Digestion-promoting salad dressing added with plant dietary fibers and preparation method of digestion-promoting salad dressing

Abstract

The invention discloses a digestion-promoting salad dressing added with plant dietary fibers and a preparation method of the digestion-promoting salad dressing. The salad dressing comprises the following raw materials in percentage by mass: 0.5-3.5% of mint powder, 0.5-3.5% of barley seedling powder, 4-6% of honey, 2-4% of xylitol, 0.3-0.5% of lactic acid bacteria, 0.2-0.4% of tea polyphenol and the balance of high-emulsibility whole egg liquid and corn oil. Wherein the mass ratio of the high-emulsibility whole egg liquid to the corn oil is 1: 4; the high-emulsibility whole egg liquid comprises the following raw materials in percentage by mass: 2%-6% of salt, 0.045%-0.055% of lipase, 0.2% of carboxymethyl cellulose, 0.1% of lactic acid, 0.1% of malic acid and the balance of egg liquid. According to the salad dressing, the stability and the water binding capacity of a dressing body are remarkably improved through a synergistic emulsification technology, the texture and the taste are optimized through dietary fibers and natural components, meanwhile, the natural antibacterial characteristic is achieved, and functional improvement and synergistic improvement of the product texture are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of food engineering, and in particular relates to a digestion-promoting salad dressing added with plant dietary fiber and a preparation method thereof. Background Art

[0002] As the pace of life accelerates, the modern diet structure gradually tends to be high-fat, high-calorie and refined, which leads to increased gastrointestinal burden, and problems such as indigestion and metabolic imbalance are becoming increasingly common. In this context, salad dressing, as a widely used condiment, needs to improve its health attributes and functional adaptability. Traditional salad dressing originated from Minorca Island in the Mediterranean. It is based on vegetable oil, eggs, sugar and salt, and forms an oil-in-water (O / W) emulsion through homogenization and emulsification. Its stability and functionality are highly dependent on the synergistic effect of eggs, emulsifiers and thickeners.

[0003] However, the existing salad dressing formula and process have the following obvious defects: (1) Imbalance of nutritional functions: The traditional formula is based on egg yolk and oil, and the proportion of fat is often more than 50%. The high calorie characteristics can easily aggravate the accumulation of intestinal fat. Its dense oil phase interface will delay the action of digestive enzymes and hinder nutrient absorption. (2) Limitations of the emulsification system: The emulsification ability of traditional whole egg liquid is limited by the physical and chemical properties of the egg itself (the natural conformation of egg protein), and long-term storage is prone to stratification and water precipitation. Although stability can be improved by adding chemical emulsifiers (such as monoglycerides), the introduction of non-natural ingredients will affect the health attributes of the product. (3) Single function: Commercially available salad dressings mostly focus on seasoning functions, and lack innovation for digestive health. Even improved products that add a small amount of dietary fiber or prebiotics often suffer from texture degradation (such as high viscosity or obvious graininess) due to poor compatibility between additives and the emulsification system. (4) Prominent technical contradictions: When functional ingredients (such as plant extracts) are introduced, their polyphenols, polysaccharides and other active substances are prone to destroy the stability of the emulsion interface film, making it difficult to balance the digestion-promoting function and emulsification performance. (5) Significant quality degradation: Salad dressings prepared by conventional processes are prone to lipid oxidation, increased acid value and color deterioration during storage, and rely on preservatives to maintain their shelf life, further weakening their health attributes. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a digestion-promoting salad dressing with added plant dietary fiber and a preparation method thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] A digestion-promoting salad dressing with added plant dietary fiber, comprising the following raw materials in proportion by mass:

[0007] 0.5% to 3.5% peppermint powder, 0.5% to 3.5% barley grass powder, 4% to 6% honey, 2% to 4% xylitol, 0.3% to 0.5% lactic acid bacteria, 0.2% to 0.4% tea polyphenols, and the rest is highly emulsifying whole egg liquid and corn oil; among them, the mass ratio of the highly emulsifying whole egg liquid to the corn oil is 1:4;

[0008] The highly emulsifying whole egg liquid includes the following raw materials by mass ratio: 2% to 6% salt, 0.045% to 0.055% lipase, 0.2% carboxymethyl cellulose, 0.1% lactic acid, 0.1% malic acid, and the rest is egg liquid.

[0009] Preferably, the salt is one or more of sodium tripolyphosphate, magnesium chloride, and disodium hydrogen phosphate.

[0010] Preferably, it also includes 0.1% to 0.3% konjac gum.

[0011] The preparation method of the digestion-promoting salad dressing with added plant dietary fiber includes the following steps:

[0012] Step 1) Break fresh eggs to obtain whole egg liquid, put the whole egg liquid into a stirring container, and stir evenly with a low-speed stirrer; then slowly add lipase, salt, carboxymethyl cellulose, lactic acid, and malic acid in sequence. After adding each raw material, appropriately increase the stirring speed, gradually transition from 300 rpm to 600 rpm, and continue stirring to ensure that each raw material can be fully mixed evenly to form a uniform egg liquid without obvious particles, and obtain highly emulsifying whole egg liquid;

[0013] Step 2) First, put the highly emulsifying whole egg liquid into a stirring container and stir evenly with a low-speed stirrer; then slowly add peppermint powder, barley grass powder, konjac gum, lactic acid bacteria, honey, xylitol, tea polyphenols, and corn oil in sequence. After adding each raw material, appropriately increase the stirring speed, gradually transition from 300 rpm to 600 rpm,

[0014] Continue stirring to ensure that each raw material can be fully mixed evenly to form a uniform sauce body without obvious particles, and that's it.

[0015] Preferably, the acceleration rate of increasing the stirring speed is 40 rpm / s.

[0016] Preferably, the stirring time is 3 min.

[0017] Preferably, the stirring temperature is 20°C.

[0018] For the digestion-promoting salad dressing prepared by the above preparation method, the storage condition of the salad dressing is 0 to 20°C.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) By introducing the synergistic regulation technology of magnesium chloride - lipase, the emulsifying ability of whole egg liquid is significantly enhanced in the present invention. The fluctuation range of absorbance data is controlled within ±2%, and emulsifying microparticles with uniform particle size (2 - 5 μm) and stable dispersion are formed. Combining with the pH - responsive network of carboxymethyl cellulose (CMC) and lactic acid, the water - holding rate is increased by 10.45%, there is no oil - phase separation phenomenon during the shelf life, and the chromaticity stability (ΔE < 3.700) is increased by 1.145 times compared with the blank group, effectively resisting the color deterioration caused by light and oxidation.

[0021] (2) The present invention adopts the composite formula of konjac gum - mint - barley seedlings in synergy with xylitol and lactic acid bacteria to construct a triple digestion - promoting mechanism of "dietary fiber solubilization - interfacial activation - flora regulation". In vitro digestion experiments show that the release amount of free fatty acids is greater than 40 g / 100 g. At the same time, through pH self - regulation, lipase is in an appropriate pH, optimizing the lipase activity and significantly improving the oil hydrolysis efficiency compared with traditional products.

[0022] (3) Through the synergistic effect of the dietary fiber network and emulsifying microparticles, the present invention endows the product with a delicate and smooth texture. The chewing force reaches 8 N ( + 20.2% compared with the blank group), the cohesiveness is increased by 53.5%, the delicate feeling is increased by 14.29%, the greasiness is reduced by 60.0%, the taste is significantly improved, and the sensory score (8.3 / 10) is significantly higher than that of commercially available competing products (5.7 / 10).

[0023] (4) In the digestion - promoting salad dressing of the present invention, plant polyphenols (tea polyphenol content > 0.15%) and lactic acid synergistically inhibit the microbial activity, and the colony count within 48 h is < 10 CFU / g. There is no addition of chemical preservatives in the formula, and the shelf life is extended to 90 days (0 - 20 °C), meeting the consumption trend of clean labels.

[0024] (5) The present invention precisely regulates the concentration of magnesium chloride, the addition amount of lipase and the proportion of carboxymethyl cellulose. While maintaining the foaming characteristics (foaming rate 95 ± 3%), it realizes the synergistic effect of high emulsifying property (emulsifying activity index EAI > 30 m 2 / g) and digestion - promoting function, cracking the industry problem of "coarse texture caused by high - fiber addition" in traditional technologies. Description of the Drawings

[0025] Figure 1 Shows the influence of different concentrations of salts on the emulsifying ability of whole egg liquid in Example 1;

[0026] Figure 2 Shows the influence of different contents of brand lipase on the emulsifying ability of whole egg liquid in Example 1;

[0027] Figure 3 Shows the comparison of the emulsifying ability between the whole egg liquid with high emulsifying property and the blank whole egg liquid in Example 1;

[0028] Figure 4 For the comparison of the color stability between the highly emulsifiable whole egg liquid and the blank whole egg liquid in Example 1;

[0029] Figure 5 For the comparison of the gel texture properties between the highly emulsifiable whole egg liquid and the blank whole egg liquid in Example 1;

[0030] Figure 6 For the comparison of the gel water holding capacity between the highly emulsifiable whole egg liquid and the blank whole egg liquid in Example 1;

[0031] Figure 7 For the comparison of the foaming properties between the highly emulsifiable whole egg liquid and the blank whole egg liquid in Example 1;

[0032] Figure 8 For the comparison of the pH change between the highly emulsifiable whole egg liquid and the blank whole egg liquid in Example 1;

[0033] Figure 9 For the comparison of the digestion promotion ability between the digestion-promoting salad dressing and other salad dressings in Example 2;

[0034] Figure 10 For the emulsion particle morphology after digestion of the digestion-promoting salad dressing and the blank salad dressing in Example 2: A is the digestion-promoting salad dressing, and B is the blank salad dressing;

[0035] Figure 11 For the comparison of the acid value between the digestion-promoting salad dressing and the blank salad dressing in Example 2;

[0036] Figure 12 For the comparison of the texture properties between the digestion-promoting salad dressing and the blank salad dressing in Example 2;

[0037] Figure 13 For the medium state after 48 h of microbial culture of the digestion-promoting salad dressing and the blank salad dressing in Example 2: A is the digestion-promoting salad dressing, and B is the blank salad dressing;

[0038] Figure 14 For the comparison of the pH change between the digestion-promoting salad dressing and the blank salad dressing in Example 2;

[0039] Figure 15 For the comparison of the color change between the digestion-promoting salad dressing and the blank salad dressing in Example 2. Detailed implementation manners

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, and the experimental methods without specific conditions are all conventional methods in the art.

[0042] The materials, reagents, etc. used in the following examples can be obtained from commercial sources without special instructions.

[0043] The lipases used in the following examples were all purchased from Shandong Longkete Enzyme Preparation Co., Ltd., and were divided into three brands of lipases: Tanggui, Longke, and Longda.

[0044] A digestive-promoting salad dressing added with plant dietary fiber includes the following raw materials by mass ratio: 0.5% - 3.5% peppermint powder, 0.5% - 3.5% barley grass powder, 4% - 6% honey, 2% - 4% xylitol, 0.3% - 0.5% lactic acid bacteria, 0.2% - 0.4% tea polyphenols, 1% - 3% konjac gum, and the rest is high-emulsifying whole egg liquid and corn oil; among them, the mass ratio of high-emulsifying whole egg liquid to corn oil is 1:4.

[0045] The high-emulsifying whole egg liquid includes the following raw materials by mass ratio: 2% - 6% salt (sodium tripolyphosphate, magnesium chloride, disodium hydrogen phosphate), 0.045% - 0.055% lipase (3 brands are used in this example), 0.2% carboxymethyl cellulose, 0.1% lactic acid, 0.1% malic acid, and the rest is egg liquid.

[0046] The preparation method of the above digestive-promoting salad dressing added with plant dietary fiber is as follows:

[0047] (1) Break fresh eggs at 20°C to obtain whole egg liquid, put the whole egg liquid into a stirring container, and stir evenly with a low-speed stirrer at 300 rpm; then slowly add lipase, salt, carboxymethyl cellulose, lactic acid, and malic acid in sequence. After adding each raw material, appropriately increase the stirring speed, and the speed increase rate is 40 rpm / s, gradually transitioning from 300 rpm to 600 rpm, and continuously stir for 3 minutes to ensure that each raw material can be fully mixed evenly, forming a uniform egg liquid without obvious particles, and obtaining high-emulsifying whole egg liquid.

[0048] (2) Put the high-emulsifying whole egg liquid into a stirring container at 20°C and stir evenly with a low-speed stirrer at 300 rpm; then slowly add peppermint powder, barley grass powder, konjac gum, lactic acid bacteria, honey, xylitol, tea polyphenols, and corn oil in sequence. After adding each raw material, appropriately increase the stirring speed, and the speed increase rate is 40 rpm / s, gradually transitioning from 300 rpm to 600 rpm, and continuously stir for 3 minutes to ensure that each raw material can be fully mixed evenly, forming a uniform sauce body without obvious particles, and that's it.

[0049] Example 1

[0050] 1. Preparation of high-emulsifying whole egg liquid

[0051] Fresh eggs were washed at room temperature and manually broken in an ultraviolet sterilization box. The egg liquid was beaten with a stirrer at room temperature until foamy and slightly white. Subsequently, different kinds of salts (sodium tripolyphosphate, magnesium chloride, disodium hydrogen phosphate) in a mass ratio of 1% - 3%, 0.045% - 0.055% lipase (Tanggui, Longda, Longke) were added to the egg liquid, and 0.2% carboxymethyl cellulose, 0.1% malic acid and 0.1% lactic acid were added and stirred well. One portion of the whole egg liquid without adding other substances was reserved for the same operation as the blank group.

[0052] 2. Process Optimization

[0053] Salts of different varieties (sodium tripolyphosphate, magnesium chloride, disodium hydrogen phosphate) and different mass concentrations (2%, 4%, 6%) were selected, and the most suitable ratio was selected based on the emulsifying ability. The experimental results are as Figure 1 shown. About 4% magnesium chloride has a greater improvement in the emulsifying ability of the whole egg liquid.

[0054] Lipases of different brands (Tanggui, Longke, Longda) and different mass concentrations (0.03%, 0.04%, 0.05%) were selected, and the most suitable ratio was selected based on the emulsifying ability. The experimental results are as Figure 2 shown. About 0.05% lipase of the Tanggui brand has a greater improvement in the emulsifying ability of the whole egg liquid.

[0055] According to the analysis of the above experimental data, three factors, namely magnesium chloride, lipase of the Tanggui brand and temperature, were selected for an orthogonal experiment to explore the optimal conditions for high emulsifying properties of the whole egg liquid. The three levels of magnesium chloride with addition amounts of 1%, 2% and 3% were selected, the three levels of lipase of the Tanggui brand with addition amounts of 0.045%, 0.05% and 0.055% were selected, and the three levels of temperature were 40°C, 50°C and 60°C (see Table 1). Considering that this orthogonal experiment is a three-factor and three-level experiment, the model of this orthogonal experiment was determined to be L9(3 4 ).

[0056] Table 1 Factors of the orthogonal experiment

[0057]

[0058] According to the analysis of the data obtained from the orthogonal experiment, as shown in Table 2.

[0059] Table 2 Data analysis of the orthogonal experiment

[0060]

[0061]

[0062] Taking the emulsifying ability of whole egg liquid as an index, as shown in Table 2, lipase has the greatest influence on the emulsifying ability of whole egg liquid, followed by magnesium chloride and temperature. Finally, the optimal process A2B3C2 was screened out, namely 0.05% lipase, 3% magnesium chloride, and 50 °C. Three parallel tests were carried out to further verify the optimal process, and the verification results met the preparation process.

[0063] 3. Performance Test of High-Emulsifying Whole Egg Liquid

[0064] The high-emulsifying whole egg liquid was prepared by the optimal process obtained from the above experimental results, and the performance of the prepared whole egg liquid was tested as follows:

[0065] (1) Emulsifying Ability

[0066] ① Dilute the samples 10 times with pH = 7.0 phosphate buffer solution respectively.

[0067] ② Use different pipettes to mix each sample and corn oil in a volume ratio of 3:1 (1.5 mL of sample plus 500 μL of corn oil) and add them to a 5 mL centrifuge tube.

[0068] ③ Use a high-speed disperser to stir at 8000 rpm (first gear) for 2 min.

[0069] ④ Take 10 μL of the bottom-layer emulsion at 0 min and add it to 1 mL of 0.1% SDS solution, and use a centrifuge to vortex and mix.

[0070] ⑤ Using 0.1% SDS solution as the blank, use a texture analyzer to measure its absorbance value at a wavelength of 500 nm.

[0071] ⑥ Calculate the emulsifying ability:

[0072] Emulsifying ability (%) = A0 × 100

[0073] where A0 is the absorbance of the sample at 0 min.

[0074] ⑦ Use software to process and organize the obtained data.

[0075] The experimental results are as Figure 3 shown. The emulsifying effect of the high-emulsifying whole egg liquid was measured multiple times, and the magnesium chloride and the lipase of the sugar cabinet brand were relatively good. This may be because magnesium chloride dissociates into magnesium ions in the solution. Magnesium ions can combine with the proteins in the egg liquid and cause them to unfold and better adsorb at the interface of the oil droplets and the water phase, thereby effectively reducing the interfacial tension and forming a stable emulsification system. And the lipase of the sugar cabinet brand may have a strong hydrolysis ability for the main lipid components in the whole egg liquid. The synergistic effect of the two greatly improves the emulsifying ability of the whole egg liquid, and the emulsification activity index EAI > 30 m 2 / g, which is extremely helpful for improving the quality of market whole egg liquid. The absorbance data fluctuations in multiple experiments are all within ±2%, indicating good repeatability of the experiment and relatively reliable results.

[0076] (2) Colorimetry of whole egg liquid

[0077] Prepare appropriate amounts of highly emulsified whole egg liquid and blank whole egg liquid samples to ensure that the samples are representative and in a uniform state. Use a professional colorimetry instrument to measure the two whole egg liquid samples respectively under the same measurement conditions (including light source, measurement angle, etc.). Measure at a fixed time every day for seven consecutive days, and record the daily color change value (ΔE).

[0078] The experimental results are as Figure 4 shown. The highly emulsified whole egg liquid is significantly superior to the blank whole egg liquid in terms of color stability. The color stability (ΔE < 3.700) is increased by 1.145 times compared with the blank group. This is mainly because of the unique emulsification system of the highly emulsified whole egg liquid, which enables components such as pigments and oils in it to be more evenly dispersed and stably present, forming a relatively stable microenvironment and tending to be stable from the fifth day to the seventh day. This structure can effectively reduce the influence of external factors (such as light, oxygen, etc.) on the internal components of the whole egg liquid, thereby reducing the color change caused by chemical reactions such as component oxidation and degradation. However, due to the low degree of emulsification of the blank whole egg liquid and the uneven distribution of components, it is more susceptible to interference from the external environment, resulting in larger fluctuations in its color.

[0079] The experimental results show that the high-emulsification process is of great significance for improving the color stability of whole egg liquid. In actual production, optimizing the high-emulsification process can effectively ensure that the whole egg liquid maintains good color during storage and sales, improving the quality and market competitiveness of the product. At the same time, for the blank whole egg liquid, its formula or emulsification process can be considered for improvement to enhance its color stability.

[0080] (3) Gel texture properties of whole egg liquid

[0081] Add the highly emulsified and blank whole egg liquids into an ice-making mold, take them out immediately after a 30-minute water bath at 90°C. Cool in an ice-water bath for 20 minutes, refrigerate overnight at 4°C, and take them out to return to room temperature. Use a texture analyzer to measure their gel texture properties.

[0082] Hardness and elasticity are two important parameters of gel texture properties. By Figure 5It can be seen that the hardness of the highly emulsified whole egg liquid is lower than that of the blank whole egg liquid, and there is no obvious change in elasticity compared with the blank whole egg liquid. Magnesium chloride in the highly emulsified whole egg liquid destroys the network structure formed by proteins or colloids, etc. Lipase can catalyze the hydrolysis of fat, making the texture of the whole egg liquid softer and the hardness lower. Carboxymethyl cellulose has good hydrophilicity and water retention, and lactic acid reduces the degree of protein aggregation or precipitation, resulting in a decrease in the hardness of the whole egg liquid. The gel pores of the highly emulsified whole egg liquid are more than those of the blank whole egg liquid. When gelation occurs, this emulsification system will affect the gel network structure. During the gel formation process, the aggregation mode of proteins around the emulsion droplets changes, and gases such as air wrapped form pores. Moreover, good emulsification makes it easier for the system to mix in air during operations such as stirring, and these airs are fixed during gelation, thus generating more pores.

[0083] (4) Determination of the water holding capacity of whole egg liquid

[0084] The gels of highly emulsified and blank whole egg liquids were prepared as above, and the gel products were centrifuged at 1200 r / min and 4 °C for 20 min. Record the gel mass before and after centrifugation respectively, and calculate using the gel water holding capacity calculation formula:

[0085] Gel water holding capacity (%) = m1 / m0 × 100

[0086] Where m0 is the gel mass before centrifugation (unit: g), and m1 is the gel mass after centrifugation (unit: g).

[0087] Water retention or water binding is one of the important functions of proteins. This property of protein gels is usually called water holding capacity. It can be Figure 6 seen that the water holding capacity of the highly emulsified whole egg liquid is higher than that of the blank whole egg liquid, and the water holding rate has increased by 10.45%. The network structure formed by magnesium chloride with high emulsification and proteins, polysaccharides, etc. in the whole egg liquid, and the lipase changes the microstructure of the whole egg liquid during the hydrolysis of fat, improving the water holding capacity. Carboxymethyl cellulose absorbs a large amount of water and forms a high-viscosity gel-like substance, fixing the water in it and preventing water from seeping out. Lactic acid improves the stability of the system, making it easier for water to be retained in the whole egg liquid.

[0088] (5) Foaming properties of whole egg liquid

[0089] ① Dilute the samples 10 times with 10 mmol / L pH = 7.0 phosphate buffer solution respectively.

[0090] ② Take 3 mL of the sample solution into a 5 mL centrifuge tube (height 120 mm, inner diameter 30 mm), and stir with a high-speed disperser at 8000 rpm for 30 s.

[0091] ③ Read the volume of the foam recorded at 0 min and 60 min respectively. The foaming ability and foam stability calculation formulas are as follows:

[0092] Foaming ability (%) = V0 / 3×100

[0093] Foam stability (%) = V 60 / V0×100

[0094] Where V0 and V 60 represent the foam volumes at 0 min and 60 min, respectively.

[0095] The experimental results are as Figure 7 shown. Although the salt ion effect of magnesium chloride can compress the protein double layer and inhibit interfacial adsorption, lipase decomposes and destroys the foam-stabilizing lipid structure, and the high viscosity of carboxymethyl cellulose hinders bubble expansion, these factors may all weaken the foaming performance of highly emulsified whole egg liquid. However, in this example, by precisely regulating the concentration of magnesium chloride, the addition amount of lipase, and the proportion of carboxymethyl cellulose, while maintaining the emulsification advantage, the foaming characteristics of the system reach 95±3% of the blank group, basically achieving the functional balance of the foaming characteristics with the blank whole egg liquid while maintaining excellent emulsification ability.

[0096] (6) pH measurement of whole egg liquid

[0097] With the help of a pH meter with high precision and accurate calibration (using standard buffer solutions with pH values of 4.01, 7.00, and 10.01 respectively), the pH values of highly emulsified whole egg liquid and blank whole egg liquid are measured at a constant temperature of 25°C. Data is collected at fixed time points every day to ensure the accuracy and comparability of the data. Measurements are carried out continuously for seven days, and the pH values of the two kinds of whole egg liquid are recorded in detail.

[0098] The experimental results are as Figure 8 shown. The pH value stability of highly emulsified whole egg liquid is significantly better than that of blank whole egg liquid. This is because the unique emulsification system of highly emulsified whole egg liquid enables the acidic components and other substances in it to be more evenly dispersed and interact with each other, forming a relatively stable chemical environment, effectively resisting the influence of external factors (such as microbial growth, chemical reactions between components, etc.) on the pH value. While the blank whole egg liquid has low emulsification degree and uneven component distribution, the internal chemical changes and microbial activities are more likely to cause pH value fluctuations.

[0099] This experimental result shows that the high-emulsification process is of great significance for maintaining the pH value stability of whole egg liquid paste. In actual production, optimizing the high-emulsification process can ensure the chemical stability of whole egg liquid, extend the shelf life and improve the quality. For blank whole egg liquid, the formula or emulsification process can be improved to enhance its pH value stability.

[0100] Example 2

[0101] 1. Process optimization of digestion-promoting whole egg liquid

[0102] Fresh eggs are washed at room temperature and manually broken in an ultraviolet sterilization box. At room temperature, the egg liquid is beaten with a blender until foamy and slightly white. Subsequently, 0.5% - 3.5% peppermint powder, 0.5% - 3.5% barley grass powder, 4% - 6% honey, 2% - 4% xylitol, 0.3% - 0.5% lactic acid bacteria, and 0.2% - 4% tea polyphenols are added to the egg liquid by mass ratio and stirred well. Six factors, namely peppermint powder, barley grass powder, honey, xylitol, lactic acid bacteria, and tea polyphenols, are selected for an orthogonal experiment to explore the optimal production process for improving the digestive ability of whole egg liquid. Three levels of 0.5%, 2%, and 3.5% addition amounts are selected for peppermint powder, three levels of 0.5%, 2%, and 3.5% addition amounts are selected for barley grass powder, three levels of 4%, 5%, and 6% addition amounts are selected for honey, three levels of 2%, 3%, and 4% addition amounts are selected for xylitol, three levels of 0.3%, 0.4%, and 0.5% addition amounts are selected for lactic acid bacteria, and three levels of 0.2%, 0.3%, and 0.4% addition amounts are selected for tea polyphenols, as shown in Table 3. Considering that this orthogonal experiment is a six-factor and three-level experiment, the model of this orthogonal experiment is determined to be L 27 (3 13 )。

[0103] Table 3 Orthogonal experiment factors

[0104]

[0105] According to the data obtained from the orthogonal experiment, as shown in Table 4.

[0106] Table 4 Data analysis of orthogonal experiment

[0107]

[0108]

[0109] Taking the digestion of oil as an indicator, as can be seen from Table 4, among the six factors, the addition amounts of peppermint powder and barley grass powder have the greatest influence on the digestive ability. These two factors are selected for the process optimization experiment of salad dressing.

[0110] 2. Preparation of digestion-promoting salad dressing

[0111] Fresh eggs are washed at room temperature and manually broken in an ultraviolet sterilization box. At room temperature, the egg liquid is beaten with a blender until foamy and slightly white. Subsequently, 1% - 3% peppermint powder, 1% - 3% barley grass powder, 5% honey, 3% xylitol, 0.4% lactic acid bacteria, and 0.3% tea polyphenols are added to the egg liquid by mass ratio and stirred well. Corn oil is added in a mass ratio of 1:4 and whipped until the salad dressing has streaks, and then 0.1% - 0.3% konjac gum is added. One portion of whole egg liquid without adding other substances except corn oil is subjected to the same operation as the blank group.

[0112] 3. Process Optimization of Digestive-promoting Salad Dressing

[0113] Select three factors, namely mint powder, barley grass powder, and konjac gum, and conduct an orthogonal experiment to explore the optimal production process of digestive-promoting salad dressing. Select three levels of 1%, 2%, and 3% for the addition amount of mint powder, three levels of 1%, 2%, and 3% for the addition amount of barley grass powder, and three levels of 1%, 2%, and 3% for konjac gum (see Table 5). Considering that this orthogonal experiment is a three-factor and three-level experiment, determine the model of this orthogonal experiment as L9(3 4 ).

[0114] Table 5 Factors of Orthogonal Experiment

[0115]

[0116]

[0117] Analyze the data obtained from the orthogonal experiment, as shown in Table 6.

[0118] Table 6 Data Analysis of Orthogonal Experiment

[0119]

[0120] Taking the fat digestion situation as the main index and the sensory evaluation as the secondary index, it can be seen from Table 6 that konjac gum has the greatest impact on fat digestion, and mint powder has the greatest impact on sensory evaluation. The best process A3B3C1 is screened out, that is, 3% mint powder, 3% barley grass powder, and 1% konjac gum. Conduct three parallel experiments to further verify the best process, and the verification results are in line with the preparation process.

[0121] 4. Performance Test of Digestive-promoting Salad Dressing

[0122] Prepare digestive-promoting salad dressing according to the best process obtained from the above experimental results, and conduct performance tests on the prepared salad dressing as follows:

[0123] (1) Determination of the Digestive Ability of Salad Dressing

[0124] Take 1 g of the prepared digestive-promoting salad dressing and put it into a test tube. Add 15 mL of artificial pancreatic juice to the test tube containing the salad dressing, and gently shake the test tube to fully mix the salad dressing with the artificial pancreatic juice. Additionally, set up four control groups, which are respectively added with 1 g of blank salad dressing or salad dressings of other brands (Zhi Xiansheng, Jian Er Yan, Ji Mei Zi), and the same amount of artificial pancreatic juice as the experimental group. At the same time, place them in a water bath at 37.5 °C and digest for 2.5 h.

[0125] Dissolve the equal - amount samples prepared above in test tubes containing 5 mL of isooctane respectively. Then add 1.0 mL of copper acetate - pyridine reagent, and strongly mix the formed two - phase with a vortex mixer for 90 s. Let the mixture stand for about 10 - 20 s to make the aqueous phase clear from the isooctane and fatty acid solution, and measure the absorbance of the sample at 715 nm.

[0126] The experimental results are as Figure 9 shown. The digestion - promoting ability of the digestion - promoting salad dressing is relatively excellent compared with other brand salad dressings. This may be because the mint powder, barley grass powder and konjac gum contain more dietary fiber. These dietary fibers are partially separated in the alkaline environment of pancreatic juice, improving the fat dispersion degree, increasing the contact area of pancreatic lipase, and promoting the release of fatty acids. At the same time, xylitol stabilizes fatty acids through hydrogen bonds, reducing their re - aggregation, increasing the concentration of free carboxyl groups, and enhancing the complexation reaction with copper ions (amplifying the absorbance signal). And the metabolites of lactic acid bacteria modify the fat globule interface, enhancing the adsorption efficiency of pancreatic lipase and increasing the hydrolysis rate. The release amount of free fatty acids is greater than 40 g / 100 g. At the same time, through pH self - regulation, the lipase is in an appropriate pH, optimizing the lipase activity, and significantly improving the oil hydrolysis efficiency compared with traditional products. The data fluctuations are not large, indicating that the repeatability of the experiment is good and the results are relatively reliable.

[0127] (2) Microscopic observation of salad dressing emulsion

[0128] Put 1 g of the prepared salad dressing into a test tube, add 15 mL of artificial pancreatic juice to the test tube containing the salad dressing, and gently shake the test tube to fully mix the salad dressing and the artificial pancreatic juice. Set up a control group, adding 1 g of blank salad dressing and the same amount of artificial pancreatic juice as the experimental group. Place them in a water bath at 37.5 °C and digest for 2.5 h.

[0129] After digestion, at room temperature, use a pipette to accurately transfer 2 μL of the digested emulsion and drop it in the center of a glass slide. Slowly cover the cover slip along the edge to avoid air bubbles, and then use an optical microscope (objective lens 40×, eyepiece 10×) to observe the morphology of the emulsified particles, as Figure 11 shown.

[0130] As Figure 10 shown in A, the emulsion particles of the digestion - promoting salad dressing are numerous and relatively uniform in size, forming emulsified particles with uniform particle size (2 - 5 μm) and dispersed stably. The overall distribution is relatively dispersed, without obvious large - particle aggregation phenomenon. This may indicate that the digestion - promoting components effectively decompose the oil and other components in the salad dressing into smaller and more uniform particles during digestion, making the digested products more delicate and evenly dispersed in the system.

[0131] As Figure 10As shown in B, obvious larger particles can be seen in the emulsion of the blank salad dressing. Although there are some smaller particles around these larger particles, the proportion of the larger particles is relatively large as a whole, and the distribution is relatively concentrated. This indicates that without the action of the digestion-promoting components, the digestion degree of components such as fats and oils in the salad dressing is relatively low, and they still remain in a state of larger particles without being fully decomposed and dispersed.

[0132] The observation results of the emulsion further illustrate the digestion-promoting ability of the digestion-promoting salad dressing.

[0133] (3) Acid value determination of salad dressing

[0134] ① Accurately weigh 1 g of the salad dressing sample and place it in a clean and dry conical flask. Add 15 mL of a neutral ether-ethanol (volume ratio 2:1) mixture to the conical flask.

[0135] ② After adding the mixture, gently shake the conical flask to completely dissolve the sample. Add 2 - 3 drops of phenolphthalein indicator to the dissolved sample solution.

[0136] ③ Titrate with a potassium hydroxide standard titration solution (0.1 mol / L). Insert the tip of the burette about 1 cm below the liquid level of the solution in the conical flask, and slowly add the potassium hydroxide solution while constantly shaking the conical flask to fully mix the solution.

[0137] ④ Observe the change in the color of the solution during the titration process. When the solution shows a faint pink color and does not fade within 30 s, it is the end point of the titration.

[0138] ⑤ According to the concentration (c, mol / L) of the potassium hydroxide standard titration solution, the volume (V, mL) consumed in the titration, and the mass (m, g) of the sample, calculate the acid value according to the following formula:

[0139] Acid value (mg KOH / g) = (c × V × 56.1) / m

[0140] Among them, 56.1 is the molar mass of potassium hydroxide (g / mol).

[0141] The experimental results are as Figure 11 shown. Lactic acid bacteria are added to the digestion-promoting salad dressing, and the lactic acid produced by the lactic acid bacteria changes the acidity of the sauce, and the increase in the acid value is 20% higher than that of the conventional product. The acid value of the blank salad dressing increases relatively slowly, probably because its components are relatively simple and there are no additional factors affecting the stability of the fats and oils. Freshness plays an important role in the oxidation and hydrolysis of fats and oils. The oxidation of fats and oils will lead to rancidity and the generation of off-flavors. The digestion-promoting salad dressing of the present invention does not add preservatives. To maintain freshness, measures such as low-temperature storage, addition of antioxidants, and use of packaging materials with good barrier properties can be adopted, so that the shelf life of the product can be extended to 90 days (0 - 20 °C), meeting the consumption trend of clean labels.

[0142] (4) Determination of the texture properties of salad dressing

[0143] Place the salad dressing sample in a 4°C refrigerator for 24 h and then restore it to room temperature. Use a texture analyzer, and set the measurement parameters as follows: TA / 36R probe, pre-test speed: 5 mm / s; test speed: 2 mm / s; post-test speed: 2.0 mm / s; test distance: 25 mm; trigger force: 5 g. Each sample is tested 3 times, and the results are averaged.

[0144] The experimental results are as Figure 12 shown. The digestion-promoting salad dressing has higher chewiness and cohesiveness than the blank salad dressing, probably because the peppermint powder and barley grass powder contain dietary fiber. Dietary fiber has strong water absorption, can increase the water content of the salad dressing, form a gel structure, and enhance the chewing feeling and cohesiveness. Among them, the chewing force reaches 8 N (20.2% higher than the blank group), and the cohesiveness increases by 53.5%. Barley grass powder is dietary fiber, which makes the texture of the salad dressing denser. The protein and polysaccharides contained in the peppermint powder and barley grass powder may cross-link with the oil and protein in the salad dressing to form a complex network structure, improving the chewiness and cohesiveness. Adding peppermint powder and barley grass powder changes the microstructure of the salad dressing. These powders are dispersed in it, filling the voids, making the structure denser, and enhancing the ability to resist external forces and the internal binding force during chewing.

[0145] (5) Microbiological culture of salad dressing

[0146] Prepare the beef extract peptone medium, and the specific steps are as follows:

[0147] ① Calculation: Calculate the amounts of beef extract, peptone, sodium chloride, and agar (for solid use) according to the formula.

[0148] ② Weighing: Weigh each component with a balance.

[0149] ③ Dissolution: Add an appropriate amount of water and stir to dissolve. For solids, heat to melt the agar.

[0150] ④ Adjust the pH: Adjust to 7.2 - 7.6 with acid or base.

[0151] ⑤ Sub-packaging and wrapping.

[0152] ⑥ Sterilize at 121°C for 20 min by high-pressure steam.

[0153] Finally, dilute the sample ten times with sterilized normal saline and perform sterilized inoculation in a laminar flow hood.

[0154] The experimental results are as Figure 13 shown. For the digestion-promoting salad dressing ( Figure 13 A in it), there are no obvious colonies on the surface after 48 h of culture, probably because tea polyphenols are added and it has strong antibacterial ability, and the number of colonies after 48 h is < 10 CFU / g; for the blank salad dressing ( Figure 13In B), multiple colonies with different morphologies appeared on the surface, indicating that the growth of microorganisms was relatively intense. This shows that under the same conditions, the blank salad dressing is more likely to breed microorganisms, and the difference in the microbial culture of the two is obvious.

[0155] (6) pH determination of salad dressing

[0156] With the help of a high-precision and accurately calibrated pH meter (using standard buffer solutions with pH values of 4.01, 7.00, and 10.01 respectively), the pH of the digestion-promoting salad dressing and the blank salad dressing was measured at a constant temperature of 25°C. Data was collected at fixed time points every day to ensure the accuracy and comparability of the data. The measurement was carried out continuously for seven days, and the pH values of the two salad dressings were recorded in detail.

[0157] The experimental results are as Figure 14 shown. The change in the pH value of the digestion-promoting salad dressing shows certain regularity and self-regulating ability. The fluctuation of its pH value may be closely related to the digestion-promoting ingredients added. These ingredients regulate the acid-base environment of the salad dressing through interactions with other ingredients at different stages to better achieve the digestion-promoting function. Although the change in its pH value is relatively large compared to the blank salad dressing, this change is within a reasonable range, and from the perspective of digestion promotion, it may be an embodiment of its unique advantages. In contrast, although the pH value of the blank salad dressing is relatively stable, it may lack the functional pH regulation mechanism possessed by the digestion-promoting salad dressing.

[0158] The experimental results show that the change characteristics of the pH value of the digestion-promoting salad dressing are closely related to its digestion-promoting function. In actual production and application, this change pattern of the pH value will not only not affect its quality, but may instead be an important guarantee for achieving the digestion-promoting effect. At the same time, it also provides a reference basis for further optimizing its formula and production process to better exert its digestion-promoting efficacy and maintain good quality stability.

[0159] (7) Colorimetric determination of salad dressing

[0160] Prepare appropriate samples of the digestion-promoting salad dressing and the blank salad dressing to ensure that the samples are representative and in a uniform state. Using a professional colorimetric determination instrument, under the same measurement conditions (including light source, measurement angle, etc.), the two salad dressing samples were measured respectively. The measurement was carried out at a fixed time every day for seven consecutive days, and the daily color change value (ΔE) was recorded.

[0161] The experimental results are as Figure 15As shown, from the perspective of the entire experimental period, the chromaticity changes of the digestion-promoting salad dressing and the blank salad dressing show different characteristics. The chromaticity change of the blank salad dressing fluctuates greatly, with obvious peaks on the second day and the fourth day. This may be because certain components in the blank salad dressing are more likely to change under specific conditions (such as oxidation, microbial action, etc.), resulting in larger fluctuations in its chromaticity. The chromaticity change of the digestion-promoting salad dressing is relatively stable, but there is a slightly larger change on the fifth day. This may be related to the special components added to the digestion-promoting salad dressing (such as mint, barley seedlings guard). These components may affect the chromaticity stability of the salad dressing to a certain extent, but overall, the amplitude of its chromaticity change is smaller than that of the blank salad dressing.

[0162] The experimental results show that there are differences in chromaticity changes between the digestion-promoting salad dressing and the blank salad dressing. This difference may be caused by the different formulations of the two. In actual production and application, it is necessary to further consider the impact of these chromaticity changes on product quality and consumer acceptance, and take corresponding measures to optimize the chromaticity stability of the product.

[0163] (8) Sensory evaluation of salad dressing

[0164] Set sensory evaluation criteria from three aspects: fineness, taste, and greasiness. The specific scoring criteria are shown in Table 7 and Table 8. The total sensory score is 3 - 30 points, and the scores for fineness, taste, and greasiness are all 1 - 10 points. The sensory evaluation panel consists of 30 people who have received sensory training for salad dressing, including 15 men and 15 women. Take the average score of the sensory evaluation panel members as the data result and record it.

[0165] Table 7 Sensory evaluation criteria for digestion-promoting salad dressing

[0166]

[0167] Through the above criteria, conduct a sensory evaluation of the digestion-promoting salad dressing to obtain its comprehensive performance in terms of fineness, taste, and greasiness.

[0168] Table 8 Sensory evaluation criteria for blank salad dressing

[0169]

[0170]

[0171] Through the above criteria, conduct a sensory evaluation of the blank salad dressing to obtain its comprehensive performance in terms of fineness, taste, and greasiness.

[0172] The comparison of the sensory evaluations of the digestion-promoting salad dressing and the blank salad dressing is shown in Table 9 below.

[0173] Table 9 Comparison of sensory evaluations

[0174]

[0175] As can be seen from Table 9, compared with the blank salad dressing, the digestion-promoting salad dressing of the present invention has a 60.0% reduction in greasiness, a 14.29% improvement in fineness, and a significant improvement in taste. The comprehensive sensory score (8.3 / 10) is significantly higher than that of the blank group (5.7 / 10), indicating that the digestion-promoting salad dressing of the present invention has great market potential and better meets the needs of the current population pursuing healthy light meals.

[0176] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A digestive-promoting salad dressing added with plant dietary fiber, characterized in that, It comprises the following raw materials by mass ratio: 0.5% - 3.5% peppermint powder, 0.5% - 3.5% barley grass powder, 4% - 6% honey, 2% - 4% xylitol, 0.3% - 0.5% lactic acid bacteria, 0.2% - 0.4% tea polyphenols, and the balance is high-emulsifying whole egg liquid and corn oil; wherein, the mass ratio of the high-emulsifying whole egg liquid to the corn oil is 1:

4. The high-emulsifying whole egg liquid comprises the following raw materials by mass ratio: 2% - 6% salt, 0.045% - 0.055% lipase, 0.2% carboxymethyl cellulose, 0.1% lactic acid, 0.1% malic acid, and the balance is egg liquid.

2. The digestive-promoting salad dressing with added plant dietary fiber according to claim 1, characterized in that The salt is one or more of sodium tripolyphosphate, magnesium chloride, and disodium hydrogen phosphate.

3. The digestive-promoting salad dressing with added dietary fiber according to claim 1, characterized in that, It also comprises 0.1% - 0.3% konjac gum.

4. The preparation method of a digestion-promoting salad dressing added with plant dietary fiber according to any one of claims 1-3, characterized in that, It comprises the following steps: Step 1) Break fresh eggs to obtain whole egg liquid, put the whole egg liquid into a stirring container, and stir evenly with a low-speed stirrer; then slowly add lipase, salt, carboxymethyl cellulose, lactic acid, and malic acid in sequence. After adding each raw material, appropriately increase the stirring speed, gradually transition from 300 rpm to 600 rpm, and continuously stir to ensure that each raw material can be fully mixed evenly to form a uniform egg liquid without obvious particles, thus obtaining high-emulsifying whole egg liquid. Step 2) First, put the high-emulsifying whole egg liquid into a stirring container, and stir evenly with a low-speed stirrer; then slowly add peppermint powder, barley grass powder, konjac gum, lactic acid bacteria, honey, xylitol, tea polyphenols, and corn oil in sequence. After adding each raw material, appropriately increase the stirring speed, gradually transition from 300 rpm to 600 rpm, and continuously stir to ensure that each raw material can be fully mixed evenly to form a uniform paste without obvious particles, and that's it.

5. The preparation method of a digestion-promoting salad dressing adding plant dietary fiber according to claim 4, characterized in that, The speed increase rate for increasing the stirring speed is 40 rpm / s.

6. The preparation method of a digestion-promoting salad dressing added with plant dietary fiber according to claim 4, characterized in that, The stirring time is 3 min.

7. The preparation method of a digestion-promoting salad dressing added with plant dietary fiber according to claim 4, characterized in that, The stirring temperature is 20°C.

8. The digestion-promoting salad dressing prepared by the preparation method according to any one of claims 4-7, characterized in that, The storage condition of the salad dressing is 0 - 20°C.

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