Soybean large cherry yoghurt production process

Abstract

The application provides a soybean big cherry yoghourt production process, which comprises the following steps: preparing raw soybean milk and tartary buckwheat bud powder, stress treating big cherries and color protection to prepare fruit pulp, adding the tartary buckwheat bud powder into the raw soybean milk to carry out heat preservation and deodorization treatment, then adding skimmed milk powder, sucrose and glucose, uniformly mixing and sterilizing and cooling, adding the big cherry fruit pulp to homogenize, carrying out pasteurization and cooling, then inoculating bacteria powder, and carrying out fermentation and post-ripening to prepare the soybean big cherry yoghourt. The application adopts the tartary buckwheat bud powder to deodorize soybean, the soybean raw milk has rich soybean flavor, no fishy smell, delicate taste, no bitter and astringent taste, the yoghourt fermented from the big cherry fruit pulp treated by stress and color protection has the special soybean and cherry flavor, no fishy smell, pure lactic acid flavor, and the natural color of the big cherry is well preserved.

Description

Technical Field

[0001] This invention belongs to the field of deep processing of agricultural products, and specifically relates to a production process for soybean and cherry yogurt. Background Technology

[0002] Soybeans, with a protein content comparable to meat, are a major source of plant protein worldwide, rich in all nine essential amino acids. As a primary and low-cost plant protein source, they are widely used in food processing. However, the processing process produces an unpleasant beany odor, limiting the sales and development of soybean-based foods. The polyunsaturated fatty acids in soybeans are oxidized, forming fatty acid hydroperoxides with conjugated double bonds. This leads to the production of volatile substances such as alcohols, ketones, and aldehydes, constituting the beany odor system. Aldehydes are the primary odor-producing compounds; a beany odor is produced when the hexanal content in food reaches 500 μg / kg. Currently, methods for removing the beany odor mainly fall into two categories: inactivation of lipoxygenase and elimination or masking of the beany odor caused by lipoxygenase activity. The activity of lipoxygenase in soybeans decreases at high temperatures; therefore, heat treatment deactivates lipoxygenase, inhibiting its enzymatic reactions. While heat treatment to inactivate the enzyme is simple, it easily causes protein denaturation, affecting its nutritional value. Soybean lipoxygenase activity is highly sensitive to pH; the activity can be inhibited by adjusting the pH of the solution with acid or alkali. While adding acid or alkali can effectively remove the beany odor, the waste liquid and residue from these chemical reagents can pollute the environment and even harm human health. Therefore, it is crucial to research a safe, healthy, simple, efficient, and nutrient-rich method for deodorizing soybeans.

[0003] Sweet cherries are deep red and bright in color, rich in nutrients, including abundant protein, vitamins, and various minerals. They also contain functional components such as anthocyanins and melatonin, giving them significant health benefits. Anthocyanins, in particular, are effective antioxidants with anti-cancer and anti-aging properties. However, sweet cherries are highly susceptible to browning during processing. Browning not only alters the fruit's flavor and color but also destroys its nutritional components. Browning in sweet cherries is primarily caused by enzymatic browning. Sweet cherries contain a relatively high amount of phenolic substances. When juiced and exposed to an aerobic environment, these substances are catalyzed by polyphenol oxidase to form quinones, which further polymerize to produce black substances, causing the cherry pulp to brown. In traditional sweet cherry processing, sulfur or sulfites are often used to preserve the color of fresh fruit and inhibit browning. This method is not only ineffective but also leaves SO2 residues, which can affect the product's flavor and may cause gastrointestinal discomfort and allergies. Therefore, exploring and developing healthy, efficient, and safe color-preserving technologies for sweet cherries is crucial.

[0004] Therefore, processing soybean and cherry yogurt in a green, environmentally friendly, and healthy way effectively solves the problem of soybean odor and browning of cherries during juicing and fermentation, as well as how to balance the quality and nutrition of soybean and cherry yogurt, are issues that have not been addressed in existing technologies. Summary of the Invention

[0005] To address the aforementioned issues, this application utilizes a complex enzyme system, including high levels of flavonoids and aldehyde dehydrogenase, produced in buckwheat and its germinated form, to inhibit and remove soybean odor substances and suppress browning during the fermentation of sweet cherry yogurt. Furthermore, it employs mechanical damage combined with metal ion stress treatment of sweet cherries to induce an emergency response that consumes enzymes related to the enzymatic browning of sweet cherries. After heat passivation, the yogurt is protected for color preservation, effectively inhibiting browning in the sweet cherry pulp. This process produces a soybean-sweet cherry yogurt without a soybean odor, possessing the unique aroma of both soybeans and cherries, with a delicate texture, retaining the natural color of sweet cherries, and capable of long-lasting color retention.

[0006] A process for producing soybean and cherry yogurt includes the following steps:

[0007] (a) Preparation of raw soy milk: Select plump, shiny soybeans without mold, wash them clean, soak them in water overnight at room temperature, rinse them with clean water, grind them into a paste, and filter them to make raw soy milk.

[0008] (b) Preparation of buckwheat sprout powder: Soak buckwheat in 0.01-5 mmol / L salicylic acid solution for 6-12 h at room temperature, drain, place in a white porcelain dish and cultivate in a constant temperature incubator at 25-28℃. After 5-6 days of cultivation, cut out the sprouts and dry them in a vacuum drying oven at 35-40℃. Grind and sieve to obtain buckwheat sprout powder.

[0009] (c) Deodorizing raw soy milk: Add a certain proportion of buckwheat sprout powder to raw soy milk, stir well, and treat for a certain period of time at a certain water bath temperature to deodorize the raw soy milk;

[0010] (d) Preparation of sweet cherry pulp: Select fresh, ripe sweet cherries without external damage, wash them with running water, remove the pits, and then use a certain concentration of Fe... 2+ Mg 2+ Ca 2+ Mn 2+ Zn 2+ Soak the sweet cherry fruits in the solution for 5-10 minutes, rinse with distilled water, blanch in boiling water for 1-2 minutes, then add citric acid, disodium stannous citrate, L-cysteine, and Mg. 2+ Ca 2+ Zn 2+ Composite color-protecting liquid, color-protecting pulping, and filtration yield large cherry pulp;

[0011] (e) Preparation of soybean and cherry yogurt: Add appropriate amounts of skim milk powder, sucrose and glucose to raw soybean milk treated with buckwheat sprout powder, mix well, sterilize, cool for a certain time, add cherry pulp, mix evenly and homogenize, pasteurize, cool and inoculate, and obtain soybean and cherry yogurt through constant temperature fermentation and post-ripening.

[0012] Preferably, in step (a), the mass ratio of soybeans to water is 1:5 to 1:8.

[0013] Preferably, in step (c), the amount of buckwheat sprout powder added is 2-3% of the mass of raw soy milk, the action temperature is 40-45℃, and the action time is 2-2.5 h.

[0014] Preferably, in step (d) Fe 2+ Concentration of 0.5-1 mmol / L, Mg 2+ Concentrations of 0.5-1.5 mmol / L, Ca 2+ Concentration of 1-2 mmol / L, Mn 2+ Concentration of 0.5-1 mmol / L, Zn 2+ The concentration is 0.5-1 mmol / L, the concentration of citric acid is 0.015%-0.02%, the concentration of disodium stannous citrate is 0.010%-0.015%, the concentration of L-cysteine ​​is 0.010%-0.015%, and the mass ratio of the color-protecting solution to the cherry is 1:8-1:10.

[0015] Preferably, in step (e), the bacterial strain is a mixed bacterial culture of Lactobacillus bulgaricus and Streptococcus thermophilus, the constant temperature fermentation temperature is 40-42℃ for 10-12 h, and the post-ripening temperature is 4℃ for 12-20 h.

[0016] The soybean and cherry yogurt prepared in this application has a protein content of (3.59±0.11) g / 100 g, a fat content of (2.73±0.04) g / 100 g, and a lactic acid bacteria content of 4.9×10⁻⁶. 8 CFU / mL, with the distinctive aroma of soybeans and cherries, no soy smell, pure lactic acid aroma, natural cherry color, and stable for more than 10 days.

[0017] This application utilizes salicylic acid stress to stimulate tartary buckwheat, causing it to produce more flavonoids such as rutin and quercetin, as well as complex enzyme systems such as aldehyde dehydrogenase during germination. Rutin and quercetin, among other flavonoids, bind to lipoxygenase, inhibiting its activity. The optimal pH range for soybean lipoxygenase is 7-9, with the highest activity at pH 9. The phenolic hydroxyl groups in flavonoid molecules carry a large number of hydrogen ions, lowering the pH of the microenvironment and thus affecting the dissociation of active groups, further inhibiting the catalytic activity of lipoxygenase. This inhibition of lipoxygenase activity reduces the enzymatic production of soybean odor substances. Furthermore, the hydrogen atoms on the phenolic hydroxyl groups of rutin and quercetin can combine with peroxide free radicals, terminating free radical chain reactions and exhibiting anti-lipid peroxidation effects, inhibiting the natural oxidation of saturated fatty acids to produce aldehydes. Aldehyde dehydrogenase can convert existing aldehydes into acids, further reducing the soybean odor. The protease in buckwheat sprout powder can also hydrolyze soybean protein during heat preservation and deodorization, which is more conducive to the fermentation of yogurt, resulting in a uniform yogurt texture, a smooth and even surface, no granules, moderate viscosity, and a delicate and smooth taste. This application also utilizes mechanical damage combined with Fe... 2+ Mg 2+ Ca 2+ Mn 2+ Zn 2+ Stress treatment of sweet cherries induces a stress response, significantly depleting the activity of peroxidase (POD), catalase (CAT), phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO) in the fruit, and then inactivates them through heat treatment. This results in lower levels of enzymes related to enzymatic browning during juicing. Citric acid, sodium stannous citrate, and L-cysteine ​​combined with Mg are added during juicing. 2+ Ca 2+ Zn 2+ The compound inhibits and regulates the activity and reaction of browning-related enzymes such as peroxidase (POD) and polyphenol oxidase (PPO). At the same time, during the fermentation process, substances such as rutin and quercetin in buckwheat sprout powder have antioxidant effects, which can also inhibit the oxidative loss of cherry pigments during fermentation and storage, so that the natural color of cherry yogurt can be maintained. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0019] The technical solution of this application is a process for producing soybean and cherry yogurt, including the following steps:

[0020] (a) Preparation of raw soy milk: Select plump, shiny soybeans without mold, wash them clean, soak them in water overnight at room temperature, rinse them with clean water, grind them into a paste, and filter them to make raw soy milk.

[0021] (b) Preparation of buckwheat sprout powder: Soak buckwheat in 0.01-5 mmol / L salicylic acid solution for 6-12 h at room temperature, drain, place in a white porcelain dish and cultivate in a constant temperature incubator at 25-28℃. After 5-6 days of cultivation, cut out the sprouts and dry them in a vacuum drying oven at 35-40℃. Grind and sieve to obtain buckwheat sprout powder.

[0022] (c) Deodorizing raw soy milk: Add a certain proportion of buckwheat sprout powder to raw soy milk, stir well, and treat for a certain period of time at a certain water bath temperature to deodorize the raw soy milk;

[0023] (d) Preparation of sweet cherry pulp: Select fresh, ripe sweet cherries without external damage, wash them with running water, remove the pits, and then use a certain concentration of Fe... 2+ Mg 2+ Ca 2+ Mn 2+ Zn 2+ Soak the sweet cherry fruits in the solution for 5-10 minutes, rinse with distilled water, blanch in boiling water for 1-2 minutes, then add citric acid, disodium stannous citrate, L-cysteine, and Mg. 2+ Ca 2+ Zn 2+ Composite color-protecting liquid, color-protecting pulping, and filtration yield large cherry pulp;

[0024] (e) Preparation of soybean and cherry yogurt: Add appropriate amounts of skim milk powder, sucrose and glucose to raw soybean milk treated with buckwheat sprout powder, mix well, sterilize, cool for a certain time, add cherry pulp, mix evenly and homogenize, pasteurize, cool and inoculate, and obtain soybean and cherry yogurt through constant temperature fermentation and post-ripening.

[0025] Preferably, in step (a), the mass ratio of soybeans to water is 1:5 to 1:8.

[0026] Preferably, in step (c), the amount of buckwheat sprout powder added is 2-3% of the mass of raw soy milk, the action temperature is 40-45℃, and the action time is 2-2.5 h;

[0027] Preferably, in step (d) Fe 2+ Concentration of 0.5-1 mmol / L, Mg 2+ Concentrations of 0.5-1.5 mmol / L, Ca 2+ Concentration of 1-2 mmol / L, Mn 2+ Concentration of 0.5-1 mmol / L, Zn 2+The concentration is 0.5-1 mmol / L, the concentration of citric acid is 0.015%-0.02%, the concentration of disodium stannous citrate is 0.010%-0.015%, the concentration of L-cysteine ​​is 0.010%-0.015%, and the mass ratio of the color-protecting solution to the cherry is 1:8-1:10.

[0028] Preferably, in step (e), the mixed bacterial culture of Lactobacillus bulgaricus and Streptococcus thermophilus is fermented at a constant temperature of 40-42℃ for 10-12 h, and the post-ripening temperature is 4℃ for 12-20 h.

[0029] Experimental Example: Deodorization Experiment of Buckwheat Sprout Powder

[0030] Buckwheat sprouts were soaked in a 0.02 mmol / L salicylic acid solution for 10 hours at room temperature, drained, and placed in a white porcelain dish in a 25°C incubator. After 6 days of cultivation, the sprouts were cut off and dried in a 35°C vacuum drying oven, then pulverized and sieved to obtain the buckwheat sprout powder used in this invention. Another batch of buckwheat was soaked in distilled water for 10 hours, drained, and placed in a white porcelain dish in a 25°C incubator. After 6 days of cultivation, the sprouts were cut off and dried in a 35°C vacuum drying oven, then pulverized and sieved to obtain ordinary buckwheat sprout powder. Soybeans were washed with water, impurities were filtered out, and the soybeans were soaked in water overnight at room temperature. After rinsing with clean water, water was added at a soybean-to-water ratio of 1:8, and the mixture was ground into a paste. The paste was then filtered twice through three layers of gauze to produce raw soy milk. Two portions of raw soy milk were mixed with 2% buckwheat sprout powder and 2% salicylic acid-stressed buckwheat sprout powder, respectively. The mixtures were then heated in a 45℃ water bath for 2 hours. Soy milk without added buckwheat sprout powder served as a control. The deodorizing effect of buckwheat sprout powder was investigated. Total aldehyde content and lipoxygenase activity were determined by titration and spectrophotometry, respectively. Sensory evaluation was conducted by 10 professional evaluators (5 of whom held senior professional titles). Experimental data were compiled using Excel 2010, analyzed by variance using SPSS 26.0 software, and performed multiple comparisons using the least significant difference (LDS) method. Each experiment was repeated three times, with a significance level set at 0.05. The results are shown in Table 1.

[0031] Table 1 Results of the deodorizing effect of buckwheat sprout powder

[0032] Buckwheat sprout powder 7.8 2930 0.019 Salicylic acid stress buckwheat sprout powder 8.1 611 0.013 Comparison 5.2 4040 0.024

[0033] Table 1 shows that buckwheat sprout powder can reduce the activity of fat oxygenase in soybean raw milk, decrease the total aldehyde content, and improve the sensory score. Salicylic acid treatment significantly enhances the deodorizing effect of buckwheat sprout powder on soybean raw milk. The following study investigated the effects of buckwheat sprout powder dosage (0%, 1%, 2%, 3%, 4% by volume), treatment temperature (30, 35, 40, 45, 50℃), and treatment time (1.0, 1.5, 2.0, 2.5, 3.0 h) on the deodorizing effect of raw soybean milk, using 2% buckwheat sprout powder, 45℃ as the base conditions. No buckwheat sprout powder was used as a control under the same conditions. The results are shown in Tables 2, 3, and 4.

[0034] Table 2. Effect of buckwheat sprout powder dosage on deodorizing effect.

[0035] 0% 5.2 4040 0.024 1% 7.5 2943 0.023 2% 8.2 597 0.0129 3% 8.1 545 0.013 4% 8.1 491 0.014

[0036] Table 2 shows that the addition of buckwheat sprout powder can inhibit lipoxygenase activity and reduce total aldehyde content, thereby improving sensory scores. When the dosage is between 0% and 2%, the activity of lipoxygenase decreases rapidly with increasing dosage because flavonoids such as rutin and quercetin in buckwheat sprout powder bind to lipoxygenase and inhibit its activity. In addition, the phenolic hydroxyl groups in the molecules of flavonoids contain a large number of hydrogen ions, which lowers the pH of the microenvironment, thereby affecting the dissociation of active groups and further reducing the catalytic activity of lipoxygenase. When the dosage is greater than 2%, the enzyme activity of lipoxygenase no longer decreases significantly with increasing dosage because the content of lipoxygenase is constant. At this point, the inhibitory sites are saturated, and the concentration of inhibitors increases, so they will no longer bind to the enzyme, and the activity will not be further inhibited. Buckwheat sprout powder can reduce the production of total aldehydes in soybeans because its active ingredients, such as rutin and quercetin, not only reduce the activity of lipoxygenase but also bind to the reactive free radicals generated when lipoxygenase catalyzes substrates, thereby inhibiting the formation of aldehydes. Since the content of fatty acids such as linoleic acid and linolenic acid in raw soy milk that can serve as substrates for lipoxygenase to produce beany-smelling substances is fixed, when the addition amount is 2%, the substrates are already consumed, and the total aldehyde content of raw soy milk has reached its minimum. Further addition of buckwheat sprout powder will not reduce the total aldehyde content further. Because aldehydes are the main source of the beany smell in raw soy milk, and the total aldehyde content is directly proportional to the beany smell—the higher the total aldehyde content in soybeans, the stronger the beany smell—adding buckwheat sprout powder can improve sensory evaluation.

[0037] Table 3. Effect of the temperature on the deodorizing effect of buckwheat sprout powder.

[0038]

[0039] Table 3 shows that the operating temperature has a significant impact on the inhibitory effect of buckwheat sprout powder on lipoxygenase. The best effect is observed at 40-45℃. This is because small molecule inhibitors such as rutin and quercetin require a suitable temperature to bind with the enzyme. At a certain temperature, they can rapidly bind with the enzyme, causing a sharp decrease in enzyme activity. The total aldehyde content in both the control and experimental groups showed a trend of first decreasing and then increasing with increasing temperature. At high temperatures, the difference in total aldehyde content between the experimental and control groups was smaller than at low temperatures, with the experimental group showing lower levels than the control group. The total aldehyde content in the experimental group decreased sharply at 40℃, which is consistent with the change in lipoxygenase activity. This is because soybean lipoxygenase maintains high catalytic activity at low temperatures, while enzyme activity decreases at higher temperatures, thus reducing the amount of aldehydes produced by catalyzing unsaturated fatty acids. The total aldehyde content increased at temperatures above 45℃, because at a certain temperature, the non-enzymatic oxidation of unsaturated fatty acids intensified. The sensory scores of the experimental group were higher than those of the control group. The sensory scores gradually increased with rising temperature, reaching their highest point at 45℃. Above 45℃, the sensory scores began to decrease, contrary to the trend of total aldehyde content changes. This indicates that buckwheat sprout powder treatment can reduce the production of aldehydes, thereby suppressing the beany odor and improving the sensory score. Below 45℃, the lipoxygenase activity and total aldehyde content of the control group were significantly higher than those of the experimental group, while the sensory scores were significantly lower, demonstrating that buckwheat sprout powder treatment can effectively reduce the beany odor.

[0040] Table 4. Effect of the reaction time of buckwheat sprout powder on the deodorizing effect

[0041]

[0042] Table 4 shows that the treatment time significantly affects the inhibitory effect of buckwheat sprout powder on lipoxygenase. With prolonged treatment time, lipoxygenase activity initially decreases and then tends towards equilibrium. In the first 1.0-2.0 h, the decrease in enzyme activity is relatively small; after 2.0 h, the decrease in enzyme activity increases; and after 2.5 h, it tends to stabilize. This is because small molecule inhibitors such as rutin and quercetin in buckwheat sprout powder can initially bind rapidly to lipoxygenase. Once a certain saturation point is reached, binding becomes difficult, requiring a certain treatment time to bind and exert an inhibitory effect. When the binding sites are completely saturated, the inhibitory effect no longer increases, reaching equilibrium. With prolonged treatment time, the total aldehyde content in both the control and experimental groups gradually decreases. Initially, the difference in total aldehyde content between the control and experimental groups is small. With prolonged treatment time, the decrease in total aldehyde content in the experimental group increases significantly, reaching a significant difference from the control group after 1.5 h. At 2.5 h, the total aldehyde content in both the control and experimental groups reaches its lowest value. Because the activity of lipoxygenase was high in the early stages of treatment, buckwheat sprout powder showed a good inhibitory effect. However, as the treatment time increased, lipoxygenase gradually denatured at the treatment temperature, its activity decreased, and the inhibitory effect weakened. The increase in total aldehyde content in the control group in the later stages was due to the natural oxidation of unsaturated fatty acids. In the experimental group, the hydrogen atoms on the phenolic hydroxyl groups of flavonoids such as rutin and quercetin in buckwheat sprout powder could combine with peroxide free radicals, thereby terminating the free radical chain reaction and exhibiting anti-lipid peroxidation effects, inhibiting the natural oxidation of total aldehydes. The decrease in the control group was due to the fact that soybeans themselves contain alcohol dehydrogenase and aldehyde dehydrogenase; over time, alcohols, aldehydes, and ketones in soybeans were decomposed, resulting in a decrease in total aldehyde content. The sensory scores of the experimental group were higher than those of the control group, and with the extension of the treatment time, the sensory scores of both the control and experimental groups showed a trend of first increasing and then stabilizing. This is consistent with the inhibitory characteristics of buckwheat sprout powder on lipoxygenase in soybeans; after a rapid effect, a certain amount of time is needed to reach the maximum inhibitory effect.

[0043] Based on the above experiments, factors A (temperature), B (time), and C (amount of buckwheat sprout powder added) were selected to conduct L9 (3 3 An orthogonal experimental design (Table 5) was used to determine the processing parameters for buckwheat sprout powder. The results are shown in Table 6.

[0044] Table 5. Factor Level Table for Orthogonal Experiment

[0045]

[0046] Table 6. Results of Orthogonal Experiments

[0047] 1 40 2.0 2 23.31 6.9 2 40 2.5 3 20.45 7.1 3 40 3.0 4 20.13 6.8 4 45 2.0 4 15.13 7.7 5 45 2.5 2 14.03 8.2 6 45 3.0 3 15.63 7.7 7 50 2.0 3 23.8 6.9 8 50 2.5 4 18.2 7.4 9 50 3.0 2 23.43 6.9 [K1 / K1'] 63.89 / 6.93 62.24 / 7.17 60.77 / 7.33 [K2 / K2'] 44.78 / 7.87 52.68 / 7.57 59.88 / 7.23 [K3 / K3'] 65.43 / 7.07 59.19 / 7.13 53.46 / 7.30 R 6.88 3.19 2.44

[0048] Note: In the table, K1 / K1', K2 / K2', and K3 / K3' represent orthogonal analysis data of total aldehyde content; K1', K2', and K3' represent orthogonal analysis data of sensory evaluation scores.

[0049] Orthogonal experimental results showed that adding 2-3% buckwheat sprout powder, at a temperature of 40-45℃, and for 2-2.5 h significantly reduced lipoxygenase activity and total aldehyde content, and improved sensory evaluation. The deodorization effect was best under the conditions of 2% buckwheat sprout powder addition, 45℃ temperature, and 2.5 h treatment time. After treatment using this method, the lipoxygenase activity in raw soy milk was 597.2582 U / mL, the total aldehyde content was 0.0140 g / 100 mL, and the sensory evaluation score was 8.2 points. In contrast, the lipoxygenase activity in the control group was 4040.5368 U / mL, the total aldehyde content was 0.0341 g / 100 mL, and the sensory evaluation score was 3.3 points. Compared to the control group, the lipoxygenase activity in raw soy milk decreased by 85%, the total aldehyde content decreased by 59%, and the sensory evaluation was significantly improved.

[0050] Experimental Example: Cherry Color Protection Experiment

[0051] Select fresh, ripe cherries without external damage, wash them under running water, remove the pits, and then soak them in 0.5 mmol / L Fe solution. 2+ 0.5 mmol / L mg 2+ 1 mmol / L Ca 2+ 0.5 mmol / L Mn 2+ 0.5 mmol / L Zn 2+ Sweet cherry fruits were soaked in a mixed metal ion solution for 8 minutes, rinsed with distilled water, and blanched in boiling water for 1 minute. Then, at a color-protecting solution-to-cherry mass ratio of 1:8, a solution containing 0.015% citric acid, 0.010% sodium stannous citrate, 0.010% L-cysteine, and 0.5 mmol / L Mg was added. 2+ 1 mmol / L Ca 2+ 0.5 mmol / L Zn 2+ The composite color-protecting solution was used to treat the cherry pulp, which was then filtered to obtain cherry pulp. Two other samples were taken, and after washing the cherries with running water and removing the pits, they were immediately blanched in boiling water for 1 minute. Distilled water and the composite color-protecting solution were added to the cherries respectively in a mass ratio of 1:8 as controls. The effects of mechanical damage combined with metal ion stress and the composite color-protecting solution on browning of cherries were studied. The results are shown in Table 7.

[0052] Table 7 Results of the color protection experiment

[0053] experimental group 0.39 0.18 Preserve the natural red color of the cherries Composite color-protecting liquid 0.56 0.63 Brown appears Blank control 0.91 1.18 Severe browning

[0054] Table 7 shows that the composite color-protecting solution treatment can partially inhibit the activity of polyphenol oxidase (PPO) in sweet cherries, thereby reducing browning of cherry pigments. However, some browning still occurs in the cherry pulp, causing it to lose its natural color. Mechanical damage combined with Fe... 2+ Mg 2+ Ca 2+ Mn 2+ Zn 2+ Stress treatment of sweet cherries induces an emergency response in the fruit, which is then immediately scalded to greatly reduce the activity of polyphenol oxidase (PPO). Combined with treatment with a compound color-protecting solution, the sweet cherries only undergo slight browning, retaining their natural red color and making them suitable for production and processing.

[0055] The examples demonstrate the preparation of soybean and cherry yogurt using the method of the present invention.

[0056] Buckwheat sprouts were soaked in a 0.02 mmol / L salicylic acid solution for 10 hours at room temperature, drained, and placed in a white porcelain dish for cultivation in a 25°C incubator. After 6 days of cultivation, the sprouts were cut off and dried in a 35°C vacuum drying oven, then pulverized and sieved to obtain the buckwheat sprout powder used in this invention. Soybeans were washed with pure water and soaked overnight at room temperature. After rinsing with clean water, the soybeans were ground with water at a soybean-to-water ratio of 1:8 and then filtered twice through three layers of gauze to produce raw soy milk. 2% buckwheat sprout powder was added to the raw soy milk, mixed thoroughly, and heated in a 45°C water bath for 2 hours. Fresh, ripe cherries without external damage were selected, washed with running water, pitted, and then treated with 0.5 mmol / L Fe... 2+ 0.5 mmol / L Mg 2+ 1 mmol / L Ca 2+ 0.5 mmol / L Mn 2+ 0.5 mmol / L Zn 2+ Sweet cherry fruits were soaked in a mixed metal ion solution for 8 minutes, rinsed with distilled water, and blanched in boiling water for 1 minute. Then, at a color-protecting solution-to-cherry mass ratio of 1:8, a solution containing 0.015% citric acid, 0.010% sodium stannous citrate, 0.010% L-cysteine, and 0.5 mmol / L Mg was added. 2+ 1 mmol / L Ca 2+ 0.5 mmol / L Zn 2+A compound color-protecting solution was used to prepare the color-protecting pulp, which was then filtered to obtain cherry pulp. Appropriate amounts of skim milk powder, sucrose, and glucose were added to raw soy milk treated with buckwheat sprout powder and mixed thoroughly. The mixture was then sterilized at 95℃ for 10 minutes. After cooling for a certain period, 24% (w / w) of cherry juice was added and mixed evenly. After homogenization, the mixture was pasteurized and cooled to 42℃. The mixture was then aseptically inoculated with Danisco yogurt starter YO-MIX883 50 dcu at an inoculation rate of 0.05 g / kg. Fermentation was carried out at 42℃ for 12 hours. The fermented soy milk was then refrigerated at 4℃ for 12 hours to further ripen, resulting in a deodorized soybean and cherry yogurt product. Sensory evaluation and physicochemical analysis were conducted on the yogurt of this application, soybean cherry yogurt made from raw soybean milk without deodorization treatment, soybean cherry yogurt made from raw soybean milk without deodorization and stress treatment but with color protection solution, and soybean cherry yogurt made from raw soybean milk without deodorization, stress treatment and color protection treatment. The comparison results are shown in Table 8 and Table 9.

[0057] Table 8 Sensory Evaluation Results

[0058] Example (Buckwheat tooth powder deodorization + mechanical damage combined with metal ion stress + color-protecting liquid) It has no fishy smell, a strong aroma of soybeans and cherry, no bitterness, a uniform color, no whey separation, and a pinkish hue. It has a delicate texture. Control 1 (no deodorization + mechanical damage combined with metal ion stress + color-protecting solution) It has a strong beany flavor, a cherry aroma, and a bitter taste. The color is uneven, a light pink, and whey is present. The texture is rough. Control 2 (no deodorization + no mechanical damage combined with metal ion stress + color-protecting solution) It has a strong beany flavor, a cherry aroma, a bitter taste, uneven color with a brownish tinge, whey separation, and a rough texture. Control 3 (no deodorization + no mechanical damage combined with metal ion stress + no color-protecting solution) It has a strong beany flavor, a cherry aroma, a bitter taste, uneven brown color, whey separation, and a rough texture.

[0059] Note: Sensory evaluation was conducted by 10 professional evaluators (5 of whom held senior professional titles).

[0060] Table 9 Physicochemical Indicators

[0061] Example <![CDATA[86±0.67 a ]]> <![CDATA[3.59±0.11 a ]]> <![CDATA[2.73±0.04 a ]]> <![CDATA[4.9×10 8 a ]]> Not detected Comparison 1 <![CDATA[78±0.55 b ]]> <![CDATA[3.47±0.08 a ]]> <![CDATA[2.69±0.03 a ]]> <![CDATA[5.1×10 8 a ]]> Not detected Comparison 2 <![CDATA[70±0.55 c ]]> <![CDATA[3.53±0.06 a ]]> <![CDATA[2.80±0.05 a ]]> <![CDATA[5.2×10 8 a ]]> Not detected Comparison 3 <![CDATA[57±0.55 d ]]> <![CDATA[3.42±0.05 a ]]> <![CDATA[2.75±0.06 a ]]> <![CDATA[4.8×10 8 a ]]> Not detected

[0062] Tables 8 and 9 show that the protein, fat content, and lactic acid bacteria count of the fermented soy milk after deodorization and the cherry pulp after stress treatment and color protection were not significantly different from those of the control group. This indicates that deodorization, stress treatment, and color protection had no significant impact on the basic nutritional quality of the soybean and cherry fermented soy milk product, but significantly improved the sensory evaluation. The fermented soy milk in the example had the unique aroma of soybeans and cherries, without any soybean smell, and had a pure lactic acid aroma, while the control group had a more obvious soybean smell. The fermented soy milk in the example had a fine and uniform texture, a smooth and flat surface, no particles, and little or no whey separation, with moderate viscosity and a delicate and smooth taste. This is because some of the soybean protein was hydrolyzed by the protease contained in the buckwheat sprout powder during the heat preservation treatment, which was more conducive to the fermentation of the fermented soy milk. The control group had a slightly rougher taste and some whey separation. Both Example 1 and Control Group 1 exhibited the characteristic pink color of sweet cherries, but the sweet cherries in Example 1 had a deeper color, and the color remained stable during storage. This is because sweet cherry pigments are easily oxidized, while substances such as rutin and quercetin in buckwheat sprout powder have antioxidant effects, mitigating the oxidation loss of sweet cherry pigments during fermentation and storage to a certain extent. Control Group 2 sweet cherries only underwent color-protecting treatment without stress treatment, resulting in browning and lower commercial value, indicating that the stress treatment played a crucial role in color protection. Control Group 3 sweet cherries underwent neither stress treatment nor color-protecting treatment; the yogurt completely browned, losing the original color of sweet cherries.

[0063] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A process for the production of soy big cherry yoghurt, characterized by, Includes the following steps: (a) Preparation of raw soy milk: Select plump, shiny soybeans without mold, wash them clean, soak them in water overnight at room temperature, rinse them with clean water, grind them into a paste, and filter them to make raw soy milk. (b) Preparation of buckwheat sprout powder: Soak buckwheat in 0.01-5 mmol / L salicylic acid solution for 6-12 h at room temperature, drain, place in a white porcelain dish and cultivate in a constant temperature incubator at 25-28℃. After 5-6 days of cultivation, cut out the sprouts and dry them in a vacuum drying oven at 35-40℃. Grind and sieve to obtain buckwheat sprout powder. (c) Deodorizing raw soy milk: Add 2-3% of the weight of raw soy milk to raw soy milk, stir well, and treat in a water bath at 40-45℃ for 2-2.5 hours to deodorize the raw soy milk; (d) Preparation of sweet cherry pulp: Select fresh, ripe sweet cherries without external damage, wash them with running water, remove the pits, and then use Fe... 2+ Concentration of 0.5-1 mmol / L, Mg 2+ Concentrations of 0.5-1.5 mmol / L, Ca 2+ Concentration of 1-2 mmol / L, Mn 2+ Concentration of 0.5-1 mmol / L, Zn 2+ Sweet cherry fruits were soaked in a mixed metal ion solution with a concentration of 0.5-1 mmol / L for 5-10 minutes, rinsed with distilled water, blanched in boiling water for 1-2 minutes, and then treated with citric acid, sodium stannous citrate, L-cysteine, and Mg. 2+ Ca 2+ Zn 2+ Composite color-protecting liquid, color-protecting pulping, and filtration yield large cherry pulp; (e) Preparation of soybean and cherry yogurt: Add appropriate amounts of skim milk powder, sucrose and glucose to raw soybean milk treated with buckwheat sprout powder, mix well, sterilize, cool for a certain time, add cherry pulp, mix evenly and homogenize, pasteurize, cool and inoculate, and obtain soybean and cherry yogurt through constant temperature fermentation and post-ripening.

2. The process for producing soy big cherry yoghurt according to claim 1, characterized in that, In step (a), the mass ratio of soybeans to water is 1:5 to 1:

8.

3. The production process of soy big cherry yoghurt according to claim 1, characterized in that, In step (d), the concentration of citric acid is 0.015%-0.02%, the concentration of disodium stannous citrate is 0.010%-0.015%, the concentration of L-cysteine ​​is 0.010%-0.015%, and the mass ratio of the color-protecting solution to the cherry is 1:8-1:

10.

4. The production process of soy big cherry yoghurt according to claim 1 or 3, characterized in that, In step (e), the bacterial strain is a mixed bacterial culture of Lactobacillus bulgaricus and Streptococcus thermophilus, the constant temperature fermentation temperature is 40-42℃, the fermentation time is 10-12 h, the post-ripening temperature is 4℃, and the post-ripening time is 12-20 h.

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