Tremella polysaccharide-corn germ globulin gel and preparation method thereof

Abstract

The present application is suitable for the field of food science and engineering technology, and provides a tremella polysaccharide-corn germ globulin gel and a preparation method thereof; when the mass ratio of the tremella polysaccharide and the corn germ globulin is 1:1, the obtained gel has the optimal performance; at this time, the electrostatic interaction between the two is the strongest, the hydrophilic group promotes the formation of hydrogen bonds, so that the hydrophilic-lipophilic balance value of the gel reaches 7.36, the wave peak of 3200-3400 cm ‑1 in the infrared spectrum is shifted to 3430 cm ‑1 , and the wave peak is widened, the emulsion stability and emulsion activity are 93.02% and 65.59 m 2 / g respectively, the gel has excellent amphiphilicity, can meet the demand for the balance of hydrophilicity and hydrophobicity in food processing, and does not need to add additional ingredients for adjustment; at the same time, the hardness of the gel is 87.27 g, the elasticity is 0.978, and the cohesiveness is 0.888, the formed gel network is tight and stable, the structure integrity and mechanical properties are excellent, and the present application provides an excellent natural amphiphilic gel for the food field.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of food science and engineering, and particularly relates to a tremella polysaccharide-corn germ globulin gel and a preparation method thereof. BACKGROUND

[0002] Gels exhibit important value in the fields of delivering unstable compounds such as curcumin and three-dimensional food printing due to their excellent biological properties and stable three-dimensional structures. With the rapid development of food science, gels have become a key focus of food additive research and are widely used in various products such as jelly and yogurt.

[0003] At present, food gels are mainly divided into hydrogels and oleogels according to their interaction with water and dispersion medium, and have hydrophilic and hydrophobic properties, respectively. However, in actual processing, it is often difficult to meet the needs by relying only on water or oil retention. For example, in the production of plant-based meat, soy protein isolate and potato starch have high viscosity and water retention capacity, but need to be combined with coconut oil to improve fluidity, which has promoted the development of amphiphilic additives.

[0004] Currently, the main forms of amphiphilic materials include the preparation of nanomaterials (such as particles and emulsions) and the use of polysaccharide gels as delivery systems, which have been applied in the fields of materials and drug transport. However, in the food industry, research on the processing performance of amphiphilic gels is still very scarce. At the same time, with the rise of a healthy lifestyle, it has become a trend to use natural substances to enhance emulsification performance to improve gel performance, such as combining soy protein isolate with corn starch, kurdan, and konjac gum to enhance hydrophobic interactions to create emulsified gels as a substitute for solid fat. Therefore, it is of great practical significance to develop an amphiphilic gel based on natural substances. To this end, the present application provides a tremella polysaccharide-corn germ globulin gel and a preparation method thereof. SUMMARY

[0005] The present application aims to provide a tremella polysaccharide-corn germ globulin gel and a preparation method thereof, which aims to solve the problems raised in the background.

[0006] The object of the present application is achieved by the following technical solutions:

[0007] A tremella polysaccharide-corn germ globulin gel is formed by the reaction of tremella polysaccharide and corn germ globulin, and the mass ratio of the tremella polysaccharide to the corn germ globulin is 0.7:1 to 1.1:1.

[0008] Further, when the mass ratio of the tremella polysaccharide and the zein globulin is 1:1, the hydrophilic-lipophilic balance value of the formed tremella polysaccharide-zein globulin gel is 7.36, the hardness is 87.27 g, the elasticity is 0.978, the cohesiveness is 0.888, and the emulsion stability and the emulsion activity are 93.02% and 65.59 m 2 / g, respectively.

[0009] A preparation method of the tremella polysaccharide-zein globulin gel described above, comprising the following steps:

[0010] Step 1: preparing the zein globulin;

[0011] Step 2: preparing a 4% (w / v) zein globulin solution;

[0012] Step 3: performing ultrasonic treatment on the zein globulin solution;

[0013] Step 4: adding the tremella polysaccharide into the ultrasonically treated solution, so that the mass ratio of the tremella polysaccharide and the zein globulin is 0.7:1-1.1:1, forming a polysaccharide-protein mixture; adjusting the pH value and stirring the mixture;

[0014] Step 5: placing the polysaccharide-protein mixture and incubating to obtain the tremella polysaccharide-zein globulin gel.

[0015] Further, the specific operation of Step 1 is as follows: defatting the corn germ powder, passing it through an 80-mesh sieve, dissolving it in deionized water at a ratio of 1:10 g / L, adjusting the pH value of the mixture to 7.5 with a 1.0 mol / L sodium hydroxide solution, extracting at 40°C for 2 h, centrifuging at 3800 r / min for 15 min, dissolving the precipitate in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, extracting again at 40°C for 2 h at a pH value of 13, and then adjusting the pH value of the supernatant to 4.4 with a 1.0 mol / L hydrochloric acid solution to obtain a crude protein precipitate; dissolving the crude protein precipitate in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, adjusting the pH value of the system to 9 with a 1.0 mol / L sodium hydroxide solution, and repeatedly extracting at 40°C for 3 times to obtain the zein globulin, which is washed to neutral and then freeze-dried.

[0016] Further, the specific operation of Step 2 is as follows: adding 2 g of the zein globulin into 50 mL of a PBS solution, adjusting the pH value to 7.4 with a 1.0 mol / L sodium hydroxide solution, and then stirring at 1000 r / min for 20 min to obtain a uniform zein globulin solution.

[0017] Further, in the step 3, the power of ultrasonic treatment is 300 W, and the time is 10 min.

[0018] Further, in the step 4, the pH value of the polysaccharide-protein mixture is adjusted to 4.0 by using 1.0 mol / L hydrochloric acid solution; and the stirring condition is that the magnetic stirring is carried out at a speed of 1000 r / min for 10 min.

[0019] Further, in the step 5, the standing temperature is 30 DEG C, and the standing time is 2 h; and the incubation temperature is 4 DEG C, and the incubation time is 24 h.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The silver fungus polysaccharide-corn germ globulin gel prepared by the present application has the optimal performance when the mass ratio (w / w) of silver fungus polysaccharide and corn germ globulin is 1:1, at which the electrostatic interaction between the two is the strongest, a large number of hydrophilic groups promote the formation of hydrogen bonds between the protein and water, so that the hydrophilic-lipophilic balance value (HLB) of the gel reaches 7.36, and in the infrared spectrum, the wave peak at 3200-3400 cm -1 -1 shifts to 3430 cm -1 -1, and the wave peak is widened, the emulsification stability and the emulsification activity are 93.02% and 65.59 m 2 / g respectively, the gel has excellent amphiphilicity, can meet the demand for the balance of hydrophilicity and hydrophobicity in food processing without additional ingredients for adjustment, and at the same time, the hardness of the gel reaches 87.27 g, the elasticity is 0.978, and the cohesiveness is 0.888, due to the strongest electrostatic interaction and reasonable distribution of hydrophilic groups, the formed gel network is tight and stable, and has excellent structure integrity and mechanical properties, so the gel using natural substances as raw materials solves the problems of lack of research on amphiphilic gel in the food industry in the prior art and difficulty in meeting the processing demand of single hydrophilic or hydrophobic gel, provides an excellent natural amphiphilic gel suitable for emulsification, transportation of unstable compounds or three-dimensional food printing and the like in the food field, and has outstanding practicability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Fig. 1 is a hydrophilic-lipophilic balance value (HLB) change trend chart of the gel obtained in Examples 1-5, in which a-f are significant difference identifiers (p<0.05).

[0023] Figure 2 Fig. 2 is a change trend chart of the texture properties of the gel obtained in Examples 1-5.

[0024] Figure 3 Fig. 3 is an infrared spectrum chart of the gel obtained in Examples 1-5.

[0025] Figure 4 Fig. 4 is an emulsification property chart of the gel obtained in Examples 1-5. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as limiting the implementable scope of the present application.

[0027] In the present application, the materials, reagents or instruments not specified by the manufacturer are all conventional products that can be obtained by market purchase.

[0028] One embodiment of the present application provides a preparation method of tremella polysaccharide-corn germ globulin gel, comprising the following steps:

[0029] Step 1: preparing corn germ globulin;

[0030] The specific operation of step 1 is as follows: defat the corn germ powder and pass it through an 80-mesh sieve, dissolve it in deionized water at a ratio of 1:10 g / L, adjust the pH value of the mixture to 7.5 with a 1.0 mol / L sodium hydroxide solution, extract at 40℃ for 2 h, centrifuge at a speed of 3800 r / min for 15 min, dissolve the precipitate in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, extract again at 40℃ for 2 h at a pH value of 13, and then adjust the pH value of the supernatant to 4.4 with a 1.0 mol / L hydrochloric acid solution to obtain a crude protein precipitate; dissolve the crude protein precipitate in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, adjust the pH value of the system to 9 with a 1.0 mol / L sodium hydroxide solution, and repeat the extraction at 40℃ for 3 times to obtain corn germ globulin, which is washed to neutral with water and then freeze-dried (-50℃, 0.066 mbar).

[0031] Step 2: preparing a 4% (w / v) corn germ globulin solution;

[0032] Add 2 g of corn germ globulin to 50 mL of PBS solution, adjust the pH to 7.4 with a 1.0 mol / L sodium hydroxide solution, and then stir at a speed of 1000 r / min for 20 min to obtain a uniform corn germ globulin solution.

[0033] Step 3: pretreatment of the corn germ globulin solution;

[0034] Use an ultrasonic homogenizer to ultrasonically treat the corn germ globulin solution at a power of 300 W for 10 min to promote protein dispersion.

[0035] Step 4: adding and mixing tremella polysaccharide;

[0036] Since the 4% corn germ globulin solution cannot form a gel, the tremella polysaccharide (purchased from Shandong Jiaofeng Furuida Biological Co., Ltd.) is added to the pretreated corn germ globulin solution to make the mass ratio (w / w) of the tremella polysaccharide and the corn germ globulin reach 0.7:1~1.1:1, so as to prepare a gel. Then, the pH value of the formed polysaccharide-protein mixture is adjusted to 4.0 by using a 1.0 mol / L hydrochloric acid solution, and the mixture is subjected to magnetic stirring at a speed of 1000 r / min for 10 min to ensure that the two are fully mixed.

[0037] Step 5: gel network formation and product preparation;

[0038] The polysaccharide-protein mixture is placed at 30°C for 2 h to accelerate the reaction; then the polysaccharide-protein mixture is incubated at 4°C for 24 h to promote the reaction of the tremella polysaccharide and the corn germ globulin and the formation of the gel network, and finally the tremella polysaccharide-corn germ globulin gel is obtained.

[0039] The specific implementation of the present application is described in detail in combination with specific examples.

[0040] Example 1;

[0041] A method for preparing a tremella polysaccharide-corn germ globulin gel, comprising the following steps:

[0042] Step 1: preparation of corn germ globulin;

[0043] After the corn germ powder is defatted, it is passed through an 80-mesh sieve and dissolved in deionized water at a ratio of 1:10 g / L. The pH value of the mixture is adjusted to 7.5 by using a 1.0 mol / L sodium hydroxide solution. After extraction at 40°C for 2 h, the precipitate is dissolved in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, and the pH value is adjusted to 13. The mixture is extracted again at 40°C for 2 h. Then the pH value of the supernatant is adjusted to 4.4 by using a 1.0 mol / L hydrochloric acid solution to obtain a crude protein precipitate. The crude protein precipitate is dissolved in a 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L, and the pH value of the system is adjusted to 9 by using a 1.0 mol / L sodium hydroxide solution. The extraction is repeated three times at 40°C to obtain corn germ globulin. After washing to neutral, the corn germ globulin is freeze-dried (-50°C, 0.066 mbar).

[0044] Step 2: preparation of a 4% (w / v) corn germ globulin solution;

[0045] 2g of zein was added into 50mL PBS solution, and the pH was adjusted to 7.4 with 1.0mol / L NaOH solution, followed by stirring at 1000r / min for 20min to obtain a uniform zein solution.

[0046] The zein used in this step was obtained by Figure 1 and Figure 2 It was known that the HLB value of zein itself was 4.65 (strong hydrophobicity) (see Figure 1 ), the hardness was 0g, the elasticity was 0, and the cohesiveness was 0. It was known from Figure 3 and Figure 4 that the wave peak of 3200-3400cm -1 in the infrared spectrum of zein shifted to 3298cm -1 , and the emulsion stability and emulsifying activity were 85.43% and 42.66m 2 / g, respectively. The intramolecular hydrogen bond interaction was weak, and it was difficult to form a stable gel network and excellent amphiphilicity when used alone, which limited its application in the food industry.

[0047] Step 3: Pretreatment of zein solution;

[0048] The zein solution was treated with an ultrasonic homogenizer at a power of 300W for 10min to promote protein dispersion.

[0049] Step 4: Addition and mixing of tremella polysaccharide;

[0050] Tremella polysaccharide was added to the pretreated zein solution to make the mass ratio (w / w) of tremella polysaccharide to zein reach 0.7:1 to form a polysaccharide-protein mixture. Then, the pH of the polysaccharide-protein mixture was adjusted to 4.0 with 1.0mol / L HCl solution, and the mixture was stirred at 1000r / min for 10min to ensure that the two were fully mixed.

[0051] Step 5: Gel network formation and product preparation;

[0052] The polysaccharide-protein mixture was placed at 30°C for 2h to accelerate the reaction, and then the polysaccharide-protein mixture was incubated at 4°C for 24h to promote the reaction of tremella polysaccharide and zein and the formation of gel network, and finally the tremella polysaccharide-zein gel was obtained.

[0053] It was known from Figure 1 and Figure 2 that the HLB value of the tremella polysaccharide-zein gel obtained in this embodiment was 5.55, the hardness was 38.75g, the elasticity was 0.954, and the cohesiveness was 0.835. It was known from Figure 3 andFigure 4 It can be seen that its infrared spectrum has a range of 3200-3400 cm⁻¹ -1 The peak shifted to 3358cm -1 Furthermore, the peak broadened, and the emulsification stability and emulsification activity were 90.09% and 45.94%, respectively. 2 / g. This is because at this ratio (the mass ratio of Tremella polysaccharide to corn germ protein is 0.7:1), the electrostatic interaction between the two is weak, which can only promote the formation of hydrogen bonds between a small amount of hydrophilic groups of Tremella polysaccharide and corn germ protein. The slight shift and mild broadening of the infrared peak confirm the initial formation of hydrogen bond interaction. This weak intermolecular force results in limited improvement in gel hydrophilicity and a low HLB value. At the same time, the gel network structure is loose, resulting in basic hardness and emulsifying properties.

[0054] Example 2;

[0055] A method for preparing a Tremella polysaccharide-corn germ globulin gel differs from Example 1 in that the mass ratio (w / w) of Tremella polysaccharide to corn germ globulin is 0.8:1, while the remaining steps are the same as in Example 1.

[0056] Depend on Figure 1 and Figure 2 It can be seen that the tremella polysaccharide-corn germ globulin gel obtained in this embodiment has an HLB value of 6.19, a hardness of 44.82g, an elasticity of 0.952, and a cohesiveness of 0.849. (From...) Figure 3 and Figure 4 It can be seen that its infrared spectrum has a range of 3200-3400 cm⁻¹ -1 The peak shifted to 3374cm -1 Furthermore, the peak width increased, and the emulsification stability and emulsification activity were 89.52% and 48.39%, respectively. 2 / g. This is because as the proportion of Tremella polysaccharide increases, the electrostatic interaction between the two is enhanced, and more hydrophilic groups participate in the formation of hydrogen bonds. The further shift and broadening of the infrared peak directly reflects the increase in the number of hydrogen bonds. This enhanced intermolecular interaction not only improves the hydrophilicity of the system (increases the HLB value), but also makes the gel network more compact, and the hardness and emulsification properties are improved accordingly.

[0057] Example 3;

[0058] A method for preparing a Tremella polysaccharide-corn germ globulin gel differs from Example 1 in that the mass ratio (w / w) of Tremella polysaccharide to corn germ globulin is 0.9:1, while the remaining steps are the same as in Example 1.

[0059] Depend on Figure 1 and Figure 2It can be seen that the tremella polysaccharide-corn germ globulin gel obtained in this embodiment has an HLB value of 6.50, a hardness of 48.30 g, an elasticity of 0.971, and a cohesiveness of 0.854. Figure 3 and Figure 4 It can be seen that its infrared spectrum has a range of 3200-3400 cm⁻¹ -1 The peak shifted to 3391cm -1 Furthermore, the peak broadened, and the emulsification stability and emulsification activity were 87.41% and 61.82%, respectively. 2 / g. At this point, the electrostatic interaction is further enhanced, driving more hydrophilic groups to align and form dense hydrogen bonds. The characteristic changes in the infrared spectrum clearly indicate that the hydrogen bonding interaction has entered an enhanced stage. This synergistic effect continuously improves the hydrophilicity of the gel, makes the network structure more stable, and increases the hardness while significantly improving the emulsifying activity, reflecting the progressive influence of intermolecular forces on macroscopic properties.

[0060] Example 4;

[0061] A method for preparing a Tremella polysaccharide-corn germ globulin gel differs from Example 1 in that the mass ratio (w / w) of Tremella polysaccharide to corn germ globulin is 1:1, while the remaining steps are the same as in Example 1.

[0062] Depend on Figure 1 and Figure 2 It can be seen that the tremella polysaccharide-corn germ globulin gel obtained in this embodiment has an HLB value of 7.36, a hardness of 87.27g, an elasticity of 0.978, and a cohesiveness of 0.888. (From...) Figure 3 and Figure 4 It can be seen that its infrared spectrum has a range of 3200-3400 cm⁻¹ -1 The peak shifted to 3430cm -1 Furthermore, the peak width increased, and the emulsification stability and emulsification activity were 93.02% and 65.59%, respectively. 2 / g. At this ratio (1:1 ratio of Tremella polysaccharide to corn germ protein), the electrostatic interaction between the two is strongest, providing optimal conditions for full contact between hydrophilic groups and protein molecules. A large number of hydrogen bonds are formed and a dense network is constructed. The significant changes in the infrared spectrum directly confirm the maximization of hydrogen bonding. This super-strong intermolecular force enables the gel to achieve optimal amphiphilicity (moderate HLB value), a tight and stable network structure (highest hardness), and peak emulsification performance, demonstrating the decisive influence of microscopic effects on macroscopic properties.

[0063] Example 5;

[0064] A method for preparing a Tremella polysaccharide-corn germ globulin gel differs from Example 1 in that the mass ratio (w / w) of Tremella polysaccharide to corn germ globulin is 1.1:1, while the remaining steps are the same as in Example 1.

[0065] By Figure 1 and Figure 2 It can be seen that the HLB value of the tremella polysaccharide-corn germ globulin gel obtained in the embodiment is 8.01, the hardness is 67.13 g, the elasticity is 0.97, and the cohesiveness is 0.866. By Figure 3 and Figure 4 Figure 1 Figure 2 Figure 3 Figure 4 It can be seen that the wave peak of 3200-3400 cm -1 in the infrared spectrum is shifted to 3383 cm -1 and the wave peak is widened, the emulsion stability and the emulsifying activity are 91.39% and 52.65 m 2 / g, respectively. Excessive tremella polysaccharide leads to self-aggregation between molecules, which instead weakens the electrostatic interaction with the protein, so that the effective combination of the hydrophilic group with the protein is reduced, and the hydrogen bond interaction is weakened. The readjustment change in the infrared spectrum proves this point, thus causing the gel hydrophilicity to be too strong (the HLB value is too high), the network structure pore to increase (the hardness to decrease), and the emulsification performance to fall accordingly, which reflects the negative impact of the imbalance between the intermolecular interactions on the performance.

[0066] The above is only a preferred embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which should also be considered as the protection scope of the present application, and these will not affect the effect and practicality of the present application.

Claims

1. A method for preparing a Tremella fuciformis polysaccharide-corn germ globulin gel, characterized in that, Includes the following steps: Step 1: Preparation of corn germ globulin; the specific operation is as follows: defatted corn germ powder is passed through an 80-mesh sieve and dissolved in deionized water at a ratio of 1:10 g / L. The pH of the mixture is adjusted to 7.5 with 1.0 mol / L sodium hydroxide solution. After extraction at 40℃ for 2 h, it is centrifuged at 3800 r / min for 15 min. The precipitate is dissolved in 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L and extracted again at pH 13 and 40℃ for 2 h. Then, the pH of the supernatant is adjusted to 4.4 with 1.0 mol / L hydrochloric acid solution to obtain crude protein precipitate. The crude protein precipitate is dissolved in 0.5 mol / L sodium chloride solution at a ratio of 1:10 g / L. The pH of the system is adjusted to 9 with 1.0 mol / L sodium hydroxide solution. The extraction is repeated 3 times at 40℃ to obtain corn germ globulin. After washing with water to neutrality, it is freeze-dried. Step 2: Prepare a 4% (w / v) corn germ globulin solution; Step 3: Sonicate the corn germ globulin solution; Step 4: Add Tremella polysaccharide to the ultrasonically treated solution, so that the mass ratio of Tremella polysaccharide to corn germ globulin is 0.9:1~1:1, to form a polysaccharide-protein mixture; adjust the pH and stir to mix. Step 5: After the polysaccharide-protein mixture is allowed to stand, it is incubated to obtain Tremella polysaccharide-corn germ globulin gel; In step 4, the pH of the polysaccharide-protein mixture is adjusted to 4.0 using a 1.0 mol / L hydrochloric acid solution; the stirring conditions are: magnetic stirring at 1000 r / min for 10 min.

2. The preparation method according to claim 1, characterized in that, The specific operation of step 2 is as follows: add 2g of corn germ globulin to 50mL of PBS solution, adjust the pH to 7.4 with 1.0mol / L sodium hydroxide solution, and then stir at 1000r / min for 20min to obtain a uniform corn germ globulin solution.

3. The preparation method according to claim 1, characterized in that, In step 3, the ultrasonic treatment power is 300W and the time is 10min.

4. The preparation method according to claim 1, characterized in that, In step 5, the settling temperature is 30°C and the settling time is 2 hours; the incubation temperature is 4°C and the incubation time is 24 hours.

5. A Tremella fuciformis polysaccharide-corn germ globulin gel prepared by the preparation method according to any one of claims 1 to 4, characterized in that, It is formed by the reaction of Tremella polysaccharide and corn germ globulin, wherein the mass ratio of Tremella polysaccharide to corn germ globulin is 0.9:1 to 1:

1.

6. The Tremella fuciformis polysaccharide-corn germ globulin gel according to claim 5, characterized in that, When the mass ratio of the Tremella fuciformis polysaccharide to corn germ globulin is 1:1, the resulting Tremella fuciformis polysaccharide-corn germ globulin gel has a hydrophilic-lipophilic balance value of 7.36, a hardness of 87.27 g, an elasticity of 0.978, a cohesiveness of 0.888, and emulsifying stability and emulsifying activity of 93.02% and 65.59 m, respectively. 2 / g.

Images