阅读说明：本技术 一种提高蚕蛹蛋白功能特性的方法及制备得到的改性蚕蛹蛋白 (Method for improving functional characteristics of silkworm pupa protein and modified silkworm pupa protein prepared by method ) 是由 邵俊花 高艳慧 丁雨欣 佟新 郑艳 岳喜庆 马跃 杨梅 于 2020-06-16 设计创作，主要内容包括：本发明提供了一种提高蚕蛹蛋白粉功能特性的方法及制备得到的改性蚕蛹蛋白,属于食品加工技术领域。本发明提供的方法包括：将蚕蛹蛋白粉悬浮液依次进行超声处理和冻干处理。本发明提供的方法可以有效提高蚕蛹蛋白的溶解度和其他的功能特性,有利于柞蚕蛹蛋白粉的规模化生产,制备复合功能性食品的要求。(The invention provides a method for improving the functional characteristics of silkworm chrysalis protein powder and modified silkworm chrysalis protein prepared by the method, and belongs to the technical field of food processing. The method provided by the invention comprises the following steps: and sequentially carrying out ultrasonic treatment and freeze-drying treatment on the silkworm pupa protein powder suspension. The method provided by the invention can effectively improve the solubility and other functional characteristics of the silkworm pupa protein, is beneficial to the large-scale production of the tussah silkworm pupa protein powder and meets the requirements of preparing composite functional food.)

1. A method for improving the functional properties of silkworm pupa protein, comprising: and sequentially carrying out ultrasonic treatment and freeze-drying treatment on the silkworm pupa protein powder suspension.

2. The method of claim 1, wherein the amplitude of the sonication is between 20% and 40%.

3. The method according to claim 1, wherein the time of the ultrasonic treatment is 20min to 100 min.

4. A method according to any one of claims 1 to 3, wherein the ultrasonication is batch ultrasonication.

5. The method according to claim 4, wherein the intermittent ultrasound is ultrasound for 2-10 s, and the intermittent ultrasound is ultrasound for 2-10 s.

6. The method according to claim 1, wherein the freeze-drying process comprises freeze-cooling and freeze-drying in sequence; the environment temperature of freezing and cooling is-40 to-80 ℃, and the time is 1 to 2 days; the temperature of the freeze drying is-40 to-80 ℃, and the processing time is 24 to 48 hours.

7. The method according to claim 1 or 6, further comprising centrifugation before the lyophilization process, wherein the rotation speed of the centrifugation is 3000-4000 r/min.

8. The method of claim 1, wherein the mass concentration of the silkworm chrysalis protein powder suspension is 1-10%.

9. The method of claim 1 or 8, wherein the silkworm pupa protein powder is tussah pupa protein powder.

10. The modified silkworm pupa protein obtained by the method of any one of claims 1 to 9, wherein the modified silkworm pupa protein has a solubility of 16.53mg/g to 99.44mg/g, a foaming property of 50.0% to 52.0%, a foaming stability of 75.0% to 92.30%, and an emulsifiability of 11.58m²/g～12.08m²The emulsion stability is 62.22-71.88%.

Technical Field

The invention relates to the technical field of food processing, in particular to a method for improving the functional characteristics of silkworm pupa protein powder and modified silkworm pupa protein prepared by the method.

Background

The tussah pupa contains protein with rich nutrition, the content of the protein reaches 60 percent, the nutrient content and the value of the tussah pupa are far higher than those of other common foods, the types of essential amino acids in the protein are rich and comprehensive, 18 amino acids exist in the tussah pupa, the tussah pupa cannot be synthesized in a human body, the content of 8 essential amino acids which are required to be absorbed by the outside is very high, the amino acids account for more than 42 percent of the total amount of the amino acids, the proportion of the amino acids is proper, and the requirement of FAO/WHO is met.

The tussah pupa protein is rich in nutrition and can be used as a nutritional supplement in food. However, the functional characteristics of the tussah pupa protein cannot be compared with other animal proteins, for example, the solubility and emulsibility of the tussah pupa protein are poor, and the application of the tussah pupa protein in the fields of food processing and production is limited, so that the improvement of the functional characteristics of the tussah pupa protein is an effective method for improving the utilization rate of the tussah pupa protein.

Disclosure of Invention

In order to solve the problems, the invention provides a method for improving the functional characteristics of silkworm pupa protein powder and modified silkworm pupa protein prepared by the method. The silkworm pupa protein prepared by the method provided by the invention has good solubility, stable emulsibility and stable foamability, and the functional characteristics of the silkworm pupa protein are improved.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for improving the functional characteristics of silkworm pupa protein, which comprises the following steps: and sequentially carrying out ultrasonic treatment and freeze-drying treatment on the silkworm pupa protein powder suspension.

Preferably, the amplitude of the ultrasonic treatment is 20% to 40%.

Preferably, the time of the ultrasonic treatment is 20min to 100 min.

Preferably, the sonication is batch sonication.

Preferably, the intermittent ultrasound is ultrasound for 2-10 s, and the intermittent ultrasound is intermittent for 2-10 s.

Preferably, the freeze-drying treatment comprises centrifugation, freezing and cooling and freeze-drying which are sequentially carried out; the environment temperature of freezing and cooling is-40 to-80 ℃, and the time is 1 to 2 days; the temperature of the freeze drying is-40 to-80 ℃, and the processing time is 24 to 48 hours.

Preferably, the freeze-drying treatment further comprises centrifugation, and the rotation speed of the centrifugation is 3000-4000 r/min.

Preferably, the mass fraction of the silkworm chrysalis protein powder suspension is 1-10%.

Preferably, the silkworm pupa protein powder is tussah pupa protein powder.

The modified silkworm pupa protein prepared by the preparation method provided by the invention has the solubility of 16.53-99.44 mg/g, the foamability of 50.0-52.0%, the foaming stability of 75.0-92.30%, and the emulsibility of 11.58m²/g～12.08m²The emulsion stability is 62.22-71.88%.

The invention provides a method for improving the functional characteristics of silkworm pupa protein, which sequentially carries out ultrasonic treatment and freeze-drying treatment on a silkworm pupa protein powder suspension. The invention physically modifies the silkworm pupa protein powder suspension by ultrasonic treatment, utilizes the force, heat, pressure and the like generated by specific physical means to act on protein, promotes the spatial structure of the protein to be changed, modifies the structure of the protein, promotes hydrophilic amino acid residues to migrate to the outside of the protein, enhances the water-binding capacity of the protein, and improves the solubility of the protein. Because the transient cavitation of ultrasonic treatment can gather energy density and height, physical effects such as pressure, temperature and the like are generated at the moment of sound pressure collapse to change the molecular structure of the protein. The silkworm pupa protein with the highest ratio is globulin, the volume of the globulin is reduced after ultrasonic treatment, and the compressibility of the globulin in a solvent is enhanced, so that the protein is more easily dispersed in the solvent, and various properties of the protein are obviously improved. As shown in the examples, the silkworm pupa protein treated by the preparation method provided by the invention has the solubility as high as 16.53-99.44 mg/g and the foamability as high as 50.0-52.0%Foaming stability of 75.0-92.30%, emulsibility of 11.58m²/g～12.08m²The emulsion stability is 62.22-71.88%.

Detailed Description

The invention provides a method for improving the functional characteristics of silkworm chrysalis protein powder, which comprises the following steps: and sequentially carrying out ultrasonic treatment and freeze-drying treatment on the silkworm pupa protein powder suspension. The method provided by the invention can effectively improve the solubility, foamability and emulsibility of the silkworm chrysalis protein powder.

In the invention, the silkworm pupa protein powder is preferably tussah pupa protein powder; the silkworm pupa protein powder is preferably extracted by an alkali-soluble acid-precipitation method.

In the invention, the preparation method of the silkworm pupa protein powder is preferably as follows: crushing the degreased silkworm chrysalis to obtain silkworm chrysalis powder; and sequentially carrying out primary pH value adjustment, shaking treatment and secondary pH value adjustment on the obtained silkworm chrysalis powder, and freeze-drying treatment on the precipitate to obtain the silkworm chrysalis protein powder.

The invention has no special requirements on the specific implementation mode of crushing, and the method is well known by the technical personnel in the field; the invention preferably screens the degreased silkworm chrysalis into silkworm chrysalis powder with a grain size of more than or equal to 40 meshes.

In the present invention, the first pH adjustment is preferably performed by: uniformly mixing the silkworm chrysalis powder with a sodium hydroxide aqueous solution to obtain a silkworm chrysalis alkali solution, and adjusting the pH value of the silkworm chrysalis alkali solution to 8-10 by using hydrochloric acid; the mass concentration of the sodium hydroxide aqueous solution is preferably 1%; the mass ratio of the silkworm chrysalis powder to the sodium hydroxide aqueous solution is preferably 1: 6-10, and more preferably 1: 8-10, most preferably 1: 10; the concentration of the hydrochloric acid is preferably 1-3 mol/L, and more preferably 1 mol/L.

In the invention, the time of the oscillation treatment is preferably 4-8 h, more preferably 5h, and the temperature is preferably 50-70 ℃, more preferably 60 ℃; in the embodiment of the present invention, the oscillation process is preferably performed in a constant temperature oscillator; the rotational speed of the thermostatic oscillator is preferably 160 r/min.

The invention preferably filters the silkworm pupa alkali liquor obtained by the oscillation treatment to obtain the protein leaching liquor.

In the present invention, the second pH adjustment is preferably performed by: the pH of the protein leach solution was adjusted to 4.5 using hydrochloric acid. In the invention, the concentration of the hydrochloric acid is preferably 1-3 mol/L, and more preferably 1 mol/L.

Preferably, the protein leaching liquor obtained by regulating the pH value is kept stand, and then the lower layer of sediment is taken to obtain protein sediment; washing the protein precipitate until the washing liquid is clear and transparent to obtain pure protein precipitate; and freeze-drying the pure protein precipitate to obtain the silkworm pupa protein powder. In the present invention, the condition of the standing is preferably a standing at 4 ℃; in the embodiment of the invention, the effect of completely separating the upper solution from the lower precipitate can be achieved after the solution is stood for 12 hours.

The washing of the invention is preferably carried out by using distilled water for multiple times, the freeze-drying is preferably carried out by using a freeze dryer, and the freeze-drying time is preferably 48 h. The silkworm chrysalis protein powder prepared by the specific alkali-soluble acid-precipitation method has the characteristics of simple process, low cost, short time consumption, high equipment utilization rate and the like; and the yield of the silkworm pupa protein is improved on the premise of ensuring the product quality.

In the present invention, the mass concentration of the silkworm pupa protein powder suspension is preferably 1% to 10%, more preferably 5% to 9%, and most preferably 9%. The suspension with specific concentration of the invention avoids the increase of the viscosity of the suspension caused by overhigh concentration, prevents the high-efficiency transmission of ultrasonic energy and enhances the efficiency of ultrasonic treatment.

In the present invention, the amplitude of the ultrasonic treatment is preferably 20% to 40%, more preferably 30% to 40%, and most preferably 40%; the time of the ultrasonic treatment is preferably 20min to 100min, more preferably 60min to 100min, and most preferably 100 min; the power of the ultrasonic treatment is preferably 750W; the mode of the ultrasonic treatment is preferably intermittent ultrasonic treatment, the intermittent ultrasonic treatment is preferably ultrasonic for 2-10 s and 2-10 s, and further preferably ultrasonic for 5s and 5 s. When the invention adopts intermittent ultrasonic treatment, the sum of the ultrasonic time and the intermittent time is the ultrasonic treatment time. When the ultrasonic treatment is carried out, the distance between the bottom of the ultrasonic probe and the bottom of the silkworm chrysalis protein powder suspension liquid loading container is preferably 1-3 cm. In the invention, the power of an ultrasonic instrument used for ultrasonic treatment is 750W, and the generation frequency is 20 KHz; in the embodiment of the present invention, the ultrasonic treatment implementing device is an ultrasonic cell disruptor model VCX750, which is well known to those skilled in the art; the invention has no requirement on the environmental temperature and the solution temperature in the ultrasonic treatment process, and the temperature is room temperature; in a particular embodiment of the invention, the sonication is carried out in particular in an ultrasonic cell disruptor. The invention strengthens the cavitation effect by limiting the amplitude and intermittent treatment in the ultrasonic treatment, so that the silkworm pupa protein improves the solubility to the maximum extent.

In the present invention, the lyophilization process preferably includes freezing-cooling and freeze-drying which are performed sequentially. In the invention, the environment temperature of freezing and cooling is preferably-40 to-80 ℃, more preferably-60 to-80 ℃, and most preferably-80 ℃; the freezing and cooling time is preferably 1-2 days; the temperature of the freeze drying is preferably-40 to-80 ℃, more preferably-60 to-80 ℃, and most preferably-80 ℃; the freeze drying time is 24-48 h. According to the invention, through freeze-drying treatment, 95-99% of water in the silkworm pupa protein powder suspension can be removed, and the functional characteristics and flavor of the silkworm pupa protein subjected to ultrasonic treatment are retained to the greatest extent.

Before the freeze-drying treatment, the centrifugation of the invention preferably further comprises the step of centrifuging the suspension obtained by the ultrasound, and carrying out freeze-drying treatment on the sediment obtained by the centrifugation. In the invention, the rotation speed of the centrifugation is preferably 3000-4000 r/min, and more preferably 4000 r/min. In the invention, the centrifugal treatment can effectively reduce the freeze-drying time, thereby achieving the effect of saving the preparation time and cost.

The invention also provides the modified silkworm pupa protein obtained by the method in the technical scheme, the solubility of the modified silkworm pupa protein obtained by the treatment of the method is 16.53-99.44 mg/g, the foamability is 50.0-52.0%, and the foaming stability is high75.0 to 92.30 percent of the total weight of the emulsion, and the emulsibility of the emulsion is 11.58m²/g～12.08m²The emulsion stability is 62.22-71.88%.

In order to further illustrate the present invention, the method for improving the functional properties of silkworm pupa protein and the modified silkworm pupa protein prepared by the method are described in detail with reference to the following examples, which should not be construed as a prerequisite for the protection scope of the present invention.