Deodorization method of yeast fermented shellfish processing waste

Abstract

The invention relates to the technical field of biology, and particularly discloses a method for removing fishy smell of shellfish processing waste through yeast fermentation, multiple enzymes and metabolites can be generated through compound fermentation of yeast (saccharomyces cerevisiae and arrowia lipolytica), and the substances have a synergistic effect, so that fishy smell substances in the shellfish processing waste can be effectively degraded, and the fishy smell removing effect is achieved. The flavor can be improved, and the overall quality of the product is improved. In addition, the yeast fermentation process is relatively simple and easy to control, the technical requirements on operators are not high, the production cost is reduced, and the production efficiency is improved; according to the fishy smell removing method, a large amount of waste of shellfish processing waste is reduced, and the treated shellfish processing waste has the potential of being applied as raw materials such as seasonings and food additives, so that the fishy smell removing method has wide market prospects and application value.

Description

Technical Field

[0001] The present application relates to the field of biotechnology, and in particular to a method for removing the odor of yeast fermentation shellfish processing waste. Background Art

[0002] The waste generated during shellfish processing is rich in nutrients, such as protein, minerals, amino acids, etc. These characteristics make shellfish processing waste an ideal raw material for developing new nutritious foods and special condiments, greatly broadening the source of raw materials for food production. In addition, by rationally utilizing these wastes, it can not only effectively reduce resource waste, but also significantly reduce environmental pollution, achieve a win-win situation of economic and environmental benefits, and show huge market potential and social value.

[0003] However, shellfish processing waste has a huge fishy smell, which limits its wide application. In the field of shellfish processing waste deodorization technology, the existing technologies that can be used include traditional removal methods, chemical removal methods, enzymatic treatment methods, microbial fermentation methods, etc.; traditional removal methods include salt pickling, spice treatment and other methods. For example, the Chinese patent with publication number CN 105105066A uses a variety of natural ingredients with a unique ratio in the preparation of a shellfish seafood fresh edible dipping sauce, such as pepper, angelica, parsley, mint, bay leaves, cumin powder, honey, vinegar and fermented fish sauce, etc., in order to remove the fishy smell of shellfish seafood. However, the traditional deodorization methods such as spice treatment are unstable in deodorization effect, which is greatly affected by personal experience and operating conditions. The chemical removal method uses specific chemical substances and chemical reactions to remove the fishy substances by chemical reactions. For example, the Chinese patent with publication number CN111671072A proposes a method for removing the fishy smell of oyster juice. The technical scheme effectively decomposes and transforms the fishy components in oyster juice through precisely controlled chemical reactions and heat treatment steps. This method not only removes the fishy smell, but also improves the quality and taste of oyster juice, providing high-quality raw materials for the development of seasoning compositions, but the heat treatment step may consume more energy and have high requirements for equipment; for example, the Chinese patent with publication number CN 117918447A uses the Maillard reaction to remove the fishy smell of shellfish hydrolysates in the process of preparing protein powder from shellfish processing waste. Chemical treatment methods are usually fast and efficient, but may introduce new residues, and strict control of reaction conditions is required to ensure food safety. Enzymatic treatment methods use the specificity and efficiency of biological enzymes to accurately degrade fishy substances. For example, the Chinese patent with publication number CN106666632A uses enzymatic hydrolysates from specific parts such as scallop skirts to remove fishy smell in the process of preparing composite seafood seasonings from shellfish processing waste. Although it can improve the flavor and increase the added value of waste to a certain extent, the high enzyme cost, complex operating conditions and high dependence on specific conditions limit its popularity in large-scale industrial applications. Microbial fermentation is an environmentally friendly and efficient food processing technology for removing fishy odors. For example, Chinese patent publication number CN110257301A proposes a lactic acid bacteria fermentation liquid with the function of removing fishy odors and enhancing flavors. Through its low-temperature fermentation characteristics, it provides an ideal solution for removing fishy odors for meat processing. At present, there are no reports on the use of microbial fermentation to remove fishy odors in shellfish waste processing. Summary of the invention

[0004] The purpose of the present application is to overcome the deficiencies of the above-mentioned prior art and to provide a method for removing the odor of yeast fermented shellfish processing waste.

[0005] To achieve the above purpose, the technical solution adopted by this application is:

[0006] The present application provides a method for removing the odor of yeast fermented shellfish processing waste, comprising the following steps:

[0007] S1. Obtain shellfish processing waste, dilute it with water, stir it evenly, and then perform heat treatment to obtain a heat-treated solution;

[0008] S2, adding yeast to the heat-treated solution obtained in step S1 for fermentation to obtain a fermentation product;

[0009] S3, heat-treating the fermentation product obtained in step S2 again, and detecting flavor substances in the fermentation product;

[0010] The yeasts include Saccharomyces cerevisiae and Yarrowia lipolytica.

[0011] The special fishy smell of shellfish processing waste makes it difficult to make suitable products, and it is often wasted in large quantities. In the technical solution of the present application, yeast is a natural, environmentally friendly and relatively low-cost microbial resource. The inventors of the present application have found through a lot of research and experiments that the present application can produce a variety of enzymes and metabolites through the composite fermentation of yeast (Saccharomyces cerevisiae and Yarrowia lipolytica). These substances work synergistically, which can not only effectively degrade the fishy substances in shellfish processing waste (such as dimethyl disulfide, methyl mercaptan, 2-[(methylthio)methyl]-furan, 2-[(methyldisulfide)methyl]-furan), but also improve its flavor and enhance the overall quality of the product.

[0012] In addition, the yeast fermentation process is relatively simple and easy to control, and does not require high technical skills from operators, which is conducive to reducing production costs and improving production efficiency. Therefore, the yeast fermentation shellfish processing waste deodorization solution provided in this application has opened up a new way for the resource utilization of shellfish processing waste, and has broad market prospects and application value.

[0013] In some specific embodiments, the deposit number of the Saccharomyces cerevisiae is CICC 1001; the deposit number of the Yarrowia lipolytica is CICC 33063, which is from the China Industrial Microbiological Culture Collection Administration Center.

[0014] The yeast of the present application may also include yeast strains with different characteristics. Three or more yeast strains with different characteristics are mixed and used, and through the interaction between them, a comprehensive deodorizing effect on shellfish processing waste is achieved. A variety of different yeast strains may have different metabolic pathways and products. These metabolites can more effectively mask or decompose the fishy substances in shellfish processing waste under synergistic effects.

[0015] As a preferred embodiment of the method for removing the fishy smell of yeast fermented shellfish processing waste described in the present application, the mass ratio of the brewer's yeast to the lipolytica yeast is (1-2): (1-2).

[0016] The present application adopts microbial fermentation technology, avoids the use of chemical reagents, and has mild reaction conditions. The brewer's yeast and Yarrowia lipolytica of the present application effectively degrade the fishy substances (such as dimethyl disulfide, methyl mercaptan, 2-[(methylthio)methyl]-furan, 2-[(methyldisulfide)methyl]-furan) in shellfish processing waste through their specific metabolic pathways and enzyme systems. Yeast will produce a variety of aroma substances during the fermentation process, such as esters, alcohols, etc. These substances can enhance the overall flavor quality of shellfish processing waste, and while removing the fishy smell, they can also give the shellfish processing waste a unique flavor.

[0017] As a preferred embodiment of the method for removing fishy smell from yeast fermentation shellfish processing waste described in the present application, the mass ratio of the brewer's yeast to the lipolytic yeast is 1:1.

[0018] The present application uses a mixture of brewer's yeast and Yarrowia lipolytica in the above-mentioned mass ratio, which can better degrade the fishy substances in shellfish processing waste (such as dimethyl disulfide, methyl mercaptan, 2-[(methylthio)methyl]-furan, 2-[(methyldisulfide)methyl]-furan), and better improve the flavor of shellfish processing waste, thereby improving the overall quality of the product.

[0019] As a preferred embodiment of the method for removing the fishy smell of shellfish processing waste by yeast fermentation described in the present application, the addition amount of the brewer's yeast or Yarrowia lipolytica is 1% to 3% of the amount of the shellfish processing waste.

[0020] When the addition amount of the brewer's yeast or Yarrowia lipolytica of the present application is within the above range, the fishy substances in the shellfish processing waste are effectively degraded at the same time, and the effect of improving the flavor of the shellfish processing waste is better.

[0021] As a preferred embodiment of the method for removing the fishy smell of shellfish processing waste by yeast fermentation described in the present application, the addition amount of the brewer's yeast or Yarrowia lipolytica is 1.5-2% of the amount of the shellfish processing waste.

[0022] When the brewer's yeast or Yarrowia lipolytica of the present application is added in the above-mentioned amount, it can ensure the deodorizing effect while avoiding the negative effects caused by excessive fermentation, such as flavor changes, loss of nutrients, and other problems.

[0023] As a preferred embodiment of the method for removing the odor of yeast fermentation shellfish processing waste described in the present application, in the step S1, the heat treatment temperature is 121° C., and the heat treatment time is 15 to 25 minutes.

[0024] As a preferred embodiment of the method for removing fishy smell from yeast fermentation shellfish processing waste described in the present application, in the step S1, the mass ratio of the shellfish processing waste to water is 1:2.

[0025] As a preferred embodiment of the method for removing the odor of shellfish processing waste by yeast fermentation described in the present application, in the step S2, the fermentation temperature is 30-35°C and the fermentation time is 1-3 days.

[0026] The present application adopts the above fermentation conditions to ensure the optimal growth and metabolic state of yeast.

[0027] As a preferred embodiment of the method for removing the odor of yeast fermentation shellfish processing waste described in the present application, in the step S3, the heat treatment temperature is 85 to 95° C., and the heat treatment time is 15 to 25 minutes.

[0028] The method for removing the fishy smell of shellfish processing waste by yeast fermentation provided in the present application has a short process and simple technology, which can solve the disadvantage that by-products such as shellfish processing waste are difficult to be utilized due to their fishy smell, and make shellfish processing waste have a broader application prospect.

[0029] The present application can effectively remove the fishy odor substances in shellfish processing waste through the preferred steps of the above-mentioned microbial fermentation technology, such as dimethyl disulfide removal rate of more than 89%, methyl mercaptan removal rate of more than 78%, 2-[(methylthio)methyl]-furan removal rate of more than 91%, and 2-[(methyl disulfide)methyl]-furan removal rate of more than 90%; it can also increase the various flavor substances produced during the fermentation process, thereby improving the overall flavor of the product. These flavor substances can give the product a unique aroma and taste, and enhance consumer acceptance and satisfaction.

[0030] The present application uses yeast fermentation. Yeast is a common microbial resource with a wide range of sources and a relatively low price. In addition, no large amount of chemical reagents need to be added during the yeast fermentation process, which reduces the cost of reagent procurement and waste disposal. At the same time, due to the mild fermentation conditions, energy consumption is relatively low.

[0031] The yeast fermentation process of the present application is easy to realize automated control, such as maintaining optimal fermentation conditions through automatic adjustment of parameters such as temperature. Automated production methods can reduce the frequency and intensity of manual operations, thereby reducing labor costs. The yeast fermentation method of the present application is a biological deodorization method with the characteristics of being green and environmentally friendly. No harmful waste is generated during the fermentation process, and the waste is easy to handle. Compared with the environmental pollution problems that may be caused by traditional methods, the yeast fermentation method is more in line with the concept of sustainable development.

[0032] Compared with the prior art, this application has the following beneficial effects:

[0033] The present application provides a method for removing the fishy smell of shellfish processing waste by yeast fermentation. The present application can produce a variety of enzymes and metabolites through the composite fermentation of yeast (Saccharomyces cerevisiae and Yarrowia lipolytica). These substances work synergistically to not only effectively degrade the fishy smell substances in shellfish processing waste, but also improve its flavor and enhance the overall quality of the product. In addition, the yeast fermentation process is relatively simple and easy to control, and the technical requirements for operators are not high, which is conducive to reducing production costs and improving production efficiency; the method for removing the fishy smell of the present application reduces a large amount of waste of shellfish processing waste, and the treated shellfish processing waste has the potential to be used as raw materials such as condiments and food additives, thus having broad market prospects and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the result of the removal rate of fishy odor of shellfish processing waste by brewer's yeast at different fermentation times (1 day, 2 days and 3 days);

[0035] Figure 2 This is the result of Yarrowia lipolytica removing fishy odor from shellfish processing waste at different fermentation times (1 day, 2 days and 3 days);

[0036] Figure 3 This is the result of removing the fishy smell of shellfish processing waste by mixing Saccharomyces cerevisiae and Yarrowia lipolytica at different fermentation times (1 day, 2 days and 3 days);

[0037] Figure 4 This is the result of the removal rate of fishy smell of shellfish processing waste by the combination of Zygosaccharomyces rouxii, Saccharomyces cerevisiae and Yarrowia lipolytica at an addition rate of 1%;

[0038] Figure 5 This is the result of the removal rate of fishy smell of shellfish processing waste by the combination of Zygosaccharomyces rouxii, Saccharomyces cerevisiae and Yarrowia lipolytica at an addition rate of 2%;

[0039] Figure 6 This is the result of the removal rate of fishy smell of shellfish processing waste by the combination of Zygosaccharomyces rouxii, Saccharomyces cerevisiae and Yarrowia lipolytica at an addition rate of 3%;

[0040] Figure 7 This is the result of removing fishy odor from shellfish processing waste by using Saccharomyces cerevisiae and Yarrowia lipolytica in different ratios (1:2, 1:1, 2:1). DETAILED DESCRIPTION

[0041] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0042] In the following examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are of the same type.

[0043] In the following examples, the deposit number of Saccharomyces cerevisiae is CICC 1001; the deposit number of Yarrowia lipolytica is CICC 33063; the deposit number of Zygosaccharomyces rouxii is CICC 31259, and they were purchased from the China Industrial Microbiological Culture Collection Administration Center.

[0044] Example 1: Effects of different types of yeast and fermentation time on the deodorization of shellfish processing waste

[0045] This embodiment provides a method for removing the odor of yeast fermentation shellfish processing waste, comprising the following steps:

[0046] Obtain an equal amount of shellfish processing waste (processing waste produced by enzymatic hydrolysis of shellfish such as oysters, mussels, and scallops), for example, using Enzymatic approaches in the bioprocessing of shellfish wastes literature, which mainly utilizes proteases and chitinases to degrade proteins and chitin in shellfish wastes to obtain shellfish processing waste.

[0047] The shellfish processing waste obtained is processed as follows:

[0048] 1. Add water to shellfish processing waste at a ratio of 1:2 to dilute, stir evenly, and place in a 121°C sterilizer for heat treatment for 20 minutes to obtain a heat-treated solution;

[0049] 2. Saccharomyces cerevisiae (group A), Yarrowia lipolytica (group B), Saccharomyces cerevisiae and Yarrowia lipolytica (group C) were added to the solution after heat treatment in step 1, respectively, and the amount of each yeast added was 2% of the mass of shellfish processing waste, and the ratio of the two bacteria in group C was 1:1.

[0050] 3. The mixed materials were loaded into fermentation tanks for fermentation, and the fermentation temperature was controlled at 30°C to obtain fermentation products. The fermentation products were then heat-treated at 90°C for 20 min according to the following different fermentation times (fermentation for 1 day, the fermentation products were numbered as Group A1, Group B1, Group C1, and Group D1; fermentation for 2 days, the fermentation products were numbered as Group A2, Group B2, Group C2, and Group D2; fermentation for 3 days, the fermentation products were numbered as Group A3, Group B3, Group C3, and Group D3) to obtain shellfish processing waste of different groups (Group A1, Group B1, Group C1, Group A2, Group B2, Group C2, Group A3, Group B3, and Group C3).

[0051] Example 2: Evaluation method and result analysis of the fishy smell of shellfish processing waste

[0052] In this example, 15 experienced appraisers were convened to form a sensory evaluation team to comprehensively evaluate the smell (fishy smell, characteristic aroma of shellfish) and taste (umami, bitter taste) of untreated (not treated by the method of Example 1) raw shellfish processing waste (Group D), Group A1, Group B1, Group C1, Group A2, Group B2, Group C2, Group A3, Group B3, and Group C3 shellfish processing waste. The results of the sensory evaluation are summarized in Table 1.

[0053] Table 1 Sensory evaluation results of shellfish processing waste before and after treatment

[0054]

[0055]

[0056] Note: The data in the table are the average of the evaluation results of 15 assessors. The score of each indicator ranges from 1 to 5. The higher the score, the more prominent the indicator is. For example, the raw shellfish processing waste with a fishy smell sensory evaluation of 5 points has a fishier smell than the shellfish processing waste with a fishy smell sensory evaluation of 1 point.

[0057] Compared with group D, the fishy smell of shellfish processing waste in groups A1, B1, C1, A2, B2, C2, A3, B3, and C3 was significantly reduced. This indicates that fermentation with Saccharomyces cerevisiae and / or Yarrowia lipolytica can not only reduce the fishy smell of shellfish processing waste, but also enhance the flavor of shellfish processing waste. Among them, group C3 has a significant effect in reducing the fishy smell, indicating that by extending the fermentation time to remove the fishy smell of shellfish processing waste, the fishy smell of shellfish processing waste in the product can be reduced to a certain extent, and the umami taste can be improved to a certain extent.

[0058] Example 3: Changes in odorous substances in samples

[0059] The sample raw materials of shellfish processing waste (before deodorization, group D), group A1, group B1, group C1, group A2, group B2, group C2, group A3, group B3, and group C3 shellfish processing waste (after being treated by the method of Example 1, after deodorization) were selected, and the changes in flavor substances in the shellfish processing waste were further analyzed, and the shellfish processing waste was ground to prepare shellfish processing waste samples suitable for solid phase microextraction. The quartz fiber coated with the extraction stationary phase was directly inserted into the sample matrix for extraction. The diffusion of the analytical components from the sample matrix to the edge of the extraction stationary phase was accelerated by stirring until the extraction equilibrium state was reached. During the extraction process, the coating on the extraction fiber selectively adsorbed the target compound (i.e., flavor substance) in the sample, while most of the interference substances were excluded, thereby achieving the preliminary purification and enrichment of the target compound. After the extraction was completed, the extractor needle was inserted into the gasification chamber of the gas chromatography injection device to expose the extraction fiber to the high-temperature carrier gas. Under high temperature conditions, the target compounds adsorbed on the extraction fiber will be desorbed and released, and then enter the gas chromatography analysis process to further analyze the changes in flavor substances in the enriched product.

[0060] Compared with the shellfish processing waste before deodorization, the shellfish processing waste obtained by the method of the present application has significantly reduced the fishy smell and improved the flavor quality after yeast fermentation treatment.

[0061] The removal rate of fishy odor from shellfish processing waste by Saccharomyces cerevisiae and / or Yarrowia lipolytica at different fermentation times (1 day, 2 days and 3 days) Figure 1-3 As shown in the figure, the shellfish processing waste fermented for 3 days is generally better than the shellfish processing waste fermented for 1 day and 2 days in removing flavor and fishy smell. Among them, the shellfish processing waste of group C3 obtained has an average removal rate of more than 75% for the representative fishy substances methyl mercaptan, dimethyl disulfide, 2[(methylthio)methyl]-furan and 2-[(methyldisulfide)methyl]-furan, and the removal rate of 2-[(methyldisulfide)methyl]-furan is the highest, with a removal rate of more than 90%. Figure 3 shown.

[0062] The present application can effectively remove the fishy odor substances in shellfish processing waste through the preferred steps of the above-mentioned microbial fermentation technology, such as dimethyl disulfide removal rate of more than 89%, methyl mercaptan removal rate of more than 78%, 2-[(methylthio)methyl]-furan removal rate of more than 91%, and 2-[(methyl disulfide)methyl]-furan removal rate of more than 90%; it can also increase the various flavor substances produced during the fermentation process, thereby improving the overall flavor of the product. These flavor substances can give the product a unique aroma and taste, and enhance consumer acceptance and satisfaction.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

[0064] Example 4: Effects of different types of yeast and strain addition on the deodorization of shellfish processing waste

[0065] This embodiment provides a method for removing the odor of yeast fermentation shellfish processing waste, comprising the following steps:

[0066] Obtain an equal amount of shellfish processing waste (processing waste produced by processes such as enzymatic hydrolysis of shellfish such as oysters, mussels, and scallops, as in Example 1), and perform the following treatment on the obtained shellfish processing waste:

[0067] 1. Add water to shellfish processing waste at a ratio of 1:2 to dilute, stir evenly, and place in a 121°C sterilizer for heat treatment for 20 minutes to obtain a heat-treated solution;

[0068] 2. Saccharomyces cerevisiae and Yarrowia lipolytica (group E), Saccharomyces cerevisiae and Zygosaccharomyces rouxii (group F), and Zygosaccharomyces rouxii and Yarrowia lipolytica (group G) are added to the solution after heat treatment in step 1, respectively, and the amount of each yeast added is 1%-3% of the mass of shellfish processing waste, and the ratio of the two bacteria in group C is 1:1.

[0069] 3. The mixed materials were respectively loaded into fermentation tanks for fermentation. The fermentation temperature was controlled at 30°C and the fermentation time was 2 days. The fermentation products were obtained and heat-treated at 90°C for 20 min. The fermentation products were then numbered according to different inoculation amounts (inoculation amount 1%, the fermentation products were numbered as E1 group, F1 group, and G1 group; inoculation amount 2%, the fermentation products were numbered as E2 group, F2 group, and G2 group; inoculation amount 3%, the fermentation products were numbered as E3 group, F3 group, and G3 group) to obtain shellfish processing waste of different groups (E1 group, F1 group, G1 group, E2 group, F2 group, G2 group, E3 group, F3 group, and G3 group).

[0070] Example 5: Evaluation method and result analysis of the fishy smell of shellfish processing waste

[0071] In this example, 15 experienced appraisers were convened to form a sensory evaluation team to conduct a comprehensive evaluation of the odor (fishy smell, characteristic aroma of shellfish) and taste (umami, bitter taste) of shellfish processing wastes of Group E1, Group F1, Group G1, Group E2, Group F2, Group G2, Group E3, Group F3, and Group G3. The results of the sensory evaluation are summarized in Table 2.

[0072] Table 2 Sensory evaluation results of shellfish processing waste before and after treatment

[0073] Group Fishy smell fragrance Umami Bitter taste E1 2 2 4 2 F1 3 2 2 2 G1 3 2 3 2 E2 1 4 4 2 F2 2 2 4 2 G2 2 3 3 3 E3 1 3 4 3 F3 2 2 2 2 G3 2 3 3 3

[0074] Note: The data in the table are the average of the evaluation results of 15 assessors. The score of each indicator ranges from 1 to 5. The higher the score, the more prominent the indicator is. For example, the raw shellfish processing waste with a fishy smell sensory evaluation of 5 points has a fishier smell than the shellfish processing waste with a fishy smell sensory evaluation of 1 point.

[0075] Group E can effectively reduce the fishy smell of shellfish processing waste under different inoculation conditions, while the deodorization effect of Group F and Group G is not as good as that of Group E, indicating that not any combination of two yeasts can achieve a good deodorization effect, but it is necessary to select a yeast combination with specific metabolic characteristics and synergistic effects to achieve the best deodorization effect. And as the inoculation amount increases from 1% to 2%, the deodorization effect shows a significant enhancement trend, and the increase in inoculation amount from 2% to 3% does not significantly improve the deodorization effect. This shows that 2% is the best addition amount, and at this addition amount, the umami taste of shellfish processing waste will be improved to a certain extent.

[0076] Example 6: Changes in odorous substances in samples

[0077] Shellfish processing wastes from Group E1, Group F1, Group G1, Group E2, Group F2, Group G2, Group E3, Group F3, and Group G3 (after being treated by the method of Example 4 and after being deodorized) were selected, and the changes in flavor substances in the shellfish processing wastes were further analyzed. The shellfish processing wastes were ground to prepare shellfish processing waste samples suitable for solid phase microextraction. The quartz fiber coated with the extraction stationary phase was directly inserted into the sample matrix for extraction. The diffusion of the analytical components from the sample matrix to the edge of the extraction stationary phase was accelerated by stirring until the extraction equilibrium state was reached. During the extraction process, the coating on the extraction fiber selectively adsorbed the target compounds (i.e., flavor substances) in the sample, while most of the interferences were excluded, thereby achieving preliminary purification and enrichment of the target compounds. After the extraction was completed, the extractor needle was inserted into the gasification chamber of the gas chromatography injection device to expose the extraction fiber to the high-temperature carrier gas. Under high temperature conditions, the target compounds adsorbed on the extraction fiber will be desorbed and released, and then enter the gas chromatography analysis process to further analyze the changes in flavor substances in the enriched product.

[0078] Compared with the shellfish processing waste before deodorization, the shellfish processing waste obtained by the method of the present application has significantly reduced the fishy smell and improved the flavor quality after yeast fermentation treatment.

[0079] The removal rate of odor from shellfish processing waste by the combination of Zygosaccharomyces rouxii, Saccharomyces cerevisiae and Yarrowia lipolytica at different addition amounts (1%, 2%, 3%) is as follows Figure 4-6 As shown in the figure, the effects of removing flavor and fishy smell from shellfish processing waste with addition of 2% and 3% are significantly better than those with addition of 1%, and the effects of removing flavor and fishy smell from shellfish processing waste with addition of 3% are slightly better than those with addition of 2%, but the amount of strain used will be greatly increased, so 2% is determined to be the optimal addition amount. The average removal rate of the E2 group of shellfish processing waste for the representative fishy substances methyl mercaptan, dimethyl disulfide, 2[(methylthio)methyl]-furan and 2-[(methyldisulfide)methyl]-furan exceeded 75%, and the removal rate of 2-[(methyldisulfide)methyl]-furan was the highest, reaching more than 90%, as shown in the figure. Figure 6 shown.

[0080] Example 7: Effect of different proportions of yeast on the deodorization of shellfish processing waste

[0081] This embodiment provides a method for removing the odor of yeast fermentation shellfish processing waste, comprising the following steps:

[0082] Obtain an equal amount of shellfish processing waste (processing waste produced by processes such as enzymatic hydrolysis of shellfish such as oysters, mussels, and scallops, as in Example 1), and perform the following treatment on the obtained shellfish processing waste:

[0083] 1. Add water to shellfish processing waste at a ratio of 1:2 to dilute, stir evenly, and place in a 121°C sterilizer for heat treatment for 20 minutes to obtain a heat-treated solution;

[0084] 2. Adding Saccharomyces cerevisiae and Yarrowia lipolytica (group H) to the solution after heat treatment in step 1, the amount of each yeast added is 2% of the mass of shellfish processing waste, and the ratio of the two bacteria is 1:2-2:1.

[0085] 3. The mixed materials were loaded into fermentation tanks for fermentation, and the fermentation temperature was controlled at 30°C to obtain fermentation products. The fermentation products were then heat-treated at 90°C for 20 min according to the following different strain ratios (strain ratio 1:2, fermentation products were numbered as group H1; strain ratio 1:1, fermentation products were numbered as group H2; strain ratio 2:1, fermentation products were numbered as group H3) to obtain shellfish processing waste of different groups (group H1, group H2, group H3).

[0086] Example 8: Evaluation method and result analysis of the fishy smell of shellfish processing waste

[0087] In this example, 15 experienced evaluators were convened to form a sensory evaluation panel to conduct a comprehensive evaluation of the odor (fishy smell, characteristic aroma of shellfish) and taste (umami, bitter taste) of shellfish processing wastes in groups H1, H2, and H3. The results of the sensory evaluation are summarized in Table 3.

[0088] Table 3 Sensory evaluation results of shellfish processing waste before and after treatment

[0089] Group Fishy smell fragrance Umami Bitter taste H1 2 3 2 2 H2 1 3 4 2 H3 2 2 3 2

[0090] Note: The data in the table are the average of the evaluation results of 15 assessors. The score of each indicator ranges from 1 to 5. The higher the score, the more prominent the indicator is. For example, the raw shellfish processing waste with a fishy smell sensory evaluation of 5 points has a fishier smell than the shellfish processing waste with a fishy smell sensory evaluation of 1 point.

[0091] Comparing the deodorizing effects of the fermentation products of the three groups (group H1, group H2, and group H3), it was found that when the addition ratio of brewer's yeast to Yarrowia lipolytica was 1:1 (group H2), the deodorizing effect was the most significant. The fermentation products under this ratio not only greatly reduced the fishy smell, but also optimized the flavor and taste of the products.

[0092] Example 9: Changes in fishy smell substances in samples

[0093] Shellfish processing wastes from groups H1, H2, and H3 (after being treated by the method of Example 1 and after being deodorized) were selected, and the changes in flavor substances in the shellfish processing wastes were further analyzed. The shellfish processing wastes were ground to prepare shellfish processing waste samples suitable for solid phase microextraction. The quartz fiber coated with the extraction stationary phase was directly inserted into the sample matrix for extraction. The diffusion of the analytical components from the sample matrix to the edge of the extraction stationary phase was accelerated by stirring until the extraction equilibrium state was reached. During the extraction process, the coating on the extraction fiber selectively adsorbed the target compounds (i.e., flavor substances) in the sample, while most of the interferences were excluded, thereby achieving preliminary purification and enrichment of the target compounds. After the extraction was completed, the extractor needle was inserted into the gasification chamber of the gas chromatography injection device to expose the extraction fiber to the high-temperature carrier gas. Under high temperature conditions, the target compounds adsorbed on the extraction fiber were desorbed and released, and then entered the gas chromatography analysis process to further analyze the changes in flavor substances in the enriched product.

[0094] Compared with the shellfish processing waste before deodorization, the shellfish processing waste obtained by the method of the present application has significantly reduced the fishy smell and improved the flavor quality after yeast fermentation treatment.

[0095] The removal rate of odor of shellfish processing waste by Saccharomyces cerevisiae and Yarrowia lipolytica in different ratios (1:2, 1:1, 2:1) Figure 7 As shown in the figure, the shellfish processing waste with a ratio of 1:1 is significantly better than the shellfish processing waste with a ratio of 1:2 and 2:1 in removing flavor and fishy smell. Among them, the shellfish processing waste of group H2 obtained has an average removal rate of more than 75% for the representative fishy substances methyl mercaptan, dimethyl disulfide, 2[(methylthio)methyl]-furan and 2-[(methyldisulfide)methyl]-furan, and the removal rate of 2-[(methyldisulfide)methyl]-furan is the highest, with a removal rate of more than 90%. Figure 7 shown.

[0096] The present application can effectively remove the fishy odor substances in shellfish processing waste through the preferred steps of the above-mentioned microbial fermentation technology, such as dimethyl disulfide removal rate of more than 89%, methyl mercaptan removal rate of more than 78%, 2-[(methylthio)methyl]-furan removal rate of more than 91%, and 2-[(methyl disulfide)methyl]-furan removal rate of more than 90%; it can also increase the various flavor substances produced during the fermentation process, thereby improving the overall flavor of the product. These flavor substances can give the product a unique aroma and taste, and enhance consumer acceptance and satisfaction.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A method for removing the odor of yeast fermentation shellfish processing waste, characterized in that: The following steps are involved: S1. Obtain shellfish processing waste, dilute it with water, stir it evenly, and then perform heat treatment to obtain a heat-treated solution; S2, adding yeast to the heat-treated solution obtained in step S1 for fermentation to obtain a fermentation product; S3, heat-treating the fermentation product obtained in step S2 again, and detecting flavor substances in the fermentation product; The yeasts include Saccharomyces cerevisiae and Yarrowia lipolytica.

2. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: The mass ratio of the saccharomyces cerevisiae to the Yarrowia lipolytica is (1-2): (1-2).

3. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 2, characterized in that: The mass ratio of the cerevisiae yeast to the Yarrowia lipolytica is 1:

1.

4. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: The added amount of the brewer's yeast or Yarrowia lipolytica is 1% to 3% of the waste material from shellfish processing.

5. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 4, characterized in that: The added amount of the brewer's yeast or Yarrowia lipolytica is 1.5-2% of the shellfish processing waste.

6. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: In the step S1, the heat treatment temperature is 121° C., and the heat treatment time is 15 to 25 minutes.

7. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: In step S1, the mass ratio of the shellfish processing waste to water is 1:

2.

8. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: In step S2, the fermentation temperature is 30-35° C. and the fermentation time is 1-3 days.

9. The method for removing the odor of yeast fermentation shellfish processing waste according to claim 1, characterized in that: In step S3, the heat treatment temperature is 85-95° C., and the heat treatment time is 15-25 min.

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