CN104311952A - Antioxidant LDPE (Low-Density Polyethylene) film containing rutin component and application of LDPE film - Google Patents

Abstract

The invention discloses an anti-oxidation LDPE film containing rutin component and its application. The LDPE film in the invention is made by adding rutin to low-density polyethylene particles and mixing them, and then plasticizing them. The mass concentration of the rutin in the prepared LDPE film is 3-8%. In the present invention, rutin, a natural product extracted from Sophora japonica, is added to low-density polyethylene particles to make an LDPE active film. The application effect shows that the natural product rutin has good migration in the prepared LDPE active film rate and can migrate into the contained food. When the peanut oil is packaged and preserved with the LDPE active film, the shelf life of the peanut oil can be effectively extended. Moreover, the method for extracting and purifying the natural product rutin from pagoda japonica provided by the present invention improves the extraction purity of rutin without reducing the yield of rutin.

Description

A kind of antioxidant LDPE film containing rutin component and its application

technical field

The invention belongs to the technical field of active material application, and in particular relates to an anti-oxidation LDPE film containing rutin component and its application.

Background technique

Low-density polyethylene (LDPE) film is a plastic material with low crystallinity and a molecular weight of 50,000 to 500,000. LDPE film is a milky white and translucent waxy solid resin with a low softening point and melts when it exceeds the softening point. It has good thermal welding performance, good molding and processing performance, good softness, impact resistance toughness and low temperature resistance. , can work at -60°C to -80°C, and has excellent electrical insulation (especially high-frequency insulation), so it is suitable for thermoplastic molding to process various molding processes, and has good molding processability.

LDPE film is non-toxic, has very low water absorption, hardly absorbs water, and has excellent chemical stability, such as being relatively stable to acids, alkalis, salts, and organic solvents. However, due to the chemical structure of low-density polyethylene is composed of non-polar molecules, its macromolecules are formed by van der Waals force and hydrogen bonds, and the composition of non-polar molecules makes the internal intermolecular force weak , the tensile strength of plastic is small, according to the principle of "like dissolves like", it has high permeability to non-polar gases such as CO ₂ and O ₂ , and has poor permeability to polar gases such as water vapor. Because of its excellent physical and chemical properties, it is currently It is generally recognized and widely used in food inner packaging, such as beverages, dairy products, biscuits, fruit and vegetable juices, etc. According to statistics, China's LDPE consumption in 2005 was 2.43 million tons, an increase of 0.7% year-on-year, accounting for 40.6% of the total polyethylene consumption, and about 3% of the consumption was used in the field of food inner packaging, and this figure is still growing.

However, the ordinary LDPE film has a high oxygen permeability rate, and when it is used as the inner packaging of food, the anti-oxidation protection effect on the food inside is weak. Therefore, how to improve the protection ability of LDPE film to the food contained in it, and how to preserve the food contained in it more effectively is a difficult problem to solve.

Contents of the invention

The purpose of the present invention is to provide an anti-oxidation LDPE film containing rutin component and its application, so as to make up for the deficiencies in the prior art.

In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions to achieve:

An anti-oxidation LDPE film containing rutin components, the LDPE film is made by adding rutin to low-density polyethylene particles and mixing, and then plasticizing, the rutin is prepared in the LDPE The mass concentration of the film is 3-8%.

The density of the low-density polyethylene particles is 0.9200-0.9240g/cm ³ , the melt flow rate is 4.5-7.5g/10min, and the melting point is 106-111°C.

Described rutin is extracted from Huai Mi, and its extraction steps are as follows:

1) Add Sophora japonica to the ethanol solution after crushing, perform ultrasonic vibration, adjust the temperature and heat the extraction, then collect the extract; rotate the extract to remove the ethanol solution by rotating and concentrating under reduced pressure, add petroleum ether to the extract, mix well and let stand , after removing the petroleum ether layer, the remaining solution was allowed to stand overnight at 4°C, centrifuged the extract at 4000r/min for 15min, discarded the supernatant, and dried the lower precipitate in an oven at 80°C to obtain crude rutin;

2) The crude rutin was dissolved in methanol, passed through a silica gel chromatography column, washed with petroleum ether and chloroform, and then eluted with methanol, the eluate was collected, concentrated under reduced pressure, and dried to obtain pure rutin.

The volume ratio concentration of ethanol in the ethanol solution is 70%, the solid-liquid ratio of the extract is 1:40, the extraction time is 45min, and the extraction temperature is 40°C.

The silica gel in the silica gel chromatography column is 100-160 mesh silica gel.

The invention also provides the application of the oxidation-resistant LDPE film in the preparation of high-fat food or edible oil preservative.

The LDPE film is used as the inner packaging of food.

Described edible oil is peanut oil or olive oil.

Methanol extraction method is used to detect rutin in edible oil. The specific steps are: prepare a series of rutin standard solutions, weigh the oil samples to be tested, add different amounts of said rutin standard solutions respectively and stir, so that the two phases are fully mixed. Uniform; add methanol, shake and extract at a constant temperature of 25°C for 60 minutes, centrifuge after extraction, dilute the upper extract to volume, filter through a 0.45 μm microporous membrane filter, inject it into a high-performance liquid chromatography system for detection, and calculate the content of rutin ;

The HPLC detection conditions are: Agilent1200; UV detector; analytical column: Lichrospher C-18, 2.1mm×250mm; mobile phase: methanol-water-acetic acid gradient elution; column temperature: 30°C; flow rate: 0.3 ml/min; injection volume: 10 μL.

In the present invention, the natural product extracted from pagoda japonica--rutin is added to low-density polyethylene particles to make an LDPE active film, and the application effect shows that the natural product--rutin has a good The migration rate can be migrated into the contained food. When the peanut oil is packaged and preserved with the LDPE active film, the shelf life of the peanut oil can be effectively extended. Moreover, the method for extracting and purifying the natural product rutin from pagoda japonica provided by the present invention improves the extraction purity of rutin without reducing the yield of rutin.

Description of drawings

Figure 1: Rutin content in peanut oil added with 3% and 5% LDPE active film at 30°C;

Figure 2: Rutin content in peanut oil added with 3% and 5% LDPE active film at 60°C;

Figure 3: Peanut oil peroxide value of adding LDPE film (A film: 0.0mg/g, B film: 30.0mg/g, C film: 50.0mg/g) (a) and directly adding rutin (b) at 30°C change map;

Figure 4: Peanut oil peroxide value of adding LDPE film (A film: 0.0mg/g, B film: 30.0mg/g, C film: 50.0mg/g) (a) and directly adding rutin (b) at 60°C change map;

Figure 5: Rutin standard curve.

Detailed ways

The present invention will be described in detail below in conjunction with the examples.

1. Extract and purify rutin from Huai Mi

1. Ultrasonic-assisted ethanol extraction method

Accurately weigh 10.0000g of crushed Sophora japonica in a filter paper tube, place it in a stoppered Erlenmeyer flask, add a certain volume fraction of ethanol solution, put it in an ultrasonic oscillator, adjust the temperature and heat for a certain period of time, collect the extract, and heat it Wash the filter paper cylinder with water several times, combine the extracts, rotate and concentrate under reduced pressure (temperature 30°C, speed 25r/min) to remove ethanol, then transfer the extracts to a separatory funnel, add petroleum ether at a volume of 1:1, mix well, Let it stand for 15 minutes, remove the petroleum ether layer (to remove chlorophyll), repeat 3-4 times. After standing overnight in the refrigerator at 4°C, centrifuge the extract at 4000r/min for 15min, discard the supernatant, dry the lower layer in an oven at 80°C for 3h, and weigh it. This is crude rutin, and record the weight.

Take by weighing 10.0g Huai Mi that has baked to constant weight, carry out the test according to factor level table (table 1) and above-mentioned ultrasonic-assisted ethanol extraction method, analyze ethanol volume ratio concentration, solid-liquid ratio, ultrasonic treatment time and ultrasonic temperature effect Sophorae rutin extraction rate, to determine the best extraction process.

Table 1: L9(3 ⁴ ) Orthogonal Factors and Levels

Table 2: Orthogonal test result table

From the results of the orthogonal test in Table 2, we can see that the influencing factors of the extraction process of rutin from Sophora japonica are A>C>B>D. The greater the range R value, the greater the impact of this factor on the comprehensive index, that is, this factor is an important influencing factor. Therefore, the main factor affecting the extraction of rutin from Sophora japonica is the volume fraction of ethanol, followed by time, solid-liquid ratio, and ultrasonic treatment temperature. Among them, the best process for extracting rutin from Sophora japonica is A ₂ B ₃ C ₃ D ₃ , that is, the volume ratio concentration of ethanol is 70%, the ratio of solid to liquid is 1:40, the extraction time is 45min, and the temperature is 40℃. The results showed that the extraction amount of crude rutin from Sophora japonica was 1.712g, and the extraction rate reached 17.12%. The rutin obtained by the method has high extraction rate, simple method, low cost and is more suitable for large-scale production.

2. Purification of rutin

Column chromatography is used to separate rutin from other impurities according to the different adsorption forces of crude rutin extract on silica gel. Use 100-160 mesh silica gel as filler, weigh about 50 times the loading amount of silica gel into the flask, add sufficient amount of chloroform, stir and mix with a glass rod to form a suspension with good fluidity, put it into ultrasonic cleaning In the container, treat it for 10-15 minutes to remove the air; shake the suspension and quickly pour it into the column, open the valve at the lower end, let the eluent flow out, until the height of the packing remains unchanged, and the entire chromatography column does not stop during use. dry up. After the preparation of the chromatographic column is completed, take 0.05g of the crude extract and load it, and then use petroleum ether, chloroform, and methanol for elution, and collect the methanol eluate; concentrate the collected methanol eluate, and repeat the above chromatographic process , the collected methanol eluate was concentrated under reduced pressure, dried at 60°C, and the yellow powder was collected and weighed.

After dissolving the yellow powder of rutin obtained by separation into methanol, carry out liquid chromatography detection, and adopt the external standard method, use rutin standard substance as contrast, do purity detection to the methanol solution (2 μ g/ml) of Sophorae rutin, three times parallel.

Chromatographic analysis conditions: Agilent1200; UV detector; analytical column: Lichrospher C-18 (2.1mm×250mm); mobile phase: methanol-water-acetic acid (mass fraction 1%) gradient elution; column temperature: 30°C; flow rate: 0.3ml/min; injection volume: 10μL. The results are shown in Table 3:

Table 3: Determination table of rutin purity

It can be seen from Table 3 that the average peak area of rutin is 30.5612 (RSD=0.176%), the precision of the results meets the detection requirements, and the data is reliable. The purity of the rutin obtained by separation and purification is more than or equal to 98.5%.

It can be seen that the method provided by the invention is used to prepare rutin, a natural product of Sophora japonica, without sacrificing the yield under the condition of ensuring the purity.

2. Preparation of LDPE Antioxidant Active Film

The rutin prepared in the experiment was added to the low-density polyethylene particles to make the rutin-containing LDPE film. Under the corresponding production conditions, by controlling the content of rutin added to the LDPE film, four different types of film A (0%), film B (3%), film C (5%) and film D (8%) were prepared respectively. LDPE active film with rutin content. First, the initial concentration of rutin in the LDPE film was determined to determine the actual content of rutin in the LDPE film. 5% here represents the mass percent content of rutin in the produced LDPE film.

The prepared rutin/LDPE active film was added to peanut oil, and the effect of rutin migrated from the film on the oxidation resistance of peanut oil was studied at different temperatures for a continuous period of time, and compared with the method of directly adding rutin Contrast, compare the difference in the antioxidant effect of the two treatment methods on oil, and analyze the superiority of the LDPE active film.

1. Preparation of LDPE active film

First describe the material equipment used:

1) Low-density polyethylene particles have a density of 0.9200-0.9240g/cm ³ , a melt flow rate of 4.5-7.5g/10min, and a melting point of 106-111°C; they can be purchased from Honghui Plastic Co., Ltd., Dongguan City, Guangdong Province;

Rutin standard product: purity UV ≥ 98%, Shanghai Yuanye Biotechnology Co., Ltd.

Peanut oil (pressed peanut oil)

Methanol, ethanol, sodium thiosulfate, potassium iodide, potassium hydroxide, etc. (all of the above are analytically pure).

The rutin extracted from Sophora japonica is mixed with low-density polyethylene particles and then added to a small precision blow molding machine to produce rutin-containing LDPE film. The process flow is as follows:

LDPE raw material feeding→material plasticizing and extruding at 160℃→blowing traction→air ring cooling→herringbone splint→traction roller traction→corona treatment→film winding.

The produced LDPE film containing rutin has a smooth surface, uniform color, has the aroma of Sophora japonica, no peculiar smell, no foreign matter inside, and no adhesion.

2. Detection of rutin mobility in LDPE active film

1) Determination of initial concentration of rutin in LDPE film

(1) Preparation of standard curve

Accurately weigh 5mg of rutin standard substance, put it in a 50ml measuring bottle, add 20ml of methanol, put it on a water bath to slightly heat to dissolve, let it cool, add methanol to the mark, shake well, and get 0.1mg/ml rutin standard solution. Draw 25ml therefrom, and dilute it to a 50ml measuring bottle with distilled water to obtain a 0.05mg/ml rutin standard solution.

Pipette 0.0, 0.2, 0.3, 0.5, 0.8, 1.0ml of rutin use solution into No. 1-6 volumetric flasks respectively, and dilute to 5ml with methanol. Prepare a series of standard solutions with concentrations of 0.0, 2, 3, 5, 8, and 10 μg/ml. Qualitative by retention time, quantitative by peak area, make rutin peak area-concentration standard curve.

(2) Membrane sample processing

Accurately weigh 0.5000g of LDPE film (3%, 5%, 8%), dip it in deionized water with absorbent cotton, scrub it with ether, cut it into 0.5cm×0.5cm pieces, place it in a Soxhlet extractor, and add it accurately 150ml of isopropanol:cyclohexane mixed extraction solvent with a volume ratio of 92.5:7.5, the temperature of the water bath was controlled at 80(±0.3)°C, and the time was 4h, 6h, 9h, 12h and 24h. Rotary evaporate the extract, concentrate to dryness, dilute to 10ml with methanol, filter through a 0.45μm filter membrane, inject into high performance liquid chromatography, and determine the content of rutin.

Table 4: Initial content of rutin in LDPE film (mg/g)

(Note: *: Compared with the rutin content measured in the previous time period, there is a significant difference, p<0.05)

As shown in Table 4, after Soxhlet extraction of LDPE film for 12 hours, the amount of rutin measured basically no longer increased. It can be concluded that the rutin in the LDPE film has been basically extracted completely. After 24 hours of extraction, B film (30mg/g), C The initial concentrations of rutin in film (50mg/g) and film D (80mg/g) were 28.62±0.16, 46.79±0.32, 75.82±0.59mg/g respectively, and the calculated rutin contents were 2.86%, 4.68% and 7.58% respectively . It can be seen that there is a small difference between the measured initial concentration of rutin and the added concentration in production.

3. Rutin/Active Membrane Migration Experiment

Accurately add 0.1000g of LDPE films (0%, 3%, 5%) with different rutin contents to the peanut oil, place in a constant temperature incubator at 30±1°C, and shake once every 12 hours to ensure full contact between the film and the peanut oil . On days 0, 2, 4, 6, 8, 10, 15, 20, 25 and 30, 5.0000 g of peanut oil was accurately weighed from the Erlenmeyer flask, and the content of rutin in the peanut oil was determined.

The peanut oil itself contains rutin, and the initial content of rutin in the peanut oil on day 0 is 6.42 μg. Figure 1 shows the content of rutin in the peanut oil with the addition of rutin-containing LDPE films (3% and 5%) at 30°C. trend of change. Within 0-15 days, the rutin content in the experimental group showed an upward trend. The rutin content of the peanut oil of the 5% LDPE film reached the maximum value of 124.375 μg on the 15th day, and the maximum value of 91.875 μg was reached on the 20th day of the peanut oil film of the 3% LDPE film. Then the amount of rutin showed a slow downward trend.

Figure 2 shows that at 60°C, the content of rutin in the oil added with 3% and 5% LDPE film changed significantly, the measured maximum amount was 73.12 μg and 157.5 μg respectively, and the rutin content showed an upward trend within 0-10 days , 10-15 days after the rutin content decreased slightly, the change tended to be stable. It can be seen from the increase of rutin at the initial stage of the test that its migration rate at 60°C is greater than that at 30°C, and it can be seen that the higher the temperature, the greater the migration rate of rutin.

3. The use effect experiment of LDPE active film

The LDPE active film prepared by the present invention is used to preserve peanut oil, and at the same time, the LDPE film prepared without adding rutin and the group directly added with rutin are used as controls. After standing for a specified time, the peroxide value (POV) of peanut oil was detected.

Accurately add 0.1000g of LDPE films with different rutin contents (A film: 0.0mg/g, B film: 30.0mg/g, C film: 50.0mg/g) to 15g of peanut oil, and place them at a constant temperature of 30°C. At 0, 2, 6, 10, 15, 20, 25 and 30 days, the peroxide value of peanut oil was determined. As shown in Figure 3, the peroxidation value of peanut oil added with film B and film C was lower than that of film group A, the POV value of film C added was lower than that of film group B, and its POV value change trend was higher than that of film B Group calm. After being placed at 30°C for 30 days, the POV values of peanut oil added with film B and film C did not exceed the national standard (GB1534-2003, POV<6.0mmol/kg), and the POV values were 4.32mmol/kg and 4.82mmol/kg respectively; on the contrary , 0-30d, the peroxide value of the group added with A film increased significantly. At 30d, the peroxide value was 6.34mmol/kg, exceeding the upper limit of the national standard of 6.0mmol/kg.

It can be seen from the calculation that the actual addition amounts of rutin in groups B and C are 0.019% and 0.033%, respectively, which are equivalent to the amounts of 0.020% and 0.040% in the groups directly adding rutin. Comparing the graphs a and b in Figure 3, it can be seen that under the same storage conditions and the same amount of addition, the LDPE active film has a better effect on inhibiting oil oxidation, because the rutin in the active film migrates slowly into the oil , to maximize the antioxidant effect. In addition, slow migration has less impact on the fragrance and transparency of oils, which shows higher advantages in food packaging.

At 60°C, the antioxidant effect of the LDPE active film group on peanut oil was more significant than that of the rutin direct addition group (Figure 4), and the POV values of the peanut oil added with the active film (B film, C film) were 5.021mmol at 15 days respectively /kg and 4.108mmol/kg. In the peanut oil added with film B and film C, the actual content of rutin added is 0.019% and 0.033%, which is similar to the amount of 0.020% and 0.040% in the group directly added with rutin. In terms of the same added amount, the LDPE active film inhibited Oil oxidation is better. The use effect shows that the LDPE active film added with rutin is used to preserve peanut oil. Under the same storage conditions, the peroxide value is significantly lower than that of the LDPE active film without rutin (p<0.05), which can effectively prolong the life of peanut oil. shelf life.

4. Establishment of detection method for rutin in vegetable oil

The present invention uses methanol and acetonitrile saturated n-hexane as two extraction solvents to extract rutin from oil, and combines high-performance liquid chromatography to perform chromatographic scanning on the extracted rutin, and quantitatively determines the ideal recovery and extraction of rutin Methods.

1. Preparation of standard curve

Accurately weigh 5mg of rutin standard substance, put it in a 50ml measuring bottle, add 20ml of methanol, put it on a water bath to dissolve, let it cool, add methanol to the mark, shake well, and get 0.1mg/ml rutin standard solution. Draw 25ml therefrom, and dilute it to a 50ml measuring bottle with distilled water to obtain a 0.05mg/ml rutin standard solution.

Pipette 0.0, 0.2, 0.3, 0.5, 0.8, 1.0ml of rutin use solution into No. 1-6 volumetric flasks respectively, and dilute to 5ml with methanol. Prepare a series of standard solutions with concentrations of 0.0, 2, 3, 5, 8, and 10 μg/ml. Qualitative by retention time, quantitative peak area, make rutin peak area-concentration standard curve, as shown in Figure 5, as can be seen from Figure 5, rutin standard curve equation is: Y=17.019X-2.0905, correlation coefficient R ² =0.9994 , The content of rutin has a good linear relationship with the peak area.

2. Sample processing and determination

2.1 Methanol extraction method

Weigh 5.0000g of oil sample, place it in a 250ml Erlenmeyer flask with a stopper, add different amounts of standard rutin solution and stir on a circular oscillator for 30 minutes to fully mix the two phases. Accurately add 50.0ml methanol solvent, place in a constant temperature oscillating water tank for extraction for 60min (constant temperature 25°C, oscillating speed is medium speed), transfer to a 100ml centrifuge tube, centrifuge at 4000r/min for 10min, pour the upper extract into a 50ml graduated test tube , and set the volume to 50ml. Filter through a 0.45 μm microporous membrane filter, and inject it into the high-performance liquid chromatography system for injection.

The chromatographic conditions of high performance liquid chromatography are: Agilent1200; UV detector; analytical column: LichrospherC-18, 2.1mm × 250mm, methanol-water-acetic acid (mass fraction 1%) gradient elution; column temperature 30 ℃; flow rate 0.3mL /min.

2.2 Acetonitrile saturated n-hexane extraction method

Weigh 5.0000g of oil sample into the extractor, add different amounts of rutin standard use solution respectively, place it on a circular oscillator and stir for 30 minutes to fully mix the two phases. Add 25mL of n-hexane (saturated with acetonitrile), shake and mix well, then add 30mL of acetonitrile (saturated with n-hexane), fully extract for 1min, centrifuge at 3000r/min for 3min, transfer the acetonitrile layer to a flask, and continue to extract the n-hexane layer with acetonitrile Twice, each 10mL, combined acetonitrile layer. The combined extracts were concentrated in a water bath at 40°C to about 1 mL by rotary vacuum, transferred to a 10 mL volumetric flask, and the flask was washed several times with a small amount of methanol. Filter, carry out chromatographic analysis, obtain rutin content in the sample according to above-mentioned standard curve.

2.3 Extraction rate calculation formula

W: rutin extraction rate, %;

m2: the measured amount of rutin in the sample, μg;

m0: background content of rutin in the sample, μg;

m1: the amount of rutin added in the sample, μg.

Referring to the aforementioned sample processing method, add 0.1, 0.2, 0.5, 0.8, 1.0ml of standard rutin solution to peanut oil respectively, and use two extraction methods: methanol extraction and acetonitrile saturated n-hexane. According to the extraction rate of rutin, the extraction effects of the two solvents were compared and analyzed, and the experimental results are shown in Table 5.

Table 5 Different solvents extract rutin test result

It can be seen from Table 5 that under different rutin addition conditions, the methanol extraction rate is higher than the acetonitrile-saturated n-hexane extraction rate, and the methanol extraction method consumes less time and is easy and quick to operate, while the acetonitrile-saturated n-hexane method requires step-by-step extraction and extraction. Rotary evaporation, this method will have a greater loss of rutin during the experiment. Acetonitrile is highly toxic, and n-hexane is an extremely flammable and explosive solvent with poor safety. The extraction method was selected based on comprehensive consideration of methanol extraction.

According to the aforementioned chromatographic conditions, the rutin standard and the oil sample were injected in parallel several times. Because the background content of rutin in the oil sample did not reach the minimum detection limit determined by liquid chromatography, 1 mL of 100 μg/mL was added to the oil sample. The rutin standard solution in mL was mixed evenly, and the average value, standard deviation, and relative standard deviation were calculated according to the measured peak area, so as to analyze the precision of the determination method.

Table 6 Determination of precision of standard products

Table 7 Precision of Sample Determination

It can be seen from Table 6 and Table 7 that the precision of the standard product test results is relatively high, except for the first group which is 2.58%, the other groups are all less than 1%. The precision of the sample determination is 1.497%, which meets the requirements of the detection. It can be seen that the accuracy of this method is high and the data is reliable.

3. Recovery test

Rutin was extracted from peanut oil and olive oil by methanol extraction method according to the aforementioned sample processing method, and the recovery rate of this method was mainly used to evaluate the loss during sample pretreatment. Weigh an appropriate amount of sample into a stoppered Erlenmeyer flask, add an appropriate amount of standard solution, and measure the recovery rate. The recovery rate was calculated according to the measured amount of rutin to compare the influence of the two oil samples on the extraction effect of rutin. The experimental results are shown in Table 8.

Table 8 Determination of recovery rate

It can be seen from Table 8 that the recovery rate of the method of the present invention is 90.54%-103.78%, which can meet the needs of sample extraction and measurement. The background content of rutin in olive oil was higher than that in peanut oil, but the recovery rate of rutin was generally lower than that in peanut oil.

From the results of the precision and recovery experiments, it can be seen that the test results of the standard and samples have high precision, the precision of the standard is 0.21% to 2.58%, and the precision of the sample is 1.497%. In the recovery experiment, The recoveries of rutin were all greater than 90%, meeting the detection requirements, so this method is an ideal detection method.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art can still understand the foregoing embodiments. Modifications are made to the technical solutions described, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions claimed in the present invention.

Claims (9)

1. the anti-oxidant LDPE film containing rutin component, is characterized in that, described LDPE film is added to by rutin in Low Density Polyethylene particle after mixing, then made by plasticizing, described rutin is 3-8% in the mass concentration of the LDPE film prepared.

2. anti-oxidant LDPE film as claimed in claim 1, is characterized in that the density of described Low Density Polyethylene particle is 0.9200 ~ 0.9240g/cm ³, melt flow rate (MFR) is 4.5 ~ 7.5g/10min, fusing point: 106 ~ 111 DEG C.

3. anti-oxidant LDPE film as claimed in claim 1 or 2, it is characterized in that described rutin is extracted from the sophora bud, its extraction step is as follows:

1) add in ethanolic soln after the sophora bud being pulverized, carry out ultrasonic oscillation, after regulating heating temperatures to extract, collect extracting solution; By extracting solution rotating pressure-decreasing concentrated removing ethanolic soln, sherwood oil is added by extracting solution, leave standstill after mixing, after removing petroleum ether layer, by surplus solution after 4 DEG C of hold over night, centrifugal by extracting solution 4000r/min, centrifugal 15min, abandoning supernatant, puts into 80 DEG C of baking oven dryings and obtains rutin crude product by lower sediment;

2) by rutin crude product dissolve with methanol use, cross silica gel column chromatography, first with after sherwood oil, chloroform cleaning, then carry out wash-out with methyl alcohol, collect elutriant and carry out concentrating under reduced pressure, after drying, obtain rutin sterling.

4. anti-oxidant LDPE film as claimed in claim 3, it is characterized in that in described ethanolic soln, ethanol contend specific concentration is 70%, the solid-liquid ratio 1:40 of extracting solution, extraction time is 45min, and Extracting temperature is 40 DEG C.

5. anti-oxidant LDPE film as claimed in claim 3, is characterized in that the silica gel in described silica gel column chromatography is 100 ~ 160 object silica gel.

6. the application of anti-oxidant LDPE film according to claim 1 in preparation high fat content food or edible oil preservatives.

7. apply as claimed in claim 6, it is characterized in that, described LDPE film is used as the internal layer packaging of food.

8. apply as claimed in claim 6, it is characterized in that, described edible oil is peanut oil or sweet oil.

9. apply as claimed in claim 6, it is characterized in that, adopt methanol extraction method to detect rutin in edible oil, concrete steps are: prepare a series of rutin reference liquid, take oil sample to be measured, the described rutin reference liquid adding different amount respectively stirs, and two-phase is fully mixed; Add methyl alcohol, be placed in constant temperature 25 DEG C of mechanical shaking extraction 60min, centrifugal after extracting, by upper strata extracting solution constant volume, filtered by the microporous membrane filters of 0.45 μm, inject highly effective liquid phase chromatographic system and detect, calculate the content of rutin;

Described high performance liquid chromatography testing conditions is: Agilent 1200; UV-detector; Analytical column: Lichrospher C-18,2.1mm × 250mm; Moving phase: methanol-water-acetic acid gradient elution; Column temperature: 30 DEG C; Flow velocity: 0.3ml/min; Sample size: 10 μ L.