing 2% water and an eluent of n-hexane-ether (volume ratio 99:1) to elute and separate the wax component, and detected the wax content by gas chromatography, which can effectively detect the content of C40-C46 aliphatic groups.After that, the European Commission issued (EU) No. 61 / 2011 to use this method to identify the grade of olive oil (MARIANI C, FEDELI E. Minor components of vegetable oils: non-glyceridic esters [J]. Riv Ital Sostanze Gr, 1989, 66 (7): 397-401.). However, the gas chromatography method requires the wax to be separated by column chromatography or thin layer chromatography, and then detected by gas chromatography. The pre-treatment of this method is complicated and takes a long time. Therefore, a safer, faster and more suitable detection method for the wax content in baking demoulding oil is needed for product quality detection to improve work efficiency. Summary of the invention

[0004] In order to achieve the above object, the present invention provides a method for detecting the wax content in baking demoulding oil, which utilizes the reaction principle that fatty acids in natural wax react with alkali to generate fatty acid salts that precipitate at room temperature, establishes a standard curve of natural wax content and turbidity in baking demoulding oil, and determines the content of natural wax in baking demoulding oil according to the change of turbidity. The method can accurately and quickly detect the wax content in baking demoulding oil, which is of great significance to product development and quality control.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A rapid detection method for the wax content in baking release oil combines a saponification reaction method and a standard addition method to detect the wax content in the baking release oil, specifically comprising the following steps:

[0007] (1) Accurately weigh 3-6 portions of baking release oil with unknown wax content and place them in containers;

[0008] (2) adding different proportions of natural wax and vegetable oil into a container containing baking release oil to obtain a mixed test solution;

[0009] (3) Add 20-30 mol / L KOH solution and anhydrous ethanol to the mixed test solution obtained in step (2), mix well, connect the container containing the mixed solution to a reflux condenser, pass condensed water, and place the container in a constant temperature water bath at 95-100° C. and reflux until the reaction is complete;

[0010] (4) taking out the completely reacted solution, cooling it, dispersing it evenly, and measuring the turbidity;

[0011] (5) Draw a standard curve and calculate the wax content in baking release oil.

[0012] Preferably, the natural waxes in different proportions in step (2) are any 3-6 kinds of natural waxes with concentrations of 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%.

[0013] Preferably, the natural wax in step (2) is carnauba wax or beeswax, and the vegetable oil is any one of soybean oil, peanut oil, rapeseed oil and corn oil.

[0014] Preferably, the concentration of the KOH solution in step (3) is 5-30 mol / L, and the volume ratio of the mixed test solution: KOH solution: anhydrous ethanol is 2:1:15-25.

[0015] Further preferably, the mass fraction of the KOH solution in step (3) is 25%-60%; and the volume ratio of the mixed test solution: KOH solution: anhydrous ethanol is 2:1:25.

[0016] Preferably, the temperature of the thermostatic water bath is 97° C., and a stirrer is added to the reaction vessel to accelerate the reaction.

[0017] Preferably, the standard curve described in step (5) is drawn with the added natural wax concentration as the abscissa and the turbidity value as the ordinate to draw the standard curve, and the standard curve formula y=ax+b is obtained, and the intercept of the standard curve on the abscissa is the unknown concentration. The wax content in baking release oil is Where m0 is the total mass of baking release oil, natural wax and vegetable oil, and m1 is the mass of baking release oil.

[0018] The beneficial effects of the present invention are as follows: the present invention adopts a combination of a saponification reaction method, a standard addition method and a turbidity meter method to detect the wax content in baking demoulding oil, utilizes the reaction principle that the fatty acid contained in the natural wax undergoes a saponification reaction with an alkali, and the generated fatty acid salt is precipitated at room temperature, combines the saponification reaction with the standard amount addition method, accurately measures the fatty acid content in the baking demoulding oil, and eliminates the influence of phospholipids, emulsifiers or other auxiliary materials on the accuracy of the detection result, then utilizes the solid matter precipitated in the solution obtained by the reaction, detects the turbidity of the solution by the turbidity meter method, establishes a standard curve by the added natural wax concentration and the turbidity value, and finally calculates the wax content in the baking demoulding oil, simplifies the experimental steps, reduces the amount of calculation, expands the application scope of the detection method, and improves the applicability of detecting the wax content in different types of baking demoulding oil. The present invention has guiding significance for the detection and quantification of a certain component or substance in a substance containing complex components. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the standard curve of carnauba wax in Example 1.

[0020] Figure 2 This is the standard curve of beeswax in Example 2.

[0021] Figure 3This is the solution after the reaction using KOH solution as the saponifier in Example 3, in which A represents the addition amount of carnauba wax is 0%, B represents the addition amount of carnauba wax is 0.5%, C represents the addition amount of carnauba wax is 1%, D represents the addition amount of carnauba wax is 1.5%, E represents the addition amount of carnauba wax is 2%, F represents the addition amount of carnauba wax is 2.5%, and G represents the addition amount of carnauba wax is 3%.

[0022] Figure 4 This is the solution after the reaction using NaOH solution as the saponifier in Comparative Example 1, in which A represents 0% carnauba wax addition, B represents 0.5% carnauba wax addition, C represents 1% carnauba wax addition, D represents 1.5% carnauba wax addition, E represents 2% carnauba wax addition, F represents 2.5% carnauba wax addition, and G represents 3% carnauba wax addition. DETAILED DESCRIPTION

[0023] The following embodiments are only preferred embodiments of the invention and should not be construed as limiting the invention. The protection scope of the invention shall be subject to the contents of the claims. Any replacement or modification of the technical solution of the invention made by those skilled in the art without creative work shall fall within the protection scope of the invention.

[0024] The baking release oil containing carnauba oil and the baking release oil containing beeswax used in the following embodiments are both homemade, the carnauba wax was purchased from Shanghai Yiba Chemical Raw Materials Co., Ltd., and the beeswax was purchased from Cangzhou Fengzhiyi Wax Industry Co., Ltd.

[0025] Example 1 Detection of carnauba wax content

[0026] (1) Use an electronic balance to accurately weigh 1 g of baking release oil containing 4% carnauba wax into a ground-mouth bottle, a total of 6 portions;

[0027] (2) Add different amounts of carnauba wax to six ground-mouth bottles, add soybean oil to 1 g, and obtain 6 test solutions containing release oil, carnauba wax, and vegetable oil, each weighing 2 g, wherein the concentrations of carnauba wax added to the 6 samples are 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%, respectively;

[0028] (3) Accurately weigh 15 g of potassium hydroxide and add it to 10 mL of water, stirring to melt to prepare a KOH solution with a mass fraction of 60%;

[0029] (4) Take 1 mL of the KOH solution obtained in step (3) and 25 mL of anhydrous ethanol and add them to the 6 test solutions obtained in step (2), respectively, put a magnetic stirrer, connect the ground-mouth bottle to the reflux condenser, condense and reflux in a 97° C. water bath, turn on the magnetic stirring to mix and react, and stop heating when there is no obvious oil-liquid separation in the solution;

[0030] (5) Take out the solution after the reaction, pour it into a test tube immediately, cool it to room temperature, vortex it to make the particles disperse evenly, pour it into the sample cup of the turbidity meter to measure the turbidity. The measurement results are shown in Table 1:

[0031] Table 1 Carnauba wax standard curve

[0032]

[0033]

[0034] A standard curve was prepared according to the turbidity values ​​measured in Table 1, with the concentration of added carnauba wax as the horizontal axis and the measured turbidity value as the vertical axis, and a standard curve was drawn ( Figure 1 ), and the linear regression equation y=145.67x+277.51 was obtained by linear fitting. 2 is 0.9924.

[0035] Standard addition method quantitative formula:

[0036]

[0037] Where: m0 is the total mass of the solution to be tested;

[0038] m1 is the mass of baking release oil containing carnauba wax;

[0039] When y in the linear regression equation is 0, the calculated absolute value of x is 1.91%. The value of x is the value of c in the quantitative formula of the standard addition method. This value is substituted into the quantitative formula of the standard addition method for calculation. In the formula, m0 is 2g, m1 is 1g, and the calculated content of carnauba wax in baking release oil A is 3.82%.

[0040] The wax content detected in this embodiment differs from the actual wax content by only 0.18%, which is a very small difference. This shows that the detection method used in the present invention can accurately detect the wax content in the baking release oil.

[0041] Embodiment 2 Detection of beeswax content

[0042] (1) Use an electronic balance to accurately weigh 1 g of baking release oil containing 3.5% beeswax into a ground-mouth bottle, for a total of 6 portions;

[0043] (2) Add different amounts of beeswax to six ground-mouth bottles, add peanut oil to 1 g, and obtain 6 test solutions containing release oil, beeswax and vegetable oil, each weighing 2 g, wherein the concentrations of carnauba wax added to the 6 samples are 0%, 0.5%, 1%, 1.5%, 2% and 2.5%, respectively;

[0044] (3) Accurately weigh 15 g of potassium hydroxide and add it to 10 mL of water, stirring to melt to prepare a KOH solution with a mass fraction of 60%;

[0045] (4) Take 1 mL of the KOH solution obtained in step (3) and 25 mL of anhydrous ethanol and add them to the 6 test solutions obtained in step (2), respectively, put a magnetic stirrer, connect the ground-mouth bottle to the reflux condenser, condense and reflux in a 97° C. water bath, turn on the magnetic stirring to mix and react, and stop heating when there is no obvious oil-liquid separation in the solution;

[0046] (5) Take out the solution after the reaction, pour it into a test tube immediately, and cool it to room temperature ( Figure 3 ), vortex to disperse the particles evenly, pour into the turbidity meter sample cup to measure the turbidity. The measurement results are shown in Table 2:

[0047] Table 2 Beeswax standard curve data

[0048]

[0049]

[0050] A standard curve was prepared according to the turbidity values ​​measured in Table 2, with the concentration of added beeswax as the horizontal axis and the measured turbidity value as the vertical axis, and a standard curve was drawn ( Figure 2 ), and the linear regression equation y=305.63x+526.49 was obtained by linear fitting. 2 It is 0.992.

[0051] Standard addition method quantitative formula:

[0052]

[0053] Where: m0 is the total mass of the solution to be tested;

[0054] m1 is the mass of baking release oil containing beeswax;

[0055] When y in the linear regression equation is 0, the calculated absolute value of x is 1.72%. The value of x is the value of c in the quantitative formula of the standard addition method. This value is substituted into the quantitative formula of the standard addition method for calculation. In the formula, m0 is 2g, m1 is 1g, and the calculated content of beeswax in baking release oil B according to the quantitative formula of the standard addition method is 3.44%.

[0056] The wax content detected in this example differs from the actual wax content by only 0.06%, which is a very small difference. This indicates that the wax content in baking demoulding oil can be accurately detected by this detection method.

[0057] Example 3

[0058] The method and steps are the same as those in Example 1, wherein the content of carnauba wax in the baking release oil is 6%, and the concentration of the KOH solution is changed to 50%, the dosage is 1 mL, and the dosage of anhydrous ethanol is 20 mL. The measurement results are shown in Table 3:

[0059] Table 3 Carnauba wax standard curve

[0060]

[0061] The linear regression equation is: y = 13668x + 134.6, R 2 is 0.990.

[0062] The content of carnauba wax in baking release oil A was calculated to be 5.91%.

[0063] The wax content detected in this example differs from the actual wax content by only 0.09%, which is a very small difference.

[0064] Example 4

[0065] The method and steps are the same as those in Example 1, wherein the content of beeswax in the baking release oil is 6%, and the concentration of the KOH solution is changed to 25%, the amount used is 1 mL, and the amount of anhydrous ethanol used is 15 mL. The measurement results are shown in Table 4:

[0066] Table 4 Carnauba wax standard curve

[0067]

[0068]

[0069] The linear regression equation is: y = 13912x + 136.12, R 2 is 0.995.

[0070] The content of carnauba wax in baking release oil A was calculated to be 5.87%.

[0071] The wax content detected in this example differs from the actual wax content by only 0.13%, which is a very small difference.

[0072] Comparative Example 1

[0073] The method and steps are the same as those in Example 1, wherein the content of carnauba wax in the baking release oil is 6%, and the KOH solution is replaced with a 50% by mass NaOH solution in an amount of 1 mL, and the amount of anhydrous ethanol is 20 mL. The test results are shown in Table 5:

[0074] Table 5 Carnauba wax standard curve

[0075]

[0076] The linear regression equation is: y = 8820x + 5766.8, R 2 It is 0.1504.

[0077] The content of carnauba wax in baking release oil A was calculated to be 3.92%.

[0078] The wax content detected in this example differs from the actual wax content by 2.08%, which is a large difference. 2 Less than 0.99, the result is not linear. The solution after the reaction is in a semi-solid state. Figure 4 The measured turbidity value is relatively large. However, the particles in the reaction solution after saponification with KOH solution in Example 3 are relatively dispersed. Figure 3 , and it can remain stable for a long time after vortexing, so KOH was selected as the saponifying agent.

[0079] Comparative Example 2

[0080] Use external standard method to detect the wax content in baking release oil:

[0081] (1) Use an electronic balance to accurately weigh 0.5 g of baking release oil containing 6% carnauba wax into a ground-mouth bottle, and add 0.5 g of soybean oil as the test solution;

[0082] (2) Add different amounts of carnauba wax to six ground-mouth bottles, and add soybean oil to 1 g to obtain 6 standard solutions containing beeswax and soybean oil, each weighing 2 g. The concentrations of carnauba wax added to the 6 samples are 0.5%, 1%, 2%, 3%, 4%, and 5%, respectively;

[0083] (3) Accurately weigh 10 g of potassium hydroxide and add it to 10 mL of water, stirring to melt to prepare a KOH solution with a mass fraction of 50%;

[0084] (4) Take 1 mL of the KOH solution obtained in step (3) and 20 mL of anhydrous ethanol and add them to 6 parts of the standard solvent obtained in step (2) and the test solution obtained in step (1), respectively, put in a magnetic stirrer, connect the ground-mouth bottle to a reflux condenser, condense and reflux in a 97° C. water bath, turn on the magnetic stirrer to mix and react, and stop heating when there is no obvious oil-liquid separation in the solution;

[0085] (5) Take out the solution after the reaction, pour it into a test tube immediately, cool it to room temperature, vortex it to make the particles disperse evenly, pour it into the sample cup of the turbidity meter to measure the turbidity. The measurement results are shown in Table 6:

[0086] Table 6 Brazil palm wax standard curve data

[0087]

[0088] A standard curve was prepared according to the turbidity values ​​measured in Table 6, with the concentration of added carnauba wax as the abscissa and the measured turbidity value as the ordinate. A linear regression equation y=7914.2x+6.7849 was obtained by linear fitting, R 2 is 0.998.

[0089] External standard method quantitative formula:

[0090] Where: m0 is the total mass of the solution to be tested;

[0091] m1 is the mass of baking release oil containing carnauba wax;

[0092] A is the turbidity value of the liquid to be tested;

[0093] a is the slope value in the standard curve;

[0094] b is the intercept value in the standard curve;

[0095] The turbidity value of the test liquid, 343.1, is put into the formula for calculation, and the calculated C value is 8.50%, that is, the content of carnauba wax in the baking release oil is 8.50%.

[0096] The wax content detected in this comparative example differs from the actual wax content by 2.5%, which is a large difference and the value is too large, indicating that the wax in phospholipids and vegetable oils will affect the detection results of the external standard method. Therefore, the external standard method cannot be used to accurately detect the wax content in the baking release oil.

Claims

1. A method for detecting wax content in baking release oil, characterized in that: The detection method combines the saponification reaction method and the standard addition method to detect the wax content in the baking demoulding oil.

2. The method for detecting wax content in baking release oil according to claim 1, characterized in that: The following steps are involved: (1) Accurately weigh 3-6 portions of baking release oil with unknown wax content and place them in containers; (2) adding different proportions of natural wax and vegetable oil into a container containing baking release oil to obtain a mixed test solution; (3) Add KOH solution and anhydrous ethanol to the mixed test solution obtained in step (2), mix well and place in a constant temperature water bath for saponification reaction until the reaction is complete; (4) Take out the solution after the reaction is complete, cool it, disperse it evenly, and then measure the turbidity; (5) Draw a standard curve and calculate the wax content in baking release oil.

3. The method for detecting wax content in baking release oil according to claim 2, characterized in that: The different proportions of natural waxes described in step (2) are any 3-6 kinds of natural waxes with concentrations of 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%, respectively.

4. The method for detecting the wax content in baking release oil according to claim 2, characterized in that: The natural wax in step (2) is carnauba wax or beeswax, and the vegetable oil is any one of soybean oil, peanut oil, rapeseed oil and corn oil.

5. The method for detecting the wax content in baking release oil according to claim 2, characterized in that: The mass fraction of the KOH solution in step (3) is 25%-60%, and the volume ratio of the mixed test solution: KOH solution: anhydrous ethanol is 2:1:15-25.

6. The method for detecting the wax content in baking release oil according to claim 5, characterized in that: The mass fraction of the KOH solution in step (3) is 60%; the volume ratio of the mixed test solution: KOH solution: anhydrous ethanol is 2:1:

25.

7. The method for detecting the wax content in baking release oil according to claim 2, characterized in that: The conditions for the saponification reaction in step (3) are as follows: the container containing the mixed solution is connected to a reflux condenser, condensed water is introduced, and the container is placed in a constant temperature water bath at 95-100° C. and refluxed until the reaction is complete.

8. The method for detecting the wax content in baking release oil according to claim 7, characterized in that: The temperature of the thermostatic water bath was 97°C, and a stirring bar was added to the reaction vessel to accelerate the reaction.

9. The method for detecting the wax content in baking release oil according to claim 2, characterized in that: The standard curve described in step (5) is drawn with the added natural wax concentration as the horizontal axis and the turbidity value as the vertical axis to draw the standard curve, and the standard curve formula is obtained: The intercept of the standard curve on the horizontal axis is the unknown concentration , the wax content in baking release oil is , where m0 is the total mass of baking release oil, natural wax and vegetable oil, and m1 is the mass of baking release oil.

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