Method for determining acid value in propolis soft capsules

Abstract

The application provides a method for determining the acid value of propolis soft capsules, and relates to the field of determination of the acid value of oils and fats. Specifically, the method comprises the following steps: 1) extraction: the content of the propolis soft capsules is extracted with an extraction solvent, and then separated to obtain an oil-containing extraction liquid 1; 2) washing: the extraction liquid 1 is added into a mixture of anhydrous sodium sulfate and a washing liquid, extracted, and then allowed to stand to separate into layers, and the lower layer of the washing liquid is discarded, and the extraction liquid 2 is obtained by washing 1-5 times in the same manner; 3) oil preparation: the extraction liquid 2 is dehydrated and filtered, and then the solvent is removed by rotary evaporation under reduced pressure to obtain the oil; and 4) the acid value in the oil is determined by using a potentiometric titration method. According to the method, flavonoids and phenolic acids in the oil of the propolis soft capsules are effectively separated, the interference of the flavonoids and the phenolic acids on the determination of the acid value is reduced, and then the acid value in the oil is accurately characterized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of determination of acid value in oil and fat, in particular to a method for determining acid value in propolis soft capsules. BACKGROUND

[0002] The acid value refers to the milligrams of potassium hydroxide required to neutralize one gram of free fatty acid. The acid value can indicate the freshness of the oil and fat, and is closely related to the safe storage of the oil and fat. Propolis soft capsules are a functional health food, and the contents mainly consist of propolis, vegetable oil, beeswax, antioxidants and the like. The main functional component is propolis, which has the effect of enhancing human immunity.

[0003] Patent CN 109580613 A discloses a method for determining the acid value in cakes and breads by cold solvent indicator titration, which comprises the following steps: (1) extracting liquid oil: crushing the sample, adding an extraction agent with a volume of 3-5 times the volume of the sample, and stirring for 30-60 min, then standing for extraction, filtering and evaporating the extraction agent to obtain liquid oil; (2) determining the acid value: dissolving the liquid oil obtained in step (1) with an ether-isopropanol mixture, and then determining the acid value by titration. The present application determines the acid value by titration, and the extraction process is more simple and fast, and the experimental data is reliable and reproducible.

[0004] Patent CN 103776825 A discloses a method for determining the acid value of deep-colored oil. The method comprises the following steps: accurately weighing an appropriate amount of oil sample and placing it in a 250 mL conical flask, adding 50 mL of a neutral ether-ethanol mixed solvent, and thoroughly shaking to dissolve the oil sample completely. Add 2-3 drops of 1% phenolphthalein-ethanol solution, and then add 50 mL of saturated neutral saline solution and shake thoroughly. Titrate with a calibrated KOH standard solution until the color of the saline solution layer turns pink and does not disappear within 30 seconds. The acid value can be calculated according to the volume of KOH standard solution consumed.

[0005] Propolis contains a large amount of flavonoids and phenolic acids. The present inventors accidentally found during the propolis soft capsule sample retention test that flavonoids and phenolic acids in propolis can slowly migrate into oil, and flavonoids and phenolic acids can react with alkali, causing the acid value in oil to gradually increase. Flavonoids and phenolic acids do not belong to the category of free fatty acids, and in order to accurately characterize the acid value in oil, it is necessary to separate flavonoids and phenolic acids from oil.

[0006] At present, for the determination of acid value in propolis soft capsules, the most commonly used detection method is GB 5009.229-2016 National Food Safety Standard Determination of Acid Value in Food, which is to extract the oil in the soft capsule with petroleum ether I first, then remove the petroleum ether I under reduced pressure to obtain the oil, and then test the acid value in the oil by titration method. As described in patent CN 109430782 A, but the method of extracting oil with petroleum ether I cannot remove the flavonoids and phenolic acids migrated to the oil, resulting in false high acid value detection results, which cannot accurately represent the acid value in the oil. After consulting relevant literature, there is no literature on separating flavonoids and phenolic acids from oil before determining the acid value in the oil.

[0007] In order to solve the problem that the existing acid value determination method cannot effectively remove the interference of flavonoids and phenolic acids in propolis soft capsules on the acid value in the oil, the present application provides a method for determining the acid value in the oil, which can separate a large amount of flavonoids and phenolic acids from the oil to reduce the interference of flavonoids and phenolic acids on the acid value determination, and then accurately represent the acid value in the oil. SUMMARY

[0008] The purpose of the present application is to provide a method for determining the acid value in propolis soft capsules, which can separate a large amount of flavonoids and phenolic acids from the oil to reduce the interference of flavonoids and phenolic acids on the acid value determination, and then accurately represent the acid value in the oil.

[0009] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0010] A method for determining the acid value in propolis soft capsules is provided, characterized in that it comprises the following steps:

[0011] 1) Extraction: The contents of propolis soft capsules are extracted with an extraction solvent, separated, and an oil-containing extract 1 is obtained;

[0012] 2) Washing: The extract 1 is added with a mixture of anhydrous sodium sulfate and a washing liquid, extracted, and allowed to stand and separate into layers, and the lower layer of washing liquid is discarded, and the same method is used for washing 1-5 times to obtain an extract 2;

[0013] 3) Oil preparation: The extract 2 is dehydrated and filtered, and the solvent is removed by rotary evaporation under reduced pressure to obtain oil;

[0014] 4) The acid value in the oil is determined by potentiometric titration method.

[0015] Preferably, in step (1), the volume of the extraction solvent is 8-12 times, and further preferably 10 times, the mass of the propolis contents.

[0016] Preferably, the extraction solvent in step 1) is selected from petroleum ether, n-hexane and cyclohexane.

[0017] Preferably, the petroleum ether in step 1) is petroleum ether I with a boiling range of 30-60℃.

[0018] Preferably, the separation in step 1) is at least one of centrifugation, extraction, filtration, and liquid separation, and further preferably, is centrifugation.

[0019] Preferably, the washing liquid in step 2) is selected from a mixture of alcohol and water. Further preferably, the alcohol is at least one of ethanol, methanol, and isopropanol.

[0020] Preferably, the volume fraction of alcohol in the washing liquid in step 2) is 30-70%, further preferably, is 40-60%, and most preferably, is 50%.

[0021] Preferably, the amount of the washing liquid used in step 2) is 2-3 times, and further preferably, is 2 times, the amount of the extraction liquid 1.

[0022] Preferably, the drying agent used in step 3) is anhydrous sodium sulfate.

[0023] Preferably, the specific steps of the potentiometric titration method in step 4) are as follows: weigh 0.5-2g of the oil sample and place it in a titration cup, add 60-80mL of a mixture of neutral ether-ethanol (2:1), stir to dissolve the oil, and titrate to the endpoint with a sodium hydroxide titrant according to the potentiometric titration method; and further preferably, the specific steps of the potentiometric titration method in step 5) are as follows: weigh 0.8-1.4g of the oil sample and place it in a titration cup, add 60mL of a mixture of neutral ether-ethanol (2:1), stir to dissolve the oil, and titrate to the endpoint with a sodium hydroxide titrant according to the potentiometric titration method.

[0024] Preferably, the concentration of the sodium hydroxide titrant is 0.05mol / L.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1) The patent can effectively separate flavonoids and phenolic acids in propolis soft capsule oil, reduce the interference of flavonoids and phenolic acids on acid value detection, and thus accurately characterize the acid value of the oil.

[0027] 2) The patent has good specificity and does not adversely affect the acid value of the oil itself. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the following specific examples are further illustrated, but the following examples are only preferred embodiments of the present application, not all. Based on the examples in the embodiments, other examples obtained by those skilled in the art without creative labor are within the scope of the present application. It is worth mentioning that the raw materials used in the present application are ordinary market products, and their sources are not specifically limited. The technical and scientific terms used in the examples have the meanings generally understood by those skilled in the art to which the present application belongs.

[0029] Example group 1

[0030] Example 1-1: Take 9 parts of mixed uniform propolis soft capsule sample, each 5g, add 50mL petroleum ether I (30-60℃), shake vigorously, and make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 100mL of saturated anhydrous sodium sulfate containing 40%, 50%, 60% volume ratio of ethanol water, methanol water, isopropanol water washing liquid, shake vigorously for about 1min, stand for stratification, discard the lower washing liquid, and wash 3 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate, transferred to a 100mL flat bottom flask, and dried under reduced pressure at 50℃ water bath, to obtain oil removing flavonoids and phenolic acids. Take the oil and determine the acid value in the oil by potentiometric titration.

[0031] Example 1-2: Take 9 parts of mixed uniform propolis soft capsule sample, each 5g, add 50mL n-hexane, shake vigorously, and make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 100mL of saturated anhydrous sodium sulfate containing 40%, 50%, 60% volume ratio of ethanol water, methanol water, isopropanol water washing liquid, shake vigorously for about 1min, stand for stratification, discard the lower washing liquid, and wash 3 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate, transferred to a 100mL flat bottom flask, and dried under reduced pressure at 50℃ water bath, to obtain oil removing flavonoids and phenolic acids. Take the oil and determine the acid value in the oil by potentiometric titration.

[0032] Example 1-3: Take 9 parts of the mixed and uniform propolis soft capsule sample, each 5 g, add 50 mL of cyclohexane, shake vigorously to make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 100 mL of 40%, 50%, 60% volume ratio of saturated anhydrous sodium sulfate containing ethanol water, methanol water, isopropanol water washing liquid to each part, shake vigorously for about 1 min, stand for stratification, discard the lower layer of washing liquid, and wash 3 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate dehydration, transferred to a 100 mL flat bottom flask, and rotary evaporated at 50°C water bath under reduced pressure to obtain oil and fat without flavonoids and phenolic acids. Take the oil and fat to determine the acid value in the oil and fat by potential titration method.

[0033] Example 1-4: Take 7 g of the mixed and uniform propolis soft capsule sample, add 56 mL of petroleum ether I (30-60°C), shake vigorously to make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 112 mL of 40% volume ratio of saturated anhydrous sodium sulfate containing ethanol water washing liquid to each part, shake vigorously for about 1 min, stand for stratification, discard the lower layer of washing liquid, and wash 4 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate dehydration, transferred to a 100 mL flat bottom flask, and rotary evaporated at 50°C water bath under reduced pressure to obtain oil and fat without flavonoids and phenolic acids. Take the oil and fat to determine the acid value in the oil and fat by potential titration method.

[0034] Example 1-5: Take 10 g of the mixed and uniform propolis soft capsule sample, add 100 mL of n-hexane, shake vigorously to make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 250 mL of 50% volume ratio of saturated anhydrous sodium sulfate containing methanol water washing liquid to each part, shake vigorously for about 1 min, stand for stratification, discard the lower layer of washing liquid, and wash 3 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate dehydration, transferred to a 100 mL flat bottom flask, and rotary evaporated at 50°C water bath under reduced pressure to obtain oil and fat without flavonoids and phenolic acids. Take the oil and fat to determine the acid value in the oil and fat by potential titration method.

[0035] Example 1-6: Take 5 g of the mixed and uniform propolis soft capsule sample, add 60 mL of cyclohexane, shake vigorously to make the sample fully dispersed and uniform. Centrifuge, transfer the centrifugal liquid to the extraction funnel, add 180 mL of 60% volume ratio of saturated anhydrous sodium sulfate containing isopropanol water washing liquid to each part, shake vigorously for about 1 min, stand for stratification, discard the lower layer of washing liquid, and wash 2 times in the same way. The extraction solvent layer is filtered by anhydrous sodium sulfate dehydration, transferred to a 100 mL flat bottom flask, and rotary evaporated at 50°C water bath under reduced pressure to obtain oil and fat without flavonoids and phenolic acids. Take the oil and fat to determine the acid value in the oil and fat by potential titration method.

[0036] Comparative Example 1: 3 portions of the mixed propolis soft capsule sample, each 5 g, were dissolved in 50 mL of petroleum ether I (30-60℃), n-hexane, and cyclohexane, respectively, and dispersed by vigorous shaking. Centrifugation was performed, and the centrifugal liquid was transferred to a 100 mL flat-bottom flask and dried by rotary evaporation under reduced pressure at 50℃ water bath to obtain propolis-containing oil. The acid value of the oil was determined by potential titration.

[0037] Table 1. Acid value results of Example 1-1, 1-2, and 1-3

[0038]

[0039]

[0040] Table 2. Acid value results of Example 1-4, 1-5, and 1-6

[0041] Sample Acid value, mg / g Example 1-4 1.03 Example 1-5 1.12 Example 1-6 1.25

[0042] Table 3. Acid value results of Comparative Example 1

[0043] Extraction solvent Petroleum ether I (30-60°C) n-Hexane Cyclohexane Acid value, mg / g 2.02 1.96 2.01

[0044] As can be clearly seen from Tables 1 and 2, the acid value determination results of the propolis soft capsules are very small under the relevant variables, indicating that the patent method has good applicability.

[0045] As can be clearly seen from the comparison of Example 1-1-1-6 and Comparative Example 1, the method provided by the present application significantly reduces the influence of flavonoids and phenolic acids on the acid value of the oil, and the effect of separating flavonoids and phenolic acids is obvious; and by adjusting the relevant parameters, the acid value determination results of the propolis soft capsules are very small, indicating that the patent method has good applicability.

[0046] Comparative Example Group 2:

[0047] According to the process of propolis soft capsules, propolis-free propolis soft capsule negative samples were prepared.

[0048] Comparative Example 2-1: 3 portions of the mixed propolis soft capsule negative sample, each 5 g, were dissolved in 50 mL of petroleum ether I (30-60℃), n-hexane, and cyclohexane, respectively, and dispersed by vigorous shaking. Centrifugation was performed, and the centrifugal liquid was transferred to a 100 mL flat-bottom flask and dried by rotary evaporation under reduced pressure at 50℃ water bath to obtain oil. The acid value of the oil was determined by potential titration.

[0049] Comparative Example 2-2: Take 9 portions of the mixed propolis soft capsule negative sample, each 5 g, add 50 mL of petroleum ether I (30-60°C), and shake vigorously to disperse the sample evenly. Centrifuge, and transfer the centrifugal liquid to an extraction funnel. Add 100 mL of saturated anhydrous sodium sulfate-containing ethanol water, methanol water, and isopropanol water with a volume ratio of 40%, 50%, and 60% to each portion, shake vigorously for about 1 min, and let it stand to separate the layers. Discard the lower layer of the washing liquid, and wash it in the same way for 3 times. Dehydrate the extraction solvent layer through anhydrous sodium sulfate, transfer it to a 100 mL flat-bottom flask, and evaporate it under reduced pressure at 50°C water bath to obtain the washed oil. Take the oil and determine the acid value in the oil by potentiometric titration.

[0050] Comparative Example 2-3: Take 9 portions of the mixed propolis soft capsule negative sample, each 5 g, add 50 mL of n-hexane, and shake vigorously to disperse the sample evenly. Centrifuge, and transfer the centrifugal liquid to an extraction funnel. Add 100 mL of saturated anhydrous sodium sulfate-containing ethanol water, methanol water, and isopropanol water with a volume ratio of 40%, 50%, and 60% to each portion, shake vigorously for about 1 min, and let it stand to separate the layers. Discard the lower layer of the washing liquid, and wash it in the same way for 3 times. Dehydrate the extraction solvent layer through anhydrous sodium sulfate, transfer it to a 100 mL flat-bottom flask, and evaporate it under reduced pressure at 50°C water bath to obtain the washed oil. Take the oil and determine the acid value in the oil by potentiometric titration.

[0051] Comparative Example 2-4: Take 9 portions of the mixed propolis soft capsule negative sample, each 5 g, add 50 mL of cyclohexane, and shake vigorously to disperse the sample evenly. Centrifuge, and transfer the centrifugal liquid to an extraction funnel. Add 100 mL of saturated anhydrous sodium sulfate-containing ethanol water, methanol water, and isopropanol water with a volume ratio of 40%, 50%, and 60% to each portion, shake vigorously for about 1 min, and let it stand to separate the layers. Discard the lower layer of the washing liquid, and wash it in the same way for 3 times. Dehydrate the extraction solvent layer through anhydrous sodium sulfate, transfer it to a 100 mL flat-bottom flask, and evaporate it under reduced pressure at 50°C water bath to obtain the treated oil. Take the oil and determine the acid value in the oil by potentiometric titration.

[0052] Table 4. Acid value results of Comparative Example 2-1

[0053] Extraction solvent Petroleum ether I (30-60°C) n-Hexane Cyclohexane Acid value, mg / g 1.24 1.23 1.19

[0054] Table 5. Acid value results of Comparative Examples 2-2, 2-3, and 2-4

[0055]

[0056]

[0057] From the results of Table 4 and Table 5, compared with the data of Comparative Example 2-1, the acid value difference under each comparative test data is very small, it is determined that the patent method has very small influence on the acid value of oil itself, which shows that the patent method has good specificity.

[0058] Finally, it should be noted that the above content is only used to illustrate the technical solutions of the present application, and is not a limitation on the protection scope of the present application. Simple modifications or equivalent replacements of the technical solutions of the present application made by those skilled in the art do not deviate from the essence and scope of the technical solutions of the present application.

Claims

1. A method for determining the acid value in propolis soft capsules, characterized by, The method comprises the following steps: 1) extraction: the content of propolis soft capsule is extracted with an extraction solvent, separated, and an extract 1 containing oil and fat is obtained; the extraction solvent is at least one selected from petroleum ether, n-hexane and cyclohexane; 2) washing: the extract 1 is added into a mixture of anhydrous sodium sulfate and a washing liquid, extracted, and separated into two layers; the lower washing liquid is discarded, and the upper extract 2 is obtained by washing 1-5 times; the washing liquid is a mixture of alcohol and water; the alcohol is at least one selected from ethanol, methanol and isopropanol; the volume fraction of alcohol in the washing liquid is 50%; 3) oil and fat preparation: the extract 2 is dehydrated and filtered, and the solvent is removed by rotary evaporation under reduced pressure to obtain oil and fat; 4) the acid value of the oil and fat is determined by using a potential titration method.

2. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The amount of the extraction solvent in step 1) is 8-12 times.

3. The method for determining the acid value of propolis soft capsules according to claim 2, characterized in that, The amount of the extraction solvent in step 1) is 10 times.

4. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The petroleum ether in step 1) is petroleum ether I with a boiling range of 30-60℃.

5. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The separation in step 1) is at least one of centrifugation, extraction, filtration and liquid separation.

6. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The amount of the washing liquid in step 2) is 2-3 times of the extract 1.

7. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The drying agent used in step 3) is anhydrous sodium sulfate.

8. The method for determining the acid value of propolis soft capsules according to claim 1, characterized in that, The specific steps of the potential titration method in step 4) are as follows: 0.5-2 g of the oil and fat sample is weighed and placed in a titration cup, 60-80 mL of 2:1 neutral ethyl ether-ethanol mixed liquid is added, the oil is dissolved by stirring, and the end point is titrated with sodium hydroxide titration liquid according to the potential titration method; the concentration of the sodium hydroxide titration liquid is 0.05 mol / L.

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