Probiotic salad dressing with intestinal regulation function and preparation method thereof

Abstract

The invention discloses probiotic salad dressing with an intestinal regulation function and a preparation method of the probiotic salad dressing, and belongs to the technical field of food processing. The salad dressing comprises the following components in parts by weight: 40-60 parts of a grease base material, 5-15 parts of an acidulant, 3-10 parts of probiotic microcapsules, 3-10 parts of seasonings and 10-30 parts of water. The preparation method adopts a core sterile post-addition process, namely, firstly, the salad dressing base is subjected to high-temperature instantaneous sterilization and cooling, and then the probiotics and the sterile base are mixed and filled in a sterile environment. Through combination of a microcapsule embedding technology and a sterile post-addition technology, the problem that probiotics are prone to inactivation in the salad dressing acid environment, the production process and the storage period is effectively solved, it is ensured that the product keeps a high viable count in the whole shelf life, the product can tolerate the human digestive tract environment, and the exact intestinal tract regulation function is achieved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a salad dressing with intestinal health regulating function and its preparation method, particularly a salad dressing with added probiotic ingredients to promote intestinal flora balance. Background Technology

[0002] Salad dressing, a common condiment, is widely used in vegetable salads, fruit salads, sandwiches, and other foods to enhance flavor and texture. Currently, mainstream salad dressing products on the market, especially emulsified salad dressings (such as mayonnaise and Thousand Island dressing), typically have formulas primarily composed of large amounts of edible oils, sugar, salt, and egg products. To achieve a stable emulsified state, extend shelf life, and pursue the ultimate flavor, manufacturers often need to add various food additives, including synthetic emulsifiers (such as monoglycerides and sucrose fatty acid esters), thickeners (such as xanthan gum and sodium carboxymethyl cellulose), and preservatives (such as potassium sorbate).

[0003] This traditional formula and production process has led to several significant drawbacks: First, an unbalanced nutritional structure. The products are generally high in calories, fat, sugar, and sodium. Long-term excessive intake is associated with health risks such as obesity and cardiovascular disease, deterring many health-conscious consumers. Second, a lack of functionality. Traditional salad dressings are considered "empty calories," providing almost no beneficial nutrients such as dietary fiber, and have no function in regulating bodily functions. Third, they contradict healthy eating trends. Modern consumers increasingly seek foods with "clean labels," low nutritional burden, and positive health benefits, which traditional salad dressings, containing numerous additives and low nutritional value, can no longer meet. On the other hand, with the development of life science research, the importance of gut health has become a consensus. As the cornerstone of overall health, supplementing with probiotics through daily diet has become a widely accepted health management method. Introducing probiotics into salad dressing products theoretically provides consumers with a convenient way to ingest probiotics, possessing significant market value and health significance. However, successfully applying live probiotics to salad dressing products and ensuring their ultimate efficacy presents serious technical challenges. First, salad dressings are typically acidic, and their high-oil, high-salt base is not conducive to the long-term survival of most probiotics. Second, to achieve a commercially viable shelf life, salad dressing production often involves heat treatment to kill unwanted bacteria, which directly leads to the death of a large number of heat-sensitive probiotics. Even if the probiotics survive in the early stages of production, factors such as oxygen penetration, water activity, and temperature fluctuations during product storage, transportation, and sales will continuously reduce the number of live bacteria, resulting in a product with a live bacteria count far below the effective dose by the time it reaches the consumer.

[0004] Therefore, there is an urgent need in this field for an innovative product formula and production process that can comprehensively protect the activity of probiotics. This process can overcome the high-calorie and low-nutrient deficiencies of traditional salad dressings, and at the same time, through the scientific compounding of prebiotics, endow the product with a clear intestinal regulatory function without sacrificing taste and stability, so as to meet the market's urgent demand for healthy, delicious and functional condiments. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a prebiotic salad dressing with intestinal regulation function and its preparation method. This salad dressing, by adding stable prebiotic components, imparts the function of promoting intestinal health without altering the traditional flavor and texture of salad dressing. Furthermore, the product exhibits good stability, a long shelf life, and a simple preparation process.

[0006] To achieve the above objectives, the present invention first provides a probiotic salad dressing with intestinal regulation function, made from the following ingredients in parts by weight: Oil base: 40-60 parts; Acidulant: 5-15 parts; Probiotic microcapsules: 2-8 servings; Seasonings: 3-10 servings; Water: 10-30 parts.

[0007] In one embodiment of the present invention, the oil base is selected from one or more of soybean oil, olive oil, sunflower seed oil, and corn oil.

[0008] In one embodiment of the present invention, the acidulant is selected from one or more of vinegar, lemon juice, and apple cider vinegar. The emulsifier is acetylated distarch adipate.

[0009] In one embodiment of the present invention, the seasoning includes one or more of salt, white sugar, honey, minced garlic, onion powder, and herbs.

[0010] In one embodiment of the present invention, the salad dressing may further contain an emulsifier, wherein the emulsifier is lecithin or acetylated distarch adipate, and the emulsifier is present in parts by weight of 2 to 8 parts.

[0011] In one embodiment of the present invention, the probiotic microcapsules are probiotic powder encapsulated in microcapsules, and the amount added is such that the number of live bacteria in the finished salad dressing is not less than 1×10⁻⁶. 8 CFU / g.

[0012] In one embodiment of the present invention, the probiotic is at least one of Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, and Lactobacillus acidophilus.

[0013] In one embodiment of the present invention, the wall material of the probiotic microcapsules is a composite wall material composed of sodium alginate and high-ester pectin. In this composite wall material, the degree of esterification of the high-ester pectin is greater than 50%, preferably 55%-75%. The mass ratio of sodium alginate to high-ester pectin is 1-2.5:1. Experiments have shown that using high-ester pectin allows its gel properties to match the inherent acidic, high-solids environment of salad dressing, thereby forming a stable and dense protective network both inside the microcapsules and after being added to the final product. Low-ester pectin (degree of esterification less than 50%), due to its calcium-ion-dependent gelation mechanism, is incompatible with this system and cannot provide predictable and durable protective effects. The aforementioned specific ratio range ensures optimal synergy between the two hydrocolloids, endowing the microcapsules with excellent processing adaptability, mechanical strength, and tolerance to acidic environments.

[0014] In one embodiment of the present invention, the method for preparing the probiotic microcapsules is as follows: S1. Pretreatment and primary encapsulation: The probiotic powder is mixed with a protective agent solution containing whey protein isolate, trehalose and ascorbic acid, and stirred at low speed at 25°C to obtain the primary protective slurry of probiotics. S2. Preparation of composite wall material solution: Sodium alginate and high ester pectin are dissolved in water, heated and stirred continuously at 75°C for 1 hour, and then cooled to obtain composite wall material solution; S3. Emulsification: The probiotic primary protective slurry from step S1 is mixed with the composite wall material solution from step S2 to obtain an aqueous mixture. The aqueous mixture is then mixed with vegetable oil and pumped into a high-shear emulsifier, where it is sheared at high speed to form a coarse emulsion. The coarse emulsion is homogenized under high pressure to obtain a fine oil-in-water (O / W) emulsion with uniform and stable oil droplet size distribution. S4. Spray drying and electrostatic layer-by-layer encapsulation: The emulsion obtained in step S4 is spray dried to obtain probiotic microcapsules.

[0015] In one embodiment of the present invention, in step S1, the concentration of whey protein isolate in the protective agent solution is 1.0~5.0% (w / v), the concentration of trehalose is 5.0~15.0% (w / v), the concentration of ascorbic acid is 0.05~0.5% (w / v), and the mass-to-volume ratio of the probiotic powder to the protective agent solution is 1g:(15~25)mL, preferably 1:18~22.

[0016] In one embodiment of the present invention, in step S1, the low-speed stirring refers to stirring at a speed of 200-300 rpm for 1 hour.

[0017] In one embodiment of the present invention, in step S2, after dissolving in water, the mass fraction of sodium alginate is 1~2.5% and the mass fraction of high ester pectin is 1~2.5%.

[0018] In one embodiment of the present invention, in step S3, the volume ratio of the probiotic primary protective slurry to the composite wall material solution is 1:3~5.

[0019] In one embodiment of the present invention, in step S3, the vegetable oil is selected from one or more of soybean oil, olive oil, sunflower seed oil, and corn oil, preferably the same as the oil base in salad dressing, and the amount of vegetable oil added is 15 to 25% of the mass of the aqueous mixture.

[0020] In one embodiment of the present invention, in step S3, the rotation speed during high-speed shearing is 3000~5000 rpm, the shearing time is 5-15 min, and the high-pressure homogenization is performed 1-3 times under a pressure of 15~35 MPa. The material temperature should be controlled to not exceed 35°C throughout the entire emulsification and homogenization process, and the emulsion should be rapidly cooled to below 30°C after homogenization.

[0021] In one embodiment of the present invention, in step S4, the inlet air temperature during spray drying is 150~170°C and the outlet air temperature is 60~70°C.

[0022] The present invention also provides a probiotic microcapsule prepared by the above preparation method.

[0023] This invention also provides a method for preparing probiotic salad dressing, comprising the following steps: (1) Base preparation and sterilization: The oil base, acidulant, emulsifier, seasoning and water are mixed and first pre-emulsified at a high shear speed of 3000-5000 rpm for 5-10 minutes, followed by homogenization. High-pressure homogenization is performed 1-3 times at a pressure of 15-35 MPa to obtain a stable emulsion with an oil droplet size of 1-5 μm. The homogenized emulsion is then sterilized at high temperature for 15-30 seconds at 85-95°C, and then cooled to below 25°C to obtain a sterile salad dressing base.

[0024] (2) Probiotic pretreatment: Under aseptic conditions, the probiotic microcapsules are premixed with one-third of the cooled aseptic salad dressing base and stirred at a low speed of ≤ 50 rpm for 5 to 15 minutes until a uniform bacterial sauce mixture without visible lumps is formed.

[0025] (3) Aseptic mixing: In an aseptic environment, the mushroom sauce mixture obtained in step (2) and the remaining aseptic salad dressing base are continuously stirred at a speed of 30-70 rpm for 20-30 minutes until the mixture has a uniform color and texture and no visible particles. The temperature of the materials should be controlled not to exceed 25°C throughout the mixing process.

[0026] (4) Aseptic filling: The uniformly mixed final product is filled and sealed in an aseptic environment to obtain the probiotic salad dressing.

[0027] Beneficial effects: 1. This invention uses sodium alginate and high-ester pectin as composite wall materials. Probiotic powder is pretreated in a whey protein-containing protective agent solution, and then encapsulated using the composite wall material. The encapsulated probiotics not only maintain excellent stability in the acidic, high-oil system of salad dressings, but the microcapsules also help prevent unpleasant flavors from developing in acidic sauces. Furthermore, the specific ratio of sodium alginate and high-ester pectin as wall materials contributes to the formation of a dense and elastic network structure with excellent chemical stability, thus providing comprehensive and long-lasting protection. This effectively overcomes the inhibitory effect of acidic sauce environments on probiotic activity, achieving unexpected long-term stability.

[0028] 2. In this invention, a protective agent solution containing whey protein is used to prehydrate probiotics. The hydrated probiotics are then mixed with a composite wall material solution to encapsulate the probiotics. This step not only significantly improves the heat tolerance and survival rate of the probiotics during the subsequent spray drying process, but more importantly, the protein layer acts as a functional interface, promoting a tight bond with the sodium alginate-pectin composite wall material.

[0029] 3. This invention utilizes a "sterile post-addition" process, completely bypassing the heat sterilization step for probiotics and ensuring their survival rate from the source. Microencapsulation technology provides dual protection for the probiotics, enabling them to withstand the acidic environment of salad dressings and the erosion from oxygen and moisture during storage, significantly extending the shelf life of the live bacteria.

[0030] 4. The selected strains themselves have good acid and bile salt resistance. Combined with the targeted enteric release effect of microcapsules, it can ensure that a large number of live bacteria can pass through the digestive tract smoothly and colonize the intestines, thus exerting a real probiotic function.

[0031] 5. The prebiotics added to the formula not only improve the taste, but also serve as "food" for probiotics, promoting their proliferation in the intestines and achieving a synergistic effect. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process for preparing probiotic salad dressing according to the present invention. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0034] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention are commercially available. The *Lactobacillus plantarum* powder was purchased from Qijun Biotechnology Co., Ltd., and its activity was 1.0 × 10⁻⁶. 10 The CFU / g Lactobacillus rhamnosus powder was purchased from Qijun Biotechnology Co., Ltd., and its activity was 1.0 × 10⁻⁶. 10 The CFU / g Lactobacillus paracasei powder was purchased from Guangzhou Haoxiang Chemical Co., Ltd., and its activity was 1.0 × 10⁻⁶. 10 CFU / g.

[0035] The testing method involved in this invention: Emulsification stability test: The salad dressing was stored at 4°C for 30 days. The appearance, texture, and presence of layering or separation were checked and recorded. If the salad dressing maintained a uniform texture and appearance at both refrigeration and room temperature, without significant layering or separation, it exhibited good temperature stability. After centrifugation, if the salad dressing showed minimal layering or quickly returned to a uniform state after layering, its emulsification stability was strong.

[0036] Shelf life stability test: The stability of the probiotics in the example and comparative examples was tested by storing the salad dressing at 4°C for 7, 14, and 28 days.

[0037] Taste test: Ten trained professionals were invited to conduct sensory evaluation of the product. Before scoring, the evaluators rinsed their mouths with warm water, and then scored each indicator of the product according to the scoring method and scoring standard. After scoring once, they rinsed their mouths with warm water again and conducted the next scoring. After the evaluation, they wrote down their overall opinions in the remarks, including those listed and those not listed in the product sensory evaluation standard.

[0038] Evaluation criteria: Texture: 1-5 points. 1-2 points means very refreshing but too thin and thin in taste; 3-4 points means refreshing and moderate in texture; 5 points means thick but not too sticky and has a rich texture. Flavor richness: 1-5 points. 1-2 points indicates a simple and bland flavor, making it difficult to distinguish the flavor of the ingredients; 3-4 points indicates a distinct spice flavor, but with average layering; 5 points indicates a rich and harmonious flavor, where the flavors of various ingredients can be clearly perceived and layered.

[0039] Taste persistence: 1-5 points. 1-2 points means the taste disappears quickly without any aftertaste; 3-4 points means the taste can remain for a certain period of time after swallowing, but it is not persistent enough; 5 points means the taste has a long aftertaste in the mouth, which is persistent and pleasant.

[0040] Example 1 A probiotic salad dressing, by weight, the dressing base is made from the following ingredients: 40 parts olive oil, 10 parts apple cider vinegar, 5 parts fructooligosaccharides, 3 parts egg yolks, 2 parts minced garlic, 1 part salt, 0.5 parts black pepper, and 25 parts water.

[0041] The added probiotic microcapsules were Lactobacillus plantarum powder encapsulated in sodium alginate-pectin microcapsules, and the amount added was 4 parts (based on the total weight of the base). In this embodiment, the salad dressing base, or simply the base, specifically refers to the dressing made from olive oil, apple cider vinegar, fructooligosaccharides, egg yolks, minced garlic, salt, black pepper, and water, after mixing, homogenizing, sterilizing, and cooling, before the addition of probiotic microcapsules. The probiotic microcapsules were added as an independent component under aseptic conditions after the base preparation was completed.

[0042] The preparation method of probiotic salad dressing is as follows: (1) All base ingredients except probiotic microcapsules were mixed and pre-emulsified at 4000 rpm under high shear for 7 minutes, followed by homogenization at 20 MPa. The homogenized emulsion was then subjected to high-temperature instantaneous sterilization at 85°C for 20 seconds, followed by cooling to below 25°C and transferring to an aseptic mixing tank to obtain aseptic base sauce.

[0043] (2) In a sterile operating room, 4 parts of probiotic microcapsules and 6 parts of cooled sterile base sauce were premixed in a sterile pot to form a uniform paste.

[0044] (3) Put the mushroom paste obtained in step (3) into a sterile mixing tank and mix it with the remaining base sauce at a low speed of ≤ 50 rpm for 15 minutes to ensure uniformity.

[0045] (4) The final product is filled and capped on an aseptic filling line to obtain the finished product.

[0046] The preparation method of probiotic microcapsules is as follows: S1. Pretreatment: *Lactobacillus plantarum* powder was dispersed at a mass-to-volume ratio of 1 g:20 mL in a protective agent solution containing whey protein isolate. The protective agent solution contained whey protein isolate at a mass concentration of 3.0% (w / v), trehalose at a mass concentration of 10.0% (w / v), and ascorbic acid at a mass concentration of 0.2% (w / v). Mild hydration was performed at 25°C and stirred at 250 rpm for 1 hour to obtain the primary protective slurry of probiotics.

[0047] S2. Preparation of composite wall material: Sodium alginate and high-ester pectin are dissolved in water, so that the mass fraction of sodium alginate is 2.5% and the mass fraction of high-ester pectin is 1.0%. The solution is stirred and dissolved at 75°C for 1 hour, and then cooled to 30°C to obtain the composite wall material liquid. The degree of esterification of the high-ester pectin is 65%.

[0048] S3. Emulsification and homogenization: The probiotic primary protective slurry obtained in step S1 and the composite wall material adhesive obtained in step S2 are mixed at a volume ratio of 1:4; 20% of the mixed slurry is added with extra virgin olive oil, and the mixture is first sheared for 10 minutes using a high-shear disperser (4000 rpm). Then, the crude emulsion is subjected to high-pressure homogenization three times under a pressure of 50 MPa to form a stable oil-in-water (O / W) type fine emulsion.

[0049] S4. Spray drying: Pump the emulsion obtained in step S4 into a centrifugal spray drying tower, control the inlet air temperature to 170°C and the outlet air temperature to 70°C, and collect the dried powder.

[0050] Example 2 A probiotic salad dressing whose base is made from the following ingredients: 40 parts sunflower seed oil, 12 parts fermented lemon juice, 4 parts inulin, 4 parts yellow mustard, 3 parts honey, 1 part chopped parsley, and 30 parts water. The added probiotic microcapsules are a mixture of Lactobacillus rhamnosus powder and Lactobacillus paracasei powder encapsulated in pectin microcapsules (mass ratio 1:1), added at a rate of 5 parts.

[0051] Example 3 The difference between Example 3 and Example 1 is that lecithin was added to the salad dressing as an emulsifier, at a rate of 0.5% of the total weight of the base. The preparation method is the same as that of Example 1.

[0052] Comparative Example 1 Traditional salad dressing consists of: 60 parts soybean oil, 8 parts egg yolks, 10 parts vinegar, 6 parts sugar, 2 parts salt, and 14 parts water.

[0053] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in step (1), the probiotic microcapsules and salad dressing base are mixed together.

[0054] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that Lactobacillus plantarum powder was used instead of probiotic microcapsules.

[0055] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the wall material of the probiotic microcapsules is changed. In step S2, a sodium alginate solution with a mass fraction of 3.5% is used as the wall material solution.

[0056] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the wall material of the probiotic microcapsules is changed. In step S2, the mass ratio of sodium alginate to pectin is changed to 1:4, and the total mass fraction of sodium alginate and pectin in the composite wall material solution is still 3.5%.

[0057] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the wall material of the probiotic microcapsules is changed, and in step S2, gelatin is used to replace pectin.

[0058] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the preparation method of the probiotic microcapsules is different. In steps S1 to S3, Lactobacillus plantarum powder is mixed with a protective agent solution containing whey protein isolate and composite wall material at 25°C.

[0059] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that high-ester pectin was replaced with low-ester pectin, which had a degree of esterification of 35%.

[0060] Table 1. Stability of salad dressings during storage in Examples 1-4 and Comparative Examples 1-8

[0061] Table 2. Texture characteristics of salad dressings from Examples 1-4 and Comparative Examples 1-8

[0062] Table 3. Changes in viable bacterial counts during storage of salad dressings in Examples 1-4 and Comparative Examples 1-8 (unit: CFU / g)

[0063] As shown in Tables 1 and 2, the probiotic-containing salad dressing prepared in the embodiments of the present invention exhibits excellent storage stability. Long-term static stability experiments show that after being stored at 25°C for one month, all embodiments of the present invention maintained a uniform texture, with no oil-water separation or sedimentation, demonstrating excellent physical stability. In contrast, Comparative Example 3 (with unencapsulated bacterial powder) showed significant sedimentation, while Comparative Example 6 (using other composite wall materials) showed a thinning or uneven distribution of the system. This proves that the specific composite microcapsule technology used in the present invention is key to ensuring that the probiotic salad dressing maintains its long-term shelf-stable appearance and texture while achieving functionality. Furthermore, the core solution of the present invention (Example 1) received the highest evaluation in terms of texture, flavor richness, and taste persistence. Its smooth and full-bodied taste, harmonious flavor layers, and long-lasting and pleasant aftertaste demonstrate that the composite microcapsule wall material combined with aseptic post-addition process is an effective path to achieve both functional and sensory excellence. First, compared with Comparative Example 1 (traditional formula, total score 8.0), the present invention achieves significant improvements in flavor richness and persistence through formula optimization (such as the use of olive oil and fructooligosaccharides) and system stabilization. Second, Comparative Example 2, due to the addition of probiotics before sterilization, resulted in the inactivation of residual bacteria, leading to the lowest scores in texture and persistence. This proves that post-addition is an absolutely necessary process to avoid heat processing contamination and ensure a pure taste. Comparative Example 3, by directly adding unencapsulated bacterial powder, suffered from a persistent bitter aftertaste, resulting in a significant reduction in flavor persistence. This indicates that microencapsulation is a key technical barrier to prevent live bacteria from producing undesirable flavors in acidic sauces. Although Comparative Examples 4 to 6 are similar to the present invention in texture and basic flavor, their flavor persistence is systematically lower than that of Example 1. This consistent difference is not accidental; it indicates that suboptimal wall materials (single type, poor ratio, different system) do not adequately protect the probiotics, causing the bacteria to prematurely inactivate and release their contents during storage or in the oral environment, thus introducing undesirable factors affecting the purity of the aftertaste. Comparative Example 7, which directly mixed the protective agent and wall material with the probiotics, showed comprehensive and significant deterioration in both physical stability (stratification, precipitation) and sensory quality (flavor, texture). This is related to the fundamental failure of the microcapsule structure and the direct exposure of the probiotics and excipients to disrupt the system. While Comparative Example 8 initially had a flavor close to that of this invention, due to the long-term instability of the low-ester pectin wall material in an acidic environment, its product became thinner, showed slight stratification, and experienced a decrease in texture score after storage. This is consistent with the mechanism by which the protective function of the microcapsules decays over time and cannot maintain the long-term activity of the probiotics. This also demonstrates that the specific composite system and ratio of sodium alginate and pectin used in this invention provides optimal protection while offering an irreplaceable advantage in maintaining the superior sensory quality of the final product.

[0064] As can be seen from the data in Table 3, after refrigeration at 4°C for 28 days, the viable bacterial count in each embodiment of the present invention remained at 3.9 × 10⁻⁶. 8The attenuation rate was significantly lower than that of products without encapsulation (Comparative Example 3), with single wall material encapsulation (Comparative Example 4), and with other composite wall material encapsulation (Comparative Example 6). Specifically, in Example 1, the attenuation rate was 5.2 × 10⁻⁶ CFU / g from day 0. 8 CFU / g reached 4.0 × 10⁻⁶ on day 28. 8 The absolute value of CFU / g decreased gradually, remaining consistently at 10. 8 The CFU / g level was high; while the viable counts of comparative examples 3, 4, and 6 on day 28 were only 1.0 × 10⁻⁶. 7 CFU / g, 1.2×10 8 CFU / g and 1.0×10 8 CFU / g. This significant difference reveals the inherent mechanistic defects of different protective systems: unencapsulated probiotics are rapidly inactivated when directly exposed to a high-acid, high-oil environment; and sodium alginate wall materials, due to their loose network and poor long-term stability in acidic environments, cannot effectively block H+. + The slow penetration and self-swelling of the protective agent are detrimental. Inferior wall materials, due to component imbalance, result in a brittle gel structure that is prone to cracking under micro-stress, becoming a shortcut for penetration. Other composite wall materials, such as gelatin, are fundamentally chemically incompatible with acidic environments, leading to irreversible hydrolytic degradation and accelerated loss of protective function. Furthermore, Comparative Example 7 directly combined the protective agent with the wall material and probiotic powder, causing the complete collapse of the "gradient protection" structure. The probiotics suffered severe damage in the early stages of processing and received no subsequent protection, resulting in a precipitous drop in viable bacteria count within 28 days. Comparative Example 8 incorrectly replaced high-ester pectin with low-ester pectin. While initial encapsulation was acceptable, the gel mechanism was fundamentally incompatible with the product's acidic environment, causing the resulting microcapsule walls to continuously deteriorate during storage, failing to provide a long-term barrier and leading to an accelerated decline in viable bacteria count. Therefore, the specific sodium alginate-pectin composite system used in this invention, through a precisely proportioned, dense and elastic network structure, possesses excellent chemical stability, thus providing comprehensive and long-lasting protection. This effectively overcomes the inhibition of probiotic activity by the acidic sauce environment, achieving unexpected long-term stability. Based on the above experimental results, this invention successfully endows salad dressings with intestinal health-promoting functional properties by adding probiotics encapsulated in sodium alginate-pectin composite microcapsules. Research data confirms that these probiotic microcapsules exhibit excellent stability in acidic sauce systems, providing consumers with truly effective probiotic functions. Simultaneously, this technical solution does not affect the product's basic quality: the salad dressing exhibits excellent physical stability, with no oil separation or layering, a smooth and full-bodied taste, harmonious flavor layers, and a long, pleasant aftertaste, achieving a perfect balance between functionality and sensory experience. This provides an innovative and feasible technical path to solve the industry challenge of maintaining and delivering probiotic activity in high-acid, high-oil systems.

[0065] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A probiotic salad dressing with intestinal regulating function, characterized in that, Made from the following parts by weight of raw materials: Oil base: 40-60 parts; Acidulant: 5-15 parts; Probiotic microcapsules: 2-8 servings; Seasonings: 3-10 servings; Water: 10-30 parts; The preparation method of probiotic microcapsules includes the following steps: S1. Pretreatment and primary encapsulation: The probiotic powder is mixed with a protective agent solution containing whey protein isolate, trehalose and ascorbic acid, and stirred at 200-300 rpm for 1 hour at 25°C to obtain the probiotic primary protective slurry. S2. Preparation of composite wall material solution: Sodium alginate and high-ester pectin are dissolved in water at a mass ratio of 1~2.5:1, and heated and stirred continuously at 75°C for 1 hour. After cooling, the composite wall material solution is obtained. The degree of esterification of the high-ester pectin is greater than 50%. S3. Emulsification: The probiotic primary protective slurry from step S1 is mixed with the composite wall material solution from step S2 to obtain an aqueous mixture. The aqueous mixture is then mixed with vegetable oil and pumped into a high-shear emulsifier, where it is sheared at high speed to form a coarse emulsion. The coarse emulsion is homogenized under high pressure to obtain a fine oil-in-water (O / W) emulsion with uniform and stable oil droplet size distribution. S4. Spray drying and electrostatic layer-by-layer encapsulation: The emulsion obtained in step S4 is spray dried to obtain probiotic microcapsules. The inlet air temperature during spray drying is 150~170℃ and the outlet air temperature is 60~70℃.

2. The method for preparing salad dressing according to claim 1, characterized in that, The oil base is selected from one or more of soybean oil, olive oil, sunflower oil, and corn oil; the acidulant is selected from one or more of vinegar, lemon juice, and apple cider vinegar; the emulsifier is acetylated distarch adipate; and the seasonings include one or more of salt, white sugar, honey, minced garlic, onion powder, and herbs.

3. The method for preparing salad dressing according to claim 1, characterized in that, The salad dressing may also contain an emulsifier, which is lecithin or acetylated distarch adipate, and the emulsifier is present in parts by weight of 2 to 8 parts.

4. The method for preparing salad dressing according to claim 1, characterized in that, The amount of probiotic microcapsules added ensures that the number of live bacteria in the finished salad dressing is not less than 1×10⁻⁶. 8 CFU / g, wherein the probiotic is at least one of Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei, and Lactobacillus acidophilus.

5. The method for preparing salad dressing according to claim 1, characterized in that, In step S1, the whey protein isolate in the protective agent solution has a mass concentration of 1.0-5.0%, a trehalose mass concentration of 5.0-15.0%, an ascorbic acid mass concentration of 0.05-0.5%, and the mass-volume ratio of the probiotic powder to the protective agent solution is 1g:(15-25)mL.

6. The method for preparing salad dressing according to claim 1, characterized in that, In step S2, after dissolving in water, the mass fraction of sodium alginate is 1~2.5%, and the mass fraction of high ester pectin is 1~2.5%.

7. The method for preparing salad dressing according to claim 1, characterized in that, In step S3, the volume ratio of the probiotic primary protective slurry to the composite wall material solution is 1:3~5, the vegetable oil is selected from one or more of soybean oil, olive oil, sunflower seed oil, and corn oil, and the amount of vegetable oil added accounts for 15~25% of the mass of the aqueous mixture.

8. The preparation of salad dressing according to claim 1, characterized in that, In step S3, the rotation speed during high-speed shearing is 3000~5000 rpm, the shearing time is 5-15 min, and the high-pressure homogenization is carried out 1~3 times under a pressure of 15~35 MPa.

9. The probiotic microcapsules prepared by the preparation method according to claim 1.

10. A method for preparing a probiotic salad dressing, characterized in that, Includes the following steps: (1) Base preparation and sterilization: The oil base, acidulant, emulsifier, seasoning and water are mixed. First, the mixture is pre-emulsified at a high shear speed of 3000-5000 rpm for 5-10 minutes. Then, it is homogenized and subjected to high pressure homogenization treatment 1-3 times at a pressure of 15-35 MPa to obtain a stable emulsion with an oil droplet size of 1-5 μm. The homogenized emulsion is sterilized at high temperature for 15-30 seconds at 85-95°C. Then it is cooled to below 25°C to obtain a sterile salad dressing base. (2) Probiotic pretreatment: Under aseptic conditions, the probiotic microcapsules are premixed with one-third of the cooled aseptic salad dressing base and stirred at a low speed of ≤ 50 rpm for 5 to 15 minutes until a uniform bacterial sauce mixture without visible lumps is formed. (3) Aseptic mixing: In an aseptic environment, the mushroom sauce mixture obtained in step (2) and the remaining aseptic salad dressing base are continuously stirred at a speed of 30-70 rpm for 20-30 minutes until the mixture has a uniform color and texture and no visible particles; the temperature of the material should be controlled not to exceed 25°C throughout the mixing process. (4) Aseptic filling: The uniformly mixed final product is filled and sealed in an aseptic environment to obtain the probiotic salad dressing.

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