A method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment

Abstract

The object of the present invention is to provide a method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment, belonging to the technical field of food processing. The present invention combines the emerging ultrasonic technology with kidney beans and supplements it with low-concentration H2O2. The germination method of the present invention is simple, environmentally friendly, rapid and effective, can significantly shorten the germination time of kidney beans, reduce the germination cost, effectively improve the antioxidant property of germinated kidney beans, increase the nutritional value of germinated kidney beans, and is a germination method for comprehensively improving the quality of germinated kidney beans. Moreover, applying ultrasonic treatment to the germination of kidney beans can accelerate germination, effectively improve the texture and nutritional value of miscellaneous beans, and increase their commercial value.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to a method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment. Background Art

[0002] Kidney beans (Phaseolus vulgaris L.), also known as common beans, have a long planting history, with good stress and drought resistance, strong drought resistance and adaptability, and can grow normally even in arid and semi-arid regions. As an important food crop, kidney beans not only contain nutrients such as carbohydrates, proteins, dietary fiber, minerals and vitamins, but also contain rich polyphenol compounds, which have potential health benefits for human health, such as preventing cardiovascular diseases, obesity, diabetes and cancer. However, ordinary kidney beans have a certain bean smell, and certain properties need to be improved, such as solubility. In addition, the content of their phenolic substances is limited, and the antioxidant capacity is far from enough.

[0003] Germination is an important process of rapid changes in plant growth. During this process, complex physical and chemical changes occur, including water absorption, cell structure change, root and bud formation, enzyme activation, enhanced respiration and degradation change of macromolecular substances. Germination treatment can effectively improve the nutritional value of seeds, reduce anti-nutritional factors, improve digestibility and functionality, and is a simple and economical processing method. Usually, germination treatment is directly carried out under the conditions of 25°C - 30°C and 60% - 80% humidity. However, under general germination methods, the seed germination cycle is long, the cost is high, and the effect is not good.

[0004] As an emerging non-thermal physical treatment technology, ultrasonic waves mainly change the molecular structure through cavitation effect, and are commonly used to improve food quality or develop new products. Because ultrasonic technology has the advantages of convenience, speed, environmental friendliness, economy and effectiveness, it has gradually attracted people's attention in recent years. In addition, it is reported that hydrogen peroxide can not only decompose into oxygen, but also inhibit the growth of molds. Summary of the Invention

[0005] To solve the above problems and expand the application of kidney beans in the food field. The present invention combines the emerging ultrasonic technology with kidney beans and supplements with low-concentration H2O2, providing a germination method for improving the quality of germinated kidney beans by ultrasonic treatment. The germination method of the present invention is simple, environmentally friendly, fast and effective, can significantly shorten the germination time of kidney beans, reduce the germination cost, effectively improve the antioxidant property of germinated kidney beans, increase the nutritional value of germinated kidney beans, and is a germination method for comprehensively improving the quality of germinated kidney beans. Moreover, applying ultrasonic treatment to the germination of kidney beans can accelerate germination, effectively improve the texture and nutritional value of miscellaneous beans, and increase their commercial value.

[0006] The present invention adopts the following technical solutions:

[0007] A method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment, comprising the following steps:

[0008] First step, select plump kidney beans with intact seed coats and similar sizes, and rinse to remove surface impurities;

[0009] Second step, add alcohol to the washed seeds for disinfection;

[0010] Third step, then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface;

[0011] Fourth step, place the disinfected seeds in a beaker, add H2O2 to completely immerse the seeds, and soak in the dark at room temperature;

[0012] Fifth step, subject the soaked kidney bean seeds to water bath ultrasonic treatment, and ensure that the temperature < 25°C throughout the ultrasonic process;

[0013] Sixth step, disinfect the seeds treated by ultrasonic treatment with 75% alcohol by mass for 30 s, and wash with deionized water;

[0014] Seventh step, evenly distribute 50 washed seeds in a 15 cm petri dish lined with double-layer filter paper, then cover with another layer of filter paper, and spray with deionized water;

[0015] Eighth step, place the petri dish in a constant temperature incubator, culture for 12 cycles at 30°C in the dark, record every 8 h, germinate for 96 h, spray water once every 16 h, disinfect with 75% alcohol by mass for 30 s every 48 h, then wash three times with deionized water to wash away the surface alcohol, and, replace the filter paper in the petri dish after each disinfection.

[0016] In the second step, the mass concentration of the alcohol is 70% - 75%, and the disinfection time is 30 s - 60 s.

[0017] In the fourth step, the mass concentration of the H2O2 is 0.8% - 1%, the addition amount is two to three times the volume of the seeds, and the soaking time is 10 h - 12 h.

[0018] In the fifth step, the water bath ultrasonic treatment time is 8 min - 12 min.

[0019] The ultrasonic conditions are a frequency of 20 Hz and a power of 250 W - 450 W.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. A germination method for improving the quality of germinated kidney beans by ultrasonic treatment of the present invention is simple, fast and efficient, significantly shortening the germination time of kidney beans, increasing the germination rate, promoting the growth of bud length, reducing the germination cost, increasing the content of soluble protein in germinated kidney beans, enhancing the antioxidant property of germinated kidney beans, and comprehensively improving the quality of germinated miscellaneous beans.

[0022] 2. The dissolved oxygen in hydrogen peroxide is used to provide the oxygen required for seed germination. At the same time, the oxidation of hydrogen peroxide can also disinfect and sterilize the seeds, improving seed vigor.

[0023] 3. When germinated for 96 h, the content of soluble protein reaches 19.35 g / 100 g, the DPPH free radical scavenging rate is as high as 85.12%, the ABTS free radical scavenging rate is as high as 92.66%, and the Fe 2+ chelating ability reaches 56.94%. Specific Embodiments

[0024] The following are descriptions of the preferred embodiments of the present invention. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0025] A method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment, comprising the following steps:

[0026] First step, select plump, intact seed coats and kidney beans of similar size, and rinse to remove surface impurities;

[0027] Second step, add alcohol with a mass percentage of 75% to the washed seeds for disinfection for 1 min;

[0028] Third step, then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface;

[0029] Fourth step, place the disinfected seeds in a beaker, add H2O2 with a mass concentration of 1% to submerge the seeds, and soak in the dark at room temperature for 12 h;

[0030] Fifth step, subject the soaked kidney bean seeds to water bath ultrasonic treatment for 10 min, and ensure that the temperature < 25 °C throughout the ultrasonic process;

[0031] Sixth step, disinfect the seeds after ultrasonic treatment with alcohol with a mass percentage of 75% for 30 s, and wash with deionized water;

[0032] Seventh step, evenly distribute 50 washed seeds in a 15-cm petri dish lined with double-layer filter paper, then cover with another layer of filter paper, and spray deionized water;

[0033] Step 8: Place the petri dish in a constant temperature incubator and incubate it for 12 cycles at 30°C under dark conditions. Record once every 8 h. Germination takes 96 h. Spray water once every 16 h. Disinfect with 75% (mass percentage) alcohol for 30 s every 48 h, then wash three times with deionized water to remove the surface alcohol. Also, replace the filter paper in the petri dish after each disinfection.

[0034] 1. Example

[0035] Example 1 (ultrasonic treatment conditions: 20 kHz, power 250 W, treatment time 10 min, temperature 25°C)

[0036] (1) Select plump kidney beans with intact seed coats and similar sizes, and rinse to remove surface impurities.

[0037] (2) Add 75% (mass percentage) alcohol to the washed seeds and disinfect for 1 min.

[0038] (3) Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface.

[0039] (4) Place the disinfected seeds in a beaker, add 1% (mass concentration) H2O2 to cover the seeds, and soak in the dark at room temperature for 12 h.

[0040] (5) Subject the soaked kidney bean seeds to ultrasonic treatment in a water bath at an ultrasonic frequency of 20 kHz and a power of 250 W for 10 min, and ensure that the temperature < 25°C throughout the ultrasonic process.

[0041] (6) Disinfect the seeds after ultrasonic treatment with 75% (mass percentage) alcohol for 30 s, and wash with deionized water.

[0042] (7) Evenly distribute 50 washed seeds into a 15-cm petri dish lined with double-layer filter paper (disinfected with 75% (mass percentage) alcohol and washed with deionized water), then cover with another layer of filter paper and spray deionized water.

[0043] (8) Place the petri dish in a constant temperature incubator and incubate it for 12 cycles at 30°C under dark conditions. Record once every 8 h. Germination takes 96 h. Spray water once every 16 h. Disinfect with 75% (mass percentage) alcohol for 30 s every 48 h, then wash three times with deionized water to remove the surface alcohol. Also, replace the filter paper in the petri dish after each disinfection.

[0044] Example 2 (ultrasonic treatment conditions: 20 kHz, power 350 W, treatment time 10 min, temperature 25°C)

[0045] (1) Select plump kidney beans with intact seed coats and similar sizes, and rinse to remove surface impurities.

[0046] (2) Add alcohol with a mass percentage of 75% to the washed seeds and disinfect for 1 min.

[0047] (3) Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface.

[0048] (4) Place the disinfected seeds in a beaker, add H2O2 with a mass concentration of 1% to cover the seeds, and soak in the dark at room temperature for 12 h.

[0049] (5) Subject the soaked kidney bean seeds to ultrasonic treatment in a water bath at an ultrasonic frequency of 20 kHz and a power of 350 W for 10 min. During this period, ensure that the temperature < 25 °C throughout the ultrasonic process.

[0050] (6) Disinfect the seeds treated ultrasonically with alcohol with a mass percentage of 75% for 30 s, and wash with deionized water.

[0051] (7) Evenly distribute 50 washed seeds in a 15-cm petri dish lined with double-layer filter paper (disinfected with alcohol with a mass percentage of 75% and washed with deionized water), then cover with another layer of filter paper, and spray with deionized water.

[0052] (8) Place the petri dish in a constant-temperature incubator and culture for 12 cycles at 30 °C in the dark, recording every 8 h. Germinate for 96 h, spray water every 16 h, disinfect with alcohol with a mass percentage of 75% for 30 s every 48 h, then wash three times with deionized water to wash away the surface alcohol. Also, replace the filter paper in the petri dish after each disinfection.

[0053] Example 3 (ultrasonic treatment conditions: 20 kHz, power 450 W, treatment time 10 min, temperature 25 °C)

[0054] (1) Select plump kidney beans with intact seed coats and similar sizes, and remove surface impurities by rinsing.

[0055] (2) Add alcohol with a mass percentage of 75% to the washed seeds and disinfect for 1 min.

[0056] (3) Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface.

[0057] (4) Place the disinfected seeds in a beaker, add H2O2 with a mass concentration of 1% to cover the seeds, and soak in the dark at room temperature for 12 h.

[0058] (5) Subject the soaked kidney bean seeds to ultrasonic treatment in a water bath at an ultrasonic frequency of 20 kHz and a power of 450 W for 10 min. During this period, ensure that the temperature < 25 °C throughout the ultrasonic process.

[0059] (6) The seeds after ultrasonic treatment were disinfected with 75% alcohol by mass for 30 s and then washed with deionized water.

[0060] (7) Fifty washed seeds were evenly placed in a 15-cm petri dish lined with double-layer filter paper (disinfected with 75% alcohol by mass and washed with deionized water), covered with another layer of filter paper, and sprayed with deionized water.

[0061] (8) The petri dish was placed in a constant-temperature incubator and cultured for 12 cycles at 30 °C in the dark, and recorded every 8 h. After 96 h of germination, it was sprayed with water every 16 h, disinfected with 75% alcohol by mass for 30 s every 48 h, then washed three times with deionized water to remove the surface alcohol. And the filter paper in the petri dish was replaced after each disinfection.

[0062] Control Example 1 (soaked in deionized water and directly cultured for germination without ultrasonic treatment)

[0063] (1) Select plump kidney beans with intact seed coats and similar sizes, and remove surface impurities by rinsing.

[0064] (2) Add 75% alcohol by mass to the washed seeds and disinfect for 1 min.

[0065] (3) Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface.

[0066] (4) The disinfected seeds were placed in a beaker, and deionized water was added to cover the seeds, and soaked in the dark at room temperature for 12 h.

[0067] (5) The soaked kidney bean seeds were disinfected with 75% alcohol by mass for 30 s and then washed with deionized water.

[0068] (6) Fifty washed seeds were evenly placed in a 15-cm petri dish lined with double-layer filter paper (disinfected with 75% alcohol by mass and washed with deionized water), covered with another layer of filter paper, and sprayed with deionized water.

[0069] (7) The petri dish was placed in a constant-temperature incubator and cultured for 12 cycles at 30 °C in the dark, and recorded every 8 h. After 96 h of germination, it was sprayed with water every 16 h, disinfected with 75% alcohol by mass for 30 s every 48 h, then washed three times with deionized water to remove the surface alcohol. And the filter paper in the petri dish was replaced after each disinfection.

[0070] Control Example 2 (soaked in 1% H2O2 by mass concentration and directly cultured for germination without ultrasonic treatment)

[0071] (1)Select plump kidney beans with intact seed coats and similar sizes, and rinse them to remove surface impurities.

[0072] (2)Add 75% alcohol by mass percentage to the washed seeds and disinfect for 1 minute.

[0073] (3)Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface.

[0074] (4)Place the disinfected seeds in a beaker, add 1% H2O2 by mass concentration to cover the seeds, and soak them in the dark at room temperature for 12 hours.

[0075] (5)Disinfect the soaked kidney bean seeds with 75% alcohol by mass percentage for 30 seconds, and wash them with deionized water.

[0076] (6)Evenly distribute 50 washed seeds into 15-cm petri dishes lined with double-layer filter paper (disinfected with 75% alcohol by mass percentage and washed with deionized water), then cover with another layer of filter paper and spray with deionized water.

[0077] (7)Place the petri dishes in a constant temperature incubator and culture for 12 cycles at 30°C in the dark, recording every 8 hours. After 96 hours of germination, spray water every 16 hours, disinfect with 75% alcohol by mass percentage for 30 seconds every 48 hours, then wash three times with deionized water to wash away the surface alcohol. Also, replace the filter paper in the petri dish after each disinfection.

[0078] 2. Data determination

[0079] (1)Determination of germination rate and germination index: After each group of experimental treatments, count the number of germinated miscellaneous bean seeds in each group every 8 hours. The germination standard is 1 / 2 of the seed length.

[0080] Germination rate: GR (%) = Nt / NTS × 100%;

[0081] Germination index: GI (%) = Σ(NDt / t × 100%);

[0082] Among them, GR and GI represent the germination rate and germination index of the seeds respectively. Nt represents the number of germinated seeds; NTS represents the total number of test seeds on the petri dish; NDt represents the number of germinated seeds at time t; t represents the germination time of the seeds.

[0083] Determination of germination length: Randomly select 5 germinated miscellaneous beans from the petri dish every 8 hours, measure their bud lengths with a ruler, and set three replicates for each group. Use L to represent the germination length of the seeds.

[0084] (2)Determination of soluble protein content: Determined by Coomassie brilliant blue method. First, weigh 0.1 g of Coomassie brilliant blue G250, add 50 mL of 95% ethanol and 100 mL of 85% phosphoric acid, make up to 1000 mL with distilled water, and then filter to obtain Coomassie brilliant blue solution. Then prepare the standard protein solution, weigh 0.01 g of solid BSA, add 100 mL of distilled water, stir with a glass rod until the solid dissolves and set aside. Next, take 0.01 g of freeze-dried sample, add 10 mL of distilled water, stir well with a glass rod until it dissolves completely, then filter with a 0.22 μm filter membrane and place it in a centrifuge tube. Use the Coomassie brilliant blue solution and the standard protein solution to draw a standard curve (0 - 100 μL), then pipette 100 μL of the sample solution, add 5 mL of Coomassie brilliant blue solution, after reacting for 2 min, measure its absorbance at 595 nm using a UV-spectrophotometer, and obtain the protein content according to the standard curve.

[0085] (3)Determination of antioxidant property: Determination of DPPH radical scavenging ability: First, take 1 g of the sample, add 15 mL of 80% methanol for extraction, centrifuge at 4500 rpm for 10 min, and take the supernatant for use. Then, prepare a 0.1 mM DPPH solution, wrap the centrifuge tube with tin foil and store it in the dark throughout the process. Then, react with the sample, add 85 μL of the sample and 165 μL of the DPPH solution into the centrifuge tube wrapped with tin foil, and shake well for 1 min. Next, react for 30 min under dark conditions. Fourth, measure the absorbance value at 517 nm. Use 80% methanol instead of the sample as a control. The result is calculated according to the following formula:

[0086] DPPH radical scavenging rate (%) = (Abs control -Abs test ) / Abs control × 100;

[0087] Where Abs control represents the absorbance value of the control group at 517 nm; Abs test represents the absorbance value of the experimental group at 517 nm.

[0088] (4)Determination of ABTS radical scavenging ability: First, weigh 1 g of the sample, add 15 mL of 80% methanol for extraction, centrifuge at 4500 rpm for 10 min, and take the supernatant for later use. Then, prepare a 14 mM ABTS solution and a 4.9 mM potassium persulfate solution. Next, mix 5 mL of the ABTS solution and 5 mL of the potassium persulfate solution, store in the dark at 25 °C for 16 h to obtain the ABTS mother liquor. Then, take an appropriate amount of the ABTS mother liquor, dilute it with distilled water to an absorbance value of 0.900 ± 0.02 at 734 nm. Then, react with the sample. Take 200 μL of the ABTS solution, add 50 μL of the sample, and stir for 1 min. Finally, store in the dark for 6 min and measure the absorbance at 734 nm. Use 80% methanol instead of the sample as a control. Calculate according to the following formula:

[0089] ABTS radical scavenging rate (%) = (Abs control -Abs test ) / Abs control × 100;

[0090] Where Abs control represents the absorbance value of the control group at 734 nm; Abs test represents the absorbance value of the test group at 734 nm.

[0091] (5)Determination of Fe 2+ chelating ability: First, weigh 1 g of the sample, add 15 mL of 80% methanol for extraction, centrifuge at 4500 rpm for 10 min, and take the supernatant for later use. Then, prepare a 0.002 M ferrous chloride solution and a 0.005 M phenanthroline. Then, react with the sample. Add 25 μL of the FeCl2 solution and 200 μL of the phenanthroline solution to 50 μL of the sample, react in the dark at 25 °C for 10 min. Finally, measure the absorbance at 562 nm. Use 80% methanol instead of the sample as a control. Calculate the results according to the following formula:

[0092] Fe 2+ chelating ability = (Abs control -Abs test ) / Abs control × 100;

[0093] Where Abs control represents the absorbance value of the control group at 562 nm; Abs test represents the absorbance value of the test group at 562 nm.

[0094] 3. Measurement results

[0095] The germination of kidney beans obtained in Examples 1-3 and Control Examples 1-2 was evaluated, and the changes in the soluble protein content and antioxidant capacity of each group after 96 h of germination were measured. The results are shown in Tables 1, 2, 3, 4, and 5.

[0096] Table 1 shows the detection results of the germination rate of kidney beans under different treatment conditions

[0097]

[0098] Table 2 shows the detection results of the sprout length of kidney beans under different treatment conditions

[0099]

[0100] Table 3 shows the detection results of the germination index of kidney beans under different treatment conditions

[0101]

[0102] Table 4 shows the detection results of the soluble protein of kidney beans after 96 h of germination in different treatment groups

[0103]

[0104] Table 5 shows the antioxidant capacity (DPPH radical scavenging rate, ABTS radical scavenging rate, and Fe 2+ chelating ability) of kidney beans after 96 h of germination in different treatment groups

[0105]

[0106] As can be seen from Tables 1, 2, and 3: Ultrasonic treatment can promote the germination of kidney beans. First, ultrasonic waves can increase the germination rate of kidney beans. After treating kidney beans with 20 kHz ultrasound at 250 W, 350 W, or 450 W for 10 min and then culturing them to germinate, the germination rates after 96 h of germination reach 81.84%, 85.02%, and 82.93% respectively, which are significantly higher than those of the deionized water immersion group without ultrasound (58.90%) and the 1% H2O2 immersion group (76.52%). Second, ultrasonic treatment can increase the sprout length of kidney beans. After treating kidney beans with 20 kHz ultrasound at 250 W, 350 W, or 450 W for 10 min and germinating them for 96 h, the sprout lengths reach 2.60 cm, 2.65 cm, and 2.71 cm respectively, which are significantly higher than those of the deionized water immersion group without ultrasound (2.16 cm) and the 1% H2O2 immersion group (2.23 cm). In addition, ultrasonic treatment can improve the germination vigor of seeds. After treating kidney beans with 20 kHz, 350 W, or 450 W ultrasound for 10 min, they start to germinate within 8-16 h and still have a certain germination ability until 80 h.

[0107] As can be seen from Table 4: After treating kidney beans with ultrasound at 20 kHz and 350 W for 10 min and then culturing them for germination for 96 h, the soluble protein content is as high as 19.35 g / 100 g. Moreover, the soluble protein content of germinated kidney beans under ultrasonic treatment conditions is greater than that of the non-ultrasonic treatment group.

[0108] As can be seen from Table 5: After treating kidney beans with ultrasound at 20 kHz and 350 W for 10 min and then germinating them for 96 h, the DPPH free radical scavenging rate is as high as 85.12%, the ABTS free radical scavenging ability is 92.66%, and the Fe 2+ chelating ability can reach 56.94%. Moreover, under ultrasonic treatment conditions, the DPPH free radical scavenging rate, ABTS free radical scavenging rate, and Fe 2+ chelating ability are all greater than those of germinated kidney beans without ultrasonic treatment.

[0109] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment, characterized in that: It includes the following steps: First step: Select plump kidney beans with intact seed coats and similar sizes, and rinse them to remove surface impurities; Second step: Add alcohol for disinfection to the washed seeds; Third step: Then wash the kidney bean seeds three times with deionized water to wash away the residual alcohol on the surface; Fourth step: Place the disinfected seeds in a beaker, add H2O2 to completely immerse the seeds, and soak them in the dark at room temperature; Fifth step: Subject the soaked kidney bean seeds to water bath ultrasonic treatment, and ensure that the temperature < 25°C throughout the ultrasonic process; Sixth step: Disinfect the seeds after ultrasonic treatment with 75% alcohol by mass for 30 s, and wash them with deionized water; Seventh step: Evenly distribute 50 washed seeds in a 15-cm petri dish lined with double-layer filter paper, cover with another layer of filter paper, and spray deionized water; Eighth step: Place the petri dish in a constant temperature incubator and culture it for 12 cycles at 30°C in the dark. Record every 8 h. Germinate for 96 hours, spray water every 16 hours, disinfect with 75% alcohol by mass for 30 s every 48 h, then wash three times with deionized water to wash away the surface alcohol, and replace the filter paper in the petri dish after each disinfection; In the fourth step, the mass concentration of the H2O2 described is 0.8% - 1%, the addition amount is two to three times the volume of the seeds, and the soaking time is 10 h - 12 h; In the fifth step, the water bath ultrasonic treatment time described is 8 min - 12 min; The ultrasonic conditions are a frequency of 20 Hz and a power of 250 W - 450 W.

2. A method for improving the functional properties of germinated kidney beans by high-intensity ultrasonic treatment according to claim 1, characterized in that: In the second step, the mass concentration of the alcohol described is 70% - 75%, and the disinfection time is 30 s - 60 s.

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