Preparation method of red bean water with high polyphenol content

Abstract

The invention discloses a preparation method of red bean water with high polyphenol content, and belongs to the field of beverage processing. Small red beans and phaseolus calcaratus are used as raw materials, water-soluble components in beans are completely released through microwave-high pressure synergistic extraction, the content of polyphenol in the prepared red bean water is high, and pectinase is used for replacing a centrifugal filtration step, so that the energy consumption cost is greatly reduced. The red bean water with high polyphenol content prepared by the preparation method disclosed by the invention is rich in taste, fresh and cool in mouth feel and free from obvious astringent taste, meets the flavor and mouth feel requirements of people while providing rich nutritional ingredients, and is clear and free from precipitates after being stored for a long time.

Description

Technical Field

[0001] The invention relates to a method for preparing red bean water with high polyphenol content, and belongs to the field of beverage processing. Background Art

[0002] Adzuki beans and red beans are rich in nutrients. The carbohydrate content in red beans is about 58-62%, and the dietary fiber content is about 20-30%, of which soluble dietary fiber is 5.04-5.95%, insoluble dietary fiber is 20.41-24.73%, protein content is about 23.5%, fat content is about 3.5-4.2%, and it is rich in mineral elements. It has the effects of nourishing blood, clearing away heat and detoxifying, strengthening the spleen and stomach, moisturizing the skin and beautifying the face. The carbohydrate content in red bean is about 50-60%, and the protein content is about 22-24%, of which about 60% is digestible protein. It is rich in essential amino acids, such as methionine, tryptophan, lysine, tyrosine and valine. The fat content is about 2-3%, and the mineral content is about 2-4%. Its main beneficial ingredients include polyphenols, saponins, functional proteins and polypeptides. It has the effects of removing dampness, strengthening the spleen and removing dampness, promoting diuresis and reducing swelling. Red bean has a strong effect and is often used in Chinese medicinal materials.

[0003] Adzuki beans and red beans are a common ingredient in people's daily diet and have good nutritional and health functions. The current red bean beverage uses red beans as the main raw material, and the processed liquid products have a strong red bean flavor, but they need to be soaked and steamed for a long time during the processing, which consumes a lot of energy; compared with red beans, adzuki beans have good medicinal effects, but there is a significant astringency during the processing, which is not conducive to consumer acceptance. While improving the nutrition and health level of the general public, reducing energy consumption as much as possible, improving nutritional content and good taste is a technical difficulty for food processing companies.

[0004] At present, a series of studies have been conducted on the preparation method of red bean water, mainly through crushing and grinding, cooking, infrared, microwave and ultrasonic treatment methods. For example, patent CN114403317A discloses a method for preparing red bean water, which uses a microwave-ultrasonic synergistic treatment method to extract red beans, improves the nutritional content of red bean water, and prolongs the shelf life of red bean water; patent CN106721827B discloses a method for preparing red bean beverage, which ensures the stability of polyphenols, the basic nutrient source of red bean beverage, and eliminates starch and protein precipitation by cooking red beans and filtering three times; although the above preparation methods maintain the nutritional content of red bean water to a certain extent, they have high energy consumption and low polyphenol content in red bean water. Summary of the invention

[0005] [Technical issues]

[0006] The technical problem to be solved by the present invention is to reduce the energy consumption in the process of preparing red bean water and to increase the polyphenol content in the red bean water.

[0007] [Technical solution]

[0008] In order to solve the above problems, the present invention provides a method for preparing red bean water with a high polyphenol content, which adopts raw materials of adzuki beans and red beans, and adopts microwave-high pressure synergistic extraction, which reduces production energy consumption while ensuring that the produced red bean water has safe ingredients, high polyphenol content, and rich nutrition, and the solution is clear and has no precipitation after long-term storage.

[0009] The first object of the present invention is to provide a method for preparing red bean water with high polyphenol content, comprising the following steps:

[0010] S1, mixing the raw materials adzuki beans and red beans in a mass ratio of 4 to 10:1, and then performing microwave processing;

[0011] S2, adding the microwave-treated adzuki beans and red adzuki beans to deionized water at a material-liquid ratio of 1:4-9 g / L, high-pressure treatment, and filtering to obtain a clear liquid and a substrate;

[0012] S3, adding deionized water to the substrate obtained in S2 at a material-liquid ratio of 1:2-8 g / L, filtering to obtain a clear liquid, and mixing the clear liquid obtained in S2 to obtain a mixed clear liquid;

[0013] S4. Add pectinase to the mixed clear solution, stir at 40-50°C for 2-3h to obtain a mixed solution, check the turbidity and sugar content of the mixed solution, and control the turbidity to <20 and the sugar content to <0.5g / 100mL;

[0014] S5. Pasteurize the mixed liquid. After the sterilization is completed, check the turbidity and sugar content again. If they are qualified, fill them and get red bean water.

[0015] As a preferred embodiment of the present invention, the raw materials in S1 are all subjected to a pretreatment process, specifically including drying at 60-75° C. to a moisture content of ≤10% after washing.

[0016] As a preferred embodiment of the present invention, the microwave processing conditions in S1 are: microwave power 200-1000 W, microwave time 2-10 min.

[0017] As a preferred embodiment of the present invention, the high pressure treatment condition in S2 is 20-100 kPa, and the treatment time is 10-40 min.

[0018] As a preferred embodiment of the present invention, the amount of pectinase added in S3 is 0.2-0.4% of the mass of the mixed clear solution.

[0019] As a preferred embodiment of the present invention, the pasteurization condition in S4 is sterilization at a temperature of 85° C. for 15 minutes.

[0020] As a preferred embodiment of the present invention, the test standards for checking turbidity and sugar content in S4 and S5 comply with GB / T13200-1991 and GB 5009.8-2016, and turbidity <20 and sugar content <0.5g / 100mL are qualified.

[0021] The second object of the present invention is to provide red bean water prepared by the above method.

[0022] The third object of the present invention is to provide the application of the red bean water in food.

[0023] [Beneficial Effects]

[0024] (1) By adopting the above technical scheme, red bean is rich in dietary fiber, with a dry weight of 20.02% to 30.68%, protein 23.5%, fat 3.5 to 4.2%, ash content 3.1%, calcium 0.076%, phosphorus 0.386%, iron 0.0045%, thiamine 0.00043%, riboflavin 0.00016%, niacin 0.0021%, and has the effects of nourishing blood, clearing away heat and detoxifying, strengthening the spleen and stomach, moisturizing the skin and beautifying the face, and removing dampness. Red bean has carbohydrates (50 to 60%), protein (2 2-24%), rich in essential amino acids, such as methionine, tryptophan, lysine, tyrosine and valine, fat (2-3%), minerals (2-4%), including relatively high levels of calcium and phosphorus, and B group substances such as thiamine and niacin. Its main beneficial ingredients include polyphenols, saponins, functional proteins and polypeptides, etc. It has the effects of clearing away heat and detoxifying, promoting diuresis and relieving stranguria, nourishing blood and nourishing the skin, reducing weight and reducing swelling, etc. The red bean water made from red beans and adzuki beans is rich in nutrients and is suitable for long-term drinking by people of all constitutions (including cold and hot diseases). It is a nutritious and health drink.

[0025] (2) The present invention adopts microwave-high pressure synergistic extraction to completely release the water-soluble components in beans, and the obtained red bean water has a high polyphenol content of 800-1400 mg / L, which is much higher than the polyphenol content of red bean water sold on the market (340 mg / L).

[0026] (3) The preparation process of the red bean water with high polyphenol content prepared by the present invention has low energy consumption, no need to soak or crush the beans, short processing time, no need for long-term steaming, and pectinase is used instead of the centrifugal filtration step, which greatly reduces energy consumption costs.

[0027] (4) The red bean water with high polyphenol content prepared by the present invention has a strong flavor, a refreshing taste, and no obvious astringency. While providing rich nutrients, it meets people's flavor and taste requirements, and the solution is clear and has no precipitation after long-term storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Comparison of color and clarity of red bean water between Examples 1 to 5 and Comparative Examples 1 to 3;

[0029] Figure 2 Example 1 Polyphenol content and appearance of red bean water after storage for 30 days. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0031] The amounts of raw materials added in the various embodiments and comparative examples of the present invention are all expressed in mass percentage.

[0032] The method for determining turbidity shall be in accordance with GB / T 13200-1991.

[0033] The method for determining sugar content shall be in accordance with GB 5009.8-2016.

[0034] Determination of polyphenol content: Take 2mL of distilled water and add 0.5mL of Folin-Ciocaheu reagent, then add 100μL of sample extract and mix well. After 3min, add 900μL of 20% Na2CO3 solution, keep away from light for 2h, and measure its absorbance at 765nm. Use gallic acid as the standard and calculate the polyphenol content in the sample according to the standard curve. The total polyphenol content is the sum of free polyphenol and bound polyphenol.

[0035] Sensory evaluation: The color, taste and smell of the prepared red bean water were comprehensively scored. The color, taste and smell of the prepared red bean water were comprehensively scored.

[0036] Table 1 Red bean water scoring criteria

[0037]

[0038]

[0039] Example 1

[0040] A method for preparing red bean water with high polyphenol content, specifically comprising the following steps:

[0041] S1. Wash the raw materials adzuki beans and red beans, and dry them at 60° C. until the moisture content reaches 10%. Mix the adzuki beans and red beans in a ratio of 6:1 by weight;

[0042] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0043] S3, adding the mixed sample after microwave treatment into deionized water at a material-liquid ratio of 1:4 g / L, treating it under a high pressure of 40 kPa for 20 min, and filtering it with a 60-mesh filter to obtain a clear liquid and a substrate;

[0044] S4, adding deionized water to the substrate at a material-liquid ratio of 1:6 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% (0.3% of the mass of the mixed clear liquid) of pectinase thereto, treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0045] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0046] Example 2

[0047] A method for preparing red bean water with high polyphenol content, specifically comprising the following steps:

[0048] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0049] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0050] S3, material-liquid ratio 1:5g / L, add the mixed sample after microwave treatment into deionized water, treat it under 40kpa high pressure condition for 20min, and filter it with 60-mesh filter to obtain clear liquid and substrate;

[0051] S4, adding deionized water to the substrate at a material-liquid ratio of 1:5 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid) thereto, treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0052] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0053] Example 3

[0054] A method for preparing red bean water with high polyphenol content, specifically comprising the following steps:

[0055] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0056] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0057] S3, material-liquid ratio 1:6 g / L, add the mixed sample after microwave treatment into deionized water, treat it under 40 kPa high pressure for 20 min, and filter it with a 60-mesh filter to obtain the clear liquid and substrate;

[0058] S4, adding deionized water to the substrate at a material-liquid ratio of 1:4 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid) thereto, treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0059] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0060] Example 4

[0061] A method for preparing red bean water with high polyphenol content, specifically comprising the following steps:

[0062] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0063] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0064] S3, material-liquid ratio 1:7g / L, add the mixed sample after microwave treatment into deionized water, treat it under 40kpa high pressure for 20min, and filter it with a 60-mesh filter to obtain the clear liquid and substrate;

[0065] S4, adding deionized water to the substrate at a material-liquid ratio of 1:3 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid), treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0066] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0067] Example 5

[0068] A method for preparing red bean water with high polyphenol content, specifically comprising the following steps:

[0069] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0070] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0071] S3, material-liquid ratio 1:8g / L, add the mixed sample after microwave treatment into deionized water, treat it under 40kpa high pressure for 20min, and filter it with a 60-mesh filter to obtain the clear liquid and substrate;

[0072] S4, adding deionized water to the substrate at a material-liquid ratio of 1:2 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid) thereto, treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0073] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0074] Comparative Example 1

[0075] A method for preparing red bean water specifically comprises the following steps:

[0076] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0077] S2, solid-liquid ratio 1:4g / L, add adzuki bean and adzuki bean mixed sample into deionized water, treat under 40kpa high pressure condition for 20min, and filter with 60 mesh filter to obtain clear liquid and substrate;

[0078] S3, according to the material-liquid ratio of 1:6g / L, add deionized water to the substrate, filter with a 60-mesh filter to obtain a clear liquid, mix the obtained clear liquid with the clear liquid obtained in S2, add 0.3% pectinase (0.3% of the mass of the mixed clear liquid), treat at 50°C for 2h, the stirrer speed is 600r / min, check the turbidity and sugar content of the mixed liquid, control the turbidity to 18, and the sugar content to 0.4g / 100mL;

[0079] S4. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0080] Comparative Example 2

[0081] A method for preparing red bean water specifically comprises the following steps:

[0082] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0083] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0084] S3, material-liquid ratio 1:4g / L, add the mixed sample into deionized water, cook for 20min, and filter with a 60-mesh filter to obtain the clear liquid and substrate;

[0085] S4, adding deionized water to the substrate at a material-liquid ratio of 1:6 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid), treating at 50°C for 2 h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0086] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0087] Comparative Example 3

[0088] A method for preparing red bean water specifically comprises the following steps:

[0089] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. The raw materials adzuki beans and adzuki beans are mixed evenly at a ratio of 6:1 by weight.

[0090] S2, mixing adzuki bean and red bean into a grinder to grind them, and grinding them evenly to obtain 10 μm red bean and red bean powder;

[0091] S3, with a material-liquid ratio of 1:4g / L, the mixed micropowder was added to deionized water, and ultrasonic-microwave extraction was performed at 50°C for 20min, with the ultrasonic power at 100W and the microwave power at 600W, and then the temperature was raised to 90°C, and after heat treatment for 3h, the supernatant was collected by centrifugation, the centrifugal speed was controlled to be 1000r / min, the centrifugal time was controlled to be 20min, and the clear liquid and substrate were filtered through a 60-mesh filter;

[0092] S4, adding deionized water to the substrate at a material-liquid ratio of 1:6 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, adding 0.3% pectinase (0.3% of the mass of the mixed clear liquid), treating at 50°C for 2h, with a stirrer speed of 600 r / min, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 mL;

[0093] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the inspection is qualified (turbidity <20, sugar content <0.5g / 100mL), cool and fill the solution to obtain the required red bean water.

[0094] Table 2 Test results of sensory evaluation of different red bean water

[0095]

[0096]

[0097] As can be seen from Table 2, compared with Comparative Examples 1 to 3, the red bean water of Examples 1 to 5 has a strong smell, moderate sweetness, and a soft taste. The red bean fragrance of Comparative Examples 1 to 3 is relatively weak, the sweetness is average, and there is a slight astringency, indicating that the method for preparing red bean water by microwave and high pressure synergistic treatment has a significant improvement in the smell and taste of red bean water. Based on the method of the present invention, the flavor and taste of red bean water are successfully improved, which can meet the sensory needs of consumers.

[0098] The color of Examples 1 to 5 and Comparative Examples 1 to 3 is as follows: Figure 1 It can be seen that the solutions of Examples 1 to 5 are dark red in color, clear, free of suspended matter and precipitate, while the colors of Comparative Examples 1 and 2 are red, and the color of Comparative Example 3 is light yellow. The solutions of Comparative Examples 1 and 2 are relatively clear without suspended matter and precipitate, but the clarity of the solution of Comparative Example 3 is reduced, with trace suspended matter or precipitate, indicating that microwave and high pressure synergistic treatment can deepen the color of red bean water. Based on the method of the present invention, the color of red bean water is successfully improved, which can meet the sensory needs of consumers.

[0099] Table 3 Test results of polyphenol content in different red bean water

[0100] Polyphenol content (mg / L) Example 1 1021±8.72 Example 2 1399±14.63 Example 3 1174±10.31 Example 4 932±9.64 Example 5 858±11.57 Comparative Example 1 592±9.40 Comparative Example 2 403±5.96 Comparative Example 3 450±7.12

[0101] As can be seen from Table 3, compared with Comparative Examples 1 to 3, the polyphenol concentration in the red bean water of Examples 1 to 5 is significantly higher than that of the comparative examples, and the concentration is 800 to 1400 mg / L, indicating that the microwave high-pressure synergistic treatment method can effectively increase the content of polyphenols in red bean water, and the polyphenol content in this method is significantly higher than that of the microwave and high-pressure single treatment method and the traditional method of crushing beans to extract red bean water. Based on the method of the present invention, the polyphenol content in red bean water is successfully increased, the nutritional value of red bean water is increased, and people's health needs are met.

[0102] Embodiments 6 to 13

[0103] The preparation method is consistent with that in Example 1, except that the power and time of the microwave treatment in Example 1 are adjusted, as shown in Table 4.

[0104] Embodiments 14 to 20

[0105] The preparation method is consistent with that in Example 1, except that the pressure and time of the high pressure treatment in Example 1 are adjusted, as shown in Table 4.

[0106] Table 4 Test results of sensory evaluation of different red bean waters

[0107]

[0108] As shown in Table 4, compared with Comparative Example 3, Examples 6 to 20 reduce the preparation time and energy consumption of red bean water. The red bean water prepared in Examples 6 to 13 has a coordinated flavor, a soft and astringent taste, and can meet market demand. As the microwave treatment time and power increase, the polyphenol content of the red bean water increases significantly, which can significantly improve the nutritional value of the red bean water. As shown in Table 4, the optimal range of microwave treatment is 600 to 800 W, and the treatment time is 6 to 10 min. As the high-pressure treatment time and pressure increase, the red bean water prepared in Examples 14 to 20 has a deeper color, a richer smell, and a significantly increased polyphenol content, which can meet market demand. As shown in Table 4, the optimal range of high-pressure pressure treatment is 40 to 100 kpa, and the treatment time is 20 to 40 min. In summary, microwave and infrared treatment can improve the color, taste, flavor and polyphenol content of red bean water, reduce energy consumption, and meet the actual application needs of red bean water.

[0109] Embodiment 21

[0110] The preparation method is consistent with that in Example 1, except that the amount of pectinase added and the treatment time in Example 1 are adjusted to 0.2% and 2 h, respectively. See Table 5 for details.

[0111] Embodiment 22

[0112] The preparation method is consistent with that in Example 1, except that the amount of pectinase added and the treatment time in Example 1 are adjusted to 0.2% and 3 h, respectively. See Table 5 for details.

[0113] Embodiment 23

[0114] The preparation method is consistent with that in Example 1, except that the amount of pectinase added and the treatment time in Example 1 are adjusted to 0.4% and 2 h, respectively. See Table 5 for details.

[0115] Comparative Example 4

[0116] The preparation method is consistent with that in Example 1, except that the amount of pectinase added and the treatment time in Example 1 are adjusted to 0.2% and 1 h, respectively. See Table 5 for details.

[0117] Comparative Example 5

[0118] The preparation method is consistent with that in Example 1, except that the amount of pectinase added and the treatment time in Example 1 are adjusted to 0.1% and 2 h, respectively. See Table 5 for details.

[0119] Comparative Example 6

[0120] This comparative example does not use pectinase to prepare red bean water, and specifically includes the following steps:

[0121] S1. Wash the raw materials adzuki beans and adzuki beans and dry them at 60° C. until the moisture content reaches 10%. Mix the raw materials adzuki beans and adzuki beans in a ratio of 4:1 by weight;

[0122] S2, mixing adzuki beans and red beans and putting them into a microwave device for processing, the microwave power is 600W, and the processing time is 10min;

[0123] S3, material-liquid ratio 1:4g / L, add the mixed sample after microwave treatment into deionized water, treat it under 40kpa high pressure for 20min, and filter it with a 60-mesh filter to obtain the clear liquid and substrate;

[0124] S4, adding deionized water to the substrate at a material-liquid ratio of 1:6 g / L, filtering with a 60-mesh filter to obtain a clear liquid, mixing the obtained clear liquid with the clear liquid obtained in S3, centrifuging at 5500 r / min for 20 min in a centrifuge, filtering the supernatant, checking the turbidity and sugar content of the mixed liquid, controlling the turbidity to 18 and the sugar content to 0.4 g / 100 ml;

[0125] S5. Place the mixed solution at 85°C for pasteurization for 15 minutes. After the pasteurization is completed, check the turbidity and sugar content of the mixed solution again. If the test is qualified, cool and fill it to obtain the required red bean water.

[0126] Table 5 Test results of sensory evaluation of different red bean water

[0127]

[0128] As shown in Table 5, compared with Comparative Example 6, the red bean water prepared in Examples 21 to 23 has clear color, moderate sweetness, and soft entrance. The red bean water prepared in Comparative Examples 4 to 5 has turbid color, general sweetness, and astringent aftertaste. Comparative Example 6 has clear color, but general sweetness and astringent aftertaste. Check the turbidity and sugar content of the mixed solution. As shown in Table 5, the optimal conditions for pectinase treatment are 0.2 to 0.4% pectinase addition and 2 to 3 hours of treatment time. At this time, the turbidity range of the red bean water is 15 to 19, and the sugar range is 0.2 to 0.5 g / 100 mL, which can meet market demand. Based on the method of the present invention, pectinase treatment can improve the taste and flavor of red bean water, and adding pectinase instead of centrifugal filtration method reduces energy consumption, reduces the production cost of red bean water, and meets the actual application needs of red bean water.

[0129] The red bean water of the present invention was subjected to storage stability test and microbial detection. The red bean water prepared in Example 1 was stored at 40°C for 30 days, and samples were taken every 5 days to detect changes in product appearance and total phenol content. Microbial detection: The samples were stored at 40°C for 30 days and then tested, wherein the coliform group was determined according to GB4789.3-2016; the salmonella determination was determined according to GB4789.4-2016; the Staphylococcus aureus determination was determined according to GB4789.10-2016; the total colony count was determined according to GB4789.2-2022; and the mold and yeast count was determined according to GB4789.15-2016.

[0130] Table 6 Red bean water microbial detection results

[0131]

[0132]

[0133] As shown in Table 6, after being stored at 40°C for 30 days, the red bean water passed the microbial test. Figure 2 It can be seen that the red bean water is clear in color and has no precipitation after being stored at 40°C for 30 days, and the total phenol content does not change significantly, indicating that the red bean water prepared by this process is relatively stable and can be stored for a long time. The problem of quality deterioration of samples during storage was successfully overcome.

[0134] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing red bean water with high polyphenol content, characterized in that: The steps include: S1, uniformly mixing the raw materials adzuki beans and red beans, and performing microwave processing; S2, adding the microwave-processed adzuki beans and adzuki beans into deionized water, performing high pressure treatment, and then filtering to obtain a clear liquid and a substrate; S3, adding deionized water to the substrate obtained in S2, filtering to obtain a clear solution, and mixing the clear solution with the clear solution obtained in S2 to obtain a mixed clear solution; S4. adding pectinase to the mixed clear solution to obtain a mixed solution, and checking the turbidity and sugar content of the mixed solution; S5. Sterilize the mixed solution, check the turbidity and sugar content again after sterilization, and fill it after passing the inspection to obtain red bean water.

2. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S1, the mass ratio of adzuki bean to red bean is 4-10:

1.

3. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S1, the microwave processing conditions are: microwave power 200-1000W, time 2-10min.

4. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S2, the material-liquid ratio of microwave-treated adzuki beans and adzuki beans to deionized water is 1:4-9 g / L.

5. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S2, the high pressure treatment conditions are: 20-100 kPa, and the treatment time is 10-40 min.

6. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S3, the material-liquid ratio of the substrate obtained in S2 to deionized water is 1:2-8 g / L.

7. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S4, the pectinase accounts for 0.2-0.4% of the mass of the mixed clear liquid; after adding the pectinase, stirring is performed at 40-50° C. for 2-3 hours.

8. The method for preparing red bean water with high polyphenol content according to claim 1, characterized in that: In S4 and S5, check the turbidity and sugar content. When the turbidity is less than 20 and the sugar content is less than 0.5g / 100mL, it is qualified.

9. Red bean water prepared by the method according to any one of claims 1 to 8.

10. Application of the red bean water according to claim 9 in food.

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