Low-sour salted egg yolk flavored compound seasoning and application thereof

Abstract

The invention discloses a low-sour salted egg yolk flavored compound seasoning and application thereof. According to the seasoning, salted egg yolk is taken as a core, directional fermentation is carried out through a compound flora composed of staphylococcus xylosus and lactobacillus plantarum, and a compound yeast extract, whey protein powder and the like are compounded. The technical problems that a traditional fermented condiment is too strong in sour feeling and thin in flavor are effectively solved. The seasoning obtained by the invention has strong fragrance of salted egg yolk, remarkable sandy taste and mellow flavor deposit, and is widely applied to the field of foods such as baking.

Description

Technical Field

[0001] This application belongs to the field of food processing and condiment research and development, specifically involving a low-acid salted egg yolk flavored compound condiment and its application. Background Technology

[0002] Egg products, as a naturally nutritious food, have become an indispensable part of people's lives. Compared with other foods, egg products are rich in nutrients and are one of the most nutritionally complete foods known to humankind, serving as a source of many nutrients for the human body. Eggs and egg products not only have nutritional and health benefits, but also serve as important raw materials in many industries such as food, biology, and chemistry. In the food industry, eggs and egg products can improve the flavor and texture of food and enhance its nutritional value.

[0003] Salted duck eggs are a traditional egg product, with the salted egg yolk being particularly popular due to its "loose, sandy, and oily" characteristics. Traditionally, salted egg yolks are made by pickling fresh duck eggs in saturated brine or by wrapping them in salty red or yellow mud or wood ash until mature, then removing the egg white. Traditional pickling methods result in high salt content in the yolks, potentially leading to various health risks. Furthermore, natural salted egg yolks are high in fat and easily oxidize, developing a rancid or sour taste, resulting in poor stability and a short shelf life. In addition, commercially available salted egg yolk sauces and seasonings often contain large amounts of citric acid, lactic acid, or acetic acid to extend shelf life and adjust flavor. This gives the product a pronounced sour aftertaste, masking the natural salty and oily aroma of the salted egg yolk. Moreover, existing fermented flavor bases often have a strong lactic or acetic acid flavor, further masking the yolk's natural salty and savory taste and failing to recreate the unique "sandy and oily" texture of authentic salted egg yolks. In addition, ordinary semi-solid seasonings are prone to oil separation (layering) and darkening of color during long-term storage. Therefore, it is of great significance to develop a salted egg yolk seasoning that can maintain low acidity and low salt content while taking into account both microbial safety and physical stability. Summary of the Invention

[0004] This invention aims to provide a low-acidity salted egg yolk flavored compound seasoning and its applications. The seasoning uses salted egg yolk as its core, undergoing directional fermentation through a complex microbial community composed of *Staphylococcus xylitol* and *Lactobacillus plantarum*, and is further formulated with compound yeast extract, whey protein powder, etc. This effectively solves the technical problems of traditional fermented seasonings being excessively acidic and having a thin flavor. The seasoning obtained by this invention has a rich salted egg yolk aroma, a pronounced sandy texture, and a mellow umami base, and can be widely used in baking and other food industries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] The present invention provides a low-acid salted egg yolk flavored compound seasoning, characterized in that, by weight, it comprises the following components: 30-40 parts salted egg yolk powder, 15-20 parts whey protein powder, 5-10 parts compound yeast extract, 0.05-0.3 parts microbial fermentation agent, and 1-5 parts flavor stabilizer.

[0007] Preferably, the compound yeast extract is a high nucleotide yeast extract, wherein the content of disodium 5'-ribonucleotide I+G is ≥10%, and the content of free amino acids is ≥35%.

[0008] Preferably, the preparation method of the seasoning includes the following steps:

[0009] S1. Mix salted egg yolk powder with deionized water at a mass ratio of 1:4-1:6, then add whey protein powder and compound yeast extract, and adjust the initial pH to 6.5-7.0; stir at 500-800 rpm for 30 minutes to obtain the fermentation substrate;

[0010] S2. Inoculate the fermentation medium with microbial starter and ferment at a constant temperature of 30-35℃ for 12-20 hours to obtain the fermentation product;

[0011] S3. Add flavor protease to the fermentation product and hydrolyze it at 50-55℃ for 2-4 hours to obtain the hydrolysate.

[0012] S4. Heat the enzymatic hydrolysis product to 90-105℃ for 10-15 minutes to obtain the enzyme-inactivated and flavor-enhancing product.

[0013] S5. The enzyme-inactivating and flavor-enhancing products are concentrated and spray-dried to obtain a powdered compound seasoning.

[0014] Preferably, the microbial fermentation agent is Staphylococcus xylose and Lactobacillus plantarum in a mass ratio of (3-5):(1-2).

[0015] Preferably, the inoculum amount of Staphylococcus xylose in the microbial fermentation agent is 1.0×10⁶-1.0×10⁷ cfu / g, and the inoculum amount of Lactobacillus plantarum is 1.0×10⁶-1.0×10⁷ cfu / g.

[0016] Preferably, the pH is adjusted in step S1 by acetic acid or citric acid.

[0017] In another aspect, the present invention provides the application of the aforementioned low-acid salted egg yolk flavored compound seasoning in the food industry, including its application in baking fillings and ready-to-eat sauce products.

[0018] In another aspect, the present invention provides a baking product, characterized in that it includes a compound seasoning with a low-acidity salted egg yolk flavor as described in any one of claims 1-6.

[0019] Preferably, the seasoning also includes β-carotene, gardenia yellow, and microcrystalline cellulose.

[0020] In another aspect, the present invention provides a method for producing a baked product, the method comprising the preparation method described in claim 3.

[0021] In this invention, the flavor protease is common knowledge in the art. The flavor protease in this invention is derived from Aspergillus oryzae, with an enzyme activity of 30,000 U / g and a ratio of aminopeptidase activity to endopeptidase activity of 2:1.

[0022] In this invention, the fresh amino acids include Asp and Glu, and their determination methods are common knowledge in the art, based on GB 5009.124-2016. The determination method for carotenoid content is common knowledge in the art, based on GB 5009.83-2016. The color difference ΔE is mainly measured by a colorimeter (spectrometer), based on the CIE Lab color space, to quantify the transmitted light on the object surface. The difference between the sample and the standard sample in terms of lightness (L×), red-green axis (a×), and yellow-blue axis (b×) is measured, and the determination method is common knowledge in the art. In this invention, the method for determining carotenoid content includes saponifying the sample to release carotenoids into a free state, extracting with petroleum ether and adjusting the volume with dichloromethane, separating by reversed-phase chromatography, and quantifying by external standard method, based on GB 5009.83-2017.

[0023] In this invention, both the high-nucleotide yeast extract and the common yeast extract were purchased from Fruiterco. MSG was purchased from Haitian.

[0024] The technical solution provided in this application may include the following beneficial effects:

[0025] First, it significantly reduces the sourness, preserving the pure aroma of the egg yolk. Traditional seasonings often produce a sharp sour taste due to the addition of acidic flavorings or the accumulation of lactic acid from microorganisms, masking the original mellow aroma of the egg yolk. This invention uses non-acid-producing Staphylococcus xylitol as the dominant microbial community, combined with the taste compensation of high nucleotide yeast extract, to control the fermentation endpoint and greatly suppress the sourness. This allows the seasoning to retain the fermentation layers while presenting a purer and fuller salty and savory flavor of salted egg yolk.

[0026] Secondly, this invention has a rich, oily texture and a unique flavor. By introducing whey protein powder as a fermentation substrate, the fermentation process degrades it into flavor precursors, which, in conjunction with salted egg yolk powder, produce a rich "oily" texture. The flavor is superior to that of products with added chemical flavorings, exhibiting prominent salty, savory, and fragrant characteristics.

[0027] Finally, the salted egg yolk seasoning has a golden color that is natural and long-lasting. It protects the natural pigments in the salted egg yolks and slows down their oxidation and discoloration. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] 1.1 Raw Material Preparation

[0031] Prepare the following ingredients by weight: 35 parts salted egg yolk powder, 15 parts whey protein powder, 8 parts compound yeast extract, 0.1 parts microbial starter (of which, the mass ratio of Staphylococcus xylose (CGMCC No. 26373) to Lactobacillus plantarum (CGMCC NO. 15467) is 3:1), and 3 parts flavor stabilizer (citric acid: glycine: microcrystalline cellulose = 3:2:2).

[0032] 1.2 Preparation steps

[0033] S1. Mix salted egg yolk powder with deionized water at a mass ratio of 1:5, then add whey protein powder and compound yeast extract, and adjust the initial pH to 7.0; stir at 600 rpm for 30 minutes to obtain the fermentation substrate.

[0034] S2, the fermentation substrate is heated to 85℃ for sterilization, and after cooling to room temperature, microbial fermentation agent is added (inoculum amount is 1.5×107cfu / g), and fermentation is carried out at a constant temperature of 32℃ for 16h. During the process, the pH is monitored, and fermentation is stopped when the pH drops to 5.9 to obtain the fermentation product.

[0035] S3. Add 0.1 part of flavor protease to the fermentation product and enzymatically hydrolyze it at 52℃ for 3 hours to obtain the enzymatic hydrolysate;

[0036] S4. Heat the enzymatic hydrolysis product to 98℃ for 12 minutes, and add the remaining flavor stabilizer at the beginning of the heating stage. Use the thermal reaction to induce aroma generation to obtain the enzyme-inactivated and flavor-enhancing product.

[0037] S5. The enzyme-inactivating and flavor-enhancing product is concentrated and spray-dried (inlet air temperature 170℃, outlet air temperature 85℃) to obtain a powdered compound seasoning.

[0038] Example 2: Formula Proportion Adjustment Scheme

[0039] 2.1 Raw material preparation (by weight):

[0040] Prepare 30 parts by weight of salted egg yolk powder, 20 parts of whey protein powder, 10 parts of compound yeast extract, 0.3 parts of microbial starter (of which, the mass ratio of Staphylococcus xylose and Lactobacillus plantarum is 3:1, and the strain is the same as in Example 1), and 3 parts of flavor stabilizer (citric acid:glycine:microcrystalline cellulose = 3:2:2).

[0041] 2.2 Preparation steps:

[0042] Similar to Example 1, except that the fermentation temperature in step S2 is set to 35°C, the fermentation time is shortened to 12 hours, and the final pH of the fermentation is controlled at 6.1.

[0043] Comparative Example 1-1

[0044] Same as Example 1, except that before inoculation, the microbial agent is first sterilized by high-pressure steam (121°C, 20 min) to completely inactivate the microorganisms before inoculation.

[0045] Comparative Examples 1-2

[0046] Same as Example 1, except that in step S2, the fermentation substrate is heated to 85°C for sterilization, and after cooling to room temperature, no microbial fermentation agent is added. Edible acetic acid is added directly to adjust the pH value of the fermentation substrate to be consistent with the fermentation endpoint (pH 5.9).

[0047] Comparative Examples 1-3

[0048] Same as Example 1, except that in step S2, deionized water is used instead of microbial suspension, and the volume added is the same.

[0049] Effect detection

[0050] 1) Sensory evaluation method

[0051] Ten evaluators (aged 20-40, 5 males and 5 females) with good physical condition, high sensory sensitivity, and strong ability to distinguish stimuli were recruited. A 10-point scale was used for evaluation, and the scoring criteria are shown in Table 1. The scoring intensity was: 0 None; 1-2 Slight; 3-4 Mild; 5-6 Moderate; 7-8 Strong; 9-10 Very Strong. The scoring criteria are shown in Table 1.

[0052] Table 1 Sensory rating criteria

[0053]

[0054] 2) Physicochemical testing

[0055] According to GB 12456-2021 "National Food Safety Standard - Determination of Total Acid in Food", the third method, based on the principle of acid-base neutralization, involves titrating the acid in the test solution with a standard sodium hydroxide solution. The titration endpoint is determined when the pH of the sample solution reaches 8.2. The total acid content in the food is calculated based on the amount of alkali solution consumed. Potentiometric titration is used, and the total acid content is calculated by recording the volume of standard sodium hydroxide solution consumed. The test results are shown in Table 2.

[0056] Table 2 Evaluation Results

[0057]

[0058] The results showed that Example 1 had a richer flavor than Example 2, making it more suitable for use in heavily processed baked goods. In contrast, Example 2 was more suitable for light meals. Furthermore, compared to Comparative Examples 1-1 and 1-4, the aroma provided by the intracellular components of the inactivated bacteria was higher than that of the pure water group. However, it only contained inactivated bacteria and could not provide the active components of bacterial metabolism. Its characteristic aroma component content was lower than that of the present invention, and its acidity was higher. This indicates that the flavor precursors produced by *Staphylococcus xylose* and *Lactobacillus plantarum* through biotransformation during fermentation provided the aroma of the fermentation product. In addition, in food fermentation, a high total acid content does not necessarily equate to a strong sour taste. The amino acids and peptides produced during fermentation have a strong buffering capacity, resulting in a smoother texture. Example 1 of the present invention, with a total acid content (0.39 g / 100g) similar to Comparative Examples 1-1 and 1-3, exhibited a significantly reduced sensory sourness intensity. This indicates that the metabolic system of synergistic fermentation by *Staphylococcus xylose* and *Lactobacillus plantarum* effectively masked the sourness and endowed the product with excellent oiliness and aroma. Compared with Comparative Examples 1-2, the total acid content was lower than that adjusted using acid reagents, and it had a significant advantage in sensory flavor.

[0059] Comparative Examples 1-5: Strain Screening

[0060] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CGMCC No. 11352) and Lactobacillus plantarum (CGMCC NO. 15467) is 3:1).

[0061] Comparative Examples 1-6

[0062] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CICC No. 22943) and Lactobacillus plantarum (CGMCC NO. 15467) is 3:1).

[0063] Comparative Examples 1-7

[0064] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CGMCC No. 26373) and Lactobacillus plantarum (CGMCC No. 16189) is 3:1).

[0065] Comparative Examples 1-8

[0066] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CGMCC No. 26373) and Lactobacillus plantarum (CGMCC No. 21288) is 3:1).

[0067] Comparative Examples 1-9

[0068] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CGMCC No. 11352) and Lactobacillus plantarum (CGMCC No. 16189) is 3:1).

[0069] Comparative Examples 1-10

[0070] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CGMCC No. 11352) and Lactobacillus plantarum (CGMCC No. 21288) is 3:1).

[0071] Comparative Examples 1-11

[0072] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CICC No. 22943) and Lactobacillus plantarum (CGMCC NO. 16189) is 3:1).

[0073] Comparative Examples 1-12

[0074] Same as Example 1, except that the microbial fermentation agent is 0.1 parts (of which the mass ratio of Staphylococcus xylose (CICC No. 22943) and Lactobacillus plantarum (CGMCC NO. 21288) is 3:1).

[0075] Effect detection

[0076] 1) Determination of total acidity. See the determination method in Example 1.

[0077] 2) Determination of free amino acid (FAA) content and fresh amino acid content: According to GB 5009.124-2016 "National Food Safety Standard - Determination of Amino Acids in Food", the sample to be tested was dissolved in 0.02N-HCl, hydrolyzed into free amino acids, and then determined using an analyzer (LA8080).

[0078] The results of the effectiveness test are shown in Table 3.

[0079] Table 3 Results of the bacterial strain comparison test

[0080]

[0081] The results showed that fermentation using the microbial fermentation agent of Example 1 of this invention resulted in significantly higher levels of free amino acids and saturated amino acids in the product compared to other formulations. Specifically, when using *Staphylococcus xylose* (CGMCC No. 26373), the free amino acid content was approximately 14.0%-18.9% higher than other *Staphylococcus xylose* groups, indicating that the *Staphylococcus xylose* strain used in this invention can efficiently degrade components such as salted egg yolk and whey protein, thereby increasing the free amino acid content. Furthermore, when using *Lactobacillus plantarum* (CGMCC NO. 15467), the total acid content of the product increased from 0.33 to 0.47-0.49, indicating that the *Lactobacillus plantarum* strain used in this invention can effectively balance acids and reduce sour taste during metabolism. Moreover, comparative examples 1-9 to 1-12 showed generally higher total acid content and significantly lower free amino acid content, indicating that the strain combination of this invention has a good synergistic effect. *Lactobacillus plantarum* produces acid to maintain the environment and promotes enzyme production by *Staphylococcus xylose*; the products degraded by *Staphylococcus xylose* are then converted into aroma precursors by *Lactobacillus plantarum*.

[0082] Problems with yeast extract in Comparative Example 2-1

[0083] Same as Example 1, except that in step S1, the compound yeast extract is replaced with a regular yeast extract.

[0084] Comparative Example 2-2

[0085] Same as Example 1, except that in step S1, the compound yeast extract is replaced with MSG.

[0086] Comparative Examples 2-3

[0087] Same as Example 1, except that in step S1, the compound yeast extract is replaced with pure water.

[0088] Effect detection

[0089] 1) Sensory evaluation method, see the evaluation method in Example 1.

[0090] 2) Determination of free amino acid (FAA) content, see the methods described above.

[0091] The results are shown in Table 4.

[0092] Table 4. Experimental results of yeast extract

[0093]

[0094] The results showed that the high nucleotide yeast extract had the effect of enhancing flavor and masking sourness in the system. When the compound yeast extract was used, its sensory intensity of sourness was reduced by about 38% compared with that of ordinary yeast extract.

[0095] Color difference test

[0096] Equal weights of the products from Example 1, Comparative Examples 1-1, 1-3, and 2-3 were placed in petri dishes and left at room temperature for 30 days. Afterward, the samples were placed in transparent petri dishes, and colorimetric characterization was performed using a colorimeter (CR-400). Three color parameters were recorded: luminance (L×), red-green hue (a×), and yellow-blue hue (b×), with b representing the more golden color. The carotenoid content before and after placement was detected using HPLC (Agilent). The formula for calculation was: Retention rate (%) = (Content after placement / Initial content) × 100%. The results are shown in Table 5.

[0097] Table 5 Color difference test results

[0098]

[0099] Therefore, it can be seen that the initial b× setting of Example 1 is the highest, indicating that the product fermented by adding yeast extract formed a more stable color development system with the highest yellowness retention rate. In contrast, the yellowness retention rates of Comparative Examples 1-1, 1-3, and 2-3 decreased, indicating that the lack of synergistic color protection from microbial fermentation and yeast extract led to increased lipid oxidation, which in turn accelerated the destruction of carotenoids. This invention demonstrates the outstanding technical effect of improving color stability.

[0100] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A compound seasoning with a low-acidity salted egg yolk flavor, characterized in that, By weight, it includes the following components: 30-40 parts salted egg yolk powder, 15-20 parts whey protein powder, 5-10 parts compound yeast extract, 0.05-0.3 parts microbial starter, and 1-5 parts flavor stabilizer.

2. The low-acidity salted egg yolk flavored compound seasoning according to claim 1, characterized in that, The compound yeast extract is a high nucleotide yeast extract, wherein the content of 5'-inosodium 5'-nucleotide disodium I+G is ≥10%, and the content of free amino acids is ≥35%.

3. The low-acidity salted egg yolk flavored compound seasoning according to claim 2, characterized in that, The preparation method of the seasoning includes the following steps: S1. Mix salted egg yolk powder with deionized water at a mass ratio of 1:4-1:6, then add whey protein powder and compound yeast extract, and adjust the initial pH to 6.5-7.0; stir at 500-800 rpm for 30 minutes to obtain the fermentation substrate; S2. Inoculate the fermentation medium with microbial starter and ferment at a constant temperature of 30-35℃ for 12-20 hours to obtain the fermentation product; S3. Add flavor protease to the fermentation product and hydrolyze it at 50-55℃ for 2-4 hours to obtain the hydrolysate. S4. Heat the enzymatic hydrolysis product to 90-105℃ for 10-15 minutes to obtain the enzyme-inactivated and flavor-enhancing product. S5. The enzyme-inactivating and flavor-enhancing products are concentrated and spray-dried to obtain a powdered compound seasoning.

4. The low-acidity salted egg yolk flavored compound seasoning according to claim 3, characterized in that, The microbial fermentation agent is Staphylococcus xylose and Lactobacillus plantarum in a mass ratio of (3-5):(1-2).

5. A low-acid salted egg yolk flavored compound seasoning according to claim 3, characterized in that, In the microbial fermentation agent, the inoculum amount of Staphylococcus xylose is 1.0×10⁶-1.0×10⁷ cfu / g, and the inoculum amount of Lactobacillus plantarum is 1.0×10⁶-1.0×10⁷ cfu / g.

6. The low-acidity salted egg yolk flavored compound seasoning according to claim 3, characterized in that, In step S1, the pH is adjusted by acetic acid or citric acid.

7. The application of a low-acid salted egg yolk flavored compound seasoning according to any one of claims 1-6 in the food industry, characterized in that, The applications include use in baking fillings and ready-to-eat sauce products.

8. A baked product, characterized in that, The compound seasoning with a low-acidity salted egg yolk flavor, as described in any one of claims 1-6.

9. The baked product according to claim 8, characterized in that, The seasoning also includes beta-carotene, gardenia yellow, and microcrystalline cellulose.

10. A method for producing a baked product, characterized in that, The method includes the preparation method described in claim 3.

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