Bean curd yellow serofluid tomato red sour soup and preparation method thereof

Abstract

According to the bean curd yellow serofluid tomato red sour soup and the preparation method thereof, tomatoes are selected, pedicles are removed, the tomatoes are cleaned and crushed to prepare tomato homogenate, clarified bean curd yellow serofluid is added, after sterilization, activated lactobacillus plantarum is inoculated, anaerobic fermentation is conducted, and the bean curd yellow serofluid tomato red sour soup is obtained. And the volatile components are mainly prepared from alcohol (linalool), ketone (damascenone and damascenone) and aldehyde (phenylacetaldehyde, nonanal and trans-2-nonanal). The invention further provides a fermentation culture medium containing the bean curd yellow serofluid freeze-dried substance. The fermentation culture medium is a low-cost lactobacillus fermentation culture medium prepared by compounding the bean curd yellow serofluid freeze-dried substance and an MRS culture medium. On the basis of the bean curd yellow serofluid, the ecological characteristic food development concept in Guizhou is integrated, and the method has important significance in the aspects of improving the fermentation efficiency of the red sour soup, reducing the production cost and promoting the resource utilization of the yellow serofluid.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a sour tofu and yellow pulp soup with red tomatoes and a preparation method thereof. Background Art

[0002] During tofu processing, processes such as soaking the raw materials, heat coagulation of soy milk, and filter pressing produce byproducts with high water content. This yellowish color, due to the presence of soy isoflavones and carotenoid pigments, is why it is called "tofu yellow slurry." Yellow slurry is rich in whey protein, oligosaccharides (sucrose, raffinose, and stachyose), saponins, and isoflavones. Simply discharged into the natural environment, it is easily affected by microorganisms, causing acidification and odor, often resulting in resource waste and environmental pollution. Currently, the main disposal methods for tofu yellow slurry include harmless treatment and high-quality utilization. With the continuous discovery of functional components and the continued development of membrane separation and flocculation technologies, the resource recovery and reuse of tofu yellow slurry, centered on the extraction of functional substances, the development of fermentation biological products and culture media, and the development of new foods, has made significant progress. Compared with the former two, the development of new foods offers significant advantages such as low cost, rapid results, and strong innovation.

[0003] Previous researchers have conducted relevant work on the preparation of culture medium for strains using tofu yellow slurry. For example, Wang Hongtu et al. (Using tofu yellow slurry to prepare culture medium (I) Trial preparation of attenuated freeze-dried vaccine for fowl cholera G190E40. Chinese Journal of Veterinary Medicine, 1988, 34(1): 12-16.) used tofu yellow slurry to prepare culture medium in 1989 and used it to culture fowl cholera G190E40 strain, achieving the result of 20 generations without changing the colony morphology, virulence and biochemical properties. OUNIS WB et al. (Utilization of tofu whey pre-treated by electromembrane process as a growth medium for Lactobacillus plantarum LB17. Desalination, 2008, 229(1-3): 192-203.) used tofu yellow slurry as raw material to prepare tofu whey culture medium, and the cultured Lactobacillus plantarum LB17 could reach 10 9CFU / mL, significantly improving fermentation efficiency and reducing fermentation costs. Liu Li (Isolation, Identification, Metabolism, and High-Density Culture of Lactic Acid Bacteria from Tofu Slurry. South China University of Technology, 2015) used tofu slurry as a base medium to study the effects of multiple factors, including peptone, yeast extract powder, and corn starch, on the growth of Lactobacillus amyloliquefaciens L6, ultimately determining the optimal culture medium formula and fermentation conditions for this strain. Regarding the fermentation of tofu yellow slurry to prepare other foods, Yu Lu (Research on the production of functional flavored fermented milk using tofu yellow slurry. Ocean University of China, 2013.) developed a functional flavored fermented milk rich in free soy isoflavones by fermenting Lactococcus lactis subsp.cremoris, realizing the resource utilization of tofu yellow slurry; Li Suijun et al. (Research on the flavor characteristics of tofu whey fermented by lactic acid bacteria. Journal of Chinese Institute of Food Science and Technology, 2021, 21(12): 242-253.) used tofu whey as raw material and combined it with Harbin Lactobacillus M1, Lactobacillus mucosa M2 and other strains as starting strains for fermentation, and finally obtained a flavor product with characteristic flavor and 4-aminobutyric acid (GABA) and choline, providing new ideas for the product development of tofu yellow slurry.

[0004] Hongsuantang, a representative specialty ecological food, has a nearly thousand-year history in Guizhou. By 2024, Qiandongnan Prefecture alone had established 77 production lines for various types of sour soup, with an annual production capacity of 160,000 tons and a total industry output value of 2.537 billion yuan. Combining tofu yellow pulp with traditional red sour soup fermentation to develop a new tofu yellow pulp-red sour soup product would not only reduce costs and increase efficiency from a resource and cost perspective, but also innovate and diversify the red sour soup category, providing new research targets for the development of functional red sour soup products. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a tofu yellow slurry and tomato red sour soup and a preparation method thereof in response to the deficiencies of the above-mentioned prior art. The freeze-dried tofu yellow slurry is used as a raw material, and a low-cost lactic acid bacteria enrichment culture medium is prepared by compounding it with an MRS culture medium. At the same time, the tofu yellow slurry is used as the fermentation raw material for the red sour soup, and a tofu yellow slurry-type red sour soup product is developed by optimizing factors such as the fermentation temperature, the strain inoculation amount, and the ratio of tofu yellow slurry to tomatoes. The composition of its volatile flavor substances is also studied, in order to provide technical support for the resource utilization of tofu yellow slurry and the development of new red sour soup products.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing tofu yellow pulp water tomato red sour soup, comprising the following steps:

[0007] S1. Take the tofu yellow slurry, centrifuge it, and collect the supernatant to obtain the clarified tofu yellow slurry;

[0008] S2. Pick, remove the stems of tomatoes, wash, and crush them to make a tomato homogenate;

[0009] S3, mixing the clarified tofu yellow slurry obtained in S1 and the tomato homogenate obtained in S2, sterilizing and cooling to room temperature to obtain a mixed slurry;

[0010] S4. Take the activated Lactobacillus plantarum liquid and inoculate it into the mixed slurry obtained in S3. After anaerobic fermentation, obtain tofu yellow slurry and tomato red sour soup.

[0011] Preferably, the centrifugation conditions in S1 are: centrifugation at 4° C. and 4000 rpm for 10 min.

[0012] Preferably, the amount of the clarified tofu yellow slurry added in S3 is 10-50% of the mass of the tomato homogenate.

[0013] Preferably, the sterilization condition in S3 is: water bath pasteurization at 85° C. for 15 minutes.

[0014] Preferably, the Lactobacillus plantarum in S4 is Lactiplantbacillus plantarum, which has been deposited in Guangdong Provincial Microbiological Strain Collection Center with a deposit number of GDMCC No: 62217; the inoculation amount of the Lactobacillus plantarum is 1-5% of the mass of the mixed slurry.

[0015] Preferably, the temperature of the anaerobic fermentation in S4 is 25-35° C., and the time is 6-10 days.

[0016] Preferably, the activation method of Lactobacillus plantarum described in S4 is: taking the Lactobacillus plantarum strain that has been frozen and stored in glycerol at -20°C and placing it in 5 mL of fermentation medium containing lyophilized tofu yellow slurry, and culturing it with constant temperature and shaking at 37°C and 200r / min overnight to obtain an activated Lactobacillus plantarum bacterial liquid.

[0017] Preferably, the method for preparing the fermentation medium containing the freeze-dried tofu yellow pulp comprises the following steps:

[0018] The tofu yellow slurry is centrifuged and then concentrated to 1 / 3 of its volume by rotary evaporation, and then freeze-dried to obtain a freeze-dried tofu yellow slurry; the freeze-dried tofu yellow slurry is then added to an MRS broth medium, and after dissolution, sterilization, and cooling, a fermentation medium containing the freeze-dried tofu yellow slurry is obtained;

[0019] Preferably, the ratio of the freeze-dried tofu yellow slurry water added to the fermentation medium containing the freeze-dried tofu yellow slurry water is 0 to 20%;

[0020] Preferably, the tofu yellow slurry is centrifuged at 4° C. and 4000 rpm for 10 min, and the sterilization is performed at 121° C. and 30 min.

[0021] Compared with the prior art, the present invention has significant technical effects:

[0022] 1. The present invention provides a tofu yellow slurry tomato red sour soup and a preparation method thereof. The tofu yellow slurry is used as the fermentation raw material for the red sour soup. By optimizing factors such as the fermentation temperature, the amount of strain inoculation, and the ratio of tofu yellow slurry to tomatoes, a tofu yellow slurry tomato red sour soup product is developed. The overall floral and fruity aroma is rich. The volatile flavor substances are studied and it is found that the volatile components are mainly alcohols (linalool), ketones (damascenone, damascenone) and aldehydes (phenylacetaldehyde, nonanal, trans-2-nonanal). The present invention is based on tofu yellow slurry and incorporates the concept of Guizhou ecological specialty food development. It is of great significance in improving the fermentation efficiency of red sour soup, reducing production costs and promoting the resource utilization of yellow slurry.

[0023] The present invention also provides a fermentation medium containing freeze-dried tofu yellow slurry. This low-cost lactic acid bacteria fermentation medium is prepared by combining the freeze-dried tofu yellow slurry with MRS medium. The tofu yellow slurry, which contains nutrients such as whey protein and oligosaccharides, is concentrated and freeze-dried before being added to a microbial culture medium for use as a fermentation medium. This allows for resource recycling and reduces fermentation costs.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a growth curve of Lactobacillus plantarum in a fermentation medium containing different proportions of the freeze-dried tofu yellow pulp according to Example 1 of the present invention;

[0026] Figure 2 The effect of fermentation temperature on the total acid of red sour soup in Example 2 of the present invention;

[0027] Figure 3 The effect of the inoculation amount on the total acidity of red sour soup in Example 2 of the present invention;

[0028] Figure 4 The effect of the proportion of tofu yellow pulp water on the total acidity of red sour soup in Example 2 of the present invention;

[0029] Figure 5 The effect of fermentation time on the total acid of red sour soup in Example 2 of the present invention;

[0030] Figure 6 2 is a response surface diagram of the interaction between fermentation temperature and inoculation amount in Example 2 of the present invention;

[0031] Figure 7 2 is a response surface diagram of the interaction between fermentation temperature and tofu yellow pulp water ratio in Example 2 of the present invention;

[0032] Figure 8 is a response surface diagram of the interaction between fermentation temperature and time in Example 2 of the present invention;

[0033] Figure 9 2 is a response surface diagram of the interaction between the inoculation amount and the proportion of tofu yellow pulp water in Example 2 of the present invention;

[0034] Figure 10 2 is a response surface diagram of the interaction between the inoculation amount and the fermentation time in Example 2 of the present invention;

[0035] Figure 11 This is a response surface diagram of the interaction between the proportion of tofu yellow pulp water and fermentation time in Example 2 of the present invention. DETAILED DESCRIPTION

[0036] The plant lactobacillus used in the present invention is Lactiplantbacillus plantarum, which has been deposited in Guangdong Provincial Microbiological Strain Collection Center with a deposit number of GDMCC No: 62217.

[0037] The raw materials and reagents used in the present invention are: tofu yellow pulp water, Anshun Pingba District Wanjia Agricultural Products Development Co., Ltd.; MRS broth culture medium, Shanghai Bowei Microbiology Technology Co., Ltd.; 2-octanol, Merck Chemical Technology (Shanghai) Co., Ltd.

[0038] The instrument used in the present invention is a 7890B-7000D gas chromatograph mass spectrometer, and the chromatographic column is HP-5MS (30m×0.25mm×0.25μm), Agilent Technologies, USA.

[0039] Example 1

[0040] This example uses tofu yellow pulp water as raw material to prepare a low-cost lactic acid bacteria fermentation medium. The method is as follows:

[0041] (1) Preparation of freeze-dried tofu yellow pulp

[0042] Fresh tofu yellow slurry was centrifuged at 4°C and 4000 rpm for 10 min, concentrated to 1 / 3 of its volume by a rotary evaporator, cooled to room temperature, and pre-frozen at -20°C overnight. It was then transferred to a freeze dryer and freeze-dried according to the parameters in Table 1 to obtain a freeze-dried tofu yellow slurry.

[0043] Table 1 Freeze dryer operating parameters

[0044]

[0045]

[0046] (2) Preparation of fermentation medium containing freeze-dried tofu yellow pulp

[0047] Take MRS broth culture medium, add tofu yellow slurry freeze-dried material in proportions of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%, and after dissolution, sterilization (121°C, 30min) and cooling, obtain a fermentation medium containing tofu yellow slurry freeze-dried material.

[0048] The plant lactobacillus pure strain obtained from glycerol-20 DEG C of freezing preservation is placed in 5mL MRS broth medium and spends the night constant temperature vibration (37 DEG C, 200r / min) cultivates, completes bacterial strain activation.On the fermention medium comprising the different proportions bean curd yellow slurry lyophilized product prepared by the present embodiment, inoculate the plant lactobacillus after activation, measure its growth curve, method is: adopt optical density method to measure, get the bacterium liquid 100 μ L after activation, be injected into the fermention medium comprising the different proportions bean curd yellow slurry lyophilized product prepared by 5mL present embodiment and culture with constant temperature shaking, measure the optical density value (OD600) of a strain culture fluid every 5h, continuously monitor 50h, make horizontal and vertical coordinates with incubation time (t) and optical density value (OD600) respectively, draw target strain growth curve.

[0049] Figure 1 The figure shows the growth curve of Lactobacillus plantarum in fermentation medium containing different proportions of freeze-dried tofu yellow slurry. The results show that Lactobacillus plantarum grows slowly within the time range of 0-12 hours, enters the logarithmic growth phase of the strain between 12-24 hours, and stabilizes after 24 hours. In comparison, when the replacement ratio of freeze-dried tofu yellow slurry to MRS broth medium exceeds 20%, the growth of the strain is significantly inhibited, which is not conducive to the growth and enrichment of the fermentation strain. Based on this, in order to balance the resource utilization of tofu yellow slurry and the growth effect of the strain, moderate-scale fermentation can use MRS broth medium containing 20% freeze-dried tofu yellow slurry. Tofu yellow slurry contains nutrients such as whey protein and oligosaccharides. After concentration and freeze-drying, it is added to the microbial culture medium as a fermentation medium, which can not only achieve resource recycling but also reduce fermentation costs.

[0050] Example 2

[0051] The present embodiment is a method for preparing tofu yellow pulp water tomato red sour soup, comprising the following steps:

[0052] S1. Take the tofu yellow slurry, centrifuge it at 4°C and 4000 rpm for 10 min, and collect the supernatant to obtain the clarified tofu yellow slurry;

[0053] S2. Pick, remove the stems of tomatoes, wash, and crush them to make a tomato homogenate;

[0054] S3, mixing the clarified tofu yellow slurry obtained in S1 and the tomato homogenate obtained in S2, pasteurizing the mixture in a water bath at 85°C for 15 minutes, and cooling the mixture to room temperature to obtain a mixed slurry;

[0055] S4. The pure strain of Lactobacillus plantarum preserved by glycerol freezing at -20°C was placed in 5 mL of the fermentation medium containing the freeze-dried product of tofu yellow slurry prepared in Example 1 and cultured overnight with constant temperature shaking (37°C, 200 r / min) to complete strain activation and obtain an activated Lactobacillus plantarum liquid; the activated Lactobacillus plantarum liquid was inoculated into the mixed slurry obtained in S3, and after anaerobic fermentation, to obtain tofu yellow slurry tomato red sour soup.

[0056] 1. Single-factor experiment

[0057] Four factors were selected for single-factor experiments: the ratio of tofu yellow slurry (the proportion of tofu yellow slurry to tomato homogenate mass), fermentation temperature, inoculation amount, and fermentation time. Specific factors and levels are shown in Table 2. The effect of each factor on the tofu yellow slurry and tomato red sour soup was investigated based on pH value and total acid content.

[0058] Table 2 Experimental factor level table

[0059]

[0060] Figure 2 The effect of fermentation temperature on the total acid of red sour soup. The results showed that when the fermentation time was 8 days, the inoculation amount of Lactobacillus plantarum was 3%, and the proportion of tofu yellow pulp water was 30%, the total acid content in the sample reached 12.294g / L when the fermentation temperature was 35°C, which was greater than the total acid content of red sour soup under 25°C (8.514g / L) and 30°C (12.114g / L), indicating that the higher the fermentation temperature, the faster the acid production, but the difference in total acid content after 30°C was not obvious. Figure 3 The effect of inoculation amount on the total acid of red sour soup showed that under the same fermentation time (8d), optimal fermentation temperature (35℃) and tofu yellow pulp water ratio of 30%, the total acid content (12.294g / L) of 3% Lactobacillus plantarum inoculation amount was greater than that of 1% (10.674g / L) and 5% (12.024g / L). Figure 4 The study examined the effect of the proportion of tofu yellow pulp water on the total acid content of red sour soup. It was found that the total acid content of red sour soup showed a trend of first increasing and then decreasing as the proportion of tofu yellow pulp water increased, reaching a peak of 12.114 g / L at 30%. Figure 5The effect of fermentation time on the total acid content of red sour soup showed that the total acid content was positively correlated with fermentation time, but the growth trend was not obvious after 8 days. Based on energy conservation and fermentation time, from a single factor perspective, the fermentation temperature of tofu yellow pulp tomato red sour soup can be set to 30°C, the strain inoculum to 3%, the tofu yellow pulp ratio to 30%, and the fermentation time to 8 days.

[0061] 2. Process optimization

[0062] Based on the results of the single-factor experiment, preliminary parameter ranges for the proportion of tofu yellow slurry, fermentation temperature, inoculation amount, and fermentation time were obtained. Furthermore, using total acid content as the evaluation criterion, we selected four key factors: fermentation temperature, inoculation amount, proportion of tofu yellow slurry, and fermentation time. A four-factor, three-level orthogonal experiment was designed for optimization. The detailed design is shown in Table 3. The total acid content of 29 samples of tofu yellow slurry and tomato red sour soup is shown in Table 4.

[0063] Table 3 Orthogonal test factor levels

[0064]

[0065] Table 4 Response surface experiment scheme and results of tofu yellow pulp water tomato red sour soup process

[0066]

[0067]

[0068]

[0069] The variance analysis found that within the level range of the experimental selected factors, the proportion of tofu yellow pulp (C) had a very significant effect on the total acid content of tofu yellow pulp tomato red sour soup, followed by fermentation temperature (A). The inoculation amount (B) and fermentation time (D) had a smaller effect on the total acid content of the product. The interaction between the factors and their influence on the total acid content of the samples are shown in Tables 5 and Figure 6-11 .in, Figure 6 is the interaction response surface diagram of fermentation temperature and inoculation amount, Figure 7 This is the interaction response surface diagram of fermentation temperature and tofu yellow pulp water ratio. Figure 8 is the interaction response surface diagram of fermentation temperature and time, Figure 9 This is the interaction response surface diagram of the inoculation amount and the proportion of tofu yellow pulp water. Figure 10 is the response surface diagram of the interaction between inoculation amount and fermentation time, Figure 11 This is the response surface diagram of the interaction between the proportion of tofu yellow pulp water and fermentation time.

[0070] Table 5 Analysis of variance of response surface data

[0071]

[0072]

[0073] Taking the total acid content as the response value, the regression model was obtained through binary multiple regression fitting:

[0074] R=12.19+0.3736A+0.1827B–1.08C–0.0726D+0.3418AB–0.1575AC–0.27AD+0.47BC+0.45BD–0.4878CD–1.07A 2 –0.376B 2 –1.45°C 2 –0.1888D 2 .

[0075] The optimal conditions for achieving a total acid content of 12.478 g / L in a tofu yellow pulp and tomato red sour soup were verified to be a fermentation temperature of 31.33°C, an inoculum level of 4.02%, a tofu yellow pulp percentage of 21.4%, and a fermentation time of 9.8 days. To facilitate practical production operations, these parameters can be fine-tuned and rounded to: a fermentation temperature of 31°C, an inoculum level of 4%, a tofu yellow pulp percentage of 20%, and a fermentation time of 10 days.

[0076] Example 3

[0077] This example is the determination of volatile components in tofu yellow pulp water and red tomato sour soup.

[0078] The volatile components of tofu yellow pulp and red tomato sour soup were analyzed by gas chromatography-mass spectrometry, and the substances that contributed most to its flavor were analyzed using the aroma activity value method. The method is as follows:

[0079] Weigh the tofu yellow pulp and tomato red sour soup sample into a 20mL headspace bottle, add sodium chloride to saturation, add the internal standard 2-octanol to make its concentration 3mg / L, put it into an 80℃ water bath and heat it for 30min, then insert the headspace microextraction needle into the headspace bottle and continue heating for 30min, and analyze at the 250℃ injection port for 5min.

[0080] Chromatographic conditions: headspace splitless injection, helium carrier gas, flow rate 1.0 mL / min, inlet and transfer line temperatures 250°C and 280°C, respectively. Temperature program: 50°C for 2 min, then increase at 5°C / min to 180°C for 5 min, then increase at 10°C / min to 250°C for 5 min.

[0081] Mass spectrometry conditions: ion source temperature of 230°C, quadrupole temperature of 150°C, EI source, full scan mode, mass range of 40-600 amu.

[0082] Quantitative and qualitative analysis: Gas chromatography-mass spectrometry data were analyzed and compared with the NIST 20 database. The best match with a degree of match greater than 50% was selected and combined with literature analysis for identification. The relative content of each component was calculated using the area percentage method and the internal standard method. The relative quantification using the internal standard method was calculated according to the following formula:

[0083] RC i =A i / A is ×C is

[0084] Where: RC i is the relative concentration of each volatile substance (mg / L), A i is the peak area of each volatile component, A is is the peak area of the internal standard 2-octanol, C is is the concentration of the internal standard 2-octanol (mg / L).

[0085] The results of volatile component determination and aroma activity value (OVA) calculation of tofu yellow pulp water and red tomato sour soup are shown in Table 6.

[0086] Table 6 Composition of volatile compounds in tofu yellow pulp water and red tomato sour soup

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] Note: NF means there is no literature report on the olfactory threshold of this component.

[0093] Results showed that 94 volatile compounds were detected in the tofu, yellow pulp, and red tomato sour soup. These included 9 acids, 11 alcohols, 7 esters, 17 ketones, 12 aldehydes, 3 terpenes, 4 phenols, 7 amines, and 24 other substances, including alkanes and benzenes. In terms of content, eight major categories of volatile compounds—acids, alcohols, esters, ketones, aldehydes, terpenes, phenols, and amines—accounted for over 70% of the total volatile matter. Acids, alcohols, ketones, and aldehydes were the most abundant, accounting for 15.89%, 14.189%, 18.429%, and 12.418%, respectively. Generally, an OVA value greater than 1 for a volatile compound is considered to significantly contribute to the overall flavor of the product. The results of OVA values showed that 16 components, including linalool (218.18), propyl decalactone (5.45), 6-methyl-5-hepten-2-one (1.06), methyl nonyl ketone (4.55), damascone (714.29), damascone (5500.00), β-ionone (7.74), phenylacetaldehyde (12.50), nonanal (14.55), trans-2-nonanal (94.74), decanal (2.00), β-cyclocitral (7.00), citral (2.14), eugenol (6.40), 1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene (28.00), and methyl tert-butyl ether (1.14), contributed significantly to the flavor of tofu yellow juice and tomato red sour soup, among which ketones and aldehydes were the most prominent.

[0094] Example 4

[0095] This example is a sensory evaluation of tofu yellow pulp tomato red sour soup.

[0096] The sensory evaluation of tofu yellow pulp and tomato red sour soup was based on the research on the optimization of fermentation process and quality control of red sour soup (Zhang Dongya. Research on the optimization of fermentation process and quality control of red sour soup [D]. Guizhou University, 2018.) with slight modifications. Combining the sensory characteristics of tofu yellow pulp, tomato homogenate, and red sour soup, the tofu yellow pulp and tomato red sour soup were scored from four aspects: color, tissue morphology, smell / taste, and impurities. The total score was 100 points. The sensory evaluation standards are shown in Table 7.

[0097] Table 7 Sensory evaluation standards for tofu yellow pulp water and red tomato sour soup

[0098]

[0099]

[0100] Accurately weigh 50g of the tofu, yellow pulp, and red sour tomato soup product of the present invention into a stoppered glass bottle and incubate in a 60°C water bath for half an hour. To evaluate the sensory quality of this product, three brands of red sour soup were purchased from the market for comparative evaluation. Ten participants were invited to participate in the sensory evaluation, and all participants were trained according to the relevant regulations and procedures in GB / T 16291.1. The sensory evaluation scores are shown in Table 8.

[0101] Table 8 Sensory evaluation table of tofu yellow pulp tomato red sour soup of the present invention and commercially available red sour soup products

[0102]

[0103] The results showed that this product was at an above-average level compared with the red sour soup products on the market.

[0104] The present invention provides a tofu yellow slurry tomato red sour soup and a preparation method thereof. The obtained tofu yellow slurry tomato red sour soup product has a strong overall floral and fruity aroma, and the volatile components are mainly alcohols (linalool), ketones (damascenone, damascenone) and aldehydes (phenylacetaldehyde, nonanal, trans-2-nonanal). In the present invention, the lactic acid bacteria used for the fermentation of red sour soup can be replaced by Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus namurensis or other common lactic acid bacteria, and the preparation of tofu yellow slurry tomato red sour soup can also be achieved. The present invention is based on tofu yellow slurry and incorporates the concept of Guizhou ecological specialty food development. It is of great significance in improving the fermentation efficiency of red sour soup, reducing production costs and promoting the resource utilization of yellow slurry.

[0105] The present invention also provides a fermentation culture medium comprising freeze-dried tofu yellow slurry, which is a low-cost lactic acid bacteria fermentation culture medium prepared by compounding the freeze-dried tofu yellow slurry with MRS culture medium. The tofu yellow slurry contains nutrients such as whey protein and oligosaccharides. After being concentrated and freeze-dried, it is added to the microbial culture medium and used as a fermentation culture medium, which can not only realize resource recycling but also reduce fermentation costs.

[0106] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing tofu yellow pulp tomato red sour soup, characterized in that: The following steps are involved: S1. Take the tofu yellow slurry, centrifuge it, and collect the supernatant to obtain the clarified tofu yellow slurry; S2. Pick, remove the stems of tomatoes, wash, and crush them to make a tomato homogenate; S3, mixing the clarified tofu yellow slurry obtained in S1 and the tomato homogenate obtained in S2, sterilizing and cooling to room temperature to obtain a mixed slurry; S4. Take the activated Lactobacillus plantarum liquid and inoculate it into the mixed slurry obtained in S3. After anaerobic fermentation, obtain tofu yellow slurry and tomato red sour soup.

2. The method according to claim 1, characterized in that The centrifugation conditions described in S1 are: centrifugation at 4°C and 4000 rpm for 10 min.

3. The method according to claim 1, characterized in that The amount of the clarified tofu yellow slurry added in S3 is 10-50% of the mass of the tomato homogenate.

4. The method according to claim 1, wherein The sterilization conditions described in S3 are: water bath pasteurization at 85°C for 15 minutes.

5. The method according to claim 1, wherein The plant lactobacillus in S4 is Lactiplantbacillus plantarum, which has been deposited in Guangdong Provincial Microbiological Strain Collection Center with a deposit number of GDMCC No: 62217. The inoculation amount of the plant lactobacillus is 1-5% of the mass of the mixed slurry.

6. The method according to claim 1, characterized in that The temperature of the anaerobic fermentation in S4 is 25-35° C. and the time is 6-10 days.

7. The method according to claim 1, characterized in that The activation method of Lactobacillus plantarum described in S4 is: taking the Lactobacillus plantarum strain that has been frozen and stored in glycerol at -20°C and placing it in 5 mL of fermentation medium containing lyophilized tofu yellow slurry water, and culturing it at a constant temperature and shaking at 37°C and 200r / min overnight to obtain an activated Lactobacillus plantarum bacterial liquid.

8. The method according to claim 7, characterized in that The method for preparing the fermentation medium containing the freeze-dried tofu yellow pulp comprises the following steps: The tofu yellow slurry is centrifuged and concentrated to 1 / 3 of its volume by rotary evaporation, and then freeze-dried to obtain a freeze-dried tofu yellow slurry; the freeze-dried tofu yellow slurry is then added to an MRS broth medium, and after dissolution, sterilization, and cooling, a fermentation medium containing the freeze-dried tofu yellow slurry is obtained.

9. The method according to claim 8, characterized in that The ratio of the freeze-dried bean curd yellow slurry water added to the fermentation medium containing the freeze-dried bean curd yellow slurry water is 0 to 20%.

10. The method according to claim 8, characterized in that The conditions for centrifuging the tofu yellow slurry water are: centrifugation at 4° C. and 4000 rpm for 10 min; and the sterilization conditions are 121° C. and 30 min.

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