CN105777935A - Preparation method of high-emulsibility mango peel pectin - Google Patents

Abstract

The invention discloses a preparation method of highly emulsifying mango peel pectin, which comprises the following steps: 1) scalding mango peel, freeze-drying, crushing and sieving to obtain mango peel powder; Mix the obtained mango peel powder with citric acid solution to obtain a mixed solution, preheat the mixed solution in a water bath, adjust the pH value of the mixed solution to 2.0-3.0, perform ultrasonic extraction to obtain an extract; The extract is subjected to solid-liquid separation, and the obtained liquid phase components are mixed with ethanol for precipitation to obtain mango peel pectin. The mango peel pectin obtained by the method of the invention has good emulsification performance and high extraction rate (16.70-17.15%); moreover, the method provided by the invention has short process time and good pectin thickening and stability.

Description

A kind of preparation method of high emulsifiability mango peel pectin

technical field

The invention relates to the field of mango peel pectin processing, in particular to a preparation method of mango peel pectin with high emulsifying activity.

Background technique

Pectin is a mixture of oligosaccharides and polysaccharides widely present in plant cells. In addition to gelling and thickening, it can also be used as an emulsifier to maintain the stability of the emulsion. It has been widely used in jams, In foods such as jelly, candy, lactic acid and juice drinks. The FAO/WHO Joint Committee on Food Additives recommends pectin as a safe natural food additive without limiting the daily intake.

There are many researches on pectin extraction in China, and some achievements have been made. However, compared with developed countries, there are still problems of backward technology, single finished product and poor quality. Since the source and extraction method of pectin will have a great impact on the structure and function of pectin, researchers are constantly looking for new extraction raw materials and methods in order to obtain high-quality pectin and meet the growing demand for pectin in various industries .

At present, the raw materials used for the preparation of commercial pectin are mainly citrus peel and apple pomace. In addition, there are also a lot of researches on extracting pectin from by-products such as dragon fruit, sugar beet and pomegranate peel, and the research on extracting pectin from mango peel not much. Mango is one of the important tropical fruits, and my country is the second largest mango producer after India. Due to the short harvest period of mangoes and the fact that fresh fruits are extremely perishable, mangoes are widely processed into deep-processed products such as mango pulp, mango juice, dried mangoes, and mango powder in addition to being eaten fresh. However, a large number of by-products such as mango skin and core are often produced in the process of mango processing. Improper treatment will not only cause serious waste of resources, but also may cause environmental pollution.

Contents of the invention

In view of this, the purpose of the present invention is to provide a highly efficient, environmentally friendly, simple and easy method to prepare mango peel pectin with high emulsification by using mango peel, a by-product of mango processing, as raw material.

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

The invention provides a kind of preparation method of highly emulsifying mango peel pectin, comprising the following steps:

1) Mango peels are blanched, freeze-dried, crushed and sieved to obtain mango peel powder;

2) Mixing the mango peel powder obtained in the step 1) with the citric acid solution to obtain a mixed solution, preheating the mixed solution in a water bath, adjusting the pH value of the mixed solution to 2.0-3.0, and performing ultrasonic extraction to obtain an extract;

3) performing solid-liquid separation on the extract obtained in step 2), and mixing the liquid phase components obtained by the solid-liquid separation with ethanol for precipitation to obtain mango peel pectin.

Preferably, the blanching described in step 1) is steam blanching, and the blanching time is 1-3 minutes.

Preferably, the sieving described in step 1) is through a 20-60 mesh sieve.

Preferably, the method also includes the following steps: vacuum freeze-drying the pectin precipitate obtained in step 4) to obtain mango peel pectin.

Preferably, the concentration of the citric acid solution described in step 2) is 0.1-0.3 mol/L, and the mass ratio of the citric acid solution to mango peel powder is (30-50):1.

Preferably, the temperature of the water bath preheating in step 2) is 60-80° C., and the time of the water bath preheating is 2-8 minutes.

Preferably, the power of the ultrasonic extraction in step 2) is 400-1000W, the temperature of the ultrasonic extraction is 60-80°C, and the time of the ultrasonic extraction is 20-40min.

Preferably, the solid-liquid separation described in step 3 adopts centrifugation, the rotation speed of the centrifugation is 7000-9000 rpm, and the time is 5-15 minutes.

Preferably, the volume ratio of the liquid phase component to ethanol in step 3) is 1: (1-3), and the volume concentration of ethanol is 90-95%.

Beneficial effects of the present invention: the present invention effectively utilizes mango processing by-product mango skin as raw material to prepare pectin, which not only controls the pollution to the environment, but also improves the added value of the mango processing industry; the present invention adopts ultrasonic-temperature-organic acid Combined method, the obtained pectin has good emulsification performance and high extraction rate (16.70-17.15%); and the method provided by the invention has short process time, high pectin viscosity, good thickening and stability; mass concentration 1% After the mango pectin aqueous solution is mixed with 20-40% soybean oil, the homogenized mango pectin emulsion has a particle size of <15um, and the emulsification stability is >80% after being placed for 7 days, and the emulsion stability is significantly higher than that of commercial citrus pectin .

Description of drawings

Fig. 1 is the viscosity contrast of the mango peel pectin that the embodiment of the present invention obtains and the viscosity of citrus pectin;

Fig. 2 is the particle size distribution curve figure of the emulsion prepared with the mango peel pectin obtained in the embodiment of the present invention, wherein A is the fresh emulsion within 5 minutes after completing the homogenization; B is the emulsion after storage for 7 days;

Fig. 3 is the microscopic observation of the particle size of the emulsion prepared with the mango peel pectin obtained by the embodiment of the present invention, wherein A is the citrus pectin emulsion; B-D is the mango pectin emulsion;

Fig. 4 is the emulsion storage stability state figure prepared with the mango peel pectin that the embodiment of the present invention obtains,

Among them, A is the state diagram of the pectin emulsion within 5 minutes of homogenization, and B is the state diagram of the pectin emulsion after 7 days.

detailed description

The invention provides a kind of preparation method of highly emulsifying mango peel pectin, comprising the following steps:

1) Mango peels are blanched, freeze-dried, crushed and sieved to obtain mango peel powder;

2) Mixing the mango peel powder obtained in the step 1) with the citric acid solution to obtain a mixed solution, preheating the mixed solution in a water bath, adjusting the pH value of the mixed solution to 2.0-3.0, and performing ultrasonic extraction to obtain an extract;

3) performing solid-liquid separation on the extract obtained in step 2), and mixing the liquid phase components obtained by the solid-liquid separation with ethanol for precipitation to obtain mango peel pectin.

The invention prepares the pectin by using mango skin as raw material, and the mango skin is the discarded leftovers in the process of mango product processing. In the present invention, the mango peel is preferably fresh mango peel within 1-2 days of mango processing. In the present invention, the mango peel is blanched, preferably cleaned with clear water before blanching. In the present invention, the blanching is preferably steam blanching; the time for steam blanching the mango peel is preferably 1-3 minutes, more preferably 2 minutes. In the present invention, during the steam blanching process, the high temperature of the steam can passivate the endogenous enzymes in the mango peel, thereby preventing the enzymatic reaction of the mango peel from affecting the quality of pectin in the subsequent treatment process.

In the present invention, the mango skin is blanched and then freeze-dried. The present invention preferably pre-cools the blanched mango peel before the freeze-drying; in the present invention, the pre-cooling is preferably performed with liquid nitrogen, and the pre-cooling time is preferably 2 to 10 minutes , more preferably 6min.

The vacuum degree and temperature of the freeze-drying described in the present invention have no special requirements, and the vacuum degree and temperature commonly used for freeze-drying in the art can be used; in the present invention, the time of the freeze-drying is preferably 36 to 60 hours, more preferably The best is 40-55h, most preferably 48h.

In the present invention, after the mango peel is freeze-dried, the freeze-dried mango peel is pulverized. The present invention has no special limitation on the method of pulverization, and the technical scheme of pulverization well-known to those skilled in the art can be adopted; in specific embodiments of the present invention, a small pulverizer commonly used in the field can be used to process the freeze-dried Mango peels are crushed.

After the crushing, the present invention sieves the crushed mango peel to obtain mango peel powder. In the present invention, the sieving is preferably through a 20-60 mesh sieve, more preferably 40-50 mesh sieve.

In the present invention, the mango peel powder after sieving is preferably vacuum-packed, and the vacuum packaging method commonly used in this field can be used without other special requirements; in the present invention, the vacuum-packed

The packed mango peel powder is refrigerated for future use, and the temperature of the refrigerated is preferably 1-5°C, more preferably 4°C. After obtaining the mango peel powder, the present invention mixes the mango peel powder and citric acid solution to obtain a mixed liquid, which is then preheated in a water bath. In the present invention, the concentration of described citric acid solution is preferably 0.1～0.3mol/L, more preferably 0.2mol/L; The mass ratio of described citric acid solution and mango peel powder is preferably (30～ 50): 1, more preferably 40: 1, after the preferred mango peel powder and citric acid solution of the present invention are mixed uniformly, seal in polyethylene bag, the polyethylene bag that mango peel powder and citric acid solution are housed Put it into a water bath pot for water bath preheating, the temperature of the water bath preheating is preferably 60-80°C, more preferably 70°C, the time of the water bath preheating is preferably 2-8min, more preferably 5min.

In the invention, after the mixed liquid is preheated in a water bath, the pH value of the pre-extracted liquid is adjusted to 2.0-3.0, and the ultrasonic extraction is performed to obtain the extracted liquid. In the present invention, the pH value of the pre-extraction solution is preferably adjusted to 2.5. The solution used for pH adjustment in the present invention is citric acid and sodium citrate. After the pH value of the mixed solution is adjusted, the present invention performs ultrasonic extraction on the mixed solution after adjusting the pH value to obtain an extract. The present invention has no special limitation on the instrument used for the ultrasonic extraction, and an ultrasonic breaker well known to those skilled in the art can be used. In the present invention, the power of the ultrasonic extraction is preferably 400-1000W, more preferably 500-900W, most preferably 600-800W; the temperature of the ultrasonic extraction is preferably 60-80°C, more preferably 70-80°C, most preferably 80°C; the ultrasonic extraction time is preferably 20-40 minutes, more preferably 25-35 minutes, most preferably 30 minutes. The present invention extracts the pectin fully extracted into the mango peel powder through the ultrasonic extraction.

In the present invention, after the extract is obtained, the extract is subjected to solid-liquid separation, and the obtained liquid phase components are mixed with ethanol for precipitation to obtain mango peel pectin. The present invention has no special restrictions on the method of solid-liquid separation, and the technical scheme of solid-liquid separation well-known to those skilled in the art can be adopted; in the present invention, the described solid-liquid separation is preferably centrifugal; the centrifugal The rotation speed is preferably 7000-9000 rpm, more preferably 8000 rpm; the centrifugation time is preferably 5-15 minutes, more preferably 10 minutes.

In the present invention, after solid-liquid separation of the extract, the obtained liquid phase components are mixed with ethanol for precipitation to obtain mango peel pectin. In the present invention, the volume ratio of the liquid phase component to ethanol is preferably 1: (1-3), more preferably 1:2; the volume concentration of the ethanol is preferably 90-95%, more preferably 95% is preferred. In the present invention, the time for the precipitation is preferably 10-14 hours, more preferably 12 hours, and the long-term ethanol precipitation can fully separate the pectin in the ethanol environment.

After the precipitation is finished, the present invention preferably uses ethanol with a volume concentration of 95% to repeatedly wash the obtained precipitate to obtain mango peel pectin. In the present invention, the number of washings is preferably 2-5 times, more preferably 3-4 times. The present invention carries out ethanol washing to the obtained precipitation, can remove pectin

Precipitating the pigment and free neutral sugar on the surface; after obtaining the pectin precipitation, the present invention preferably freeze-dries the precipitation to obtain mango peel pectin. In the present invention, there is no special requirement for the freeze-drying conditions of the precipitate, and conventional freeze-drying conditions in the field can be used; in the present invention, the freeze-drying temperature is preferably -10°C to -50°C, more preferably The temperature ranges from -20 to -40°C, most preferably from -25 to -35°C; the vacuum degree of the freeze-drying is preferably 1.3 to 13Pa, more preferably 2 to 10Pa.

The preparation method of the highly emulsifying mango peel pectin provided by the present invention will be described in detail below in conjunction with the examples, but they cannot be interpreted as limiting the protection scope of the present invention.

Example 1

Wash the fresh mango skin with clean water, steam blanching for 2 minutes to inactivate endogenous enzymes, pre-cool in liquid nitrogen for 6 minutes and freeze-dry for 48 hours before crushing, after crushing, pass through a 40-mesh sieve to obtain mango peel powder, after vacuum packaging the mango peel powder Store in refrigerated at 4°C for later use; mix mango peel powder with 0.2mol/L citric acid solution, the mass ratio of citric acid solution to mango peel powder is 40:1; mix sodium citrate solution with mango peel powder and seal Put the polyethylene bag in a 70°C water bath to preheat for 5 minutes to obtain a pre-extraction solution; use citric acid and sodium citrate to adjust the pH of the obtained pre-extraction solution to 2.5, and put it into a 600W power Ultrasonic extraction at 70°C for 30 minutes to fully extract the pectin to obtain an extract; centrifuge the obtained extract at 8000 rpm for 10 minutes, and add 2 times the volume of the liquid phase components to the collected liquid phase components Precipitate with 95% (v/v) ethanol for 12 hours, so that the pectin is fully separated; the resulting precipitate is repeatedly washed 3 times with 95% (v/v) ethanol, to remove the pigment and free neutral sugar in the pectin precipitate; Mango peel pectin is obtained after the obtained precipitate is vacuum freeze-dried.

Calculate the yield of the mango peel pectin obtained above to be 16.70%;

The present invention uses a viscometer to measure the viscosity of mango peel pectin, and the result is as shown in Figure 1, and Figure 1 is the pectin viscosity change curve with shear force, as can be seen from Figure 1, the pectin solution viscosity is large, thickening property Good (accompanying drawing 1-mango pectin 1); The emulsion particle size distribution that the pectin that the present invention detects prepares is as shown in Figure 2 and Figure 3, and Fig. 2 is the particle size distribution curve of pectin emulsion, and Fig. 3 is The microscopic observation figure of pectin emulsion particle diameter, as can be seen from Fig. 2 and Fig. 3, the pectin emulsion product particle diameter that the present embodiment prepares＜15 μ m (accompanying drawing 2-mango pectin 1, accompanying drawing 3-B) .

In the present invention, the mango peel pectin obtained above is formulated into an aqueous solution of mango peel pectin with a mass concentration of 1%, and a 1% commercial citrus pectin aqueous solution is used as a comparison, and the commercial citrus pectin is common commercially available citrus pectin , after mixing mango peel pectin aqueous solution and control citrus pectin aqueous solution with 40% soybean oil,

Mango pectin emulsion and citrus pectin emulsion were obtained after homogenization treatment at 10000rpm for 1min with a homogenizer. The particle size of the pectin emulsion was observed under a microscope, and its stability was observed after placing it for 7 days. The state of the pectin emulsion is as shown in Figure 4, wherein A is the state diagram of pectin emulsion in the homogeneous 5min, and B is the state diagram of pectin emulsion after 7 days. As can be seen, the mango peel pectin of the present invention has good emulsification stability after placing 7d (accompanying drawing 4-mango Pectin 1), emulsion stability is significantly higher than commercial citrus pectin.

Example 2

Wash the fresh mango skin with clean water, blanching with steam for 2 minutes to inactivate endogenous enzymes, pre-cooling with liquid nitrogen for 8 minutes and freeze-drying for 52 hours before crushing, after crushing, pass through a 40-mesh sieve to obtain mango peel powder, after vacuum packaging Store at 4°C for later use; mix mango peel powder with 0.2mol/L citric acid solution, the mass ratio of citric acid solution to mango peel powder is 30:1; mix sodium citrate solution with mango peel powder and seal Put it in a polyethylene bag, preheat it in a water bath at 60°C for 6 minutes to obtain a pre-extraction solution; use citric acid and sodium citrate to adjust the pH of the pre-extraction solution to 2.3, put it into an ultrasonic instrument with a power of 800W at 60°C Under treatment for 20 minutes, fully extract the pectin to obtain the extract, centrifuge at 7000rpm for 8 minutes and collect the extract obtained from the liquid phase components, add 2 times the volume of 95% ethanol to the collected liquid phase components to precipitate for 14 hours to fully analyze the pectin The obtained precipitate was repeatedly washed 5 times with 95% ethanol to remove the pigment and free neutral sugar in the pectin precipitate; the obtained precipitate was vacuum freeze-dried to obtain mango peel pectin.

Calculate the yield of the mango peel pectin obtained above to be 16.90%;

The present invention uses a viscometer to measure the viscosity of mango peel pectin, and the result is as shown in Figure 1, and Figure 1 is the pectin viscosity change curve with shear force, as can be seen from Figure 1, the pectin solution viscosity is large, thickening property Good (attached figure 1 - mango pectin 2);

The particle size distribution of the pectin emulsion that the present invention detects obtains, and the result is as shown in Figure 2 and Figure 3, and Fig. 2 is a pectin particle size distribution curve, and Fig. 3 is a pectin emulsion particle size microscope observation figure, by Fig. 2 and Fig. 3 It can be seen that the particle size is less than 15um (accompanying drawing 2-mango pectin 2, accompanying drawing 3-C);

In the present invention, the mango peel pectin obtained above is formulated into an aqueous solution of mango peel pectin with a mass concentration of 1%, and a 1% commercial citrus pectin aqueous solution is used as a comparison, and the commercial citrus pectin is common commercially available citrus pectin After mango peel pectin aqueous solution and contrast citrus pectin aqueous solution were mixed with 40% soybean oil, a homogenizer was used to obtain mango pectin emulsion and citrus pectin emulsion after homogeneous treatment at 10000rpm for 1min, and the microscopic observation of the pectin emulsion was carried out. Particle size, observe its stability after placing it for 7 days, the state of the pectin emulsion is shown in Figure 4, where A is the state diagram of the pectin emulsion within 5 minutes of homogenization, and B is the latex after 7 days

Liquid state diagram, it can be seen that the mango peel pectin of the present invention has good emulsification stability after being placed for 7 days (accompanying drawing 4-mango pectin 2), and the emulsion stability is significantly higher than commercial citrus pectin.

Example 3

Wash the fresh mango skin with clean water, blanching with steam for 2 minutes to inactivate endogenous enzymes, pre-cooling with liquid nitrogen for 4 minutes, freeze-drying for 40 hours, and then crushing. After crushing, pass through a 40-mesh sieve to obtain mango peel powder. Store in refrigerated at 4°C for later use; mix mango peel powder with 0.25mol/L citric acid solution, the mass ratio of citric acid solution to mango peel powder is 50:1; mix citric acid solution and mango peel powder and seal in Put it in a polyethylene bag and place it in a water bath at 80°C for 6 minutes to obtain a pre-extraction solution; use citric acid and sodium citrate to adjust the pH of the pre-extraction solution to 2.8, and put it into an ultrasonic instrument with a power of 500W at 80°C Treat for 40 minutes, fully extract the pectin to obtain the extract, centrifuge at 9000rpm for 12 minutes to collect the extract obtained from the liquid phase components, add 2 times the volume of 95% ethanol to the collected liquid phase components to precipitate for 10 hours to fully analyze the pectin, The obtained precipitate was repeatedly washed 4 times with 95% ethanol to remove the pigment and free neutral sugar in the pectin precipitate; the obtained precipitate was subjected to vacuum freeze-drying to obtain mango peel pectin.

Calculate the yield of the mango peel pectin obtained above to be 16.90%;

The present invention uses a viscometer to measure the viscosity of mango peel pectin, and the result is as shown in Figure 1, and Figure 1 is the pectin viscosity change curve with shear force, as can be seen from Figure 1, the pectin solution viscosity is large, thickening property Good (attached figure 1 - mango pectin 3);

The particle size distribution of the pectin emulsion that the present invention detects obtains, and result is as shown in Figure 2 and Figure 3, and Fig. 2 is the particle size distribution curve of pectin emulsion, as can be seen from Figure 2 and Figure 3, particle diameter＜15um (attachment Figure 2 - Mango Pectin 3, Figure 3-D);

In the present invention, the mango peel pectin obtained above is formulated into an aqueous solution of mango peel pectin with a mass concentration of 1%, and a 1% commercial citrus pectin aqueous solution is used as a comparison, and the commercial citrus pectin is common commercially available citrus pectin After mango peel pectin aqueous solution and contrast citrus pectin aqueous solution were mixed with 40% soybean oil, a homogenizer was used to obtain mango pectin emulsion and citrus pectin emulsion after homogeneous treatment at 10000rpm for 1min, and the microscopic observation of the pectin emulsion was carried out. Particle size, observe its stability after placing 7 days, the state of pectin emulsion is as shown in Figure 4, wherein A is the state diagram of pectin emulsion within 5min after completing the homogenization, and B is the state diagram of pectin emulsion after 7 days, so it can be seen that this The mango peel pectin described in the invention has good emulsification stability after being placed for 7 days (accompanying drawing 4-mango pectin 3), and the emulsion stability is significantly higher than that of commercial citrus pectin.

As can be seen from the above examples, the mango peel pectin yield obtained by the preparation method of the highly emulsifiable mango peel pectin prepared by the present invention is high, the pectin solution viscosity is large, the thickening property is good, and the emulsification stability is good (particle diameter <15um), the emulsion stability is significantly higher than commercial citrus pectin.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. a preparation method of highly emulsifiable mango peel pectin, comprising the following steps: 1) Mango peels are blanched, freeze-dried, crushed and sieved to obtain mango peel powder; 2) Mixing the mango peel powder obtained in the step 1) with the citric acid solution to obtain a mixed solution, preheating the mixed solution in a water bath, adjusting the pH value of the mixed solution to 2.0-3.0, and performing ultrasonic extraction to obtain an extract; 3) performing solid-liquid separation on the extract obtained in step 2), and mixing the liquid phase components obtained by the solid-liquid separation with ethanol for precipitation to obtain mango peel pectin. 2. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the blanching described in step 1) is steam blanching, and the time of described blanching is 1～3min . 3. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the sieving described in step 1) is to pass through 20～60 mesh sieves. 4. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the concentration of the citric acid solution described in step 2) is 0.1～0.3mol/L, and described citric acid The mass ratio of the solution to the mango peel powder is (30-50):1. 5. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the temperature of the water bath preheating described in step 2) is 60～80 ℃, and the time of described preheating 2 to 8 minutes. 6. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the power of the ultrasonic extraction described in step 2) is 400～1000W, and the temperature of described ultrasonic extraction is 60 ~80°C, the ultrasonic extraction time is 20-40 minutes. 7. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the solid-liquid separation described in step 4) is centrifugal, and the rotating speed of described centrifugal is 7000～9000rpm, so The centrifugation time is 5-15 minutes. 8. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 1, is characterized in that, the volume ratio of described liquid phase component and ethanol in step 4) is 1: (1～3). 9. the preparation method of a kind of highly emulsifying mango peel pectin according to claim 8, is characterized in that, the volume concentration of described ethanol is 90～95%. 10. according to the preparation method of a kind of highly emulsifying mango peel pectin described in any one of claims 1～9, it is characterized in that, described step 4) also comprises after obtaining precipitation: the precipitation obtained in step 4) Vacuum freeze-drying is carried out to obtain mango peel pectin.