阅读说明：本技术 一种超高压联合超声波处理提取紫玉米花色苷的方法 (Method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment ) 是由 冯颖 邓微 李斌 代佳琳 边媛媛 白茹 于 2021-09-08 设计创作，主要内容包括：本发明涉及一种超高压联合超声波处理提取紫玉米花色苷的方法,提取步骤包括：紫玉米籽粒和穗轴粉碎过筛、料液混合、超高压预处理、超声波提取、过滤、收集滤液。本方法可用于对紫玉米籽粒和穗轴花色苷的提取,操作简便,提高了花色苷的提取率,时间短,提取效率高,避免花色苷的降解,花色苷结构和活性稳定,同时,节省了能源消耗,绿色无污染。(The invention relates to a method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment, which comprises the following extraction steps: crushing and sieving purple corn kernels and cobs, mixing feed liquid, performing ultrahigh-pressure pretreatment, performing ultrasonic extraction, filtering and collecting filtrate. The method can be used for extracting anthocyanin from purple corn kernels and cobs, is simple and convenient to operate, improves the extraction rate of the anthocyanin, is short in time and high in extraction efficiency, avoids degradation of the anthocyanin, is stable in anthocyanin structure and activity, saves energy consumption, and is green and pollution-free.)

1. A method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment is characterized by comprising the following steps: the method comprises the following steps:

(1) crushing raw materials: pulverizing dried purple corn kernel and cob by an ultrafine pulverizer, and sieving to obtain purple corn kernel powder and purple corn cob powder for extraction;

(2) ultrahigh pressure pretreatment: adding anthocyanin extracting agents into the purple corn kernel powder and the purple corn cob powder obtained in the step (1), and placing the mixture in an ultrahigh pressure device for ultrahigh pressure treatment;

the anthocyanin extracting agent is a mixed solution of absolute ethyl alcohol and 0.2mol/L citric acid, and the volume ratio of the absolute ethyl alcohol to the citric acid is that the ratio of ethyl alcohol to citric acid is =7: 3;

(3) ultrasonic extraction: taking out the polyethylene bag filled with the purple corn powder and the extracting agent subjected to the ultrahigh pressure pretreatment in the step (2), and placing the polyethylene bag in an ultrasonic extractor for ultrasonic extraction;

(4) and (3) filtering: and (4) pouring out the mixture obtained after the ultrasonic extraction in the step (3), and filtering to collect filtrate, namely the purple corn anthocyanin extracting solution.

2. The method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment as claimed in claim 1, wherein the method comprises the following steps: in the step (1), the purple corn kernels are crushed and then screened by a 60-mesh sieve, and the purple corn stalks are crushed and then screened by a 40-mesh sieve.

3. The method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment as claimed in claim 1, wherein the method comprises the following steps: in the step (2), anthocyanin extracting agents are respectively added into the purple corn kernel powder and the purple corn cob powder according to the liquid-material ratio of 10:1-20:1 and 10:1-60:1(mL/g), the mixture is fully and uniformly mixed and then placed in ultrahigh pressure equipment, and the ultrahigh pressure is 150-350 MPa.

4. The method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment as claimed in claim 1, wherein the method comprises the following steps: in the step (2), the ultra-high pressure treatment time of the purple corn kernel powder is 1-3min, and the ultra-high pressure treatment time of the purple corn cob powder is 2-4 min.

5. The method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment as claimed in claim 1, wherein the method comprises the following steps: in the step (3), the ultrasonic treatment condition is that the ultrasonic temperature is 55 ℃ and the ultrasonic power is 200W.

6. The method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment as claimed in claim 1, wherein the method comprises the following steps: in the step (3), the ultrasonic treatment time of the purple corn kernel powder is 6-10min, and the ultrasonic treatment time of the purple corn cob powder is 20-30 min.

Technical Field

The invention relates to the field of food processing, in particular to a method for extracting anthocyanin from purple corn kernels and cobs by ultrahigh pressure combined ultrasonic treatment.

Background

Anthocyanin is a natural pigment widely existing in plants, has the effects of eliminating free radicals in vivo, inhibiting lipid peroxidation, preventing tumors, resisting inflammation, sterilizing, reducing capillary permeability, protecting gastric mucosa, protecting eyesight and the like, and is widely used in the fields of food and pharmacy. The purple corn is originally produced in south American areas, the purple corn in the 16 th century is introduced into China, and through long-term development, the purple corn variety resources in China already have a certain foundation and are greatly enriched. The purple corn has the same size as common corn, the kernel, the bract, the cob and the straw of the purple corn are purple black, a large amount of anthocyanin is contained, particularly, the anthocyanin content in the purple corn cob is at the head of each part, however, the purple corn cob is often used as feed or fuel as a byproduct, and the great waste of the anthocyanin resource of the purple corn is caused. At present, purple corn in China is mainly eaten fresh, and the deep processing utilization degree is low, so that natural anthocyanin is extracted from purple corn, particularly cob, the purple corn resource can be fully utilized, the comprehensive utilization economic value of the purple corn resource is improved, and the deep processing utilization level is improved.

Compared with the traditional solvent extraction method, the ultrasonic method for extracting anthocyanin has the advantages of simple and convenient operation, short extraction time and high anthocyanin extraction rate, so that the method is increasingly widely applied to the extraction of plant anthocyanin. The research finds that the plant cell wall is broken by ultrasonic waves, the cell structure is broken, and the dissolution of anthocyanin is accelerated, but the heat effect and free radicals generated by the ultrasonic waves are increased along with the time, so that the degradation of anthocyanin is caused, and the extraction amount and the biological activity of anthocyanin are reduced. The ultrahigh pressure technology is a new technology developed in recent years, a solvent can permeate into a solid raw material under the action of ultrahigh pressure, so that effective components in the raw material are dissolved in an extraction solvent, the pressure of the effective components is quickly relieved after the effective components reach the dissolution balance, and the effective components can be quickly diffused into an extraction solution around tissues under the action of osmotic pressure inside and outside cells. The invention adopts the ultrahigh pressure pretreatment combined with the ultrasonic extraction technology to extract purple corn anthocyanin, aims to extract more purple corn anthocyanin by using the ultrahigh pressure technology to assist ultrasonic extraction, shortens the ultrasonic extraction time, reduces the degradation of anthocyanin, and stabilizes the anthocyanin structure and activity.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment, wherein the anthocyanin is extracted by performing ultrahigh pressure pretreatment combined ultrasonic treatment on purple corn seeds and cobs, the ultrahigh pressure technology is utilized to assist ultrasonic extraction for more purple corn anthocyanin, the ultrasonic extraction time is shortened, the degradation of the anthocyanin is avoided, and the anthocyanin structure and activity are stabilized.

The invention aims to realize the following technical scheme, and the method for extracting purple corn anthocyanin by ultrahigh pressure combined ultrasonic treatment has the technical key points that: the method comprises the following steps:

(1) crushing raw materials: respectively pulverizing dried purple corn kernels and cobs by an ultrafine pulverizer, and sieving to obtain purple corn kernel powder and purple corn cob powder for extraction;

(2) ultrahigh pressure pretreatment: adding anthocyanin extracting agent into the purple corn kernel powder and the purple corn cob powder obtained in the step (1), putting into a polyethylene bag, vacuumizing, sealing, and putting into an ultrahigh pressure device for ultrahigh pressure treatment;

the anthocyanin extracting agent is a mixed solution of absolute ethyl alcohol and 0.2mol/L citric acid, and the volume ratio of the absolute ethyl alcohol to the citric acid is 7: 3;

(3) ultrasonic extraction: taking out the polyethylene bag filled with the purple corn powder and the extracting agent subjected to the ultrahigh pressure pretreatment in the step (2), and placing the polyethylene bag in an ultrasonic extractor for ultrasonic extraction;

(4) and (3) filtering: and (4) pouring out the mixture obtained after the ultrasonic extraction in the step (3), and collecting filtrate after centrifugal filtration to obtain the purple corn anthocyanin extracting solution.

Further, the purple corn kernels in the step (1) are crushed and then screened by a 60-mesh sieve, and the purple corn stalks are crushed and then screened by a 40-mesh sieve;

further, adding an anthocyanin extracting agent into the purple corn kernel powder and the purple corn cob powder respectively according to the liquid-material ratio of 10:1-20:1 and 10:1-60:1(mL/g), fully and uniformly mixing, and placing in an ultrahigh pressure device, wherein the ultrahigh pressure is 150-;

further, in the step (2), the ultrahigh pressure treatment time of the purple corn kernels is 1-3min, and the ultrahigh pressure treatment time of the purple corn cobs is 2-4 min;

further, in the step (3), the ultrasonic treatment condition is that the ultrasonic temperature is 55 ℃, and the ultrasonic power is 200W;

further, in the step (3), the ultrasonic treatment time of the purple corn kernels is 6-10min, and the ultrasonic treatment time of the purple corn cobs is 20-30 min.

The invention has the beneficial effects that:

(1) the purple corn has high anthocyanin content, and has the functions of resisting oxidation, resisting tumor, delaying aging, lowering blood pressure, regulating blood fat, lowering blood sugar and the like. Compared with other natural purple pigment raw materials, the purple corn has wide sources, low price and low cost. The purple corn anthocyanin extracted by the invention is safe and nontoxic, can be directly used for products such as food, medicine, cosmetics and the like, simultaneously drives the deep processing and utilization of the purple corn resource, improves the added value of the raw materials, and has important application value and development prospect.

(2) The ultrahigh pressure is insensitive to the influence of covalent bonds, so that the influence on the molecular structure of the pigment is avoided, the ultrahigh pressure extraction is carried out at room temperature, the operation time is only a few minutes, and the reduction of the physiological activity of anthocyanin caused by the structural change of the anthocyanin due to the heat effect is avoided. The ultrahigh pressure pretreatment is used for assisting ultrasonic extraction of anthocyanin, so that the extraction amount of anthocyanin is obviously increased, the ultrasonic extraction time of single ultrasonic extraction is shortened, and the problems of degradation of anthocyanin and reduction of extraction amount and biological activity caused by the increase of thermal effect and free radicals generated by ultrasonic along with the increase of ultrasonic time are solved.

(3) The ultrahigh pressure and ultrasonic extraction technology has the advantages of simple operation, short extraction time, high safety, energy conservation and environmental protection, and the ultrahigh pressure and ultrasonic extraction technology is combined with the ultrahigh pressure and ultrasonic extraction technology, has the advantages of both the ultrahigh pressure and the ultrasonic extraction technology, and has the advantages that the extraction amount of anthocyanin is larger than that of single ultrahigh pressure and ultrasonic extraction technology and the extraction time is shorter than that of single ultrasonic extraction technology. Because the ultrahigh pressure treatment consumes partial energy only in the volume compression process of extracting the solvent in the pressure boosting stage, the energy loss in the whole extraction process is very low, and therefore, compared with single ultrasonic extraction, the energy loss is lower.

Drawings

Fig. 1 is a process diagram of extracting anthocyanin from purple corn kernels and cobs by ultrahigh pressure combined ultrasonic treatment.

Detailed Description

Example 1

(1) Crushing the purple corn seeds and sieving the crushed purple corn seeds with a 60-mesh sieve to obtain purple corn seed powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn kernel powder 20: 1(ml/g) mixing the extractant and the purple corn grain powder uniformly, sealing in a polyethylene bag, vacuumizing, sealing, and treating in an ultrahigh pressure device at an ultrahigh pressure of 200MPa for 2 min.

(3) Taking out the polyethylene bag filled with purple corn kernel powder and the extractant after the ultrahigh pressure treatment, and placing the polyethylene bag in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 5 min.

(4) Centrifuging the mixture after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn kernel anthocyanin extract.

Example 2

(1) Crushing the purple corn seeds and sieving the crushed purple corn seeds with a 60-mesh sieve to obtain purple corn seed powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn kernel powder 20: 1(ml/g) mixing the extractant and the purple corn grain powder uniformly, sealing in a polyethylene bag, vacuumizing, sealing, and treating in an ultrahigh pressure device at an ultrahigh pressure of 250MPa for 2 min.

(3) Taking out the polyethylene bag filled with purple corn kernel powder and the extractant after the ultrahigh pressure treatment, and placing the polyethylene bag in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 8 min.

(4) Centrifuging the mixture after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn kernel anthocyanin extract.

Example 3

(1) Crushing purple corn cobs and sieving the crushed purple corn cobs with a 40-mesh sieve to obtain purple corn cob powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn cob powder 60:1(ml/g) mixing the extractant and purple corn cob meal uniformly, sealing in a polyethylene bag, vacuumizing, sealing, and treating in an ultrahigh pressure device at an ultrahigh pressure of 200MPa for 2 min.

(3) Taking out the polyethylene bag filled with purple corn cob powder and extractant after ultrahigh pressure treatment, and placing the polyethylene bag in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 10 min.

(4) Centrifuging the mixture obtained after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn cob anthocyanin extract.

Example 4

(1) Crushing purple corn cobs and sieving the crushed purple corn cobs with a 40-mesh sieve to obtain purple corn cob powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn cob powder 60:1(ml/g) mixing the extractant and purple corn cob meal uniformly, sealing in a polyethylene bag, vacuumizing, sealing, and treating in an ultrahigh pressure device at an ultrahigh pressure of 250MPa for 3 min.

(3) Taking out the polyethylene bag filled with purple corn cob powder and extractant after ultrahigh pressure treatment, and placing the polyethylene bag in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 25 min.

(4) Centrifuging the mixture obtained after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn cob anthocyanin extract.

Comparative example 1

(1) Crushing the purple corn seeds and sieving the crushed purple corn seeds with a 60-mesh sieve to obtain purple corn seed powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn kernel powder 20: 1(ml/g) uniformly mixing the extractant and the purple corn kernel powder, and placing the mixture in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 10 min.

(3) Centrifuging the mixture after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn kernel anthocyanin extract.

Comparative example 2

(1) Crushing purple corn cobs and sieving the crushed purple corn cobs with a 40-mesh sieve to obtain purple corn cob powder;

(2) mixing an extracting agent (absolute ethyl alcohol: 0.2mol/L citric acid, volume ratio of 7:3) and purple corn cob powder 60:1(ml/g) uniformly mixing the extractant and the purple corn kernel powder, and placing the mixture in an ultrasonic device for ultrasonic extraction, wherein the ultrasonic power is 200w, the ultrasonic temperature is 55 ℃, and the ultrasonic extraction time is 40 min.

(3) Centrifuging the mixture after ultrasonic extraction in a refrigerated centrifuge at 8000rpm for 15min to obtain supernatant as purple corn kernel anthocyanin extract.

Method for measuring anthocyanin

Determining the content of anthocyanin by adopting a pH differential method: 0.5ml of the sample solution was aspirated, mixed with 4.5ml of hydrochloric acid-potassium chloride buffer (pH 1) and hydrochloric acid-sodium acetate buffer (pH 4.5), each of which was set in parallel, and reacted in a water bath at 40 ℃ for 0.5 hour, followed by measuring absorbances a520 nm and a700 nm at wavelengths of 520 nm and 700nm, respectively, to calculate the anthocyanin yield, which was expressed by the following formula:

wherein A ═ (A520-A700) pH 1.0- (A520-A700) pH 4.5; mw is the molar mass of cornflower-3-glucoside, 449.2 g/mol; DF is dilution multiple; v is the total volume of the extracting solution, mL; epsilon is the molar extinction coefficient of cornflower-3-glucoside, 26900 L.mol/cm; m is the weight of the indigo fruit, g; l is the light distance length of the cuvette, 1 cm.

Second, the determination results of the anthocyanin extraction amount in examples and comparative examples

TABLE 1 comparison of anthocyanin extraction amount of purple corn by single ultrasonic extraction and ultrahigh pressure ultrasonic combined extraction

It can be clearly seen from table 1 that the yield of anthocyanin extracted from purple corn kernels and cobs by ultrahigh pressure combined ultrasonic treatment is obviously higher than that of anthocyanin extracted by ultrasonic alone, the ultrasonic extraction time is shortened, the whole extraction time is shortened, and the extraction efficiency is greatly improved, so that the feasibility of the method can be proved.

Finally, the description is as follows: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.