Astringent taste removal process for equatorial squid saliva amylase

Abstract

The invention relates to the field of squid processing, and discloses an equatorial squid saliva amylase deastringency process, which comprises the following steps: S1, raw material pretreatment: performing pretreatment on an equatorial squid raw material for the deastringency process; s2, preparing a salivary amylase-pectinase synergistic liquid: preparing a synergistic effect liquid mixed by salivary amylase and pectinase; s3, dynamic permeation enzymolysis astringency removal: performing astringency removal treatment in a dynamic permeation manner by utilizing the prepared enzyme liquid; and S4, enzyme deactivation and astringent substance adsorption: carrying out inactivation treatment on the enzyme, and adsorbing astringent substances remaining in the astringent taste removal process. According to the method, the synergistic effect of the salivary amylase and the pectinase is adopted, and the technologies of dynamic permeation enzymolysis, ultrasonic assistance and the like are combined, so that astringent substances such as tannin, oxalic acid and other polyphenol compounds in the equatorial squid can be effectively removed in a targeted manner, the taste and flavor of the squid product are remarkably improved, and the eating experience of consumers is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of squid processing, in particular to a process for removing astringency by using equatorial squid salivary amylase. Background Art

[0002] In the field of food processing, the development and utilization of marine biological resources has always been a hot topic of research. As a characteristic marine organism in the warm waters near the equator, equatorial squid has great development potential in the food market due to its rich nutritional value. It is rich in high-quality protein, unsaturated fatty acids, minerals, vitamins, and special ingredients such as taurine and polypeptides, which are very beneficial to human health and are favored by consumers.

[0003] At present, in the processing of equatorial squid, the conventional method for dealing with its astringency is mainly to use simple soaking, cleaning and seasoning. These methods can reduce the astringency to a certain extent, but they do not fundamentally solve the problem. For example, simply soaking the squid in water cannot specifically remove the ingredients such as tannins, oxalic acid and other polyphenol compounds that cause the astringency.

[0004] However, the existing processing methods have many defects. On the one hand, due to the failure to effectively remove astringent substances, the taste and flavor of equatorial squid products are seriously affected, which reduces the eating experience of consumers, thereby limiting the diversified development of squid products and affecting its promotion in the high-end catering market and special consumer groups. On the other hand, the presence of astringency interferes with the human body's absorption of squid nutrients, and in order to achieve a certain de-astringency effect, companies have added processing steps, increased processing difficulty and cost, but it is still difficult to ensure the consistency of product quality and taste. Therefore, it is urgent to develop an efficient and scientific de-astringency process for equatorial squid. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a process for removing astringency by using salivary amylase of equatorial squid, which solves the problem that the existing method for removing astringency of equatorial squid cannot effectively remove astringent substances, resulting in poor taste and flavor of the product and limiting the diversified development of products.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme: a process for removing astringency by using equatorial squid salivary amylase, comprising the following steps:

[0007] S1. Raw material pretreatment: pre-processing the equatorial squid raw materials used for the de-astringency process;

[0008] S2. Preparation of salivary amylase-pectinase synergistic liquid: preparing a synergistic liquid mixed with salivary amylase and pectinase;

[0009] S3, Dynamic osmotic enzyme de-astringency: Use the prepared enzyme solution to remove astringency through dynamic osmotic treatment;

[0010] S4, enzyme inactivation and astringent substance adsorption: inactivating the enzyme and adsorbing the astringent substances remaining in the astringent removal process;

[0011] S5. Chelation enhancement and post-treatment: Chelation operation is performed to enhance the astringency removal effect, and the treated product is subsequently treated.

[0012] Preferably, step S1 includes:

[0013] S101. Cutting process: remove the internal organs and skin of the equatorial squid, and cut it into slices or strips with a thickness of ≤5 mm using a cutting machine.

[0014] Preferably, step S1 also includes:

[0015] S102. Alkaline treatment: Soak in an ultrasonic cleaning tank and add 0.5%-0.8% sodium bicarbonate solution, temperature 20-25°C, use ultrasonic cleaning for 10min-15min to remove surface mucus and impurities, rinse with running water 3-4 times, and drain until the water content is ≤70%.

[0016] Preferably, step S2 includes:

[0017] S201. Enzyme solution mixing: salivary amylase and pectinase are mixed in a mass ratio of 5:1 and added to a high-speed homogenizer, and the speed of the high-speed homogenizer is adjusted to 5000rpm-6000rpm.

[0018] Preferably, step S2 also includes:

[0019] S202. Adjustment of the mixed enzyme solution: Add phosphate buffer solution with a pH of 6.0-6.5 and stir for 15-20 minutes until it is completely dissolved, to prepare a mixed enzyme solution with an enzyme concentration of 0.5-1.5%.

[0020] Preferably, step S3 includes:

[0021] S301. Constant temperature enzymolysis: immerse the drained squid in a mixed enzyme solution (mass ratio of enzyme solution to squid is 3:1), place it in a constant temperature oscillator at 40℃-45℃, with an oscillation frequency of 120rpm-150rpm, a reaction time of 30-50min, and a temperature of 40℃-45℃.

[0022] Preferably, step S3 also includes:

[0023] S302. Ultrasonic assistance: Ultrasonic assistance is applied every 8 minutes to 10 minutes to accelerate the penetration of the enzyme solution into the squid muscle fibers.

[0024] Preferably, step S4 includes:

[0025] S401. Thermal inactivation: Transfer the enzymatically hydrolyzed material to a jacketed steam heating pot and heat it to 80-85°C for 3-5 minutes to inactivate the enzyme.

[0026] Preferably, step S4 also includes:

[0027] S402. Adsorption treatment: After inactivation, transfer the finished product to a mixing drum, add an adsorption solution containing 5% activated carbon-chitosan microspheres, adjust the temperature to 45°C-50°C, stir for 25min-30min and filter.

[0028] Preferably, step S5 includes:

[0029] S501. Ion chelation: The squid is immersed in a drum-type rinsing machine and rinsed with 0.1% EDTA-2Na solution for 8-10 minutes to chelate metal ions to inhibit the regeneration of astringency;

[0030] S502. Color protection and degassing: After draining, pour into a vacuum degassing tank and immerse in a color protection solution containing 0.2% β-cyclodextrin, vacuum degassing for 15min-20min, vacuum degree -0.08MPa;

[0031] S503. Drying and curing: Finally, use a hot air dryer to dry at a low temperature of 35°C-40°C and a wind speed of 2m / s until the moisture content is ≤15%, thereby obtaining the finished product of the de-astringent equatorial squid.

[0032] The present invention provides a process for removing astringency by using equatorial squid salivary amylase. The process has the following beneficial effects:

[0033] 1. The present invention adopts the synergistic effect of salivary amylase and pectinase, and combines dynamic osmotic enzymolysis, ultrasound-assisted and other technologies to effectively remove astringent substances such as tannins, oxalic acid and other polyphenol compounds in equatorial squid, significantly improving the taste and flavor of squid products, and greatly improving consumers' eating experience.

[0034] 2. The present invention further adds activated carbon-chitosan microspheres, utilizes the amino groups on the surface of chitosan microspheres to chelate with tannic acid and oxalic acid, and the activated carbon adsorbs the residual polyphenols.

[0035] 3. The present invention further proves that the removal of astringent substances by the present de-astringency process is more effective than the traditional salt water immersion method by setting up comparative experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Embodiment 1:

[0039] Please see attached Figure 1 The embodiment of the present invention provides a process for removing astringency from equatorial squid salivary amylase, comprising the following steps:

[0040] S1. Raw material pretreatment: remove the internal organs and skin of the equatorial squid, cut it into sheets or strips with a thickness of ≤5 mm using a cutting machine, soak it in an ultrasonic cleaning tank, add 0.5% sodium bicarbonate solution (temperature 20-25° C.), use ultrasonic cleaning for 10 minutes to remove surface mucus and impurities, rinse with running water 3 times, and drain until the water content is ≤70%;

[0041] S2. Preparation of salivary amylase-pectinase synergistic solution: salivary amylase (enzyme activity ≥ 3000 U / g) and pectinase (enzyme activity ≥ 2000 U / g) were mixed in a mass ratio of 5:1 and added to a high-speed homogenizer, and the speed of the high-speed homogenizer was adjusted to 5000 rpm, and then pH 6.5 phosphate buffer was added and stirred for 15 minutes until completely dissolved to prepare a mixed enzyme solution with an enzyme concentration of 0.5-1.5%;

[0042] S3, dynamic permeation enzymatic astringency: the drained squid was immersed in a mixed enzyme solution (enzyme solution to squid mass ratio 3:1), placed in a 40°C constant temperature oscillator, oscillation frequency 120rpm, reaction time 30-50min, temperature 40°C, and ultrasonic assistance (frequency 28kHz, power 60W, pulse mode 5s on / 5s off) was applied every 10min to accelerate the enzyme solution to penetrate the squid muscle fibers;

[0043] S4, enzyme inactivation and astringent adsorption: the enzymatically hydrolyzed material is transferred to a jacketed steam heating pot and heated to 85°C for 5 minutes to inactivate the enzyme. After inactivation, the finished product is transferred to a mixing drum and a mixture containing 5% activated carbon-chitosan microspheres (particle size 0.5-1.0 mm, specific surface area ≥500 m 2 / g) adsorption solution, adjust the temperature to 50°C, stir for 30 minutes and then filter;

[0044] S5, chelation enhancement and post-treatment: The squid was immersed in a drum rinsing machine and rinsed with 0.1% EDTA-2Na solution for 10 minutes to chelate metal ions (such as Fe3+, Ca 2+) to inhibit the regeneration of astringency, drain and pour into a vacuum degassing tank, and immerse in a color protection solution (pH 7.0) containing 0.2% β-cyclodextrin, vacuum degassing for 20 minutes, the vacuum degree is -0.08MPa, and finally a hot air dryer is used to dry at a low temperature of 40°C and a wind speed of 2m / s until the water content is ≤15%, so as to obtain the finished product of the de-astringent equatorial squid.

[0045] Example 1 Beneficial effects: This example achieves efficient astringency removal of equatorial squid by synergistic hydrolysis of salivary amylase and pectinase (5:1), combined with dynamic ultrasonic penetration (28kHz, 60W pulse mode) and activated carbon-chitosan microsphere adsorption technology. Experiments show that the removal rate of tannins can reach 85.7% (only 50% in traditional processes), and the constant temperature oscillation (40°C) and vacuum degassing (-0.08MPa) during the enzymatic hydrolysis process effectively protect the squid texture, and the hardness of the finished product is reduced to 18.5N, and the elasticity is increased to 0.85mm.

[0046] Embodiment 2:

[0047] On the basis of Example 1, step S2 is adjusted to provide a rapid equatorial squid salivary amylase deastringency process, comprising the following steps:

[0048] S2. Mix α-amylase (enzyme activity ≥ 4000U / g) and alginate lyase (enzyme activity ≥ 2500U / g) in a mass ratio of 3:1 and add them to a high-speed homogenizer. Adjust the speed of the high-speed homogenizer to 5000rpm, then add pH 6.5 phosphate buffer and stir for 15 minutes until completely dissolved to prepare a mixed enzyme solution with an enzyme concentration of 0.5-1.5%.

[0049] Example 2 Beneficial Effect: This example uses α-amylase and alginate lyase (3:1) to replace the original enzyme system, and improves the decomposition efficiency of starch-tannin complex and the mucopolysaccharide removal ability, and the tannin removal rate is increased to 88%. The cost of α-amylase is 30% lower than that of salivary amylase. Combined with the precise degradation of alginate by alginate lyase, the surface finish (L* value) of the finished product is increased by 5%, and the enzymatic hydrolysis time is shortened to 25-35 minutes, which is suitable for continuous production needs.

[0050] Embodiment three:

[0051] On the basis of Example 1, step S3 is adjusted to provide a process for removing astringency by using enhanced equatorial squid salivary amylase, comprising the following steps:

[0052] S3, dynamic permeation enzymatic astringency removal: the drained squid was immersed in cellulase (enzyme activity ≥ 1500U / g, salivary amylase: cellulase = 7:1), and 0.1% xylanase (enzyme activity ≥ 800U / g) was added to assist in hydrolyzing crude fiber, and placed in a 40°C constant temperature oscillator, the oscillation frequency was 120rpm, the reaction time was 30-50min, the temperature was 40°C, and ultrasonic assistance (frequency 28kHz, power 60W, pulse mode 5s on / 5s off) was applied every 10min to accelerate the enzyme solution to penetrate the squid muscle fibers;

[0053] Example 3 Beneficial effects: This example introduces cellulase (salivary amylase: cellulase = 7:1) and xylanase (0.1%) to work synergistically, and directional cleavage is performed on the crude protein and polysaccharide structure of squid muscle fibers. The chewiness of the squid is increased to 15.2mJ (12.6mJ in Example 1), the muscle fiber breaking strength is reduced by 22%, and the loss rate of umami amino acids (glutamic acid, aspartic acid) is reduced from 15% to 5%. While maintaining a tannin clearance rate of ≥83%, xylanase inhibits the residual astringency of polysaccharide degradation products. Sensory evaluation shows that the bitterness is completely eliminated, and the finished product is more suitable for the development of high value-added snack foods.

[0054] Comparative experiment:

[0055] Experimental group and control group settings:

[0056] Experimental group: using the process flow of the present invention (S1-S5)

[0057] Control group: traditional salt water soaking method

[0058] Raw materials and grouping: Equatorial squid (caught in the same batch, size 300±20g / piece), randomly divided into 2 groups, 30 pieces in each group

[0059] Experimental steps and parameters

[0060] 1. Experimental group (process of the present invention)

[0061] Operate according to steps S1-S5 of the embodiment, and the specific parameters are as follows:

[0062]

[0063] 2. Control group (traditional salt water immersion method)

[0064] Reference industry standard process:

[0065]

[0066] Detection indicators and experimental methods

[0067] 1. Efficiency of removing astringency

[0068] Detection method: Determination of tannin residues (spectrophotometric method, refer to GB5009.204-2016) Reaction system: Folin-Ciocalteu reagent color development, 765nm absorbance calculation concentration

[0069] Data Records:

[0070]

[0071] 2. Texture characteristics

[0072] Testing instrument: Texture analyzer (TA-XTPlus)

[0073] Parameters: puncture test (probe P / 2N, speed 1mm / s, puncture depth 5mm)

[0074] Data Records:

[0075] Group Hardness(N) Elasticity(mm) Chewing properties (mJ) Experimental Group 18.5±1.2 0.85±0.03 12.6±0.8 Control group 25.3±2.1 0.62±0.05 8.2±0.7

[0076] 3. Chemical reagent residues

[0077] Test items: NaCl residue (silver nitrate titration method), EDTA-2Na residue (HPLC method)

[0078]

[0079] Experimental conclusion

[0080] Efficiency of removing astringency: The process of the present invention is significantly better than the salt water soaking method (85.7% vs. 50.0%), which is mainly due to the directional hydrolysis of salivary gland polysaccharide-tannin complex by enzyme-ultrasonic dynamic penetration technology;

[0081] Texture protection: The hardness of the experimental group decreased by 26.9% and the elasticity increased by 37.1%, proving that low-temperature enzymatic hydrolysis + vacuum degassing effectively reduced excessive contraction of muscle fibers;

[0082] Safety: There was zero salt residue in the experimental group, and the EDTA-2Na residue was better than the national standard (≤0.02 mg / kg), avoiding the risk of high salt load (5500 mg / kg) in the traditional immersion method.

[0083] (Note: The experiment was repeated 5 times, and the data are expressed as mean ± standard deviation, with significant differences P < 0.05).

[0084] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for removing astringency from equatorial squid salivary amylase, characterized in that: The following steps are involved: S1. Raw material pretreatment: pre-processing the equatorial squid raw materials used for the de-astringency process; S2. Preparation of salivary amylase-pectinase synergistic liquid: preparing a synergistic liquid mixed with salivary amylase and pectinase; S3, Dynamic osmotic enzyme de-astringency: Use the prepared enzyme solution to remove astringency through dynamic osmotic treatment; S4, enzyme inactivation and astringent substance adsorption: inactivating the enzyme and adsorbing the astringent substances remaining in the astringent removal process; S5. Chelation enhancement and post-treatment: Chelation operation is performed to enhance the astringency removal effect, and the treated product is subsequently treated.

2. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S1 includes: S101. Cutting process: remove the internal organs and skin of the equatorial squid, and cut it into slices or strips with a thickness of ≤5 mm using a cutting machine.

3. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S1 also includes: S102. Alkaline treatment: Soak in an ultrasonic cleaning tank and add 0.5%-0.8% sodium bicarbonate solution, temperature 20-25°C, use ultrasonic cleaning for 10min-15min to remove surface mucus and impurities, rinse with running water 3-4 times, and drain until the water content is ≤70%.

4. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S2 includes: S201. Enzyme solution mixing: salivary amylase and pectinase are mixed in a mass ratio of 5:1 and added to a high-speed homogenizer, and the speed of the high-speed homogenizer is adjusted to 5000rpm-6000rpm.

5. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S2 also includes: S202. Adjustment of the mixed enzyme solution: Add phosphate buffer solution with a pH of 6.0-6.5 and stir for 15-20 minutes until it is completely dissolved, to prepare a mixed enzyme solution with an enzyme concentration of 0.5-1.5%.

6. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S3 includes: S301. Constant temperature enzymolysis: immerse the drained squid in a mixed enzyme solution (mass ratio of enzyme solution to squid is 3:1), place it in a constant temperature oscillator at 40℃-45℃, with an oscillation frequency of 120rpm-150rpm, a reaction time of 30-50min, and a temperature of 40℃-45℃.

7. The process for removing astringency by using equatorial squid salivary amylase according to claim 1, characterized in that: Step S3 also includes: S302. Ultrasonic assistance: Ultrasonic assistance is applied every 8 minutes to 10 minutes to accelerate the penetration of the enzyme solution into the squid muscle fibers.

8. The process for removing astringency from equatorial squid salivary amylase according to claim 1, characterized in that: Step S4 includes: S401. Thermal inactivation: Transfer the enzymatically hydrolyzed material to a jacketed steam heating pot and heat it to 80-85°C for 3-5 minutes to inactivate the enzyme.

9. The process for removing astringency from equatorial squid salivary amylase according to claim 1, characterized in that: Step S4 also includes: S402. Adsorption treatment: After inactivation, the finished product is transferred to a mixing drum and a mixture containing 5% activated carbon-chitosan microspheres (particle size 0.5-1.0 mm, specific surface area ≥ 500 m 2 / g) of adsorption liquid, adjust the temperature to 50°C, stir for 30 minutes and then filter.

10. The process for removing astringency from equatorial squid salivary amylase according to claim 1, characterized in that: Step S5 includes: S501. Ion chelation: The squid was immersed in a drum rinsing machine and rinsed with 0.1% EDTA-2Na solution for 10 min to chelate metal ions to inhibit the regeneration of astringency; S502. Color protection and degassing: After draining, pour into a vacuum degassing tank and immerse in a color protection solution (pH 7.0) containing 0.2% β-cyclodextrin, vacuum degassing for 20 min, vacuum degree -0.08 MPa; S503. Drying and curing: Finally, use a hot air dryer to dry at a low temperature of 40°C and a wind speed of 2m / s until the moisture content is ≤15%, thereby obtaining the finished product of the de-astringent equatorial squid.

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