Method for removing fishy smell of fish product by adopting lactobacillus bulgaricus and application

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a method for removing fishy smell of a fish product by adopting lactobacillus bulgaricus and application. The method comprises the following steps: carrying out bacterial liquid soaking fermentation treatment on fresh tilapia fillets by using a lactobacillus bulgaricus bacterial liquid, and draining water on the surfaces of the tilapia fillets after fermentation is finished. According to the method disclosed by the invention, the concentration, the fermentation time and the temperature of the lactobacillus bulgaricus liquid in the treatment process are accurately regulated and controlled, and all parameters are matched with one another, so that an excellent fishy smell removal effect is achieved, the taste and the texture of the fish fillets can be maintained and even enhanced, and the flavor is improved; and the ideal dual balance and optimization of the fishy smell removal effect and the quality of the fillets are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for removing fishy smell from fish products by using Lactobacillus bulgaricus and application thereof. Background Art

[0002] The fishy smell of fresh tilapia is one of its common drawbacks when eating. The fishy smell of tilapia mainly comes from the fat, amino acids, volatile amines and certain microbial metabolites in the fish, especially the free trimethylamine and other volatile nitrogen compounds in the fish meat. These ingredients will emit a noticeable fishy smell during the cooking process. For many consumers, the fishy smell is the main factor affecting appetite and taste.

[0003] Existing methods of removing fishy smells, such as salt water soaking, liquor soaking, ginger and garlic treatment, acidic solution (such as vinegar or lemon juice) soaking, and hot water blanching, can remove some fishy smells to a certain extent, but the effects are often limited. Salt water and alcohol soaking can effectively inhibit the growth of bacteria and microorganisms, but cannot completely remove deep-seated fishy smell components. Although spices such as ginger and garlic can cover up the fishy smell, they often affect the original flavor of the fish, resulting in an impure taste. In addition, acidic solutions can neutralize volatile amines in the fish body to a certain extent, but they may also destroy the texture of the fish.

[0004] With the development of food processing technology, some studies in recent years have tried to use bio-enzymes, ultrasound, freeze-thaw and other technologies to remove the fishy smell. These methods have good results, but they still have defects such as high cost and long processing time. Therefore, in practical applications, it is still a technical problem to improve the efficiency of removing the fishy smell of fresh tilapia and retain the original flavor of the fish. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a method and application of removing fishy smell from fish products by using Lactobacillus bulgaricus, so as to fully retain the nutrients of fresh tilapia and enhance its texture while achieving a good deodorizing effect.

[0006] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0007] In a first aspect, the present invention provides a method for removing fishy smell from fish products by using Lactobacillus bulgaricus, comprising the following steps: soaking and fermenting fresh fish fillets with Lactobacillus bulgaricus bacterial solution, and draining the water on the surface of the fish fillets after the fermentation is completed.

[0008] Through experimental research, it is found that the present invention uses Lactobacillus bulgaricus to ferment fresh fish products to remove the odor, which can produce lactic acid and other organic acids during the fermentation process. These acidic substances can neutralize volatile amine compounds (such as trimethylamine, amino acid derivatives, etc.) in fish fillets, effectively reducing the fishy components in fish meat. Compared with traditional physical or chemical deodorization methods, the deodorization effect of Lactobacillus bulgaricus fermentation in the present invention is more natural and can maintain the flavor of fish meat; and compared with Angel Saccharomyces cerevisiae and Lactobacillus paracasei, the Lactobacillus bulgaricus has a more significant removal effect on volatile amine compounds, that is, a better deodorization effect.

[0009] At the same time, during the fermentation process, Lactobacillus bulgaricus will also decompose some complex proteins in the fish fillet, producing some small molecular amino acids and peptides, which not only help to remove the fishy smell, but also improve the texture and taste of the fish fillet, making it more tender and delicate. In addition, Lactobacillus bulgaricus has a strong antibacterial ability and can effectively inhibit or reduce the growth of harmful bacteria and microorganisms on the surface of the fish fillet, thereby extending the shelf life of the fish fillet.

[0010] Preferably, the soaking and fermentation time is 2-4 hours.

[0011] Preferably, the soaking and fermentation time is 2-3 hours.

[0012] More preferably, the soaking and fermentation time is 3 hours.

[0013] The experimental research found that when Lactobacillus bulgaricus was used to treat fresh fish fillets, the immersion and fermentation time of the strain had the most significant effect on the deodorization of fish products. When the immersion and fermentation time was in the preferred range of 2-4 hours, especially 3 hours, it could achieve an effective deodorization effect while maintaining the taste, flavor and texture of the fish fillets. When the fermentation time was too short, Lactobacillus bulgaricus could not fully act on the fishy substances in the fish fillets, and the deodorization effect was weak. When the fermentation time was too long, it would significantly affect the flavor and texture of the fish meat.

[0014] Preferably, the concentration of the bacterial solution is 0.5-3%.

[0015] Preferably, the concentration of the bacterial solution is 0.5-1.5%.

[0016] More preferably, the concentration of the bacterial solution is 1%.

[0017] Experimental research found that the appropriate bacterial liquid concentration can increase the number and activity of Lactobacillus bulgaricus, thereby more effectively decomposing the fishy substances in fish fillets, especially when the bacterial liquid concentration is 1%, which can not only achieve the best deodorizing effect, but also ensure that the flavor of the fish is not damaged; when the bacterial liquid concentration is too low, the deodorizing effect will be significantly weakened due to insufficient strains, and too high a concentration will lead to excessive acidification, thus affecting the taste and flavor of the fish.

[0018] Preferably, the temperature of the soaking fermentation is 20-40°C.

[0019] Preferably, the temperature of the soaking fermentation is 25-35°C.

[0020] More preferably, the temperature of the soaking fermentation is 25°C.

[0021] Fermentation temperature has an important influence on the activity of Lactobacillus bulgaricus. When the fermentation temperature of the bacterial liquid is 20-40℃, especially 25℃, it can effectively accelerate the metabolism of Lactobacillus bulgaricus and promote the production of aromatic substances, thereby significantly enhancing the deodorizing effect. Excessively high temperature may inhibit the growth of Lactobacillus bulgaricus. In addition, excessively high temperature will cause the fish fillets to tend to mature, thereby affecting the taste and texture of the fish fillets. Excessively low temperature will lead to a slower fermentation speed and a significantly weakened deodorizing effect.

[0022] Preferably, the fish product comprises tilapia.

[0023] In a second aspect, the present invention provides the use of Lactobacillus bulgaricus in removing fishy smell from fish products.

[0024] Preferably, the application method is carried out using the above-mentioned method.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention adopts Lactobacillus bulgaricus to carry out fermentation and deodorization treatment on fresh fish products, and achieves excellent deodorization effect by precisely controlling the concentration of Lactobacillus bulgaricus liquid, fermentation time and temperature during the treatment process, and can also maintain or even enhance the taste and texture of fish fillets and improve the flavor, thereby realizing the dual optimization of ideal deodorization effect and fish fillet quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Effects of different fermentation methods on the sensory properties of tilapia fillets ( Figure 1 A) Flavor Figure 1 B) Texture Figure 1 C) The results of the impact; CK is fresh fish fillet; exp_1 is the bacterial powder direct smearing treatment group; con_1 is the sterile bacterial treatment control group; exp_2 is the bacterial solution immersion treatment group; con_2 is the distilled water immersion control group; exp_3 is the bacterial solution coating treatment group; con_3 is the distilled water coating control group;

[0028] Figure 2 It is the Pearson correlation analysis diagram between each index of tilapia and the signal value of electronic nose;

[0029] Figure 3Effects of different fermentation times on the sensory properties of tilapia fillets ( Figure 3 A) Flavor Figure 3 B) Texture Figure 3 C) Effect results; CK is fresh fish fillet; LB is bacterial solution soaking group; W is distilled water soaking control group;

[0030] Figure 4 Effects of different bacterial concentrations on the sensory properties of tilapia fillets ( Figure 4 A) Flavor Figure 4 B) Texture Figure 4 C) The result diagram of the impact; CK is fresh fish fillet;

[0031] Figure 5 Effects of different fermentation temperatures on the sensory properties of tilapia fillets ( Figure 5 A) Flavor Figure 5 B) Texture Figure 5 C) Effect results; CK is fresh fish fillet; LB is bacterial solution soaking group; W is distilled water soaking control group;

[0032] Figure 6 Radar chart for comparative analysis of the optimal combination verification test and orthogonal test 8. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Unless otherwise specified, the reagents and strains used in the examples are conventional reagents and strains in the art, and can be purchased through commercial channels. The experimental operations not specifically described in the examples are conventional operations in the art or can be understood or known by those skilled in the art based on the existing technology or common knowledge they master.

[0035] In the test example, the following test method was used for the deodorization effect and texture analysis of fresh fish fillets after fermentation with Lactobacillus bulgaricus:

[0036] 1. Sensory evaluation

[0037] The evaluation team was composed of 10 sensory assessors who had undergone sensory evaluation training. 5g of sample was placed in a 100mL sealed disposable cup and sealed for equilibration for 0.5h. The odor intensity was evaluated using a 10-point system, with 0 being the weakest and 10 being the strongest. The final score was averaged. The specific evaluation criteria are shown in Table 1.

[0038] Table 1 Sensory evaluation standards

[0039]

[0040] 2. Electronic nose analysis

[0041] Randomly take 5 samples from -20℃ refrigerator (each weighs 5g of fish fillet), thaw at 25℃ room temperature for 10min, then put into 40mL headspace bottle, seal and stand for 1h, insert electronic nose syringe for detection. Detection conditions: washing 120s, injection 45s, injection flow rate 0.6L / min. The response type of each sensor to the substance is shown in Table 2.

[0042] Table 2 Aroma types corresponding to electronic nose sensors

[0043]

[0044]

[0045] 3. Texture analysis

[0046] The thawed tilapia back muscle was cut into small rectangular blocks of 20mm×20mm×10mm, and then placed at room temperature for 1h to eliminate the effects of low temperature. The test parameters are as follows: trigger force 5g, pre-test speed 2mm / s, test speed 1mm / s, post-test speed 2mm / s, TPA mode test using P6 probe, compression 60%, interval time 5s.

[0047] Experimental Example 1. Effect of different strains on the deodorization of tilapia fillets

[0048] The specific method is as follows:

[0049] (1) Sample pretreatment: Fresh tilapia slices were placed at 4°C for storage and transportation after slaughter (tilapia slices were provided by Guangdong Yujia Aquatic Food Co., Ltd.). Fresh fish slices were randomly selected for index determination and recorded as fresh samples.

[0050] (2) Deodorization: 5.0 g of fresh tilapia fillets were weighed and fermented with bacterial solutions of different concentrations (0.5%, 1%, 1.5%, 2% and 5%) of Lactobacillus bulgaricus, Angel Saccharomyces cerevisiae and Lactobacillus paracasei. The fermentation temperature was 25°C. After soaking for 6 h, the water was drained and the fillets were packed into bags and frozen in a -20°C refrigerator. On the 1st, 4th, 7th, 10th and 13th day of frozen storage, the ammonia and amine values ​​were detected by electronic nose analysis method, so as to evaluate the deodorization effect of different strains on tilapia fillets.

[0051] The specific results are shown in Table 3. Compared with Angel Saccharomyces cerevisiae and Lactobacillus paracasei, the Lactobacillus bulgaricus has a more significant effect on removing volatile amine compounds, that is, a better deodorizing effect.

[0052] Table 3

[0053]

[0054] Experimental Example 2. Effects of different treatments of Lactobacillus bulgaricus on sensory, flavor and texture of tilapia fillets

[0055] The specific method is as follows:

[0056] (1) Fresh tilapia was sliced ​​and stored at 4°C for transportation. Fresh fish fillets were randomly selected for index determination and recorded as fresh samples.

[0057] (2) Weigh 5.0 g of fresh tilapia fillets for bacterial fermentation experiment. After being treated with three different treatment methods (direct application of Lactobacillus bulgaricus powder, direct application of bacterial solution, and immersion in bacterial solution), the fillets were placed at 25°C for fermentation for 6 h, then placed in a plastic bag and stored in a -20°C refrigerator. After being taken out and thawed to room temperature the next day, various indicators were tested. The results are shown in Table 1. Figure 1 (AC).

[0058] Depend on Figure 1 (A) It can be seen that among the three different treatment methods, the best deodorizing effect is the bacterial solution immersion fermentation group (exp_2 group), whose sensory score can reach 7.9 points, which may be because the aroma substances produced during the fermentation process of Lactobacillus bulgaricus mask the fishy smell; the second is the dry powder direct application group (exp_1 group), which has a significant effect on removing the fishy smell of tilapia fillets due to dry powder fermentation, but also produces odors such as rancidity, which may be the sour taste produced by the decomposition of the excipient starch in the bacterial dry powder; the bacterial solution application fermentation group (exp_3 group) has the worst deodorizing effect, and the fish fillets in each treatment control group have a strong fishy smell or odor.

[0059] Depend on Figure 1 (B) It can be seen that the electronic nose response values ​​of tilapia fillets treated with different bacterial species were different. Among the three different treatment methods, the electronic nose response value of the dry powder smearing group was close to that of fresh fish, followed by the bacterial liquid immersion group and the bacterial liquid smearing group. This result was consistent with the sensory scoring result.

[0060] Depend on Figure 1 (C) It can be seen that the texture (hardness, stickiness, chewiness and cohesion) of tilapia fillets changed to varying degrees after being fermented with different strains of bacteria. Compared with fresh tilapia fillets, the texture of exp_2 (bacteria solution soaked group) was closest to that of fresh fillets.

[0061] Therefore, soaking and fermenting tilapia fillets in bacterial liquid can maximize the fishy smell removal effect of the fillets and effectively maintain the flavor and texture of the fillets.

[0062] Experimental Example 3. Effects of fermentation time on sensory, flavor and texture of tilapia fillets

[0063] The specific method is as follows:

[0064] (1) Fresh tilapia was sliced ​​and stored at 4°C for transportation. Fresh fish fillets were randomly selected for index determination and recorded as fresh samples.

[0065] (2) Weigh 5.0 g of fresh tilapia fillets for bacterial fermentation experiment. The tilapia fillets were soaked in Lactobacillus bulgaricus liquid and fermented at 25°C for different time periods (0, 2, 4, 6, 8, 10, 12, 14 h). Then, the surface water was drained and the fillets were placed in plastic bags and stored in a -20°C refrigerator. The fillets were taken out and thawed to room temperature the next day, and then various indicators were tested. The results are shown in Table 1. Figure 3 (AC).

[0066] Depend on Figure 3 (A) It can be seen that as the fermentation time increases, the sensory scores of each treatment group and the control group also decrease. Figure 3 (B) It can be seen that as the fermentation time increases, the response values ​​of each probe of the electronic nose also increase. Therefore, the deodorization effect of tilapia fillets is best when the bacteria are fermented for 2-4 hours, especially for 2 hours.

[0067] Depend on Figure 3 (C) It can be seen that the texture (hardness, stickiness, chewiness and cohesion) of tilapia fillets after being fermented for different times and then frozen for storage changed to varying degrees. Compared with fresh tilapia fillets, the texture of the 4-hour fermented fillets was closest to that of fresh fillets, and when the fermentation time continued to increase, the taste and texture of the fillets decreased significantly compared with fresh fillets.

[0068] Experimental Example 4. Effect of bacterial liquid concentration on sensory, flavor and texture of tilapia fillets

[0069] The specific method is as follows:

[0070] (1) Fresh tilapia was sliced ​​and stored at 4°C for transportation. Fresh fish fillets were randomly selected for index determination and recorded as fresh samples.

[0071] (2) Weigh 5.0 g of fresh tilapia fillets for bacterial fermentation experiment. The fillets were soaked in different concentrations (0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%) of Lactobacillus bulgaricus liquid and fermented at 25°C for 2 h. After draining the surface water, they were packed into plastic bags and stored in a -20°C refrigerator. The fillets were taken out and thawed to room temperature the next day, and various indicators were tested. The results are shown in Table 1. Figure 4 (AC).

[0072] Depend on Figure 4(A) It can be seen that as the concentration of the bacterial solution increases, the sensory score also shows a trend of first increasing and then decreasing. When the concentration of the bacterial solution is 1%, the sensory score is the highest, which is 8.5.

[0073] Depend on Figure 4 (B) It can be seen that as the concentration of the bacterial solution increases, the response values ​​of the electronic nose probes first decrease and then increase, which is negatively correlated with the sensory score results.

[0074] Depend on Figure 4 (C) It can be seen that with the increase of bacterial solution concentration (0.5-3%), the texture of tilapia fillets has no significant change, but when the bacterial solution concentration is greater than 3%, the texture of tilapia fillets begins to decline significantly, the hardness, stickiness and chewiness decrease, and the cohesion increases.

[0075] Experimental Example 5. Effects of fermentation temperature on sensory, flavor and texture of tilapia fillets

[0076] The specific method is as follows:

[0077] (1) Fresh tilapia was sliced ​​and stored at 4°C for transportation. Fresh fish fillets were randomly selected for index determination and recorded as fresh samples.

[0078] (2) Weigh 5.0 g of fresh tilapia fillets for bacterial fermentation experiment. The tilapia fillets were soaked in 1% Lactobacillus bulgaricus solution and fermented at different temperatures (20, 25, 30, 35, 40, 45, 50°C) for 2 h. After draining the surface water, they were packed into plastic bags and stored in a -20°C refrigerator. The next day, they were taken out and thawed to room temperature, and various indicators were tested. The results are shown in Table 1. Figure 5 (AC).

[0079] Depend on Figure 5 (A) It can be seen that as the fermentation temperature increases, the sensory score increases first and then decreases. When the fermentation temperature is 20-40°C, the sensory score is high, especially when the temperature is 35°C, the sensory score is the highest, which is 8.5. This may be because 35°C is conducive to the fermentation of Lactobacillus bulgaricus and produces more aroma substances.

[0080] Depend on Figure 5 (B) As can be seen, with the increase of fermentation temperature, the response values ​​of each probe of the electronic nose first decreased and then increased, and this result was negatively correlated with the sensory score. As can be seen from the figure, the response values ​​at 35℃ were the lowest.

[0081] Depend on Figure 5 (C) It can be seen that with the increase of fermentation temperature (20℃-40℃), the texture of tilapia fillets did not change significantly. When the fermentation temperature exceeded 40℃, the texture of tilapia fillets increased significantly compared with fresh fillets. This may be due to the high temperature, which caused the tilapia fillets to tend to mature.

[0082] Experimental Example 6. Orthogonal Optimization Experiment

[0083] According to the single factor test results of Experimental Examples 1-5, the L9(3 4 ) A three-factor three-level orthogonal test was performed to further optimize the process parameters, as shown in Table 4. The specific results of the orthogonal optimization test are shown in Table 5.

[0084] Table 4 Orthogonal factor levels

[0085]

[0086] Table 5 Orthogonal experimental design and results

[0087] Experiment No. A B C D Sensory Rating 1 1 1 1 1 7.3 2 1 2 2 2 8.0 3 1 3 3 3 8.0 4 2 1 2 3 8.2 5 2 2 3 1 7.0 6 2 3 1 2 8.3 7 3 1 3 2 7.3 8 3 2 1 3 9.3 9 3 3 2 1 7.7 k1 7.767 7.600 8.300 7.333 k2 7.833 8.100 7.967 7.867 k3 8.100 8.000 7.433 8.500 R 0.333 0.500 0.867 1.167

[0088] According to the intuitive analysis of Table 5, the range of the empty column is the largest. Among the three factors, the range of temperature is the largest, which is 0.867, followed by the concentration of bacterial solution and fermentation time, which are 0.5 and 0.333 respectively. The above results show that the influence of each factor on the deodorization effect of tilapia is: temperature> bacterial solution concentration> fermentation time. The optimal condition is A3B2C1, that is, fermentation for 3h, bacterial solution concentration of 1%, and fermentation temperature of 25℃. The verification test was carried out under the optimal conditions, and the sensory score was 9.4±0.2. The optimal combination was detected by electronic nose, and compared with the orthogonal test 8. Figure 6 ,The response values ​​of the 14 probes under the optimal combination are all lower than that in test 8, which is close to the expected results.

[0089] Therefore, the method of the present invention achieves excellent fishy removal effect by precisely controlling the concentration of Lactobacillus bulgaricus liquid, fermentation time and temperature during the processing, and each parameter cooperates with each other, and can also maintain or even enhance the taste and texture of the fish fillet, thereby achieving a dual balance and optimization of the ideal fishy removal effect and fish fillet quality.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for removing fishy smell from fish products using Lactobacillus bulgaricus, characterized in that: The following steps are involved: The fresh fish fillets are soaked and fermented with the Lactobacillus bulgaricus liquid. After the fermentation is completed, the water on the surface of the fish fillets can be drained.

2. The method according to claim 1, characterized in that The soaking and fermentation time is 2-4h.

3. The method according to claim 2, characterized in that The soaking and fermentation time is 3 hours.

4. The method according to claim 1, characterized in that The concentration of the bacterial solution is 0.5-3%.

5. The method according to claim 4, characterized in that The concentration of the bacterial solution is 1%.

6. The method according to claim 1, characterized in that The temperature of the soaking fermentation is 20-40°C.

7. The method according to claim 6, characterized in that The temperature of the soaking fermentation is 25°C.

8. The method according to any one of claims 1 to 7, characterized in that: The fish product includes tilapia.

9. Application of Lactobacillus bulgaricus in removing fishy smell from fish products.

10. The use according to claim 9, characterized in that The application method is carried out by the method according to any one of claims 1 to 7.

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