Method for preparing soybean milk with low beany flavor by combining microwaves with high-pressure homogenization

Abstract

The invention discloses a method for preparing low-beany-flavor soybean milk by combining microwaves with high-pressure homogenization, and belongs to the technical field of soybean product processing. In order to eliminate beany flavor in soybean milk and promote popularization of soybean milk and products thereof, the invention provides a preparation method of soybean milk with low beany flavor. The method mainly comprises the steps of microwave treatment, soaking, pulping, ultrasonic treatment, high-pressure homogenization, heating and the like, wherein the microwaves are mainly adopted for deodorization treatment. According to the method, the problems existing in the existing soybean milk pretreatment and pulping technology are solved, the lipoxygenase activity of the soybeans in the pulping process is reduced, meanwhile, the taste and stability of the soybean milk are enhanced, the beany flavor in the soybean milk is effectively removed, and the obtained soybean milk has the advantages of being good in stability, excellent in flavor and taste and the like.

Description

Technical Field

[0001] The invention relates to a method for preparing low-beany smell soymilk by microwave combined with high-pressure homogenization, belonging to the technical field of soy product processing. Technical Background

[0002] As a plant protein drink, soy milk is very popular among Oriental people because of its high nutritional value and health benefits. The bioactive polyphenols and plant sterols contained in soy milk are widely associated with the prevention of various diseases, including reducing the risk of heart disease, preventing osteoporosis and lowering blood cholesterol levels. In addition, soy milk is also considered a special drink commonly used by people with lactose intolerance. Soy milk can not only be further processed to produce traditional soy products, such as tofu and yuba, but also is the main raw material for many emerging plant-based products, such as soy yogurt and soy ice cream. Therefore, soy milk is also an indispensable raw material for many soy products and new plant-based foods.

[0003] However, soybeans contain highly active lipoxygenase, which catalyzes the enzymatic degradation of polyunsaturated fatty acids to produce short-chain fatty carbonyl compounds during soaking and refining, thereby producing volatile compounds such as hexanal and trans-2-hexenal that give soy milk an unpleasant flavor such as grass and leaves. These unpleasant flavors are usually described as beany, which makes consumers feel unhappy and affects consumers' desire to buy. Therefore, how to eliminate the beany smell in soy milk and improve its flavor is an urgent problem to be solved. Summary of the invention

[0004] In order to eliminate the beany smell in soy milk and promote the promotion of soy milk and its products, the present invention provides a processing method for low-beany smell soy milk, which specifically comprises the following steps:

[0005] Step 1: washing the soybeans with water, and then treating them with microwaves to obtain microwaved soybeans;

[0006] Step 2: Soak the microwaved soybeans obtained in step 1 in water containing NaHCO3 and then wash them, grind the washed soybeans, and filter to obtain a slurry;

[0007] Step 3: subjecting the slurry obtained in step 2 to ultrasonic treatment and high-pressure homogenization treatment in sequence to obtain a homogenized liquid;

[0008] Step 4: heating the homogenized liquid obtained in step 3 to obtain soymilk with low beany smell.

[0009] It is further defined that the power of the microwave in step 1 is 600-800 W, and the microwave time is 2-4 min.

[0010] Preferably, the power of the microwave in step 1 is 700 W and the microwave time is 3 min.

[0011] It is further defined that the mass fraction of the NaHCO3 aqueous solution in step 2 is 0.4-0.6%; the material-liquid ratio in the soaking process is 1g:7mL-1g:11mL, the soaking temperature is 20-30°C, and the soaking time is 10-14h.

[0012] Preferably, the mass fraction of the NaHCO3 aqueous solution in step 2 is 0.5%; the material-liquid ratio in the soaking process is 1g:9mL, the soaking temperature is 25°C, and the soaking time is 12h.

[0013] It is further defined that the solid-liquid ratio of soybean to water in the refining process of step 2 is 1g:7mL to 1g:11mL; and the filtration utilizes four layers of absorbent gauze.

[0014] Preferably, in the refining process of step 2, the material-liquid ratio of soybean to water is 1 g:9 mL.

[0015] It is further defined that the ultrasonic treatment in step 3 is ultrasonic treatment at 200-400W for 10-20min.

[0016] Preferably, the ultrasonic treatment in step 3 is performed at 300W for 15 minutes.

[0017] It is further defined that the high-pressure homogenization pressure in step three is 400-600 MPa, and the homogenization time is 10-20 min.

[0018] Preferably, the high-pressure homogenization pressure in step three is 600 MPa, and the homogenization time is 15 min.

[0019] It is further defined that the heating in step 4 is heating the homogenized liquid until it boils and then keeping it warm for 3 minutes, so as to obtain soymilk with low beany smell.

[0020] The method for preparing low-smell soybean milk provided by the invention is simple to operate and easy to mass produce. While effectively eliminating the beany smell in soybean milk, the main nutrients in the soybean milk are preserved and the taste of the soybean milk is improved. The product has good stability and excellent flavor and taste.

[0021] The present invention uses microwave heating and high-pressure homogenization on the basis of ultrasound to remove the odor of soybeans, thereby enhancing the taste and stability of soy milk. By rapidly and evenly heating soybeans, the lipoxygenase in the soybeans is inactivated, the enzyme activity is greatly reduced, and the enzymatic reaction induced by the lipoxygenase is prevented from being catalyzed, thereby reducing the formation of related volatile compounds, and effectively removing the beany odor in soy milk. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 To investigate the effect of microwave combined with high pressure homogenization on the sensory evaluation of soy milk. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0025] Embodiment 1:

[0026] Step 1: Wash the soybeans with water, and then treat them with microwaves to obtain microwaved soybeans. The microwave treatment is performed at 700 W for 3 minutes.

[0027] Step 2: Soak the microwaved soybeans obtained in step 1 in a 0.5% NaHCO3 aqueous solution with a solid-liquid ratio of 1g:9mL and a soaking temperature of 25°C. After soaking for 12 hours, wash with water; add water to the washed soybeans for pulping and filtering to obtain a slurry. During the pulping process, the solid-liquid ratio of soybeans to water is 1g:9mL, and four layers of degreased gauze are used for filtration.

[0028] Step 3: The slurry obtained in step 2 is subjected to ultrasonic treatment and high-pressure homogenization treatment in sequence to obtain a homogenized liquid. The ultrasonic treatment is performed at 300W for 15 minutes, and the high-pressure homogenization is performed at a homogenization pressure of 600MPa for 15 minutes.

[0029] Step 4: heating the homogenized liquid obtained in step 3 to boiling and then keeping it warm for 3 minutes to obtain soy milk with low beany smell.

[0030] Embodiment 2:

[0031] Step 1: Wash the soybeans with water, and then treat them with microwaves to obtain microwaved soybeans. The microwave treatment is performed at 600 W for 2 minutes.

[0032] Step 2: Soak the microwaved soybeans obtained in step 1 in a 0.4% NaHCO3 aqueous solution with a solid-liquid ratio of 1 g:7 mL and a soaking temperature of 20°C. After soaking for 10 hours, wash with water; add water to the washed soybeans for pulping and filtering to obtain a slurry. During the pulping process, the solid-liquid ratio of soybeans to water is 1 g:7 mL, and filtering is performed using four layers of degreased gauze.

[0033] Step 3: The slurry obtained in step 2 is subjected to ultrasonic treatment and high-pressure homogenization treatment in sequence to obtain a homogenized liquid. The ultrasonic treatment is performed at 200 W for 10 minutes, and the high-pressure homogenization is performed at a homogenization pressure of 400 MPa for 10 minutes.

[0034] Step 4: heating the homogenized liquid obtained in step 3 to boiling and then keeping the temperature for 3 minutes to obtain soymilk with low beany smell.

[0035] Embodiment 3:

[0036] Step 1: Wash the soybeans with water, and then treat them with microwaves to obtain microwaved soybeans. The microwave treatment is performed at 800 W for 4 minutes.

[0037] Step 2: Soak the microwaved soybeans obtained in step 1 in a 0.6% NaHCO3 aqueous solution with a solid-liquid ratio of 1 g:11 mL and a soaking temperature of 30°C. After soaking for 14 hours, wash with water; add water to the washed soybeans for pulping and filtering to obtain a slurry. During the pulping process, the solid-liquid ratio of soybeans to water is 1 g:11 mL, and four layers of degreased gauze are used for filtration.

[0038] Step 3: The slurry obtained in step 2 is subjected to ultrasonic treatment and high-pressure homogenization treatment in sequence to obtain a homogenized liquid. The ultrasonic treatment is performed at 400 W for 20 minutes, and the high-pressure homogenization is performed at a homogenization pressure of 500 MPa for 20 minutes.

[0039] Step 4: heating the homogenized liquid obtained in step 3 to boiling and then keeping the temperature for 3 minutes to obtain soymilk with low beany smell.

[0040] The lipoxygenase activity, peroxide value, and thiobarbituric acid value of the soymilk obtained in the above-mentioned Examples 1, 2, and 3 were tested, and the test results are shown in the following table:

[0041]

[0042] As can be seen from the above table, the lipoxygenase activity, peroxide value and thiobarbituric acid value in the soymilk obtained in Example 1, Example 2 and Example 3 all showed a decreasing trend with the increase of microwave frequency and homogenization pressure. Among them, Example 2 showed a higher lipoxygenase activity and lipid oxidation level, which were both higher than those in Example 1 and Example 3, indicating that microwave and high-pressure homogenization treatment can inactivate lipoxygenase and effectively reduce the lipid oxidation level.

[0043] The soymilk obtained in Examples 1, 2 and 3 was subjected to sensory evaluation.

[0044] Soy milk samples were dispensed into small tasting cups with lids and labeled with codes. Sensory evaluators were then evaluated using a 5-point scoring system. Ten sensory evaluators who had undergone sensory evaluation training were selected to score the samples for roasted aroma, cucumber flavor, grass flavor, fat flavor, mushroom flavor, and overall acceptability (total score). The highest and lowest scores were removed from the scoring results, and the average was taken as the final score.

[0045] The results are as follows Figure 1 As shown, with the increase of microwave and homogenization pressure, the sensory score of soy milk is significantly improved, so that the cucumber flavor, mushroom flavor, grass flavor and fat flavor of the soy milk obtained in Example 1 are significantly lower than those in Example 2 and Example 3, while the roasted aroma and total score are significantly increased, indicating that the combined treatment of microwave and high-pressure homogenization not only effectively eliminates the peculiar smell in the soy milk, but also gives it a unique roasted aroma, thereby further improving its taste quality and overall flavor.

Claims

1. A method for preparing low beany flavor soymilk by microwave combined with high pressure homogenization, It is characterized in that The method comprises the following steps: Step 1: washing the soybeans with water, and then treating them with microwaves to obtain microwaved soybeans; Step 2: The microwaved soybeans obtained in step 1 are treated with a 3 Soak in water and then wash with NaHCO 3 The mass fraction of the aqueous solution is 0.4-0.6%; the solid-liquid ratio in the soaking process is 1g:7mL-1g:11mL, the soaking temperature is 20-30°C, and the soaking time is 10-14h. The washed soybeans are ground, and the solid-liquid ratio of soybeans to water in the grinding process is 1g:7mL-1g:11mL, and filtered through four layers of degreased gauze to obtain a slurry; Step 3: The slurry obtained in step 2 is subjected to ultrasonic treatment and high-pressure homogenization treatment in sequence, with an ultrasonic frequency of 200 to 400 W and an ultrasonic time of 10 to 20 min to obtain a homogenized liquid; Step 4: heating the homogenized liquid obtained in step 3, and keeping the homogenized liquid warm for 3 minutes after boiling, thereby obtaining soymilk with low beany smell.

2. The preparation method according to claim 1, It is characterized in that The microwave power in step 1 is 600-800W, and the microwave time is 2-4min.

3. The preparation method according to claim 1, It is characterized in that The high-pressure homogenization pressure in step 3 is 400-600 MPa, and the homogenization time is 10-20 min.

Images