阅读说明：本技术 一种高抗氧化性的米糠多糖-肽复合物及其制备方法 (High-oxidation-resistance rice bran polysaccharide-peptide compound and preparation method thereof ) 是由 谢明勇 刘欢 高刘辉 付爱平 于 2021-06-30 设计创作，主要内容包括：本发明提出一种高抗氧化性的米糠多糖-肽复合物及其制备方法,属于米糠复合物制备技术领域,所述方法包括如下步骤：1)以脱脂米糠为原料,将脱脂米糠与水混合,加入酒石酸调节pH后,倒入高压均质机中均质,得米糠多糖提取液；然后对米糠多糖提取液离心,冷冻干燥,得相对分子质量为10k～50kDa的米糠多糖；2)将上述米糠多糖与米糠肽混合,采用干法进行美拉德反应,得多糖-肽复合物。本发明所述方法可以得抗氧化性高的多糖-肽复合物。(The invention provides a rice bran polysaccharide-peptide compound with high oxidation resistance and a preparation method thereof, belonging to the technical field of rice bran compound preparation, and the method comprises the following steps: 1) taking defatted rice bran as a raw material, mixing the defatted rice bran with water, adding tartaric acid to adjust the pH value, and pouring the mixture into a high-pressure homogenizer for homogenization to obtain a rice bran polysaccharide extracting solution; then centrifuging the rice bran polysaccharide extracting solution, and freeze-drying to obtain rice bran polysaccharide with the relative molecular mass of 10 k-50 kDa; 2) mixing the rice bran polysaccharide and the rice bran peptide, and performing Maillard reaction by adopting a dry method to obtain a polysaccharide-peptide compound. The method can obtain the polysaccharide-peptide compound with high oxidation resistance.)

1. A preparation method of a rice bran polysaccharide-peptide compound with high oxidation resistance is characterized by comprising the following steps:

1) taking defatted rice bran as a raw material, mixing the defatted rice bran with water, adding tartaric acid to adjust the pH value, and pouring the mixture into a high-pressure homogenizer for homogenization to obtain a rice bran polysaccharide extracting solution; then centrifuging the rice bran polysaccharide extracting solution, and freeze-drying to obtain rice bran polysaccharide with the relative molecular mass of 10 k-50 kDa;

2) mixing the rice bran polysaccharide and the rice bran peptide, and performing Maillard reaction by adopting a dry method to obtain a polysaccharide-peptide compound.

2. The production method according to claim 1,

in the step 1), the feed-liquid ratio of the defatted rice bran to water is 1: 15-1: 20 g/ml.

3. The production method according to claim 1,

in the step 1), tartaric acid is added to adjust the pH value to 3.5-4.0.

4. The production method according to claim 1,

in the step 1), the homogenizing pressure is 80-95 Mpa; homogenizing for 20-30 min; the number of homogenization is 4-6.

5. The production method according to claim 1,

in the step 2), the molar ratio of the rice bran polysaccharide to the rice bran peptide is 4-6: 1.

6. the production method according to claim 1,

in step 2), the dry method specifically comprises: and placing the mixture in a dryer, and then placing the dryer in a constant temperature environment of 60-80 ℃ for 1 day.

7. The production method according to claim 1,

the relative humidity in the dryer is 60-80%.

8. The rice bran polysaccharide-peptide complex with high oxidation resistance prepared by the preparation method of any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of preparation of rice bran compounds, and particularly relates to a rice bran polysaccharide-peptide compound with high oxidation resistance and a preparation method thereof.

Background

The rice bran is a main byproduct of rice, but the comprehensive utilization rate of the rice bran is low. The international association lists rice bran as one of the underutilized natural raw materials. The rice bran contains about 65% of the nutrients. In animal production, rice bran is generally used as a feed raw material, the total utilization rate of the rice bran is less than 20%, and resource waste is caused. Rice Bran Polysaccharide (RBP) is mainly composed of xylose, rhamnose, mannose, galactose, arabinoxylan, glucose, and the like. RBP has remarkable effects in promoting immunity, resisting inflammation, resisting oxidation, etc.

The maillard reaction, a reaction between a hydroxyl compound (reducing saccharide) and an amino compound (amino acid and protein), which is widely used in the food industry, is also called a hydroxyamine reaction, and finally generates a brown or even black macromolecular substance through a complicated process. The Maillard product is a substance generated in the food storage and processing process, is a natural food antioxidant without toxic and side effects, and can be compared favorably with some artificially synthesized antioxidants with potential toxic and side effects and carcinogenic effects.

Disclosure of Invention

The invention aims to change the relative molecular mass of the rice bran polysaccharide by using a homogenizer while extracting the rice bran polysaccharide, thereby obtaining the rice bran polysaccharide with high oxidation resistance and molecular weight of 10 k-50 kDa in one step, and simultaneously obtaining the polysaccharide-peptide compound with stronger oxidation resistance by the Maillard reaction of the rice bran polysaccharide and rice bran peptide.

The invention provides a preparation method of a rice bran polysaccharide-peptide compound with high oxidation resistance, which comprises the following steps:

1) taking defatted rice bran as a raw material, mixing the defatted rice bran with water, adding tartaric acid to adjust the pH value, and pouring the mixture into a high-pressure homogenizer for homogenization to obtain a rice bran polysaccharide extracting solution; then centrifuging the rice bran polysaccharide extracting solution, and freeze-drying to obtain rice bran polysaccharide with the relative molecular mass of 10 k-50 kDa;

2) mixing the rice bran polysaccharide and the rice bran peptide, and performing Maillard reaction by adopting a dry method to obtain a polysaccharide-peptide compound.

Further, in the step 1), the feed-liquid ratio of the defatted rice bran to water is 1: 15-1: 20 g/ml.

Further, in the step 1), tartaric acid is added to adjust the pH value to 3.5-4.0.

Further, in the step 1), the homogenizing pressure is 80-95 Mpa; homogenizing for 20-30 min; the number of homogenization is 4-6.

Further, in the step 2), the molar ratio of the rice bran polysaccharides to the rice bran peptides is 4-6: 1.

further, in step 2), the dry method specifically includes: and placing the mixture in a dryer, and then placing the dryer in a constant temperature environment of 60-80 ℃ for 1 day.

Further, the relative humidity in the dryer is 60% -80%. The KBr solution was shelved at the bottom of the dryer mainly to improve the stability of the complex.

It is to be noted that: the rice bran peptide may be a commercially available rice bran peptide. The preparation method can also be prepared by adopting a conventional method, and the specific preparation method comprises the following steps: adding defatted rice bran meal into 15 times (volume ratio) of distilled water, adjusting pH to about 9.0 with 20% sodium hydroxide, placing in 35 deg.C water bath for 4h, centrifuging at 2800r/min for 20min to remove lower layer residue, and collecting supernatant. Adjusting pH of the supernatant to about 4.5 with 1mol/L hydrochloric acid, standing at room temperature for 50min, centrifuging at 4000r/min for 15min, discarding the supernatant to obtain lactalbumin precipitate, washing the protein precipitate with deionized water, dissolving the lower protein precipitate in 19 times of water, adding sodium sulfite, adjusting pH to about 7.0, and heating at 100 deg.C for 30 min.

Cooling the solution to 40 ℃, then putting the solution into an enzyme hydrolysis device, adding neutral protease with the protein mass fraction of 2%, wherein the enzyme activity is 50000u/g, continuously stirring, carrying out enzyme hydrolysis for 3h, and stopping enzymolysis. Adding hydrochloric acid into the hydrolysate, adjusting pH to about 3.0, inactivating enzyme, and cooling. And putting the hydrolysate into a centrifuge, centrifuging for 10min at the speed of 2000r/min, removing the lower-layer precipitate, and leaving the upper-layer solution.

Passing a volume of protein hydrolysate through the H at a flow rate of 10 column volumes per hour⁺Na removal by type cation exchange resin⁺Until the pH of the effluent is approximately equal to 4. Passing the sodium-removed hydrolysate through OH at the same speed^—Anion exchange resin form until the effluent is weakly acidic 12. And putting the clear liquid into a vacuum concentration dryer for vacuum concentration and drying to obtain the rice bran peptide.

The invention also provides the rice bran polysaccharide-peptide compound with high oxidation resistance prepared by any one of the preparation methods.

The invention has the following advantages:

according to the embodiment of the invention, the rice bran polysaccharide extracting solution with low relative molecular mass (10 k-50 kDa) and high oxidation resistance is extracted through the combined action of organic acid and high-pressure homogenization, and then the rice bran polysaccharide extracting solution and rice bran peptide are subjected to Maillard reaction, and the dry heating temperature is controlled to enable the epsilon-amino group in the active peptide and the carbonyl group on the reducing tail end of the polysaccharide to spontaneously perform the Maillard reaction, so that the polysaccharide and the active peptide are coupled into a whole, and the polysaccharide-peptide compound with high oxidation resistance is obtained.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a graph showing the results of the antioxidative analysis of rice bran polysaccharide-peptide complex obtained in example 1 of the present invention;

FIG. 2 is a graph showing the results of the antioxidative analysis of the rice bran polysaccharide-peptide complex obtained in example 2 of the present invention;

FIG. 3 is a graph showing the results of the antioxidative analysis of rice bran polysaccharide-peptide complex obtained in example 3 of the present invention;

FIG. 4 is a graph showing the results of the oxidation resistance analysis of the rice bran polysaccharide-peptide complex according to example 1, comparative example 1 and comparative example 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

Example 1Preparation method of rice bran polysaccharide-peptide compound with high oxidation resistance

1. Extraction of rice bran polysaccharides

Pulverizing defatted rice bran, sieving with 60 mesh sieve, adding 15 times of distilled water, adjusting pH to 3.5 with tartaric acid aqueous solution, soaking for ten minutes, and softening. The upper and lower limit temperature of the low-temperature circulating pump is adjusted to be 10 ℃ to-4 ℃, and the internal temperature of the homogenizer is ensured to be normal temperature. Pouring the mixed material into a high-pressure homogenizer, adjusting to 80MPa, and homogenizing for 4 times, each time for 20 min; centrifuging the obtained homogeneous solution for 15min under the condition of 4000r/min to remove precipitates, adjusting the pH value to be neutral, and carrying out freeze drying to obtain the rice bran polysaccharide with the molecular weight of 10 k-50 kDa.

2. Maillard reaction of polysaccharide and peptide

Taking a dryer, placing a certain amount of saturated KBr solution at the bottom of the dryer to enable the relative humidity in the dryer to reach 79%, and mixing rice bran polysaccharide freeze-dried powder and rice bran active peptide freeze-dried powder according to a molar ratio of 4: 1, mixing, placing in a dryer, and finally placing the dryer at a constant temperature of 60 ℃ for one day to obtain the polysaccharide-peptide compound.

Test example 1Polysaccharide-peptide complex antioxidant assay

Taking rice bran polysaccharide, rice bran active peptide and polysaccharide-peptide compound prepared in example 1, preparing to-be-detected solutions with concentration gradients of 0.05, 0.1, 0.25, 0.5 and l.0mg/mL respectively, and taking 1mL of to-be-detected solution and 1mL of FeSO with concentration of 6mM₄Solution and 1mL of 6mM H₂O₂Mixing the solution, standing for 10min, adding 1mL salicylic acid solution with concentration of 6mM, shaking, standing for 30min, measuring absorbance at 510nm, and calculating OH free radical scavenging rate and EC₅₀。

The calculation formula is as follows:

clearance ═ 1- (sample absorbance/blank absorbance) ] × 100%;

EC₅₀concentration of polysaccharide or vitamin C solution at 50% clearance, EC₅₀The value reflects the magnitude of the antioxidant capacity, EC₅₀The lower the value, the stronger the oxidation resistance.

Referring to fig. 1, it can be seen from fig. 1 that the rice bran polysaccharides and peptides are reacted by maillard reaction, and the polysaccharide-peptide complexes have higher removal rate of OH radicals than the rice bran polysaccharides and active peptides in the experimental concentration range, which shows that the oxidation resistance of the rice bran polysaccharide-peptide complexes after maillard reaction is greatly improved and higher than that of the commonly used antioxidant Vc.

Example 2Preparation method of rice bran polysaccharide-peptide compound with high oxidation resistance

1. Extraction of rice bran polysaccharides

Pulverizing defatted rice bran, sieving with 60 mesh sieve, adding distilled water 20 times of defatted rice bran, adjusting pH to 3.8 with tartaric acid water solution, soaking for ten minutes, and softening. The upper and lower limit temperature of the low-temperature circulating pump is adjusted to be 10 ℃ to-4 ℃, and the internal temperature of the homogenizer is ensured to be normal temperature. Pouring the mixed material into a high-pressure homogenizer, adjusting to 90MPa, homogenizing for 5 times, each time for 20 min; centrifuging the obtained homogeneous solution for 20min under the condition of 4000r/min to remove precipitates, adjusting the pH value to be neutral, and carrying out freeze drying to obtain the rice bran polysaccharide with the molecular weight of 10 k-50 kDa.

2. Maillard reaction of polysaccharide and peptide

Taking a dryer, placing a certain amount of saturated KBr solution at the bottom of the dryer to enable the relative humidity in the dryer to reach 79%, and mixing rice bran polysaccharide freeze-dried powder and rice bran active peptide freeze-dried powder according to a molar ratio of 5: 1, placing the mixture in a dryer, and finally placing the dryer at a constant temperature of 70 ℃ for one day to obtain the polysaccharide-peptide complex.

Test example 2Polysaccharide-peptide complex antioxidant assay

Taking rice bran polysaccharide, rice bran active peptide and polysaccharide-peptide compound prepared in example 2, preparing to-be-detected solutions with concentration gradients of 0.05, 0.1, 0.25, 0.5 and l.0mg/mL respectively, taking 1mL of to-be-detected solution and 1mL of FeSO with concentration of 6mM₄Solution and 1mL of 6mM H₂O₂Mixing the solution, standing for 10min, adding 1mL salicylic acid solution with concentration of 6mM, shaking, standing for 30min, measuring absorbance at 510nm, and calculating OH free radical scavenging rate and EC₅₀。

The calculation formula is as follows:

clearance ═ 1- (sample absorbance/blank absorbance) ] × 100%;

EC₅₀concentration of polysaccharide or vitamin C solution at 50% clearance, EC₅₀The value reflects the magnitude of the antioxidant capacity, EC₅₀The lower the value, the stronger the oxidation resistance.

Referring to fig. 2, it can be seen from fig. 2 that the rice bran polysaccharides and peptides are reacted by maillard reaction, and the clearance rate of OH radicals of the polysaccharide-peptide complex is higher than that of the rice bran polysaccharides and active peptides and Vc in the experimental concentration range, which shows that the oxidation resistance of the rice bran polysaccharide-peptide complex after maillard reaction is greatly improved and higher than that of the commonly used antioxidant Vc.

Example 3Preparation method of rice bran polysaccharide-peptide compound with high oxidation resistance

1. Extraction of rice bran polysaccharides

Pulverizing defatted rice bran, sieving with 60 mesh sieve, adding 25 times of distilled water, adjusting pH to 4.0 with tartaric acid water solution, soaking for ten minutes, and softening. The upper and lower limit temperature of the low-temperature circulating pump is adjusted to be 10 ℃ to-4 ℃, and the internal temperature of the homogenizer is ensured to be normal temperature. Pouring the mixed material into a high-pressure homogenizer, then adjusting to 95MPa, and homogenizing for 6 times, 20min each time after the pressure is stable; centrifuging the obtained homogeneous solution for 20min under the condition of 4000r/min to remove precipitates, adjusting the pH value to be neutral, and carrying out freeze drying to obtain the rice bran polysaccharide with the molecular weight of 10 k-50 kDa.

2. Maillard reaction of polysaccharide and peptide

Taking a dryer, placing a certain amount of KBr solution at the bottom of the dryer to enable the relative humidity in the dryer to reach 79%, and mixing rice bran polysaccharide freeze-dried powder and rice bran active peptide freeze-dried powder according to a molar ratio of 6: 1, placing the mixture in a dryer, and finally placing the dryer at a constant temperature of 80 ℃ for one day to obtain the polysaccharide-peptide complex.

Test example 3Polysaccharide-peptide complex antioxidant assay

Taking rice bran polysaccharide, rice bran active peptide and polysaccharide-peptide complex prepared in example 3, preparing to-be-detected solutions with concentration gradients of 0.05, 0.1, 0.25, 0.5 and l.0mg/mL respectively, taking 1mL of to-be-detected solution and 1mL of FeS0 with concentration of 6mM₄Solution and 1mL of 6mM H₂0₂Mixing the solution, standing for 10min, adding 1mL salicylic acid solution with concentration of 6mM, shaking, standing for 30min, measuring absorbance at 510nm, and calculating OH free radical scavenging rate and EC₅₀。

The calculation formula is as follows:

clearance ═ 1- (sample absorbance/blank absorbance) ] × 100%;

EC₅₀concentration of polysaccharide or vitamin C solution at 50% clearance, EC₅₀The value reflects the magnitude of the antioxidant capacity, EC₅₀The lower the value, the stronger the oxidation resistance.

Referring to fig. 3, it can be seen from fig. 3 that the rice bran polysaccharides and peptides are reacted by maillard reaction, and the polysaccharide-peptide complexes have higher removal rate of OH radicals than the rice bran polysaccharides and active peptides in the experimental concentration range, which indicates that the oxidation resistance of the rice bran polysaccharide-peptide complexes after maillard reaction is greatly improved and higher than that of the commonly used antioxidant Vc.

Comparative example 1

The same as example 1 except that the aqueous tartaric acid solution was adjusted to pH 4.5.

Comparative example 2

The difference from example 1 is that the pressure for homogenization was 60MPa, and the number of homogenization times was 2.

Test example 3

The oxidation resistance test was performed for example 1, comparative example 1, and comparative example 2, and the procedure was as in test example 1. Referring to FIG. 4, as can be seen from FIG. 4, in comparative example 1, in which the pH of the aqueous tartaric acid solution was adjusted to 4.5, the antioxidative activity of the resulting polysaccharide-peptide complex was reduced, and it can be seen that this acidity range was not favorable for the formation of rice bran polysaccharides having a relative molecular mass of 10k to 50kDa and for the formation of polysaccharide-peptide complexes having high antioxidative activity. The polysaccharide-peptide complex obtained by varying the homogenization pressure and number in comparative example 2 has a lower clearance of OH radicals than the polysaccharide-peptide complex in example 1.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.