Food fresh-keeping antioxidant composition and preparation method thereof

Abstract

The invention relates to the technical field of antioxidant compositions, and discloses a food fresh-keeping antioxidant composition and a preparation method thereof, based on an esterification reaction mechanism, under the catalytic action of protonic acid, caffeic acid, gallic acid and pentaerythritol are used as raw materials to prepare a caffeic acid-gallic acid pentaerythritol ester monomer; the preparation method comprises the following steps: reacting a hydroxyl group in a caffeic acid-gallic acid pentaerythritol ester monomer with a carboxyl group in protonated sodium alginate to prepare a sodium alginate-based antioxidant functional component; the sodium alginate-based antioxidant functional component and deionized water are prepared, and the food fresh-keeping antioxidant composition is prepared. The food fresh-keeping antioxidant composition has excellent oxidation resistance and fresh-keeping performance, and can be applied to fresh-keeping films of baked foods such as bread, toast and cakes.

Description

Technical Field

[0001] This invention relates to the field of antioxidant composition technology, and more particularly to a food preservation antioxidant composition and its preparation method. Background Technology

[0002] Baked goods such as bread, toast, and pastries are popular with consumers due to their rich taste, high nutritional value, and convenience. However, because baked goods have a high fat content, they are prone to oxidation under the influence of oxygen, light, and temperature. This oxidation produces ketones, aldehydes, and aldehyde acids, which have distinctive odors, leading to rancidity and spoilage. This shortens the shelf life of baked goods and can also have adverse effects on the body's sensory system. Therefore, effectively controlling rancidity and spoilage of baked goods and extending their shelf life has become an urgent problem to be solved in the baking industry.

[0003] Currently, preservation methods for baked goods are mainly divided into three categories: chemical preservation, biological preservation, and physical preservation. Physical preservation, due to its high safety, significant effects, and ease of operation, has become one of the important means of preserving baked goods. Packaging helps reduce the contact between food and the outside air, prevents the growth of microorganisms inside the food, and extends the shelf life of baked goods. However, with changing consumption patterns, traditional food packaging methods are no longer sufficient to meet the diverse needs of the market. In recent years, active packaging technology has been increasingly widely used. Unlike traditional packaging technology, active packaging involves directly adding or coating antioxidants onto a plastic film to form a functional packaging film with antioxidant properties. This allows the film to come into contact with baked goods during migration or react with external environmental factors, preventing oxidation and spoilage, thereby extending the shelf life of the food.

[0004] Studies have found that sodium alginate (SA) is a natural polysaccharide with excellent biocompatibility, film-forming properties, and hydrophilicity. Coating plastic films with it for preserving baked goods can reduce moisture loss, maintain flavor and aroma, enhance appearance, and improve mechanical properties. Natural antioxidants, due to their lack of environmental pollution, pesticide residues, and health threats associated with chemically synthesized preservatives, have become a research hotspot in the food preservation industry. Introducing natural antioxidants into sodium alginate can effectively delay the oxidative deterioration of baked goods, maintain their freshness and taste, and extend their shelf life. Summary of the Invention

[0005] This invention utilizes a newly developed pentaerythritol caffeic acid-gallic acid monomer to modify sodium alginate and then dissolves it to prepare a food preservation antioxidant composition. This food preservation antioxidant composition has excellent antioxidant and preservation properties and can be used in preservation films for baked goods such as bread, toast, and pastries.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a food preservation antioxidant composition includes the following steps: Step 1: Based on the esterification reaction mechanism, under the catalysis of protic acid, caffeic acid-gallic acid pentaerythritol ester monomer was prepared from caffeic acid, gallic acid and pentaerythritol. A sodium alginate-based antioxidant functional component was prepared by reacting the hydroxyl group in the caffeic acid-gallic acid pentaerythritol ester monomer with the carboxyl group in protonated sodium alginate. Step 2: Prepare a food preservation antioxidant composition by mixing sodium alginate-based antioxidant functional components with deionized water.

[0007] Furthermore, the protic acid is either p-toluenesulfonic acid or trifluoromethanesulfonic acid.

[0008] Furthermore, the caffeic acid-gallic acid pentaerythritol ester monomer is caffeic acid-gallic acid pentaerythritol ester monomer I, and the molar ratio of caffeic acid, gallic acid and pentaerythritol is 1:1-1.05:1.

[0009] Furthermore, the caffeic acid-gallic acid pentaerythritol ester monomer is caffeic acid-gallic acid pentaerythritol ester monomer II, and the molar ratio of caffeic acid, gallic acid and pentaerythritol is 1:1-1.05:1.

[0010] Furthermore, the preparation method of the protonated sodium alginate is as follows: formamide and N,N-dimethylformamide are added to a reactor, followed by p-toluenesulfonic acid and sodium alginate. The temperature is raised to 50-60°C and stirred for 20-40 minutes to obtain protonated sodium alginate.

[0011] Furthermore, the volume ratio of formamide to N,N-dimethylformamide is 10:9-9.05.

[0012] Furthermore, the preparation method of the food preservation antioxidant composition is as follows: dissolve 1-5 parts by weight of sodium alginate-based antioxidant functional component in 90-110 parts by weight of deionized water, stir, let stand to degas, and prepare the food preservation antioxidant composition.

[0013] Furthermore, the mass fraction of the food preservation antioxidant composition is 1%-5%.

[0014] Furthermore, the food preservation antioxidant composition is used in the preservation film of baked goods, which may be bread, toast, or pastries.

[0015] The beneficial effects of this invention are as follows: Based on the esterification reaction mechanism, caffeic acid-gallic acid pentaerythritol ester monomer was prepared using caffeic acid, gallic acid and pentaerythritol as raw materials; then sodium alginate was modified to prepare sodium alginate-based antioxidant functional components. A food preservation antioxidant composition was prepared by combining sodium alginate-based antioxidant functional components with deionized water. Experimental results demonstrate that the food preservation antioxidant composition prepared in this invention possesses excellent antioxidant and preservation properties. Detailed Implementation

[0016] To reduce the physical loss of small molecule antioxidants during the processing, storage, and use of polymer materials and to fully utilize their antioxidant effects, this invention independently developed a sodium alginate-based antioxidant functional component, which was then formulated with deionized water to obtain a food preservation antioxidant composition. Utilizing the synergistic effect of caffeic acid and gallic acid in its structure to achieve the technical objective of antioxidation, this composition endows the preservation film with excellent antioxidant properties, thereby extending the shelf life of baked goods.

[0017] Example 1: A food preservation antioxidant composition a is prepared by controlling the molar ratio of caffeic acid, gallic acid, and pentaerythritol to be 1:1:1, comprising the following steps: (1) Preparation of caffeic acid-gallic acid pentaerythritol ester monomer I: The preparation mechanism is as follows: under the catalysis of p-toluenesulfonic acid, the carboxyl groups in caffeic acid and gallic acid undergo esterification reaction with the hydroxyl groups in pentaerythritol to obtain caffeic acid-gallic acid pentaerythritol ester monomer I. The specific experimental steps are as follows: 3.6g of caffeic acid and 3.4g of gallic acid are added to 100mL of N,N-dimethylformamide, stirred well, 0.5g of p-toluenesulfonic acid and 2.8g of pentaerythritol are added, the oil bath is heated to 110℃, the reaction is stirred for 6h, the solvent is removed by rotary evaporation, the product is filtered after cooling to room temperature, washed, and vacuum dried at 60℃ for 8h to obtain caffeic acid-gallic acid pentaerythritol ester monomer I; (2) Preparation of sodium alginate-based antioxidant functional component I: The preparation mechanism is as follows: Based on the carboxyl-hydroxy esterification reaction mechanism, sodium alginate reacts with caffeic acid-gallic acid pentaerythritol ester monomer to prepare sodium alginate-based antioxidant functional component I. The specific experimental steps are as follows: 50 mL of formamide / N,N-dimethylformamide solution with a volume ratio of 10:9 was added to the reactor, along with 0.1 g of p-toluenesulfonic acid and 0.2 g of sodium alginate. The system temperature was then adjusted. The temperature was raised to 55°C and stirred for 30 min to partially protonate sodium alginate, then 0.08 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.1 g of 4-dimethylaminopyridine were added, followed by 2.3 g of caffeic acid-gallic acid pentaerythritol ester monomer. The mixture was stirred at 45°C for 30 h, the solid material was separated by centrifugation, washed, and vacuum dried at 80°C for 5 h to prepare sodium alginate-based antioxidant functional component I. (3) Prepare food preservation antioxidant composition a. The specific experimental steps are as follows: Dissolve 2 parts by weight of sodium alginate-based antioxidant functional component I in 100 parts by weight of deionized water, stir thoroughly at room temperature, and after dissolution, let stand to remove bubbles to prepare food preservation antioxidant composition a.

[0018] Example 2: A food preservation antioxidant composition b is prepared by controlling the molar ratio of caffeic acid, gallic acid, and pentaerythritol to be 1:2:1, comprising the following steps: (1) Preparation of caffeic acid-gallic acid pentaerythritol ester monomer II. The preparation mechanism is as follows: under the catalysis of p-toluenesulfonic acid, the carboxyl groups in caffeic acid and gallic acid undergo esterification reaction with the hydroxyl groups in pentaerythritol to obtain caffeic acid-gallic acid pentaerythritol ester monomer II. The specific experimental steps are as follows: 3.6g of caffeic acid and 6.8g of gallic acid are added to 100mL of N,N-dimethylformamide, stirred well, 0.8g of p-toluenesulfonic acid and 2.8g of pentaerythritol are added, the oil bath is heated to 110℃, the reaction is stirred for 6h, the solvent is removed by rotary evaporation, the product is filtered after cooling to room temperature, washed, and vacuum dried at 60℃ for 8h to obtain caffeic acid-gallic acid pentaerythritol ester monomer II; (2) Preparation of sodium alginate-based antioxidant functional component II: The preparation mechanism is as follows: Based on the carboxyl-hydroxy esterification reaction mechanism, sodium alginate reacts with caffeic acid-gallic acid pentaerythritol ester monomer to prepare sodium alginate-based antioxidant functional component II. The specific experimental steps are as follows: 70 mL of formamide / N,N-dimethylformamide solution with a volume ratio of 10:9 is added to the reactor, along with 0.5 g of p-toluenesulfonic acid and 1 g of sodium alginate. The system temperature is then adjusted. The temperature was raised to 55℃ and stirred for 30 min to partially protonate sodium alginate, then 0.4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.5 g of 4-dimethylaminopyridine were added, followed by 11 g of caffeic acid-gallic acid pentaerythritol ester monomer. The mixture was stirred at 45℃ for 30 h, the solid material was separated by centrifugation, washed, and vacuum dried at 80℃ for 5 h to prepare sodium alginate-based antioxidant functional component II. (3) Prepare food preservation antioxidant composition b. The specific experimental steps are as follows: Dissolve 2 parts by weight of sodium alginate-based antioxidant functional component II in 100 parts by weight of deionized water, stir thoroughly at room temperature, and after dissolution, let stand to remove bubbles to prepare food preservation antioxidant composition b.

[0019] Example 3: The preparation of food preservation antioxidant composition c includes the following steps: Dissolve 5 parts by weight of sodium alginate-based antioxidant functional component I in 100 parts by weight of deionized water, stir thoroughly at room temperature, and after dissolution, allow to stand to remove bubbles to prepare food preservation antioxidant composition c.

[0020] Example 4: The preparation of a food preservation antioxidant composition d includes the following steps: Dissolve 5 parts by weight of sodium alginate-based antioxidant functional component II in 100 parts by weight of deionized water, stir thoroughly at room temperature, and allow to stand to remove bubbles after dissolution to prepare food preservation antioxidant composition d.

[0021] Example 5: The preparation of food preservation antioxidant composition e includes the following steps: Dissolve 1 part by weight of sodium alginate-based antioxidant functional component I in 100 parts by weight of deionized water, stir thoroughly at room temperature, and after dissolution, let stand to remove bubbles to prepare food preservation antioxidant composition e.

[0022] Example 6: The preparation of a food preservation antioxidant composition f includes the following steps: Dissolve 1 part by weight of sodium alginate-based antioxidant functional component II in 100 parts by weight of deionized water, stir thoroughly at room temperature, and after dissolution, allow to stand to remove bubbles to prepare food preservation antioxidant composition f.

[0023] Example 7: The application experiment of food preservation antioxidant composition a is as follows: The food preservation antioxidant composition a was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was dried at room temperature for 1 hour, and then the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film a.

[0024] Example 8: The application experiment of food preservation antioxidant composition b is as follows: The food preservation antioxidant composition b was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was dried at room temperature for 1 hour, and then the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film b.

[0025] Example 9: The application experiment of food preservation antioxidant composition C is as follows: The food preservation antioxidant composition c was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was then dried at room temperature for 1 hour. Subsequently, the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film c.

[0026] Example 10: The application experiment of food preservation antioxidant composition d is as follows: The food preservation antioxidant composition d was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was dried at room temperature for 1 hour, and then the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film d.

[0027] Example 11: The application experiment of food preservation antioxidant composition e is as follows: The food preservation antioxidant composition e was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was dried at room temperature for 1 hour, and then the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film e.

[0028] Example 12: The application experiment of food preservation antioxidant composition f is as follows: The food preservation antioxidant composition f was slowly poured onto the surface of a polyethylene film (20 μm thick) and spin-coated evenly. It was dried at room temperature for 1 hour, and then the film was placed in a 2% CaCl2 aqueous solution to prepare the antioxidant preservation film f.

[0029] Comparative example: Preparation of conventional food preservation film: The only difference between its preparation process and that of antioxidant food preservation film a is that a 20μm thick polyethylene film is used instead of antioxidant food preservation film a.

[0030] Performance testing: I. Antioxidant Performance Test: The antioxidant capacity of the food preservation film samples was characterized using the DPPH free radical scavenging rate. The test method was as follows: 9.85 mg of DPPH standard was dissolved in 100 mL of anhydrous ethanol, and then transferred to a 250 mL volumetric flask and diluted to volume to obtain a 0.1 mmol / L DPPH ethanol solution. 0.5 g of the sample was cut into small pieces and soaked in 10 mL of anhydrous ethanol. The sample was then sealed and stored in a 37℃ shaking incubator. After 24 h, 1 mL of the supernatant was added to 1 mL of the prepared 0.1 mmol / L DPPH ethanol solution, mixed thoroughly, and allowed to stand in the dark at room temperature for 1 h. The sample was then tested using a UV spectrophotometer. The change in absorbance at a wavelength of 517 nm was used to characterize the free radical scavenging capacity of the sample. The calculation formula is as follows: DPPH free radical scavenging rate (%) = (absorbance of blank DPPH ethanol solution - absorbance of DPPH ethanol solution after adding supernatant) / absorbance of blank DPPH ethanol solution × 100%; The test results are shown in Table 1 below; Table 1. Test results of antioxidant properties of antioxidant food preservation films Product Number DPPH free radical scavenging rate (%) Antioxidant food preservation film a 61.5 Antioxidant food preservation film b 68.4 Antioxidant food preservation film c 62.8 Antioxidant food preservation film d 69.7 Antioxidant food preservation film e 42.3 Antioxidant food preservation film f 49.9 Regular food preservation film 0 According to the experimental results in Table 1, the antioxidant preservation film prepared by this invention has good antioxidant properties. When the amount of sodium alginate-based antioxidant functional component added gradually increases, the DPPH free radical scavenging rate of the antioxidant preservation film shows a trend of first increasing and then stabilizing with the increase of its amount. Therefore, it can be seen that food preservation antioxidant composition a and food preservation antioxidant composition b can significantly improve the antioxidant properties of the preservation film.

[0031] II. Acidity Test: Fresh bread was cut into 30mm×30mm shapes and packaged with plastic wrap. All samples were then stored at 25℃ and 50% humidity for 12 days. Samples were taken on days 3, 7, and 12. The bread samples were crushed, and 3g of the sample was added to an Erlenmeyer flask. 50mL of petroleum ether was added, and the flask was sealed with aluminum foil and stored at room temperature for at least 12 hours. The sample solution was then filtered, and the filtrate was poured into a rotary evaporator (30℃, negative pressure) to evaporate and remove the petroleum ether. After complete evaporation, the oil from the bread sample was obtained. The oil was collected, and its acid value was determined according to GB5009.229-2016, "National Food Safety Standard - Determination of Acid Value in Food". The test results are shown in Table 2 below; Table 2. Acidity test results of antioxidant food preservation films III. Sensory evaluation test: Fresh bread samples were packaged with plastic wrap, while the control group was not packaged. All samples were then stored at 25°C and 50% humidity for 12 days. Samples were taken on the 3rd, 7th and 12th days of storage, and sensory evaluation was conducted on four indicators: appearance, color, smell and texture of the bread samples. The test results are shown in Table 3 below; Table 3 Sensory evaluation test results of antioxidant food preservation films Appearance: A indicates complete, full, smooth surface, and no spots; A1 indicates relatively complete, no defects, relatively smooth surface, and a few spots; A2 indicates relatively complete, with fewer defects and obvious spots; A3 indicates defective, rough surface, and many spots. Color: Normal indicates that the bread surface is light brown or brownish-gray, uniform, and without whitening; + indicates that the bread surface is light brown or brownish-gray, uniform, with slight whitening; ++ indicates that the bread surface color is relatively uniform, with whitening; +++ indicates that the bread surface color is uneven, with severe whitening. Tissue condition: B indicates fine texture, strong elasticity, uniform pores, clear texture, and no chipping after slicing; B1 indicates relatively fine texture, elasticity, relatively uniform pores, clear texture, and minimal chipping after slicing; B2 indicates locally excessive hardness, and chipping after slicing; B3 indicates hardness, lack of elasticity, uneven texture, and severe chipping after slicing. According to the experimental results in Tables 1, 2 and 3, the food preservation antioxidant composition a and food preservation antioxidant composition b prepared by the present invention have achieved significant improvements in both antioxidant and preservation performance.

Claims

1. A method for preparing a food preservative antioxidant composition, characterized in that, Includes the following steps: Step 1: Based on the esterification reaction mechanism, under the catalysis of protic acid, caffeic acid-gallic acid pentaerythritol ester monomer was prepared from caffeic acid, gallic acid and pentaerythritol. A sodium alginate-based antioxidant functional component was prepared by reacting the hydroxyl group in the caffeic acid-gallic acid pentaerythritol ester monomer with the carboxyl group in protonated sodium alginate. Step 2: Prepare a food preservation antioxidant composition by mixing sodium alginate-based antioxidant functional components with deionized water.

2. The method for preparing a food preservation antioxidant composition according to claim 1, characterized in that, The protic acid is either p-toluenesulfonic acid or trifluoromethanesulfonic acid.

3. The method for preparing a food preservation antioxidant composition according to claim 1, characterized in that, The caffeic acid-gallic acid pentaerythritol ester monomer is caffeic acid-gallic acid pentaerythritol ester monomer I, and the molar ratio of caffeic acid, gallic acid and pentaerythritol is 1:1-1.05:

1.

4. The method for preparing a food preservative antioxidant composition according to claim 1, characterized in that, The caffeic acid-gallic acid pentaerythritol ester monomer is caffeic acid-gallic acid pentaerythritol ester monomer II, and the molar ratio of caffeic acid, gallic acid and pentaerythritol is 1:1-1.05:

1.

5. The method for preparing a food preservative antioxidant composition according to claim 1, characterized in that, The method for preparing protonated sodium alginate is as follows: formamide and N,N-dimethylformamide are added to a reactor, followed by p-toluenesulfonic acid and sodium alginate. The temperature is raised to 50-60℃ and stirred for 20-40 minutes to obtain protonated sodium alginate.

6. The method for preparing a food preservation antioxidant composition according to claim 5, characterized in that, The volume ratio of formamide to N,N-dimethylformamide is 10:9-9.

05.

7. The method for preparing a food preservation antioxidant composition according to claim 1, characterized in that, The food preservation antioxidant composition is prepared by dissolving 1-5 parts by weight of sodium alginate-based antioxidant functional component in 90-110 parts by weight of deionized water, stirring, and allowing it to stand to remove bubbles, thereby obtaining the food preservation antioxidant composition.

8. A food preservative antioxidant composition prepared according to any one of claims 16, characterized in that, The mass fraction of the food preservation antioxidant composition is 1%-5%.

9. The food preservation antioxidant composition prepared according to any one of claims 1-6 is used in a food preservation film for baked goods, wherein the baked goods may be bread, toast, or pastries.

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