Method for improving solubility of ascorbyl palmitate in grease and application of ascorbyl palmitate

Abstract

The invention discloses a method for improving solubility of ascorbyl palmitate in grease and application of the ascorbyl palmitate. The method mainly comprises two steps of modification and purification. In the modification step, ascorbyl palmitate and stearoyl chloride react under pyridine catalysis, and the reaction conditions comprise specific temperature, time and magnetic stirring, so that the reaction is uniformly carried out. The purification step involves dissolving, washing, drying and filtering to obtain a purified modified product. The invention also relates to the modified ascorbyl palmitate prepared by the method, and discusses application of the modified ascorbyl palmitate as an additive in preparation of oil such as soybean oil, sunflower seed oil, rapeseed oil or palm oil. Specifically, the additive can significantly improve the oxidation resistance of grease, and reduce the viscosity and usage amount of palm oil during food frying. The ascorbyl palmitate modified by the method has better solubility in grease, and a new solution is provided for oxidation resistance and modification of the grease.

Description

Technical Field

[0001] The invention belongs to the field of food additives, and specifically discloses a method for improving the solubility of ascorbyl palmitate in oils and fats and an application thereof. Background Art

[0002] As a recognized high-efficiency, nutritious and multifunctional food additive, ascorbyl palmitate occupies an important position in the food industry, especially in the application of edible oils. However, despite its many advantages, in actual application, the solubility of ascorbyl palmitate in the oil environment has become a bottleneck problem that cannot be ignored. The low solubility not only limits its flexible application in the oil processing process, such as it is difficult to disperse evenly in the oil, resulting in uneven antioxidant effect; at the same time, in the storage link, low solubility may also affect its stability in the oil, thereby shortening the shelf life of the oil product. In addition, in some specific food formulations that require high concentrations of ascorbyl palmitate, the solubility limitation has become an insurmountable obstacle.

[0003] At present, although there are some methods aimed at increasing the solubility of ascorbyl palmitate, most of these methods rely on physical means, such as increasing the processing temperature or increasing the stirring intensity. However, the effects of these physical methods are often unsatisfactory. Not only is the solubility improvement limited, but it may also have an adverse effect on the biological activity of ascorbyl palmitate. For example, high temperature may cause its structural destruction, thereby reducing its antioxidant properties.

[0004] Therefore, there is an urgent need to develop a new method that can significantly improve the solubility of ascorbyl palmitate in oils and fats while ensuring that its biological activity is well maintained. Such a method will have far-reaching significance for broadening the application range of ascorbyl palmitate and improving the overall quality of food and oil products. Through chemical modification or bioengineering technology and other means, ascorbyl palmitate can be precisely controlled so that it has better solubility and stability while maintaining its original biological activity, which will become the focus of future research. Summary of the invention

[0005] To solve the above problems, the present invention discloses a method for improving the solubility of ascorbyl palmitate in oils and fats and its application. The method introduces a specific fatty chain into the molecular structure of ascorbyl palmitate through acylation modification, thereby significantly improving its solubility in oils and fats.

[0006] The present invention includes the following technical solutions:

[0007] A method for improving the solubility of ascorbyl palmitate in oils and fats, the method comprising modifying and purifying ascorbyl palmitate, wherein the modification step 1) is achieved by reacting ascorbyl palmitate with stearyl chloride under pyridine catalysis, and the purification step 2) is to obtain the purified modified ascorbyl palmitate by dissolving, washing, drying and filtering.

[0008] Furthermore, in the above-mentioned method for improving the solubility of ascorbyl palmitate in oils and fats, the modification step 1) includes, by weight, dissolving 10-30 parts of ascorbyl palmitate in anhydrous ethanol, adding 3-10 parts of stearoyl chloride and 0.5-1.5 parts of pyridine, reacting at 50-80°C for 3-6 hours, and maintaining magnetic stirring during the reaction to ensure uniform reaction; after the reaction, removing ethanol and unreacted stearoyl chloride by reduced pressure distillation to obtain a modified product.

[0009] Furthermore, in the above method for improving the solubility of ascorbyl palmitate in oils and fats, the mass volume ratio of ascorbyl palmitate to anhydrous ethanol is 10-30:100 g / mL.

[0010] Furthermore, in the above-mentioned method for improving the solubility of ascorbyl palmitate in oils and fats, the purification step 2) comprises: dissolving the modified product in ethyl acetate, washing with saturated brine 3-6 times, collecting the organic layer, drying with anhydrous sodium sulfate, and filtering to obtain purified modified ascorbyl palmitate; wherein the mass volume ratio of ascorbyl palmitate to ethyl acetate is 10-30:100-300 g / mL.

[0011] The invention also discloses a modified ascorbyl palmitate, which is prepared by the above method.

[0012] The invention also discloses the application of the modified ascorbyl palmitate as an additive in the preparation of oils and fats.

[0013] Furthermore, in the above application, the oil is selected from soybean oil, sunflower oil, rapeseed oil or palm oil.

[0014] Furthermore, in the above application, the additive is an additive for improving the antioxidant capacity of oils and fats.

[0015] Furthermore, in the above application, the additive is an additive that reduces the viscosity of palm oil when frying food.

[0016] Furthermore, in the above application, the additive is an additive for reducing the amount of palm oil used in frying foods.

[0017] The present invention has the following beneficial effects:

[0018] The invention discloses a method for improving the solubility of ascorbyl palmitate in oils and fats and an application thereof. By means of a specific chemical modification method, the solubility of ascorbyl palmitate in oils and fats is successfully improved, and its application range is broadened, so that it can be used in more types of oils and fats and food formulations.

[0019] The modified ascorbyl palmitate has good dispersibility and stability in oils and fats, which is beneficial to its application in oil processing and preservation, and improves the quality and shelf life of food and oil products.

[0020] The modified ascorbyl palmitate is used in fried foods to inhibit the acid value of fats, reduce the viscosity of fats, effectively reduce the oil absorption of French fries, and have higher production efficiency.

[0021] The method of the invention is simple to operate, has mild reaction conditions, is easy to industrialize for production, and has high purity and stable performance of the modified product, thus having broad market prospects and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 OSI test results of different vegetable oils;

[0023] Figure 2 Frying oil acid value results;

[0024] Figure 3 OSI test results for frying oil;

[0025] Figure 4 Average oil absorption graph of French fries;

[0026] Figure 5 Frying oil viscosity diagram. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiment of the present invention is clearly and completely described below, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, rather than all embodiments. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the scope of protection of the present invention. The reagent or instrument used in the embodiment of the present invention do not indicate the manufacturer, and are all conventional reagent products that can be obtained by commercial purchase.

[0028] Example 1

[0029] A method for improving the solubility of ascorbyl palmitate in oils and fats comprises the following steps:

[0030] 1) Modification step: 20 g of ascorbyl palmitate was dissolved in 100 mL of anhydrous ethanol, 4 g of stearoyl chloride and 0.8 g of pyridine were added, and the mixture was reacted at 65° C. for 4 hours. After the reaction was completed, the ethanol and unreacted stearoyl chloride were removed by vacuum distillation to obtain a modified product.

[0031] 2) Purification step: The modified product was dissolved in 200 mL of ethyl acetate, washed four times with saturated brine, the organic layer was collected, dried over anhydrous sodium sulfate, and filtered to obtain the purified modified ascorbyl palmitate.

[0032] Example 2

[0033] A method for improving the solubility of ascorbyl palmitate in oils and fats comprises the following steps:

[0034] 1) Modification step: 10 g of ascorbyl palmitate was dissolved in 100 mL of anhydrous ethanol, 3 g of stearoyl chloride and 0.5 g of pyridine were added, and the mixture was reacted at 5° C. for 6 hours. During the reaction, magnetic stirring was maintained to ensure uniform reaction. After the reaction, ethanol and unreacted stearoyl chloride were removed by vacuum distillation to obtain a modified product.

[0035] 2) Purification step: The modified product was dissolved in 100 mL of ethyl acetate, washed three times with saturated brine, the organic layer was collected, dried over anhydrous sodium sulfate, and filtered to obtain the purified modified ascorbyl palmitate.

[0036] Example 3

[0037] A method for improving the solubility of ascorbyl palmitate in oils and fats comprises the following steps:

[0038] 1) Modification step: 30 g of ascorbyl palmitate was dissolved in 100 mL of anhydrous ethanol, 10 g of stearoyl chloride and 1.5 g of pyridine were added, and the mixture was reacted at 80° C. for 3 hours. During the reaction, magnetic stirring was maintained to ensure uniform reaction. After the reaction, ethanol and unreacted stearoyl chloride were removed by vacuum distillation to obtain a modified product.

[0039] 2) Purification step: The modified product was dissolved in 300 mL of ethyl acetate, washed with saturated brine for 6 times, the organic layer was collected, dried over anhydrous sodium sulfate, and filtered to obtain the purified modified ascorbyl palmitate.

[0040] Comparative Example 1

[0041] Ascorbyl palmitate is not modified.

[0042] Test Example 1

[0043] Vegetable oil characterization experiments

[0044] 1. Solubility test:

[0045] A series of temperature points of 80°C, 90°C, 100°C, and 110°C were set for testing. The modified ascorbyl palmitate of Example 1 and the ascorbyl palmitate of the comparative example were weighed and added to appropriate amounts of soybean oil, sunflower oil, and rapeseed oil, respectively, to ensure that the amount of oil was sufficient to dissolve the ascorbyl palmitate that might be added. The mixture containing ascorbyl palmitate and oil was placed in a thermostatic water bath with a set temperature. A magnetic stirrer or a mechanical stirrer was used to stir the mixture until the ascorbyl palmitate was completely dissolved or reached a dissolution equilibrium. The stirring time can be adjusted according to actual conditions, but it should be ensured to be long enough to eliminate the concentration gradient during the dissolution process.

[0046] At each temperature point, observe the clarity and transparency of the solution. If there are undissolved solid particles in the solution, continue to add small amounts of ascorbyl palmitate and repeat the above steps until saturated solubility is reached. Record the mass of ascorbyl palmitate required to reach saturated solubility at each temperature point.

[0047] Solubility calculation:

[0048] The solubility was calculated using the formula: Solubility (g / 100 g oil) = (mass of ascorbyl palmitate required to reach saturated solubility / mass of oil) x 100.

[0049] The results are shown in Table 1.

[0050] Table 1 Solubility test

[0051]

[0052]

[0053] The above results show that the modified ascorbyl palmitate has higher solubility in soybean oil, sunflower oil and rapeseed oil.

[0054] 2. Antioxidant performance evaluation:

[0055] Using the samples of Example 1 and Comparative Example 1, 5% ascorbyl palmitate solution was prepared respectively:

[0056] For the sample of Example 1: weigh 5 g of the modified ascorbyl palmitate, add soybean oil (sunflower oil / rapeseed oil) to 100 g, and stir at 110° C. until it is completely dissolved.

[0057] For the sample of Comparative Example 1: weigh 5 g of the modified ascorbyl palmitate, add soybean oil (sunflower seed / rapeseed oil) to 100 g, and stir at 90° C. until completely dissolved.

[0058] The oxidation curve of the sample was obtained by the OXITEST oxidation stability analyzer. The induction period (IP) is the time required to reach the starting point of oxidation, corresponding to the detectable degree of rancidity or sudden change in oxidation rate. The longer the induction period, the higher the antioxidant activity of the sample. Test conditions: 90°C, oxygen: 6 bar.

[0059] The results are as follows Figure 1 As shown, the above results indicate that the modified ascorbyl palmitate has higher antioxidant activity.

[0060] Test Example 2

[0061] Frying oil (French fries) application experiment

[0062] Frying is a traditional processing method that allows food to mature quickly at high temperatures. The high-temperature frying process can quickly kill microorganisms in food, thereby extending the shelf life of food. At the same time, it can also improve the flavor of food and give it a golden color. Factors that affect the quality of frying oil in this process include frying methods, frying oil types, frying temperature, frying time, and antioxidants. Reasonable control of these factors during the frying process will effectively reduce the deterioration of oils and the loss of nutrients. Otherwise, the physical and chemical properties of frying oil and food will change rapidly, chemical indicators such as viscosity and acid value will increase, and harmful substances will accumulate, thereby damaging human health.

[0063] Prepare three portions of 4.5 kg of palm oil without adding antioxidants and pour them into a frying pan. Accurately weigh 0g / kg (blank group), 0.2g / kg Example 1 sample (Example 1), and 0.2g / kg Comparative Example 1 sample (Comparative Example 1), respectively, add them to the pot and heat and stir evenly, then heat to a constant temperature of 180±5°C and maintain for 15 minutes. Subsequently, 200 grams of French fries are taken each time for frying, and each frying time is 3 minutes. After 10 consecutive times, the oil in the frying pan is kept at a temperature of 180±5°C for 2 hours. After the standing period is over, the above frying operation is performed again, and a total of 20 fryings are completed per day, and this is continued for 4 days. After the frying operation is completed every day, an oil sample weighing 100±5g will be taken out of the pot and placed in a refrigerator at 2-8°C for testing.

[0064] 1. Oxidative stability of frying oil (acid value, IP value)

[0065] 1) Acid value: Dissolve 10g of frying oil sample in 50L of a mixed solution of n-hexane: isopropanol (1:1), and add three drops of phenolphthalein reagent as an indicator. Titrate with 0.01mol / L potassium hydroxide solution until the solution turns slightly red and does not change color for 30s. Repeat the same steps without adding oil sample as the blank group. The calculation formula for acid value is as follows:

[0066]

[0067] Where:

[0068] X AV : Acid value, in milligrams per gram (mg / g);

[0069] V: The volume of the standard titration solution consumed in the sample determination, in milliliters (mL);

[0070] V: The volume of the standard titration solution consumed in the corresponding blank determination, in milliliters (mL);

[0071] c: molar concentration of the standard titration solution, in moles per liter (mol / L);

[0072] 56.1: molar mass of potassium hydroxide in grams per mole (g / mol);

[0073] m: The weight of the oil sample, in grams (g).

[0074] The results of frying oil acid value are shown in Figure 2 , indicating that the acid value of oil has been well suppressed.

[0075] 2) Lipid oxidation analysis test

[0076] The oxidation curve of the sample was measured by OXITEST oxidation stability analyzer. The induction period (IP) is the time required to reach the starting point of oxidation, corresponding to the detectable rancidity or sudden change in oxidation rate. The longer the induction period, the longer the oxidation induction time, the better the oil quality, and vice versa. Test conditions: 90℃, oxygen: 6bar.

[0077] Oxidation induction time under different frying times Figure 3 As shown in Figure 2, as the frying time increases, the oxidation induction time of the frying fat decreases continuously. However, the induction period of the embodiment group is relatively the longest, and the antioxidant activity is the best.

[0078] 2. Average oil absorption of French fries

[0079] Weigh French fries of uniform size (recorded as W1 = 200g), put the French fries into hot oil for frying, and ensure that the frying time and temperature are consistent. After frying, quickly remove the French fries and place them on oil-absorbing paper or kitchen paper to drain excess oil. Weigh the total weight of the drained French fries (recorded as W2).

[0080] Calculate the weight of oil absorbed by the French fries: weight of oil absorbed by the French fries = W2-W1.

[0081] Calculating the average oil absorption: To get a more accurate average oil absorption, you can perform the above test multiple times and calculate the weight of oil absorbed by the fries in each test. Then, add these values ​​and divide by the number of tests to get the average oil absorption.

[0082] Results Figure 4 As shown in the above results, when the palm oil with modified ascorbyl palmitate was used to fry French fries, the oil absorption of the French fries was the lowest. This shows that the use of modified ascorbyl palmitate in vegetable oil for frying food can improve production efficiency, reduce costs and promote environmental protection.

[0083] 3. Frying oil viscosity

[0084] During high-temperature frying, the change in oil viscosity mainly depends on the frying time and temperature. Since oil will produce a series of degradation products during long-term high-temperature frying, such as dimers, trimers, polymers and epoxides, the accumulation of these substances in the oil causes the viscosity to increase. The viscosity of oil is an important factor affecting the oil content of fried foods. The higher the oil viscosity, the higher the oil content in the fried food. The viscosity of the product is tested at 25°C using a viscometer. The experimental results are as follows: Figure 5 , indicating that vegetable oil products using modified ascorbyl palmitate have lower viscosity and higher quality.

[0085] In summary, the present invention successfully improves the solubility of ascorbyl palmitate in oils and fats through specific chemical modification means, which provides strong support for broadening its application scope and also provides new ideas and methods for oil processing and food formulation design.

[0086] The above embodiments show and describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A method for improving the solubility of ascorbyl palmitate in oils and fats, characterized in that: The method comprises modifying and purifying ascorbyl palmitate, wherein the modification step 1) is achieved by reacting ascorbyl palmitate with stearyl chloride under pyridine catalysis, and the purification step 2) is to obtain the purified modified ascorbyl palmitate by dissolving, washing, drying and filtering.

2. The method for improving the solubility of ascorbyl palmitate in oils and fats according to claim 1, characterized in that: The modification step 1) comprises, by weight: Dissolve 10-30 parts of ascorbyl palmitate in anhydrous ethanol, add 3-10 parts of stearoyl chloride and 0.5-1.5 parts of pyridine, and react at 50-80°C for 3-6 hours. During the reaction, magnetic stirring should be maintained to ensure uniform reaction. After the reaction, remove ethanol and unreacted stearoyl chloride by reduced pressure distillation to obtain a modified product.

3. The method for improving the solubility of ascorbyl palmitate in oils and fats according to claim 2, characterized in that: The mass volume ratio of ascorbyl palmitate to anhydrous ethanol is 10-30:100 g / mL.

4. The method for improving the solubility of ascorbyl palmitate in oils and fats according to claim 2, characterized in that: The purification step 2) comprises: dissolving the modified product in ethyl acetate, washing with saturated brine for 3-6 times, collecting the organic layer, drying with anhydrous sodium sulfate, and filtering to obtain purified modified ascorbyl palmitate; wherein the mass volume ratio of ascorbyl palmitate to ethyl acetate is 10-30:100-300 g / mL.

5. A modified ascorbyl palmitate, characterized in that The method is prepared by any one of claims 1 to 4.

6. Use of the modified ascorbyl palmitate as claimed in claim 5 as an additive in the preparation of oils and fats.

7. The use according to claim 6, characterized in that: The oil is selected from soybean oil, sunflower oil, rapeseed oil or palm oil.

8. The use according to claim 6, characterized in that: The additive is an additive for improving the antioxidant capacity of oils and fats.

9. The use according to claim 6, characterized in that: The additive is an additive for reducing the viscosity of palm oil when frying food.

10. The use according to claim 6, characterized in that: The additive is an additive for reducing the amount of palm oil used in frying foods.

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