A wheat gluten plant-based salad dressing and its preparation method

Abstract

A wheat gluten plant-based salad dressing and its preparation method. The wheat gluten is added to an aqueous vinegar solution and stirred to disperse, and then homogenized and emulsified with edible vegetable oil to obtain the wheat gluten plant-based salad dressing. The method of the present invention has a simple process and provides a new direction for the utilization of wheat gluten. The salad dressing prepared by the present invention has a tissue state, aroma, taste and texture similar to those of mayonnaise prepared with egg yolks, and has the advantages of "zero cholesterol", "pure plant-based" and "clean label", and has good application prospects in the field of healthy foods.

Description

Technical Field

[0001] The present invention relates to the field of food science and engineering, and specifically to a gluten plant-based salad dressing and a preparation method thereof. Background Art

[0002] Salad dressing is one of the widely consumed condiments in daily life, mainly used in dishes such as salads and sandwiches. Traditional salad dressings are prepared with egg yolks as stabilizers, containing relatively high cholesterol, which is not conducive to blood lipid health. With the younger age trend of cardiovascular and cerebrovascular diseases in China, people are increasingly concerned about the health risks brought by cholesterol intake. Plant-based salad dressings are one of the important development directions for future foods that meet the edible needs and "zero cholesterol" intake, and are also an important measure for building a diversified food supply system currently. It is of great significance to expand food sources, enrich food supplies, and help ensure China's food security. Currently, plant-based salad dressings mainly use soy protein isolate or its aggregates, peanut protein, zein, almond protein, and chickpea protein to replace egg yolks for preparation.

[0003] Gluten is a by-product generated during the processing of wheat starch, with a protein content as high as 75% - 85%, containing 15 kinds of essential amino acids for the human body, and being the most abundant plant protein resource. Due to the water-insolubility of wheat protein in gluten, Liu et al. reported the preparation of a plant protein emulsion gel similar to salad dressing by dispersing wheat protein in an acetic acid-ethanol solution or glycerol, deep eutectic solvents. However, in the acetic acid-ethanol system, ethanol needs to be evaporated and removed subsequently, and incomplete ethanol removal causes residues, and high temperatures are prone to cause oxidation of the oil in the product; in the glycerol system, wheat protein needs to be dissolved at high temperatures (135°C), causing protein oxidation, generating off-flavors, and the product contains a large amount of glycerol (>35%); deep eutectic solvents are non-food additives or processing aids, so there are generally technical problems such as ethanol residues, easy oxidation of oils, or non-food additives. Ye Yuntong et al. prepared a plant-based mayonnaise using wheat gliadin / arabic gum composite colloidal particles, which has the problems of high pollution and high cost in the extraction of wheat gliadin and high waste of gluten, and cannot meet the industrial requirements. Summary of the Invention

[0004] The present invention aims to provide a gluten plant-based salad dressing and a preparation method thereof, overcome the problem of poor dispersibility of gluten in the preparation of salad dressing emulsified foods, and the obtained product is green, healthy and meets the industrial production requirements.

[0005] To solve the above technical problems, the specific solution adopted by the present invention is as follows: A preparation method of a gluten plant-based salad dressing, adding gluten to an acetic acid aqueous solution and stirring to disperse, and then homogenizing and emulsifying with edible vegetable oil to obtain a gluten plant-based salad dressing.

[0006] Preferably, it includes the following steps:

[0007] 1), Add gluten powder into an aqueous acetic acid solution with a mass concentration of 20 - 80%, stir and disperse to obtain a gluten powder dispersion, and the protein mass concentration in the gluten powder dispersion is 2 - 10%;

[0008] 2), Add the gluten powder dispersion obtained in step 1) into edible vegetable oil for homogenization and emulsification to obtain a gluten powder plant - based salad dressing, where the mass ratio of the edible vegetable oil is 60 - 80%.

[0009] Preferably, in step 1), stir and disperse the gluten powder at 45 - 65 °C for 2 - 18 h to obtain a gluten powder dispersion.

[0010] Preferably, in step 2), before adding the gluten powder dispersion into the edible vegetable oil, first add pigments accounting for 0.005 - 0.015% of the total mass of the gluten powder plant - based salad dressing into the edible vegetable oil, and stir and dissolve the pigments in the edible vegetable oil at 5 - 50 °C for 0.3 - 2 h.

[0011] Preferably, the pigment is one or a mixture of several of capsanthin, curcumin, and carotene.

[0012] Preferably, the homogenization and emulsification conditions in step 2) are 10000 - 30000 rpm, shearing for 40 s - 4 min.

[0013] Preferably, the edible vegetable oil in step 2) is one or a mixture of several of corn oil, soybean oil, peanut oil, rapeseed oil, sunflower oil, palm olein, linseed oil, and olive oil.

[0014] Preferably, sterilize and package the gluten powder plant - based salad dressing obtained in step 2). The sterilization method is: pasteurize at 85 °C for 30 - 32 min, or sterilize at 121 °C for 15 - 16 min, or perform high - temperature short - time sterilization at 130 - 140 °C for 5 - 15 s.

[0015] A gluten powder plant - based salad dressing is prepared by the above - mentioned preparation method.

[0016] Beneficial effects

[0017] The present invention overcomes the problem of the dispersibility of gluten powder in the preparation of salad dressing emulsified foods, provides a method for preparing a gluten powder plant - based salad dressing, provides a new and high - value - added processing method, enriches plant - based salad dressings, and the obtained product has the health benefits of "zero cholesterol", "pure plant - based", and "clean label". The method of the present invention has a simple process, is safe and nutritious, and provides a new direction for the high - value utilization of gluten powder. The gluten powder plant - based salad dressing prepared by the present invention is a pure plant - based emulsified cream analogue, enriched with plant protein, zero cholesterol, clean label, and can be used for fruit and vegetable salads, spreading, and sandwiching.

[0018] In the present invention, the wheat gluten used to replace the egg yolk component has a unique amino acid composition, rich in proline and glutamine, and the content of non-polar amino acids is about 35%. Therefore, protein molecules are prone to form strong hydrophobic interactions, which promote the formation of a strong protein network between monomeric gliadin and aggregated glutenin through cross-linking, helping to stabilize the gas expanded during dough fermentation or baking inside the structure, indicating that it has a strong network structure and interfacial activity. The vinegar-aqueous solution in the present invention adopts a solvent-free mode, using the vinegar-aqueous solution as a dispersion liquid of gluten, exploring a new dispersion method, and making full use of the structural characteristics of wheat gluten.

[0019] The function of vinegar in conventional salad dressings is to increase flavor and sterilize. In addition to the above functions, the vinegar in the present invention also forms a dispersant of gluten with water, increases the dispersibility of wheat gluten, and promotes the formation of a water-in-oil (O / W) emulsion, thereby improving the protein solubility performance by using the vinegar-aqueous solution to make full use of the network-forming ability of wheat gluten. Since the wheat gluten plant-based emulsion basically exists in the form of spherical droplets, the droplet size is basically consistent with the particle size distribution results. The presence of vinegar molecules induces the aggregation and thickening of protein molecules. This is because as the vinegar content increases, the droplet size gradually decreases, and the large-area contact between the droplets in the emulsion generates a large frictional force, hindering the free flow of the droplets in the shear field, thereby increasing the viscosity. That is, the smaller the droplet size, the larger the contact surface area between the droplets, and the higher the viscosity, greatly improving the dispersibility of wheat protein and achieving the preparation of a green, healthy and safe gluten plant-based salad dressing. Brief Description of the Drawings

[0020] Figure 1 It is a comparison chart of the average particle size of the gluten plant-based salad dressings of three preferred embodiments of the present invention and commercially available salad dressings.

[0021] Figure 2 It is a particle size distribution chart of the gluten plant-based salad dressings of three preferred embodiments of the present invention.

[0022] Figure 3 It is a microscopic image of the polarized light microscope after dilution of the gluten plant-based salad dressing in Example 1 of the present invention.

[0023] Figure 4 It is a microscopic image of the polarized light microscope after dilution of the gluten plant-based salad dressing in Example 2 of the present invention.

[0024] Figure 5 It is a microscopic image of the polarized light microscope after dilution of the gluten plant-based salad dressing in Example 3 of the present invention. Detailed Description of the Invention

[0025] The technical solution of the present invention will be described below through three groups of embodiments:

[0026] Example Group 1

[0027] (1) Dispersion of gluten: Gluten was added to an aqueous solution containing vinegar. This group of embodiments included 10 examples, and the concentrations of the aqueous vinegar solutions in the ten examples were respectively: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%. Subsequently, it was stirred and dispersed in warm water at 45°C for 3 h to obtain a gluten dispersion, and the protein mass concentration in the gluten dispersion was 5%.

[0028] (2) Preparation of the oil phase: 0.01% β-carotene and 0.005% curcumin were added to soybean oil, and it was stirred and dissolved at 40°C for 1 h to obtain the oil phase part containing natural pigments.

[0029] (3) Preparation of mayonnaise emulsion: The oil phase obtained in step (2) accounting for 75% of the total system mass was added to the gluten dispersion obtained in step (1) at one time; after stirring, it was sheared evenly at 23000 rpm for 2 min.

[0030] (4) Sterilization and packaging: The mayonnaise obtained in step (3) was sterilized and preserved (85°C, 15 min) and packaged.

[0031] From the observation results, it can be seen that the emulsions referred to in this example group are all oil-in-water emulsions. When the vinegar content in the water-vinegar reagent is 40% - 100%, as the proportion of vinegar in the water-vinegar reagent increases, the protein in the gluten disperses better, can embed more oil, and helps to form a gel-like plant protein emulsion. When the vinegar content is less than 20%, a stable emulsion cannot be formed, and most of the oil floats on the surface, and obvious stratification occurs after standing. However, because vinegar itself has a certain pungent sour taste, the water-vinegar ratio of 40% is selected as the optimal, and at this time, a stable plant protein emulsion can be formed, which has great feasibility in replacing traditional mayonnaise.

[0032] Example Group 2

[0033] (1) Dispersion of gluten: Gluten was added to an aqueous solution containing vinegar, and the concentration of the aqueous vinegar solution was 40%. Subsequently, it was stirred and dispersed in warm water at 45°C for 3 h to obtain a gluten dispersion, and the protein mass concentration in the gluten dispersion was 5%.

[0034] (2) Preparation of the oil phase: 0.01% β-carotene and 0.005% curcumin were added to soybean oil, and it was stirred and dissolved at 40°C for 1 h to obtain the oil phase part containing natural pigments.

[0035] (3) Preparation of mayonnaise emulsion: Add the oil phase obtained in step (2) to the gluten dispersion obtained in step (1) at one time; after stirring, shear evenly at 23,000 rpm for 2 min. This example group includes 5 examples, and the oil phases added in the 5 examples account for 45%, 55%, 65%, 75%, and 85% of the total system mass respectively.

[0036] (4) Sterilization and packaging: Sterilize and preserve the mayonnaise obtained in step (3) (85°C, 15 min), and then package it.

[0037] In this example group, by adjusting the content of soybean oil within the range of 45% - 85% while keeping other conditions unchanged. From the results of the examples, it can be seen that when the soybean oil content is 65% and 75%, the emulsion can remain stable without demulsification. When the soybean oil content is too low or too high, it will cause the plant-based mayonnaise to be unstable, and the emulsion will demulsify and precipitate soybean oil in a very short time, affecting the stability and edibility of the plant-based mayonnaise.

[0038] Example Group Three

[0039] (1) Dispersion of gluten: Add gluten to an aqueous solution containing vinegar, and the concentration of the aqueous solution of vinegar is 40%. Then stir and disperse it in warm water at 45°C for 3 h to obtain a gluten dispersion. This example group includes 5 examples, and the protein mass concentrations in the gluten dispersions of the 5 examples are 1%, 2.5%, 5%, 7.5%, and 10% respectively.

[0040] (2) Preparation of oil phase: Add 0.01% β-carotene and 0.005% curcumin to soybean oil, and stir and dissolve at 40°C for 1 h to obtain the oil phase part containing natural pigments.

[0041] (3) Preparation of mayonnaise emulsion: Add the oil phase obtained in step (2) accounting for 75% of the total system mass to the gluten dispersion obtained in step (1) at one time; after stirring, shear evenly at 23,000 rpm for 2 min.

[0042] (4) Sterilization and packaging: Sterilize and preserve the mayonnaise obtained in step (3) (85°C, 15 min), and then package it.

[0043] In this example, by adjusting the protein content in gluten to be 1% - 10% while keeping other conditions unchanged. From the results of the examples, it can be seen that when the gluten content is 1%, 2.5%, 5%, and 7.5%, a stable protein emulsion can be obtained after shear homogenization.

[0044] The most preferred composition ratio for preparing the gluten-based plant salad dressing of the present invention can be obtained from the above embodiments, denoted as Example 1, that is, the aqueous solution concentration of vinegar is 40%, the protein mass concentration in gluten is 5%, and the addition amount of the oil phase is 65% of the total system mass. Another two relatively preferred embodiments are denoted as Example 2 and Example 3, and their composition ratios are as follows: the aqueous solution concentration of vinegar is 40%, the protein mass concentration in gluten is 7%, and the addition amount of the oil phase is 65% of the total system mass; the aqueous solution concentration of vinegar is 40%, the protein mass concentration in gluten is 5%, and the addition amount of the oil phase is 75% of the total system mass. Figure 1 Figure 2 shows a comparison chart of the average strength of the salad dressings of the above three embodiments and commercially available salad dressings. Figure 2 Figure 3 shows the particle size distribution chart of the salad dressings of the above three embodiments. Since the particle size can be used to evaluate the emulsifying ability and physical stability of the emulsion, a small average particle size indicates that the emulsion has good emulsifying characteristics and physical stability. Therefore, compared with commercially available salad dressings, the salad dressings produced by the present invention have a lower particle size and better emulsifying characteristics and physical stability.

[0045] Figure 3 and 4 The microscopic pictures of 5 can show that the emulsion droplets of the plant-based salad dressings of the above three embodiments have regular spherical structures, but the degree of tightness of the distribution is different. Figure 3 They are more uniform and compact, so the average particle size of the corresponding Example 1 is the smallest. Figure 4 Followed by Figure 5 The distribution is the least compact.

[0046] Furthermore, commercially available ordinary mayonnaise is used as a comparative example to test and verify the technical effects of the present invention. The formula of this comparative example is egg yolk, vegetable oil, water, vinegar, edible salt, granulated sugar, and food additives. The preparation method is: mixing and shearing and homogenizing the original materials such as egg yolk and vegetable oil, and finally obtaining the salad dressing product.

[0047] The comparison of the nutritional components of Example 1 of the present invention and this comparative example is shown in Table 1 below:

[0048] Table 1 Comparison of nutritional components of the comparative example and Example 1

[0049]

[0050] As can be seen from Table 1, compared with commercially available salad dressings, the gluten-based plant salad dressing of the present invention has lower calorie and fat contents, and at the same time has a higher protein content. It completely replaces animal protein with plant protein, and the plant-based salad dressing does not contain cholesterol, which is beneficial to the health of consumers and meets the needs of consumers' healthy diets.

[0051] The main characteristics of Example 1 of the present invention and this comparative example are shown in Table 2 below:

[0052] Table 2 Comparison of Main Characteristics between Comparative Example and Example 1

[0053]

[0054] As can be seen from Table 2, compared with the commercially available salad dressings, the gluten plant-based salad dressing of the present invention has a lower pH. The strongly acidic environment can better inhibit the growth of harmful colonies in the salad dressing and extend the shelf life of the plant-based salad dressing. At the same time, the gluten plant-based salad dressing has similar viscosity and other indicators to the commercially available salad dressings, and has good ductility and spreadability.

[0055] The sensory evaluation of Example 1 of the present invention and this comparative example is shown in Table 3 below. The sensory evaluation was completed by 8 professionals and was divided into four aspects: tissue characteristics, color, odor, and taste, and scored from 1 to 100 points. 1 point represents the most dissatisfied, and 100 points represents very satisfied.

[0056] Table 3 Sensory Evaluation Results of Comparative Example and Example 1

[0057]

[0058] As can be seen from the results in Table 3, there is not much difference in the sensory evaluation between the gluten plant-based salad dressing and the commercially available salad dressings, and it can show good state and taste.

Claims

1. A method for preparing a gluten plant-based salad dressing, characterized in that: The method comprises adding gluten into a vinegar aqueous solution and stirring to disperse the mixture, and then homogenizing and emulsifying the mixture with edible vegetable oil to obtain a gluten plant-based salad dressing; the method comprises the following steps: 1) Adding gluten to a 20%-80% mass concentration of vinegar aqueous solution, stirring and dispersing to obtain a gluten dispersion, wherein the protein mass concentration in the gluten dispersion is 1%-10%; stirring and dispersing the gluten at 45-65° C. for 2-18 hours to obtain the gluten dispersion; 2) Adding the gluten dispersion obtained in step 1) to edible vegetable oil for homogenization and emulsification to obtain a gluten plant-based salad dressing, wherein the edible vegetable oil accounts for 60%-80% by mass; the homogenization and emulsification conditions are 10000-30000 rpm and shearing 40s-4min.

2. The method for preparing a gluten plant-based salad dressing according to claim 1, wherein: In step 2), before adding edible vegetable oil to the gluten dispersion, 0.005%-0.015% of the total weight of the gluten plant-based salad dressing pigment is added to the edible vegetable oil, and the pigment is stirred and dissolved in the edible vegetable oil at 5-50° C. for 0.3-2 h.

3. The method for preparing a gluten plant-based salad dressing according to claim 2, wherein: The pigment is one or a mixture of capsanthin, curcumin and carotene.

4. The method for preparing a gluten plant-based salad dressing according to claim 1, wherein: The edible vegetable oil in step 2) is one or a mixture of corn oil, soybean oil, peanut oil, rapeseed oil, sunflower oil, palm oil, linseed oil, and olive oil.

5. The method for preparing a gluten plant-based salad dressing according to claim 1, wherein: The gluten plant-based salad dressing obtained in step 2) is sterilized and packaged, and the sterilization method is: 85° C. pasteurization for 30-32 minutes, or 121° C. sterilization for 15-16 minutes, or 130-140° C. high-temperature instantaneous sterilization for 5-15 seconds.

6. A gluten plant-based salad dressing, characterized by: The salad dressing is prepared by the method for preparing a gluten plant-based salad dressing according to any one of claims 1 to 5.

Images