Low-sugar malt spinach mixed with yogurt soluble beans and preparation method thereof

Abstract

The present invention relates to a low-sugar malt spinach mixed yogurt soluble bean and a preparation method thereof, and belongs to the field of food technology. It includes the following steps: S1, sterilization and drying: spinach is blanched with water, dried, crushed, and sieved after being taken out to make spinach powder; S2, yogurt pretreatment: after the yogurt filters the water, it is heat-treated at 55-60°C for 10-15min; S3, malt pretreatment: raw malt is fried, crushed and sieved after drying to make malt powder; S4, premixing: egg white is beaten, and starch, xylitol, malt powder, and spinach powder are added separately during the beating process; S5, preparation of soluble bean slurry: the yogurt obtained by step S2 is added to the egg white obtained by step S4, and the soluble bean slurry is prepared; S6, preparation of soluble bean: the soluble bean slurry is extruded and formed, and baked to obtain soluble bean. The malt spinach mixed yogurt soluble bean obtained by the present invention is light green, has uniform pores, melts in the mouth, has obvious sweet wheat milk fragrance, and has broad market potential.

Description

Technical Field

[0001] The invention relates to the technical field of food, in particular to a low-sugar malt spinach mixed yogurt bean paste and a preparation method thereof. Background Art

[0002] Soybean is a snack made of starch, milk powder, whey powder, etc., with appropriate addition of fruits, vegetables, grains, nuts, etc., and then produced by baking, freeze drying, or vacuum drying after pre-treatment and mixing. The product is rich in nutrition, low in water content, loose and porous, and melts in the mouth.

[0003] At present, most soluble beans use vacuum freeze-drying technology, which has high production costs and is not widely used. The raw materials of soluble beans are mainly milk powder, starch and egg white. Among them, egg white has a distinct egg smell, and egg white needs to be processed by hard foaming, so the addition of other materials needs to consider whether they can cover up the egg smell and the impact on the foaming property and foaming stability of egg white. The existing technology covers up the egg smell of egg white by adding vinegar or lemon juice, but the covering effect is weak and the fragrance is not lasting and unstable.

[0004] After lactic acid fermentation, coagulated yogurt is rich in calcium, sweet and sour, and has a strong milky flavor, which can further enrich the taste and flavor of food. Spinach is an annual herb, rich in vitamin C, carotenoids, minerals and other nutrients, and is one of the most common vegetables. At the same time, spinach is a nutritious vegetable, and its nutritional density is very beneficial to human health. However, the water content of spinach and yogurt is relatively high, which is very unfavorable for the formation of soluble beans. In addition, spinach contains a lot of oxalic acid and is an alkaline vegetable, while yogurt is acidic, which has a certain effect on the foaming property and foaming stability of egg white protein. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a low-sugar malt spinach mixed yogurt soluble bean and a preparation method thereof, which solves the technical problems that the soluble bean is prone to have an eggy smell and that adding other materials during preparation will affect the foaming property and foaming stability of the egg white.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides a method for preparing low-sugar malt spinach mixed with yogurt dissolved beans, comprising the following steps:

[0010] S1. Drying: blanching the spinach with water, taking it out, drying, crushing, and sieving to make spinach powder; the water temperature for blanching is 75-85°C, the blanching time is 15-20s, and anhydrous sodium bicarbonate solution is added during blanching;

[0011] S2. Yogurt pretreatment: After filtering out the water from the yogurt, heat treat it at 55-60℃ for 10-15min;

[0012] S3, malt pretreatment: fry the raw malt, crush and sieve it after drying to make malt powder;

[0013] S4, premixing: Beat the egg whites, and separately add starch, xylitol, the malt powder obtained in step S3, and the spinach powder obtained in step S1 during the beating process;

[0014] S5, preparation of soybean milk: adding the yogurt obtained in step S2 to the egg white obtained in step S4, and stirring evenly to obtain soybean milk;

[0015] S6. Preparation of soluble beans: extruding and molding the soluble bean slurry, and baking to obtain soluble beans.

[0016] It should be noted that steps S1-S6 do not restrict the operation sequence. For example, steps S1, S2, and S3 can be processed in parallel; and steps S2 and S4 can be processed in parallel.

[0017] Optionally, the total sugar content of the soluble beans is 2.02±0.026wt%.

[0018] Optionally, in step S1, old leaves and rhizomes are removed from the spinach before blanching, and then the spinach is washed.

[0019] Optionally, in step S1, the blanching material-water mass volume ratio is 10-15%; the concentration of anhydrous sodium bicarbonate in the anhydrous sodium bicarbonate solution is 0.2-0.5wt%; and the screening is through a 200-250 mesh sieve.

[0020] Optionally, in step S2, the yogurt is a set yogurt; and the method for filtering water from the yogurt is to filter with a 200-250 mesh sieve until no dripping occurs.

[0021] Optionally, in step S3, the method for frying raw malt includes: heating to a temperature of 60-80°C and stir-frying for 15-20 minutes, with a stir-frying frequency of 3-3.5 minutes per time; heating to 85-100°C, stir-frying for 10-15 minutes, with a stir-frying frequency of 0.2-0.5 minutes per time; heating to 110-150°C, stir-frying continuously for 3-5 minutes; the screening is through a 200-250 mesh sieve.

[0022] Optionally, the mass ratio of egg white, starch, xylitol, malt powder, spinach powder and pre-treated yogurt is 40:2-5:3-5:1-2:1-2:16-20.

[0023] Optionally, the starch is corn starch.

[0024] Optionally, the baking conditions in step S6 are: bottom temperature 70-80° C., top temperature 100-110° C., and the baking time is 40-60 min.

[0025] Preferably, the optimal preparation method of low-sugar malt spinach mixed with yogurt soluble beans of the present invention is: spinach is blanched to protect color (blast 50°C, 1m / s, material-water ratio 10%, 0.2% anhydrous sodium bicarbonate solution to protect color, water temperature 80°C, blanching 20s) and then dried and powdered, yogurt is filtered and then heat treated (58°C wind speed 1m / s), raw malt is fried (to golden yellow, rich wheat aroma) and dried and then powdered as the most suitable pre-treatment method. Single factor and orthogonal experiments obtained 40g egg white as the main raw material, 5g xylitol, 1g malt, 1.5g spinach, 4g corn starch, 18g yogurt, upper and lower fire temperature combination 70°C and 110°C as the optimal formula, and the sensory evaluation is the highest score of 89.3 points. Physical and chemical indicators detected that the total sugar of the finished product was 2.02%, vitamin C was 11.7mg / 100g, and the moisture was 3.84%, which met the food safety standards.

[0026] In a second aspect, an embodiment of the present invention provides a low-sugar malt spinach mixed yogurt soluble bean prepared according to the above-mentioned preparation method, wherein the soluble bean includes the following components: egg white: starch: xylitol: malt powder: spinach powder: yogurt in a mass ratio of 40:2-5:3-5:1-2:1-2:16-20.

[0027] (III) Beneficial effects

[0028] The beneficial effects of the present invention are as follows: a low-sugar malt spinach mixed yogurt soluble bean and a preparation method thereof, the present invention proceeds from cost saving and nutritional balance, uses malt, spinach and yogurt as raw materials to process soluble beans, covering cereals, vegetables and dairy products. Currently, existing soluble bean process research mostly uses fruit homogenate as one of the materials. The homogenate is easily affected by the environment due to its high water content and even deteriorates. The present invention attempts to make the material into powder instead of homogenate, reducing the impact of environmental changes on the intermediate material, which is beneficial to the storage of raw materials. At the same time, the key flavoring material malt in the formula and the corn starch used instead of milk powder are both relatively low in market price, which can save costs on raw materials. The malt spinach mixed yogurt soluble beans obtained by the present invention are light green, have uniform pores, melt in the mouth, have obvious sweet malt and milk aroma, and have broad market potential.

[0029] The amount of yogurt added mainly affects the shape and taste of the finished product. The more yogurt is added, the more difficult it is for the finished product to be three-dimensional, and the more pores are generated. At the same time, too much yogurt will form a hard core in the finished product, which is not conducive to the formation of its melt-in-the-mouth characteristic. The yogurt obtained by pre-treatment with the method of the present invention has a rich milky aroma, and the surface part appears light beige. The mixing process has less effect on the hard foamed egg white. The prepared soluble bean product has a more obvious milky aroma. Since the yogurt pre-treatment of the present invention adopts two steps of filtration and heat treatment; water is removed, the water content in the yogurt is further reduced, and the gaps in the soluble beans obtained by baking are relatively smaller, and the appearance is more three-dimensional.

[0030] The spinach powder obtained by pretreatment according to the method of the present invention is dark green (darker than the original color of spinach), has a lighter spinach fragrance, and the powder slightly absorbs water and agglomerates. The prepared soluble beans are more three-dimensional, have an unobvious spinach fragrance, are light green, have a delicate taste, and can be melted by light chewing.

[0031] The malt powder obtained by the pretreatment method of the present invention has caramel aroma and wheat grain aroma, and its color is light wheat color. The obtained bean curd product has light wheat aroma, dried vegetable aroma, and no egg smell.

[0032] The present invention explores the influence of malt pretreatment and addition amount on the dissolving quality of malt based on sensory evaluation, enriches malt products and improves the economic added value of barley.

[0033] Malt contains β-amylase and α-amylase, which can promote the digestion of starchy foods to a certain extent, and has the function of promoting digestion such as helping digestion and strengthening the spleen. In addition, malt can give food a certain crisp, loose and crunchy taste, and has a unique aroma and flavor of malt, which can be used in food processing to enrich food characteristics.

[0034] The present invention uses xylitol instead of sucrose, starch, yogurt (coagulated type), malt, and spinach as main raw materials, performs different pretreatments on yogurt, malt, and spinach, mixes and shapes in the same way and bakes, and explores the optimal solution for the process research of low-sugar malt spinach mixed yogurt dissolving beans through a five-factor four-level orthogonal experiment based on a single-factor experiment. The highest sensory evaluation score of the dissolving beans prepared by the present invention is 89.3 points, and the physical and chemical indicators detect that the total sugar of the finished product is 2.02wt%, the vitamin C is 11.7mg / 100g, and the water content is 3.84%, which meets the food safety standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of the preparation process of low-sugar malt spinach mixed with yogurt dissolved beans according to an embodiment of the present invention.

[0036] Figure 2 This is the appearance of the dissolved beans obtained by method 1 in Example 1.

[0037] Figure 3 This is the appearance of the soluble beans obtained by method 2 in Example 1.

[0038] Figure 4 This is the appearance of the soluble beans obtained by method three in Example 1.

[0039] Figure 5 This is the appearance of the yogurt obtained by method 1 in Example 2.

[0040] Figure 6 This is the appearance of the dissolved beans obtained by method 1 in Example 2.

[0041] Figure 7 This is the appearance of the yogurt obtained by the second method in Example 2.

[0042] Figure 8 This is the appearance of the soluble beans obtained by method 2 in Example 2.

[0043] Fig. 9 This is the appearance of the malt powder obtained by the method 1 in Example 3.

[0044] Fig.10 This is the appearance of the dissolved beans obtained by method 1 in Example 3.

[0045] Fig.11 This is the appearance of the malt powder obtained by the second method in Example 3.

[0046] Fig.12 This is the appearance of the dissolved beans obtained by method 2 in Example 3.

[0047] Fig.13 This is a comparison of the appearance of the finished soluble bean product prepared with the optimal formula of Example 4 and the soluble bean of the same flavor available on the market. DETAILED DESCRIPTION

[0048] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0049] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0050] The materials used in the embodiments of the present invention can be obtained commercially, and the reagents and instruments used are conventional reagents and instruments.

[0051] Example 1

[0052] This example discusses the effects of different pre-treatment methods for spinach. Figure 1The method for preparing low-sugar malt spinach mixed with yogurt beans in this embodiment comprises the following steps:

[0053] (1) Separate the egg white

[0054] Wash off the dirt on the surface of the eggshell and dry the water. Use an egg separator to separate the egg white from the yolk. Place them in a beaker, seal and refrigerate for later use. Be careful not to get the egg yolk or water contaminated during the process.

[0055] (2) Pretreatment of yogurt

[0056] Filter the water from the coagulated yogurt (filter through a 200-mesh sieve without dripping).

[0057] (3) Pretreatment of malt

[0058] After cleaning the raw malt, stir-fry and prepare it (preparation process: first use low heat at 60-80℃, stir-fry once every three minutes, during which there is a bitter and wet malt smell, stir-fry for about 15 minutes. Slightly adjust the high heat to raise the temperature to 85-100℃, increase the frequency of stir-frying, stir-fry once every half a minute, and stir-fry for about 10 minutes. Raise the temperature to 110-150℃, stir-fry continuously, during which there is an obvious burnt malt aroma, stir-fry for about 5 minutes to obtain the required processed malt.) The surface is slightly burnt yellow, with a rich and sweet malt aroma, then dry, break it and sieve it through 200 mesh for later use.

[0059] (4) Different pre-treatment methods of spinach

[0060] Method 1: Remove old leaves from spinach, wash and cut the rhizomes, and pulp them. Use food-grade filter cloth to squeeze and filter. To promote filtration and make full use of the materials, add appropriate amount of edible water. Take the filtrate and evaporate it in a water bath for later use.

[0061] Method 2: Remove old leaves and roots from spinach, wash them, shake off the moisture and then dry them (blast drying: the baking temperature is set to 50°C and the wind speed is set to 1m / s), then use a crusher to break it into fine powder and sieve it through 200 mesh for later use.

[0062] Method 3: Remove old leaves and roots from spinach, wash them, blanch them and dry them (blast drying: baking temperature is set at 50°C, wind speed is set at 1m / s), wherein the blanching conditions are 10% (m / v) material-water ratio, 0.2wt% anhydrous sodium bicarbonate solution for color protection, water temperature is 80°C, and blanching is performed for 20s. The dried spinach is crushed into fine powder with a crusher and sieved through 200 mesh for later use.

[0063] (5) Whipping egg white

[0064] Take 40 g of egg white and beat it at high speed (1030 rpm) until foamy, then add 3 g of corn starch, 5 g of xylitol, 2 g of malt powder obtained in step (3), and 2 g of spinach powder obtained in step (4) separately, and continue beating (beating while adding, and note that during the adding process, the powder should be mixed in first and then beaten at high speed) until hard foam is formed, i.e., a clear ring-shaped texture is formed, and the egg white hangs on the whisk without dripping and forms a peak.

[0065] Wherein, for the spinach pulp of step (4) method 1, adding it when the egg white is being beaten will cause the egg white to defoam and become difficult to re-foam. Instead, it is better to mix it with the yogurt thoroughly and then add it during the yogurt stirring process.

[0066] (6) Mixing and molding

[0067] Gently add 20g of pre-treated yogurt into the whipped egg white, mix the two by turning them over, quickly transfer to a piping bag, and bake immediately after the piping is formed.

[0068] (7) Baking

[0069] The oven needs to be preheated in advance (bottom fire 75℃, top fire 100℃) for about five minutes, and the baking conditions are set to bottom fire 75℃, top fire 100℃, and bake for 50 minutes (observe the state of the finished product at the end of baking and adjust the time appropriately (±10min).

[0070] (8) Storage

[0071] The obtained soluble bean product is stored in a pasteurized glass sealed jar.

[0072] Example 2

[0073] This example discusses the effects of different pre-treatment methods for yogurt. Figure 1 The method for preparing low-sugar malt spinach mixed with yogurt beans in this embodiment comprises the following steps:

[0074] (1) Separate the egg white

[0075] Wash off the dirt on the surface of the eggshell and dry the water. Use an egg separator to separate the egg white from the yolk. Place them in a beaker, seal and refrigerate for later use. Be careful not to get the egg yolk or water contaminated during the process.

[0076] (2) Different pretreatment methods of yogurt

[0077] Method 1: Filter out the water from the solidified yogurt (filter through a 200-mesh sieve without dripping).

[0078] Method 2: Filter the water from the coagulated yogurt (filter through a 200 mesh sieve without dripping), place it in a blast drying oven at 58°C with a wind speed of 1m / s for 10 minutes, and then take it out. Appropriate heat treatment can optimize the texture, viscosity, and pH stability of the yogurt, but too high a temperature can denature the protein in the yogurt and even produce harmful substances. Based on the influence of various factors, the heat treatment condition of the yogurt is set to 58°C for 10 minutes.

[0079] (3) Pretreatment of malt

[0080] After washing the raw malt, stir-fry it (the surface is slightly browned and has a rich and sweet malt aroma), dry it, break it, and sieve it through 200 mesh for later use.

[0081] (4) Pretreatment of spinach

[0082] Remove old leaves from spinach, wash the rhizomes, blanch and dry (blast drying: baking temperature set at 50°C, wind speed set at 1m / s), wherein the blanching conditions are 10% (m / v) material-water ratio, 0.2wt% anhydrous sodium bicarbonate solution for color protection, water temperature 80°C, blanching for 20s. The dried spinach is crushed into fine powder with a crusher and sieved through 200 mesh for later use.

[0083] The subsequent steps are the same as in Example 1.

[0084] Example 3

[0085] This example discusses the effects of different pretreatment methods for malt. Figure 1 The method for preparing low-sugar malt spinach mixed with yogurt beans in this embodiment comprises the following steps:

[0086] (1) Separate the egg white

[0087] Wash off the dirt on the surface of the eggshell and dry the water. Use an egg separator to separate the egg white from the yolk. Place them in a beaker, seal and refrigerate for later use. Be careful not to get the egg yolk or water contaminated during the process.

[0088] (2) Pretreatment of yogurt

[0089] Filter the water from the coagulated yogurt (filter through a 200-mesh sieve without dripping), place in a blast drying oven at 58°C, wind speed 1m / s, treat for 10 minutes, then take out for use.

[0090] (3) Different pre-treatment methods of malt

[0091] Method 1: Wash the raw malt, stir-fry it (the surface is slightly browned and has a rich and sweet malt aroma), then dry it, break it and sieve it through 200 mesh for later use.

[0092] Method 2: Wash and dry the raw malt, crush it and sieve it through 200 mesh for later use.

[0093] (4) Pretreatment of spinach

[0094] Remove old leaves from spinach, wash the rhizomes, blanch and dry (blast drying: baking temperature set at 50°C, wind speed set at 1m / s), wherein the blanching conditions are 10% (m / v) material-water ratio, 0.2wt% anhydrous sodium bicarbonate solution for color protection, water temperature 80°C, blanching for 20s. The dried spinach is crushed into fine powder with a crusher and sieved through 200 mesh for later use.

[0095] The subsequent steps are the same as in Example 1.

[0096] The results of Examples 1-3 are analyzed as follows:

[0097] (1) Sensory evaluation

[0098] Fifteen food-related professional sensory evaluators who have no special taste preferences were invited to objectively evaluate the experimental finished products based on the sensory evaluation form (see Table 1).

[0099] Table 1: Sensory evaluation criteria

[0100]

[0101] (2) Effects of different pretreatment methods on spinach, yogurt and malt

[0102] The appropriate pretreatment methods of spinach, yogurt and malt were selected based on the average sensory score of the final product, and used as the pretreatment methods for subsequent single factor and orthogonal experimental designs. The sensory score was the average of the 15 independent evaluations by sensory evaluators, excluding the lowest and highest scores.

[0103] Table 2: Effect of different pre-treatment methods of spinach on experiment in Example 1

[0104]

[0105] Combination Figure 2-4 Table 2 compares the three pre-treatment methods of spinach. The sensory score of method 3 is 76.8 points, which is higher than that of method 2 and method 3. At the same time, from the product appearance, the product obtained by method 3 is more three-dimensional and the color is brighter, which is obviously better than method 1 and method 2. The sample obtained by method 1 after water evaporation has the best taste, the equipment cost is low, and it is suitable for home production, but the utilization of materials is the lowest, it is labor-intensive and not suitable for large-scale mass production. In addition, the main reason for the low sensory score of the dissolved beans under this method is the collapse of its shape (such as Figure 2 ), if baking is done in a baking mold, significant improvement can be achieved.

[0106] The second method has a relatively short operation time and can be used for pre-treatment of factory experiments. However, this method will destroy the vacuoles of spinach cells, causing their color to change, and the aroma of spinach will become lighter during heat treatment.

[0107] The third method adds a color protection treatment on the basis of the second method, and the blanching makes the evaporation of the spinach water relatively gentle, so that the final product is not bitter, but the blanching destroys the aromatic substances of the spinach to a certain extent.

[0108] Table 3: Effect of different pre-treatment methods of yogurt in Example 2

[0109]

[0110] After testing, the yogurt treated by method 1 of Example 2 ( Figure 5 ), the viscosity is 1000-2000CP. This yogurt is thicker than the original commercial yogurt, which can increase the viscosity of the protein and reduce the impact of stirring on the foamed protein, which is conducive to the formation of a more three-dimensional shape of the finished product. However, from the gloss on the surface of the yogurt, it can be found that the yogurt has a high water content, so the shape of the final product is not as beautiful as the method 2 (reference Figure 6 , 8). Figure 7 The yogurt processed by method 2 of Example 2 is slightly darker in color than that processed by method 1 and has a harder texture. The finished product of the yogurt processed by this method has obvious advantages in appearance.

[0111] From the experimental study on the effects of different pre-treatments of yogurt on the finished product, it can be found that moisture has a very important influence on the formation of yogurt. At the same time, because the baking process is also a process of water evaporation, the moisture content of the finished product before baking also has some influence on the pore size and the color of the finished product. Therefore, Example 2 uses two methods to try to reduce the moisture content of yogurt. Figure 5-Figure 8 Comparing the two methods, from the perspective of sensory evaluation, the difference between the two is small, but it can still be concluded that method 2 with 78.7 points is better than method 1. The direct filtration method is obviously more convenient to operate, and it can better retain the original quality of yogurt. The difference of the second method is that the heat treatment of forced air drying is added. This method can significantly thicken the yogurt, and the Maillard reaction makes the yogurt aroma more mellow and attractive. However, since yogurt is rich in whey protein, heat treatment can easily denature the protein and produce harmful substances, so the heat treatment temperature and time need to be reasonably controlled.

[0112] Table 4: Effect of different pre-treatment methods of malt in Example 3

[0113]

[0114] Fig. 9 and Fig.11 is the malt powder obtained after different pretreatments in Example 3, Fig.10 and Fig.12 The soluble beans were prepared by using the malt powder obtained by method 1 of Example 3 and method 2 of Example 3 as raw materials, and the soluble beans were prepared by combining Table 4 and Figure 9-12It can be seen that method 1 is significantly better than method 2. Processed malt has only one more frying process than raw malt, but the resulting powder has a very different smell and taste. The effects of the two are also different, and different processing methods can be targeted at different needs. For example, processed malt has a more obvious digestion effect than raw malt, but the malt used in the experiment is of smaller mass, and its main function lies in its taste and aroma. At the same time, the same weight of raw malt is smaller in volume than processed malt, which is conducive to the formation of the finished bean dissolving product. In terms of technology, there are many factors affecting the processing of malt, and the frying time and the firepower used are highly uncertain, and the resulting product is also uncertain. When the frying time is short, the malt powder is prone to moisture and agglomeration, which will cause the egg white to fail to be whipped and cannot be formed. When the malt is fried for a long time, or even black coke appears, the resulting malt powder is dark in color, and the appearance of the produced dissolving beans is prone to dark yellow and brown, and the taste is slightly bitter.

[0115] Based on the results of the above sensory evaluation, it can be concluded that the most suitable pre-treatment method for spinach is blanching to protect the color (water ratio of 10%, 80℃, 0.2% anhydrous sodium bicarbonate) followed by air blowing (50℃, 1m / s) to dry and grind the yogurt, while the most suitable pre-treatment method is to filter and then heat-treat (58℃, 1m / s), and the most suitable pre-treatment method for malt is to fry and dry it before grinding.

[0116] Example 4

[0117] Based on the basic formula, change a single factor to explore the effect of a single factor on the experimental product, in preparation for subsequent orthogonal experiments. The basic formula of the experiment is 40g egg white, 20g yogurt, 3g corn starch, 2g malt powder, 2g spinach powder, and 5g xylitol. The baking conditions are set at 75℃ for the bottom fire, 100℃ for the top fire, and 50min for baking. Among them, in addition to exploring the single factor content of the experiment, the egg white whipping time, the order of adding each material, the number of egg white flipping and the method are all kept consistent. The baking time can be adjusted appropriately according to the actual situation.

[0118] 1. Effect of yogurt addition on the quality of dissolved beans

[0119] Based on 40g egg white, 3g corn starch, 2g malt powder, 2g spinach powder and 5g xylitol, the added amounts of yogurt were set to 16.0g, 18.0g, 20.0g, 22.0g, 24.0g and 26.0g respectively, and experiments were carried out, and the obtained soluble bean products were analyzed and evaluated in time.

[0120] 2. Effect of corn starch addition on soy bean quality

[0121] Based on 40g egg white, 20g yogurt, 2g malt powder, 2g spinach powder and 5g xylitol, the added amounts of corn starch were set to 2g, 3.0g, 4.0g, 5.0g, 6.0g and 7.0g respectively, and experiments were carried out, and the obtained soluble bean products were analyzed and evaluated in time.

[0122] 3. The effect of malt powder addition on the quality of dissolved beans

[0123] Based on 40g egg white, 20g yogurt, 3g corn starch, 2g spinach powder and 5g xylitol, the added amounts of malt powder were set to 0g, 0.5g, 1.0g, 1.5g, 2.0g, 2.5g and 3.0g respectively, and the finished bean-soluble products were analyzed and evaluated in time.

[0124] 4. Effect of spinach powder addition on the quality of dissolved beans

[0125] Based on 40g egg white, 20g yogurt, 3g corn starch, 2g malt powder and 5g xylitol, the added amounts of spinach powder were set to 0.5g, 1.0g, 1.5g, 2.0g, 2.5g and 3.0g respectively for experiments, and the finished products were analyzed and evaluated in time.

[0126] 5. The influence of roasting temperature on the quality of dissolved beans

[0127] With 40g egg white, 20g yogurt, 3g corn starch, 2g malt powder, 2g spinach powder and 5g xylitol as the basis, the baking temperatures were set to 60 / 90, 60 / 100, 70 / 90, 70 / 100, 70 / 110, 80 / 100 and 80 / 110 (bottom heat / top heat, unit: °C) respectively for experiments, and the finished products were analyzed and evaluated in time.

[0128] 6. Orthogonal experiment to optimize the processing technology of low-sugar malt spinach mixed with yogurt and soy bean

[0129] According to the results of the above single-factor experiment, the appropriate addition amount of each factor and baking temperature were selected to establish an orthogonal experimental design with five factors and four levels.

[0130] Table 5: Factor level table

[0131]

[0132] Fifteen food-related professional sensory evaluators with no special taste preferences were invited to objectively evaluate the finished experimental products based on the sensory evaluation table 3. The sensory score was the average of the fifteen sensory evaluators' independent evaluations, excluding the highest and lowest scores.

[0133] 1. Effect of yogurt addition on the quality of dissolved beans

[0134] The amount of yogurt added mainly affects the shape and taste of the finished product. The more yogurt is added, the harder it is to form a three-dimensional shape, and the more pores are produced. At the same time, too much yogurt will form a hard core in the finished product, which is not conducive to the formation of its melting-in-the-mouth characteristic. However, the addition of yogurt is the key to obtaining milk flavor. Combining various factors, it can be obtained from Table 6 that the optimal amount of yogurt added is 18g. When the amount added is less than 18g, the score of the sensory evaluation increases with the increase of the amount added. When the amount added is greater than 18g, the score decreases with the increase of the amount added.

[0135] Table 6: Effect of yogurt addition on soy bean quality

[0136]

[0137]

[0138] 2. Effect of corn starch addition on soy bean quality

[0139] The appropriate amount of starch added can improve the viscosity, emulsification and foaming stability of the protein, but excessive starch will make the finished product have a noticeable gritty feeling and even a hard core. Taking all factors into consideration, it can be seen from Table 7 that the optimal amount of starch added is 4g. When the amount added is less than 4g, the sensory evaluation score increases with the increase of the amount added, and when the amount added is greater than 4g, the score decreases with the increase of the amount added.

[0140] Table 7: Effect of starch addition on soy bean quality

[0141]

[0142] 3. The effect of malt powder addition on the quality of dissolved beans

[0143] The rich aroma of malt can well cover the egg smell and also cover a certain amount of spinach smell. At the same time, because it contains maltose, the addition of malt powder should be reduced to the extent of covering the egg smell. The granularity of malt powder is much smaller than that of spinach powder, so the addition of malt powder has little effect on the grittiness of the finished product and has little effect on the taste score. Taking all factors into consideration, it can be seen from Table 8 that the optimal addition amount of malt powder is 1g. When the addition amount is less than 1g, the score of sensory evaluation increases with the increase of the addition amount. When the addition amount is greater than 1g, the score decreases with the increase of the addition amount.

[0144] Table 8: Effect of malt powder addition on bean dissolving quality

[0145]

[0146] 4. Effect of spinach powder addition on the quality of dissolved beans

[0147] The amount of spinach powder added mainly affects the color of the finished product, while the change in spinach aroma is difficult to distinguish in a change of 0.5g. In addition, since the particles of spinach powder are coarse and easy to clump, adding too much will increase the difficulty of protein foaming and make the taste slightly sandy. Taking into account the influence of various factors, it can be seen from Table 9 that the optimal amount of spinach powder added is 1.5g. When the amount added is less than 1.5g, the score of sensory evaluation increases with the increase of the amount added, and when the amount added is greater than 1.5g, the score decreases with the increase of the amount added.

[0148] Table 9 Effect of spinach powder addition on soy bean quality

[0149]

[0150]

[0151] 5. The influence of roasting temperature on the quality of dissolved beans

[0152] In the oven, the bottom of the molten beans is easier to burn than the surface, so the temperature of the top fire needs to be higher than that of the bottom fire, and the temperature difference makes the overall color and crispness of the molten beans more uniform. If the temperature of the top fire is too high, the molten beans will shrink, and if the temperature is too low, the taste will become soft. In the preliminary experimental exploration, it was found that the temperature difference between the bottom fire and the top fire should be at least 20°C, and at most 40°C, which can reduce collapse and burning while ensuring the dehydration of the finished product. Taking all factors into consideration, it can be seen from Table 10 that the optimal temperature is 70°C for the bottom fire and 110°C for the top fire. The adjustment of temperature is also related to the baking time. During the baking process, the experiment observes the state of the finished product and makes slight adjustments to the time to obtain better results.

[0153] Table 10: Effect of roasting temperature on dissolving quality

[0154]

[0155] 6. Analysis of orthogonal experimental results

[0156] Table 11: Five factors and four levels

[0157]

[0158]

[0159]

[0160] As can be seen from Table 11, yogurt has the greatest impact on the quality of the dissolved beans. As the amount of yogurt added increases, the finished product collapses more, the pores increase, and a tiny hard core appears in the taste. pH and viscosity are important factors affecting the foaming and foaming stability of egg white protein. The addition of yogurt affects the pH and viscosity of the foaming egg white, causing the foaming egg white to defoam to a certain extent, the foam becomes larger, and the shape and taste of the finished product change. The secondary factor affecting the quality of the dissolved beans is spinach. Spinach plays a key role in the color of the finished product and is the source of the color of the finished product. At the same time, spinach has a strong aroma after drying, which contributes to the aroma of the finished product and forms a special yogurt aroma. However, the particle size of spinach is larger, and its presence makes the finished product have a slight sandy feeling. The addition of malt has a certain similarity with the effect of vinegar or lemon, which is mainly to cover up the egg smell. The difference is that malt increases the obvious sweet malt aroma of the finished product, making the finished product more popular with the public. Temperature ranks last among the primary and secondary factors and is related to the baking time. One of the advantages of the baking process is that the experimenter can observe the baking process and adjust the baking time appropriately based on the macroscopic performance of the finished product. This can avoid the impact of overheating on the finished product to a certain extent and improve the success rate of the experiment.

[0161] The predicted values ​​for the optimal formula are 1g malt, 1.5g spinach, 4g corn starch, 18g yogurt, and the upper and lower heat temperature combinations are 70℃ and 110℃.

[0162] The predicted optimal formula obtained by three parallel experiments has the highest average sensory score of 89.3 points. The optimal formula of low-sugar malt spinach mixed with yogurt beans based on the influence of various factors is 1g malt, 1.5g spinach, 4g corn starch, 18g yogurt, and the upper and lower heat temperature combination is 70℃ / 110℃.

[0163] Example 5

[0164] The finished bean dissolving product prepared by the present invention has obvious advantages in taste and nutritional balance compared with the commercially available bean dissolving product with the same flavor (spinach). Fig.13 As shown, the finished bean dissolving product prepared by the present invention has the same surface as the commercially available bean dissolving product and has relatively uniform and fine pores ( Fig.13 The pores in the interior and bottom of the commercially available product are obviously larger and more numerous ( Fig.13 The finished bean curd prepared by the present invention has a sweet wheat aroma, no milk or egg smell, and is sweet but not greasy; the commercially available product has a strange milk smell, a lighter taste, and tends to produce a greasy feeling.

[0165] Example 6

[0166] The optimal formula: 1g malt, 1.5g spinach, 4g corn starch, 18g yogurt, the physical and chemical indicators of the soluble beans prepared at the upper and lower fire temperature combination of 70℃ / 110℃ are as follows:

[0167] 1. Moisture

[0168] The moisture content of the finished soluble bean product was tested with an infrared rapid moisture analyzer according to the instrument operation steps. The moisture content of the soluble bean was 3.84%, which is relatively low. The product meets the moisture content requirements of egg round biscuits in the general rules for biscuits GBT20980-2021.

[0169] The moisture content of the beans is greatly affected by the degree of roasting. Prolonging the roasting time appropriately can reduce the moisture content of the finished product, making it crispier. Lower moisture content can extend the shelf life of food and prevent it from being infected by microorganisms. At the same time, moisture content will also affect the taste and texture of the finished product. During storage, the finished product should be prevented from absorbing moisture as much as possible.

[0170] 2. Total Sugar

[0171] Referring to the total sugar determination method in "Determination of total sugar content in low-sugar candies" by Luo Suiyin et al. and processing the soluble bean samples according to the actual situation, the total sugar of the soluble bean finished product was detected by direct titration method, and the total sugar (calculated as invert sugar) was measured to be 2.02%. The absolute difference of three independent determination results was 0.026, which was less than 1.5% of the arithmetic mean.

[0172] Among the domestic brands of soluble beans currently sold on Taobao, only Chongxiang sells spinach flavored soluble beans. Taking the bottled fruit and vegetable spinach flavored soluble beans sold by Pingyuan Zhenghuo Food Co., Ltd. as an example, its ingredients are egg white, skim milk powder, trehalose, spinach juice, yogurt, lactic acid bacteria fermented milk, 5% oligofructose and edible corn starch. Its total sugar content was measured in the same way as 69.92%. In comparison, the total sugar content of the finished product is approximately one-thirtieth of that of the product, and the total sugar content is lower.

[0173] 3. Vitamin C

[0174] The vitamin C content of the finished bean dissolving product was tested by the third method 2,6-dichloroindophenol titration method of national standard GB5009.86-2016. The vitamin C content of the finished bean dissolving product was measured to be 11.7 mg / 100 g. Taking spinach as a reference, the vitamin C loss rate of the finished bean dissolving product was 59.5%.

[0175] Vitamin C plays an important role in maintaining normal physiological functions of the human body. The recommended dietary intake for Chinese residents stipulates that the recommended daily intake of vitamin C for adults is 30-500 mg / day. At the same time, vitamin C is a natural antioxidant, which can prevent food nutrition loss, color change and oxidation rancidity to a certain extent, thereby extending the shelf life of the finished product.

[0176] 4. Total colony count and E. coli

[0177] The finished product of soluble bean was tested for food microbiology according to the national standard GB4789.2-2016 for total bacterial count and GB4789.3-2016 for coliform count method 1. The total bacterial count and E. coli count of the finished product of soluble bean were less than the standard value, which met the national standard.

[0178] Table 12: Microbiological assay results

[0179]

[0180] The present invention explores the optimal process of low-sugar malt spinach mixed with yogurt and beans: in the raw material pretreatment, spinach is blanched to protect color (air blast 50℃, 1m / s, material-water ratio 10%, 0.2% anhydrous sodium bicarbonate solution to protect color, water temperature 80℃, blanching 20s) and then dried to make powder, yogurt is filtered and then heat treated (58℃ wind speed 1m / s), malt is fried (to golden yellow, rich wheat aroma) and dried to make powder as the most suitable pretreatment method. Single factor and orthogonal experiments obtained 40g egg white as the main raw material, 5g xylitol, 1g malt, 1.5g spinach, 4g corn starch, 18g yogurt, and the upper and lower fire temperature combination of 70℃ and 110℃ is the optimal formula, and the sensory evaluation is the highest score of 89.3 points. Physical and chemical indicators detected that the total sugar of the finished product was 2.02%, vitamin C was 11.7mg / 100g, and the moisture was 3.84%, which met the food safety standards.

[0181] The finished product obtained in this study is light green, three-dimensional, uniform in pores, melts in the mouth, and has a distinct sweet wheat and milk aroma. Its total sugar content is approximately one thirty-fifth of the same flavor of soluble beans on the market, and it is a "low-sugar snack soluble bean" that can meet the needs of more consumers. The product has a high vitamin C content, and a balanced combination of grains, vegetables and dairy products to achieve balanced nutritional development. The product has certain nutritional value and market competitiveness.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing low-sugar malt spinach mixed with yogurt soluble beans, characterized in that: The steps include: S1, blanching and drying: the spinach is blanched with water, taken out, dried, crushed, and sieved to make spinach powder; the water temperature for blanching is 75-85°C, the blanching time is 15-20s, and anhydrous sodium bicarbonate solution is added during blanching; the sieving is through a 200-250 mesh sieve; S2. Yogurt pretreatment: After filtering out the water from the yogurt, heat treat it at 55-60℃ for 10-15min; S3, malt pretreatment: fry the raw malt, crush and sieve it after drying to make malt powder; S4, premixing: Beat the egg whites, and separately add starch, xylitol, the malt powder obtained in step S3, and the spinach powder obtained in step S1 during the beating process; S5, preparation of soybean milk: adding the yogurt obtained in step S2 to the egg white obtained in step S4, and stirring evenly to obtain soybean milk; S6, preparation of soluble beans: extruding and molding the soluble bean slurry, and baking to obtain soluble beans; In step S1, old leaves and rhizomes are removed from the spinach before blanching, and then the spinach is washed; In step S2, the yogurt is a set yogurt; the method for filtering water from the yogurt is to filter with a 200-250 mesh sieve until no dripping occurs; In step S3, the method for frying raw malt includes: heating to a temperature of 60-80°C and stir-frying for 15-20 minutes, with a stir-frying frequency of 3-3.5 minutes per time; heating to 85-100°C, stir-frying for 10-15 minutes, with a stir-frying frequency of 0.2-0.5 minutes per time; heating to 110-150°C, and stir-frying continuously for 3-5 minutes; the sieving is sieving through a 200-250 mesh sieve; The mass ratio of egg white, starch, xylitol, malt powder, spinach powder and pre-treated yogurt is 40:2-5:3-5:1-2:1-2:16-20.

2. The method for preparing the low-sugar malt spinach mixed with yogurt soluble beans according to claim 1, characterized in that: The total sugar content of the soluble beans is 2.02±0.026 wt %.

3. The method for preparing low-sugar malt spinach mixed with yogurt soluble beans according to claim 1, characterized in that: In step S1, the mass volume ratio of the blanching material to water is 10-15%; the concentration of anhydrous sodium bicarbonate in the anhydrous sodium bicarbonate solution is 0.2-0.5wt%.

4. The method for preparing the low-sugar malt spinach mixed with yogurt soluble beans according to claim 1, characterized in that: The starch is corn starch.

5. The method for preparing the low-sugar malt spinach mixed with yogurt soluble beans according to claim 1, characterized in that: The baking conditions in step S6 are: bottom temperature 70-80° C., top temperature 100-110° C., and the baking time is 40-60 min.

6. The low-sugar malt spinach mixed yogurt soluble bean prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The bean dissolving agent comprises the following components: the mass ratio of egg white: starch: xylitol: malt powder: spinach powder: yogurt is 40:2-5:3-5:1-2:1-2:16-20.

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