High-protein low-beany-flavor pea yoghurt and preparation process thereof

Abstract

The invention discloses high-protein low-beany-flavor pea yoghourt and a preparation process thereof, and the process comprises the following steps: step (1), adding pea protein powder into water, and uniformly mixing to obtain pea protein liquid; adding oligosaccharide into the pea protein solution, and stirring until the oligosaccharide is dissolved to obtain a mixed raw material solution; (2) carrying out high-pressure homogenization treatment and high-temperature and high-pressure treatment on the mixed raw material liquid, naturally cooling to room temperature, and sieving to obtain mixed slurry; (3) adding alcohol dehydrogenase and aldehyde dehydrogenase into the mixed slurry, inoculating a fermenting agent, and fermenting to obtain a fermentation product; and (4) carrying out after-ripening treatment on the fermentation product to obtain the high-protein low-beany-flavor pea yoghourt after the after-ripening treatment is finished. The protein content of the pea yoghurt prepared by the process can reach 4g / 100g, and the pea yoghurt does not contain lactose and cholesterol and has better texture characteristics. The invention can solve the problem of serious beany flavor of the existing pea yoghurt.

Description

Technical Field

[0001] The invention relates to the technical field of pea yogurt, in particular to a high-protein, low-beany smell pea yogurt and a preparation process thereof. Background Art

[0002] According to statistics, about 2 / 3 of the world's population is lactose intolerant, so alternatives to traditional yogurt have received more attention. Plant-based yogurt can effectively avoid milk allergies, is more environmentally friendly, has zero cholesterol and more plant active substances. Pea protein yogurt is a good alternative to traditional yogurt. Pea protein is hydrolyzed and converted into flavor substances such as aldehydes under the action of lactic acid bacteria, giving yogurt a unique sweet and sour balance and mellow taste. However, the beany smell in pea yogurt seriously affects consumers' acceptance of it, resulting in a limited number of people eating it, which seriously restricts the market promotion of plant-based yogurt products. In addition, most of the existing pea yogurts are made by fermenting pea protein powder or pea powder mixed with milk. Because the higher the amount of pea protein added, the faster the pH drops during the yogurt fermentation process, resulting in poor water retention, hard texture and poor taste of the yogurt product.

[0003] Chinese patent CN109566747A discloses a pea protein vegan plant-based yogurt and its preparation method, which uses enzyme-assisted alkali dissolution and acid precipitation to extract pea protein. The pea protein has high solubility under acidic conditions, which can effectively avoid the problem of hard texture, poor taste and poor water retention caused by the rapid decrease of pH of existing pea yogurt during fermentation as the amount of peas added increases. And by hydrating the pea protein precipitate with anionic polysaccharides, the emulsification activity and emulsification stability of pea protein can be improved. However, this method has the following defects:

[0004] ① Adding more food additives such as flavor regulators. Over-reliance on flavor regulators may cause manufacturers to ignore the quality of soybean raw materials or the optimization of fermentation processes, affecting the basic quality of products; "too many additives" in the ingredient list may affect the trend of clean label products and reduce consumer trust. ② The production process is cumbersome, the cycle is long, and the time cost is high. ③ The protein content is not given, and the nutritional value is unknown. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide a high-protein, low-beany smell pea yogurt and a preparation process thereof, so as to solve the problem that the existing pea yogurt has a serious beany smell.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A preparation process of high-protein, low-beany flavor pea yogurt comprises the following steps:

[0008] Step (1), adding pea protein powder to water and mixing evenly to obtain pea protein liquid; adding oligosaccharide to the pea protein liquid and stirring until the oligosaccharide is dissolved to obtain a mixed raw material liquid;

[0009] Step (2), subjecting the mixed raw material liquid to high-pressure homogenization treatment and then high-temperature and high-pressure treatment, and after the high-temperature and high-pressure treatment, naturally cooling to room temperature and sieving to obtain a mixed slurry;

[0010] Step (3), adding alcohol dehydrogenase and aldehyde dehydrogenase to the mixed slurry, inoculating a starter culture for fermentation, and obtaining a fermentation product after the fermentation is completed;

[0011] Step (4), subjecting the fermented product to post-ripening treatment, after which the post-ripening treatment is completed, to obtain high-protein, low-beany odor pea yogurt.

[0012] The preparation process of the high-protein, low-beany flavor pea yogurt comprises the following steps: in step (1), the protein content in the pea protein powder is 75wt% to 80wt%; the oligosaccharide is sucrose and / or oligofructose; the mass volume ratio of the pea protein powder to water is 1g: (15-20)mL; and the amount of the oligosaccharide added is 3-8wt% of the mass of the pea protein liquid. The present invention is beneficial to improving the problems of excessive pH drop caused by excessive fermentation acid production during the fermentation of pea yogurt, hard texture of yogurt, poor taste, and poor water retention by controlling the protein content in the pea protein powder and the amount of oligosaccharide and water.

[0013] In the preparation process of the high-protein, low-beany smell pea yogurt, in step (1), the protein content in the pea protein powder is 80wt%; the oligosaccharide is sucrose; the mass volume ratio of the pea protein powder to water is 1g:20mL; and the amount of oligosaccharide added is 5wt% of the mass of the pea protein liquid.

[0014] In the preparation process of the high-protein, low-beany odor pea yogurt, in step (2), the conditions for high-pressure homogenization treatment are: temperature control at 4-60° C., 30-40 MPa, and single instantaneous treatment; the conditions for high-temperature and high-pressure treatment are: 120-130° C., 0.10-0.11 MPa, and 2-4 min; the mixed slurry is a slurry obtained by passing through a 180-mesh sieve, and passing through a 180-mesh sieve can remove denatured protein clots, protein aggregates, etc., so that the texture of the prepared yogurt is finer.

[0015] The preparation process of the above-mentioned high-protein, low-beany pea yogurt, in step (2), the conditions of high-pressure homogenization treatment are: temperature control 4°C, 30MPa, single instantaneous treatment; high-temperature and high-pressure treatment conditions are: 121°C, 0.10MPa, 3min. The present invention adopts the method of high-pressure homogenization first and then high-temperature and high-pressure treatment to obtain the mixed slurry because: high-pressure homogenization first can make the pea protein more evenly dispersed in the mixed slurry, and can also effectively break up protein aggregates and fat globules, eliminate the rough granularity in the pea protein slurry, refine the particles, and help improve the texture of yogurt; and the pea protein treated by the high-pressure homogenization process of the present invention can form a stable gel network structure under high-temperature and high-pressure conditions, which can better lock moisture, reduce whey precipitation, and help improve the water holding capacity of yogurt; in addition, the activity of lipoxygenase is passivated and inhibited under the high-pressure homogenization conditions of the present invention, which is conducive to reducing the generation of beany substances; after high-temperature and high-pressure treatment, most of the lipoxygenase is inactivated, blocking the generation of most beany substances. In addition, high temperature and high pressure treatment is conducive to reducing the content of trypsin inhibitors in pea protein powder, thereby improving the digestibility of pea protein. The traditional process usually involves high temperature and high pressure treatment followed by high pressure homogenization treatment, which will cause pea protein to easily aggregate during the high temperature and high pressure treatment process, and the network gel structure formed after high temperature and high pressure treatment is easily destroyed during the high pressure homogenization shear process, resulting in a high water separation rate, which not only affects the quality of yogurt, but also affects the subsequent double enzyme deodorization effect.

[0016] In the above-mentioned preparation process of high-protein and low-beany pea yogurt, in step (3), the amount of alcohol dehydrogenase added is 0.5-1.0wt% of the mass of the mixed slurry (if the amount of alcohol dehydrogenase used is less than 0.5wt% of the mass of the mixed slurry, the effect of removing the beany odor is not obvious. If the amount is too much, the ethanol content of the fermentation byproduct of lactic acid bacteria may be excessively reduced, resulting in a decrease in the flavor synergistic effect between the ethanol content and the lactic acid bacteria metabolites, making the yogurt flavor monotonous), and the amount of aldehyde dehydrogenase added is 0.5-1.0wt% of the mass of the mixed slurry (if the amount of aldehyde dehydrogenase is too much, the problem of excessive acid production will occur and affect the taste of yogurt. If the amount is too little, the effect of removing the beany odor is not obvious); the amount of the starter is 0.006-0.010wt% of the mass of the mixed slurry; in the starter, the content of live lactic acid bacteria is greater than or equal to 1×10 9CFU / 100g. The present invention adds a specific amount of dual enzymes (alcohol dehydrogenase and aldehyde dehydrogenase) and a fermentation agent to the mixed slurry at the same time, so that the removal of the beany smell is carried out simultaneously with the fermentation process, which not only saves time and improves production efficiency, but also can effectively reduce the content of the main source substances of the beany smell (hexanal, 2-pentylfuran, etc.); if the dual enzymes are added in any process before fermentation to remove the beany smell, not only the time cost will be increased, but also the uninactivated lipoxygenase in the mixed slurry will form a new beany smell during the fermentation process, thereby resulting in incomplete removal of the beany smell. The present invention controls the dosage of alcohol dehydrogenase and aldehyde dehydrogenase, the timing of adding the two enzymes, and the fermentation conditions (including the inoculation amount of the starter, the fermentation temperature, the fermentation time, etc.), so that the alcohol dehydrogenase and the aldehyde dehydrogenase can work synergistically, significantly reduce the content of beany substances such as caproic acid and 2-pentylfuran in yogurt, and have no adverse effects on the flavor and taste of the yogurt (the pH of the yogurt obtained by treating with the alcohol dehydrogenase and aldehyde dehydrogenase in the dosage of the present invention is basically the same as that of the untreated yogurt, and there is no problem of overacidity. In the detection of flavor substances, the butyric acid content of the two acids butyric acid and caproic acid detected did not increase, while the caproic acid content increased, but no difference was tasted in the sensory evaluation).

[0017] In the preparation process of the high-protein, low-beany odor pea yogurt, in step (3), the amount of alcohol dehydrogenase added is 0.5wt% of the mass of the mixed slurry, the amount of aldehyde dehydrogenase added is 0.5wt% of the mass of the mixed slurry; and the amount of the starter is 0.006wt% of the mass of the mixed slurry.

[0018] The preparation process of the high-protein, low-beany odor pea yogurt comprises the following steps: in step (3), the fermentation conditions are: 37-40° C., 8-12 h; in step (4), the post-ripening treatment conditions are: 4-6° C., 18-24 h; and after the post-ripening treatment, a sterilization treatment is performed, and the sterilization conditions are: 90-95° C., 5-10 min.

[0019] The preparation process of the high-protein, low-beany flavor pea yogurt, in step (1), the protein content in the pea protein powder is 80wt%; the oligosaccharide is sucrose; the mass volume ratio of the pea protein powder to water is 1g:20mL; the amount of the oligosaccharide added is 5wt% of the mass of the pea protein liquid;

[0020] In step (2), the conditions for high-pressure homogenization treatment are: temperature control at 4°C, 30MPa, single instantaneous treatment; the conditions for high-temperature and high-pressure treatment are: 121°C, 0.10MPa, 3min;

[0021] In step (3), the amount of alcohol dehydrogenase added is 0.5wt% of the mass of the mixed slurry, and the amount of aldehyde dehydrogenase added is 0.5wt% of the mass of the mixed slurry; the amount of the starter is 0.006wt% of the mass of the mixed slurry; the content of live lactic acid bacteria in the starter is greater than or equal to 1×109 CFU / 100g; fermentation conditions: 37°C, 10h (under this fermentation condition, the activities of alcohol dehydrogenase, aldehyde dehydrogenase and lactic acid bacteria are most ideal);

[0022] In step (4), the post-ripening treatment conditions are: 4°C, 24h; after the post-ripening treatment, sterilization treatment is also carried out, and the sterilization conditions are: 90°C, 10min.

[0023] A high-protein, low-beany flavor pea yogurt is prepared by adopting the preparation process of the high-protein, low-beany flavor pea yogurt, has a protein content greater than or equal to 4g / 100g, and does not contain lactose and cholesterol.

[0024] The technical solution of the present invention achieves the following beneficial technical effects:

[0025] 1. The process for preparing high-protein, low-beany odor pea yogurt of the present invention uses pea protein powder with a protein content of 75wt% to 80wt% as a raw material, adds sucrose and / or oligofructose in a specific proportion to replace the traditional yogurt raw material milk, and can prepare pea yogurt that does not contain lactose and cholesterol and has a good taste and fine texture without adding ingredients such as stabilizers and thickeners; by reasonably controlling the ratio of pea protein powder, oligosaccharides and water, and subjecting the mixed raw material liquid to high-pressure homogenization and high-temperature and high-pressure treatment under specific conditions in sequence, not only can the lipoxygenase in the pea protein be inactivated, but also a mixed slurry with a uniform and stable network gel structure can be obtained, which provides favorable conditions for the subsequent removal of the beany odor and the fermentation to form yogurt with a fine texture.

[0026] 2. The present invention adds a specific amount of alcohol dehydrogenase and acetaldehyde dehydrogenase during the fermentation process. Under the fermentation conditions of the present invention, the content of the main source of beany smell in yogurt (hexanal, 2-pentylfuran, etc.) can be effectively reduced, thereby effectively removing the beany smell of yogurt, and preparing pea yogurt with high protein content and low beany smell. The pea yogurt prepared by the high-protein and low-beany smell pea yogurt preparation process of the present invention does not contain lactose and cholesterol, has good texture characteristics, and is suitable for lactose intolerance and vegetarian people to drink. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the process flow for preparing high-protein, low-beany flavor pea yogurt according to Example 1 of the present invention;

[0028] Figure 2 Actual photos of the high-protein, low-beany odor pea yogurt prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] Example 1

[0030] like Figure 1As shown, the preparation process of the high-protein, low-beany flavor pea yogurt of this embodiment comprises the following steps:

[0031] Step (1), adding 10 g of pea protein powder to 200 mL of water and mixing evenly to obtain a pea protein liquid; adding 10.5 g of white sugar to the pea protein liquid and stirring until dissolved to obtain a mixed raw material liquid; in this embodiment, the protein content in the pea protein powder used is 80 wt%; the sucrose content in the white sugar is 99.5 wt%.

[0032] Step (2), subjecting the mixed raw material liquid to high pressure homogenization treatment and then high temperature and high pressure treatment, cooling naturally to room temperature after the high temperature and high pressure treatment and passing through a 180 mesh sieve to obtain a mixed slurry; the conditions for the high pressure homogenization treatment are: temperature control at 4°C, 30MPa, single instantaneous treatment; the conditions for the high temperature and high pressure treatment are: 121°C, 0.10MPa, 3min.

[0033] Step (3), adding 1g of alcohol dehydrogenase and 1g of aldehyde dehydrogenase to 200g of the mixed slurry, and inoculating 0.012g of the fermentation agent for fermentation at 37°C for 10h, and fermentation to obtain a fermentation product; the alcohol dehydrogenase is ethanol dehydrogenase (ADH) produced by Shandong Huamei Biotechnology Co., Ltd., CAS No. 9031-72-5, and the purity is 99wt%; the aldehyde dehydrogenase is acetaldehyde dehydrogenase (ALDH) produced by Shandong Huamei Biotechnology Co., Ltd., CAS No. 9028-86-8, and the purity is 99wt%; the fermentation agent is a direct-injection fermentation agent produced by Hebei Yiran Biotechnology Co., Ltd., including Lactobacillus bulgaricus and Streptococcus thermophilus, and the viable bacterial content is ≥1×10 9 CFU / 100g.

[0034] Step (4), post-ripening the fermentation product at 4° C. for 24 hours to obtain high-protein, low-beany flavor pea yogurt.

[0035] Example 2

[0036] The preparation process of the high-protein, low-beany flavor pea yogurt of this embodiment comprises the following steps:

[0037] Step (1), adding 10g of pea protein powder to 200mL of water and mixing evenly to obtain a pea protein liquid; adding 10.5g of oligofructose to the pea protein liquid and stirring until dissolved to obtain a mixed raw material liquid; in this embodiment, the protein content in the pea protein powder used is 80wt%; the content of oligofructose in the oligofructose is greater than or equal to 95wt%, and the content of glucose+sucrose+fructose is less than or equal to 5wt%.

[0038] Step (2), subjecting the mixed raw material liquid to high pressure homogenization treatment and then high temperature and high pressure treatment, cooling naturally to room temperature after the high temperature and high pressure treatment and passing through a 180-mesh sieve to obtain a mixed slurry; the conditions for the high pressure homogenization treatment are: temperature control at 4°C, 30MPa, single instantaneous treatment; the conditions for the high temperature and high pressure treatment are: 130°C, 0.11MPa, 2min.

[0039] Step (3), adding 1g of alcohol dehydrogenase and 1.5g of aldehyde dehydrogenase to 200g of the mixed slurry, and inoculating 0.012g of the fermentation agent for fermentation at 37°C for 10h, and fermentation to obtain a fermentation product; the alcohol dehydrogenase is ethanol dehydrogenase (ADH) produced by Shandong Huamei Biotechnology Co., Ltd., CAS No. 9031-72-5, and the purity is 99wt%; the aldehyde dehydrogenase is acetaldehyde dehydrogenase (ALDH) produced by Shandong Huamei Biotechnology Co., Ltd., CAS No. 9028-86-8, and the purity is 99wt%; the fermentation agent is a direct-injection fermentation agent produced by Hebei Yiran Biotechnology Co., Ltd., including Lactobacillus bulgaricus and Streptococcus thermophilus, and the viable bacterial content is ≥1×10 9 CFU / 100g.

[0040] Step (4), post-ripening the fermentation product at 5° C. for 24 h, and then treating it at 90° C. for 10 min to inactivate the lactic acid bacteria and the double enzymes, and naturally cooling it to room temperature after the sterilization treatment to obtain high-protein, low-beany odor pea yogurt.

[0041] Comparative Example 1

[0042] The difference between this comparative example and the embodiment is that in step (3), no alcohol dehydrogenase and aldehyde dehydrogenase are added. The other steps and process parameters are the same as those in the embodiment.

[0043] Comparative Example 2

[0044] The difference between this comparative example and the embodiment is that in step (3), only alcohol dehydrogenase is added. The other steps and process parameters are the same as those in the embodiment.

[0045] Comparative Example 3

[0046] The difference between this comparative example and the example is that in step (3), only aldehyde dehydrogenase is added. The other steps and process parameters are the same as those in the example.

[0047] Comparative Example 4

[0048] The difference between this comparative example and the embodiment is that in step (2), the high temperature and high pressure treatment temperature is changed to 100° C. The other steps and process parameters are the same as those in the embodiment.

[0049] Comparative Example 5

[0050] The difference between this comparative example and the embodiment is that in step (2), the high temperature and high pressure treatment temperature is changed to 150° C. The other steps and process parameters are the same as those in the embodiment.

[0051] Comparative Example 6

[0052] The difference between this comparative example and the embodiment is that in step (2), the high temperature and high pressure treatment time is changed to 10 minutes. The other steps and process parameters are the same as those in the embodiment.

[0053] Comparative Example 7

[0054] The difference between this comparative example and the embodiment is that in step (2), high temperature and high pressure treatment is first performed and then high pressure homogenization treatment is performed. The other steps and process parameters are the same as those of the embodiment.

[0055] Comparative Example 8

[0056] The difference between this comparative example and the embodiment is that in step (3), 1 g of alcohol dehydrogenase and 1 g of aldehyde dehydrogenase are added to 200 g of the mixed slurry respectively, and then the mixture is kept at 37° C. for 1 h, and then the fermentation agent is inoculated for fermentation (the fermentation conditions are still 37° C. for 10 h). The other steps and process parameters are the same as those in the embodiment.

[0057] Comparative Example 9

[0058] The difference between this comparative example and the embodiment is that in step (1), pea starch is used instead of white sugar, and the other steps and process parameters are the same as those in the embodiment.

[0059] The protein content and main beany flavor source substances in the yogurts prepared in Example 1, Example 2, and Comparative Examples 1 to 9 were measured, and sensory evaluation was performed. The method for measuring the protein content in the yogurt was: Kjeldahl nitrogen determination method; the method for measuring the content of hexanal, the main source substance of beany flavor, was: headspace-gas chromatography-mass spectrometry; the method for measuring the content of 2-pentylfuran, the main source substance of beany flavor, was: headspace-gas chromatography-mass spectrometry. The sensory evaluation standards are shown in Table 1.

[0060] Table 1 Sensory evaluation standards for yogurt

[0061]

[0062]

[0063] The results of the determination of the main sources of beany odor are shown in Table 2.

[0064] Table 2 Determination results of hexanal and 2-pentylfuran in yogurt

[0065] Group Protein Content Hexanal content 2-Pentylfuran content Example 1 4.03g / 100g 237.79 μg / kg 145.09 μg / kg Example 2 4.01g / 100g 393.40 μg / kg 276.82 μg / kg Comparative Example 1 3.91g / 100g 743.10 μg / kg 343.50 μg / kg Comparative Example 2 3.87g / 100g 604.25 μg / kg 301.23 μg / kg Comparative Example 3 3.95g / 100g 598.46μg / kg 287.64 μg / kg Comparative Example 4 3.99g / 100g 543.90μg / kg 245.68 μg / kg Comparative Example 5 3.81g / 100g 325.76 μg / kg 203.11 μg / kg Comparative Example 6 3.74g / 100g 342.19 μg / kg 219.45 μg / kg Comparative Example 7 3.86g / 100g 317.35 μg / kg 283.19 μg / kg Comparative Example 8 4.02g / 100g 410.40 μg / kg 309.65 μg / kg Comparative Example 9 3.98g / 100g 355.70 μg / kg 258.19 μg / kg

[0066] As can be seen from Table 2, the protein content of the yogurt prepared in Examples 1 and 2 is about 4 g / 100 g, which is twice that of commercially available soybean yogurt (2 g / 100 g), and is also higher than that of traditional yogurt (3.1 g / 100 g). Compared with Comparative Example 1 without adding double enzymes, the substances of the main sources of beany smell, such as hexanal and 2-pentylfuran, in the yogurt prepared in Examples 1 and 2 are significantly reduced. Compared with Comparative Example 1, the hexanal content of Example 1 is reduced by 68.00%, and the 2-pentylfuran content is reduced by 57.76%.

[0067] By comparing the contents of hexanal and 2-pentylfuran in the yogurts prepared in Comparative Examples 1, 2 and 3, it can be found that compared with Comparative Example 1 without adding the dual enzyme, the reduction in the contents of hexanal and 2-pentylfuran in the yogurt by adding only alcohol dehydrogenase or acetaldehyde dehydrogenase is not obvious. Therefore, the yogurts prepared in Comparative Examples 2 and 3 still have a relatively obvious beany smell; while in Examples 1 and 2, where alcohol dehydrogenase and acetaldehyde dehydrogenase are added at the same time, the contents of hexanal and 2-pentylfuran are greatly reduced. This shows that under the preparation process conditions of the present invention, alcohol dehydrogenase and acetaldehyde dehydrogenase work synergistically in removing the beany smell of pea yogurt. Specifically, the mechanism by which alcohol dehydrogenase and aldehyde dehydrogenase can reduce the beany smell:

[0068] ①Aldehyde dehydrogenase: catalyzes the oxidation of aldehydes to carboxylic acids

[0069] ALDH (aldehyde dehydrogenase) converts irritating aldehydes into odorless or sour carboxylic acids through the following reaction:

[0070] Key substrates: Short-chain aldehydes such as hexanal and valeraldehyde are converted into hexanoic acid and valeric acid (some carboxylic acids may be further metabolized or volatilized).

[0071] Effect: Directly eliminate the beany smell of aldehydes, and carboxylic acids usually have a higher threshold (not easily perceived) or present a weak sour aroma (such as caproic acid has a cheese aroma).

[0072] ② Alcohol dehydrogenase: bidirectional catalysis of the conversion of aldehydes and alcohols

[0073] a) ADH (alcohol dehydrogenase) reversibly catalyzes the interconversion of aldehydes and alcohols, and the reaction depends on cofactors (NADH / NAD + ):

[0074] b) Deodorization direction: When NADH is sufficient (such as lactic acid bacteria fermentation produces reducing power), ADH reduces aldehydes to alcohols with weaker odor (such as hexanal → 1-hexanol).

[0075] c) Potential risks: If the system is highly oxidizing (NAD +If there is an excess of ADH, ADH may reversely oxidize alcohols to aldehydes, which will increase the beany flavor (so it is necessary to avoid this by controlling the fermentation conditions).

[0076] Aldehyde dehydrogenase and alcohol dehydrogenase work synergistically to form a metabolic pathway of "aldehyde→alcohol→carboxylic acid", completely eliminating the accumulation of aldehydes.

[0077] In addition, by comparing Example 1 with Comparative Examples 4, 5 and 6, it can be found that the high temperature and high pressure treatment temperature is too high or too low, and the high temperature and high pressure treatment time is too long, which will lead to an increase in the content of beany substances such as hexanal and 2-pentylfuran in yogurt. It is inferred that the high temperature and high pressure treatment effect may affect the effect of double enzymes on the removal of fishy smell in pea yogurt. For Comparative Example 4, the high temperature and high pressure treatment temperature is too low, in addition to affecting the removal effect of the beany smell of yogurt, it will also lead to the inability to kill heat-resistant bacteria, and anti-nutritional factors such as trypsin inhibitors may not be completely inactivated, thereby affecting the quality of yogurt. Although Comparative Examples 5 and 6 can effectively reduce the content of hexanal and 2-pentylfuran, these two groups of yogurt have developed serious mushy taste and serious protein denaturation.

[0078] The present invention controls the high-temperature and high-pressure treatment temperature and the high-temperature and high-pressure treatment time, and controls the dosage of the double enzymes and the adding time. Under the preparation process conditions of the present invention, not only can the contents of hexanal and 2-pentylfuran in yogurt be effectively reduced, so that the beany smell of pea yogurt is effectively removed, but also the pea protein can be ensured to form a stable gel network structure in the yogurt, which is beneficial to improving the comprehensive quality of the yogurt.

[0079] Table 3 shows the texture characteristics of yogurt prepared in Example 1, Example 2, and Comparative Examples 1 to 9. The comprehensive score is calculated by principal component analysis and value standardization based on the results of hardness, viscosity, cohesion, elasticity and chewiness, which can reflect the texture characteristics of pea yogurt.

[0080] Table 3 Results of texture characteristics of yogurt

[0081]

[0082] For the texture index of pea yogurt, the smaller the hardness and chewiness, the better, while the higher the viscosity, cohesion and elasticity, the better. As can be seen from Table 3, the yogurt prepared in Example 1 has the highest comprehensive score for texture characteristics. The yogurts prepared in Comparative Examples 1 and 6 have more whey precipitation, and the yogurt prepared in Comparative Example 4 does not form a good gel state. This shows that the high temperature and high pressure treatment and the double enzyme treatment not only affect the removal effect of the beany smell of yogurt, but also jointly affect the texture characteristics of yogurt.

[0083] Table 4 shows the sensory evaluation results of the yogurts prepared in Example 1, Example 2, and Comparative Examples 1 to 9.

[0084] Table 4 Sensory evaluation results of yogurt

[0085]

[0086] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A process for preparing high-protein, low-beany flavor pea yogurt, characterized in that: The steps include: Step (1), adding pea protein powder to water and mixing evenly to obtain pea protein liquid; adding oligosaccharide to the pea protein liquid and stirring until the oligosaccharide is dissolved to obtain a mixed raw material liquid; Step (2), subjecting the mixed raw material liquid to high-pressure homogenization treatment and then high-temperature and high-pressure treatment, and after the high-temperature and high-pressure treatment, naturally cooling to room temperature and sieving to obtain a mixed slurry; Step (3), adding alcohol dehydrogenase and aldehyde dehydrogenase to the mixed slurry, inoculating a starter culture for fermentation, and obtaining a fermentation product after the fermentation is completed; Step (4), subjecting the fermented product to a post-ripening treatment, after which the post-ripening treatment is completed, to obtain a pea yogurt with high protein and low beany flavor.

2. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 1, characterized in that: In step (1), the protein content in the pea protein powder is 75wt% to 80wt%; the oligosaccharide is sucrose and / or oligofructose; the mass volume ratio of pea protein powder to water is 1g: (15-20)mL; and the amount of oligosaccharide added is 3-8wt% of the mass of the pea protein liquid.

3. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 2, characterized in that: In step (1), the protein content in the pea protein powder is 80wt%; the oligosaccharide is sucrose; the mass volume ratio of pea protein powder to water is 1g:20mL; and the amount of oligosaccharide added is 5wt% of the mass of the pea protein liquid.

4. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 1, characterized in that: In step (2), the conditions for high-pressure homogenization treatment are: temperature control at 4-60°C, 30-40MPa, and single instantaneous treatment; the conditions for high-temperature and high-pressure treatment are: 121°C, 0.10-0.11MPa, 3min; and the mixed slurry is the slurry obtained by passing through a 180-mesh sieve.

5. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 4, characterized in that: In step (2), the conditions for high-pressure homogenization treatment are: temperature control at 4°C, 30MPa, single instantaneous treatment; the conditions for high-temperature and high-pressure treatment are: 121°C, 0.10MPa, 3min.

6. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 1, characterized in that: In step (3), the amount of alcohol dehydrogenase added is 0.5-1.0wt% of the mass of the mixed slurry, and the amount of aldehyde dehydrogenase added is 0.5-1.0wt% of the mass of the mixed slurry; the amount of the starter is 0.006-0.010wt% of the mass of the mixed slurry; the content of live lactic acid bacteria in the starter is greater than or equal to 1×10 9 CFU / 100g.

7. The process for preparing the high-protein, low-beany flavor pea yogurt according to claim 6, characterized in that: In step (3), the amount of alcohol dehydrogenase added is 0.5wt% of the mass of the mixed slurry, the amount of aldehyde dehydrogenase added is 0.5wt% of the mass of the mixed slurry; and the amount of the leavening agent used is 0.006wt% of the mass of the mixed slurry.

8. The preparation process of the high-protein, low-beany flavor pea yogurt according to claim 1, characterized in that: In step (3), the fermentation conditions are: 37-40°C, 8-12h; in step (4), the post-ripening treatment conditions are: 4-6°C, 18-24h; after the post-ripening treatment, sterilization treatment is also carried out, and the sterilization conditions are: 90-95°C, 5-10min.

9. The process for preparing the high-protein, low-beany flavor pea yogurt according to claim 1, characterized in that: In step (1), the protein content in the pea protein powder is 80wt%; the oligosaccharide is sucrose; the mass volume ratio of pea protein powder to water is 1g:20mL; the amount of oligosaccharide added is 5wt% of the mass of the pea protein liquid; In step (2), the conditions for high-pressure homogenization treatment are: temperature control at 4°C, 30MPa, single instantaneous treatment; the conditions for high-temperature and high-pressure treatment are: 121°C, 0.10MPa, 3min; In step (3), the amount of alcohol dehydrogenase added is 0.5wt% of the mass of the mixed slurry, and the amount of aldehyde dehydrogenase added is 0.5wt% of the mass of the mixed slurry; the amount of the starter is 0.006wt% of the mass of the mixed slurry; the content of live lactic acid bacteria in the starter is greater than or equal to 1×10 9 CFU / 100g; fermentation conditions: 37℃, 10h; In step (4), the post-ripening treatment conditions are: 4°C, 24h; after the post-ripening treatment, sterilization treatment is also carried out, and the sterilization conditions are: 90°C, 10min.

10. A high-protein, low-beany flavor pea yogurt, characterized in that: The pea yogurt with high protein and low beany flavor is prepared by the preparation process of any one of claims 1 to 9.

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