阅读说明：本技术 一种利用酸奶作为凝固剂制备的豆腐及其制备方法 (Bean curd prepared from yogurt as coagulant and its preparation method ) 是由 李新原 侯廷帅 于 2018-07-20 设计创作，主要内容包括：本发明提供了一种利用酸奶作为凝固剂制备的豆腐及其制备方法。该利用酸奶作为凝固剂制备的豆腐的制备方法包括以下步骤：将大豆制成豆浆,加入凝固剂,制成所述豆腐；其中,所述凝固剂为酸奶,酸奶与氯化镁的组合,或者,酸奶、氯化镁与葡萄糖酸内酯的组合。本发明利用酸奶凝固剂制作的豆腐表面白析、细嫩,嗅之略有酸奶风味。烹饪过程中豆腐膨胀成多孔状且有弹性,香味扑鼻,口感滑嫩,也可以不经烹制配合果酱直接食用。以本发明的酸奶豆腐为原料可深加工成多种食品。(The invention provides bean curd prepared by using yoghourt as a coagulant and a preparation method thereof.)

1, A method for preparing bean curd using yogurt as coagulant, comprising the steps of:

preparing soybean into soybean milk, and adding a coagulant to prepare the bean curd;

the coagulant is yoghourt, the combination of yoghourt and magnesium chloride, or the combination of yoghourt, magnesium chloride and gluconolactone.

2. The preparation method according to claim 1, wherein the yogurt is obtained by sterilizing milk, cooling, inoculating lactic acid bacteria, and fermenting;

preferably, the sterilization temperature is 95 ℃ and the sterilization time is 300 s;

preferably, the lactic acid bacteria include streptococcus thermophilus and lactobacillus bulgaricus;

preferably, the fermentation end point pH value is 3.8-4.5;

preferably, the storage temperature of the yoghurt after fermentation is < 4 ℃.

3. The preparation method according to claim 1, wherein when yogurt is used as the coagulant, the amount of yogurt added is 5-15% of the total mass of the soy milk, based on the mass of the soy milk;

when the combination of the yoghourt and the magnesium chloride is used as a coagulant, the addition amount of the yoghourt and the addition amount of the magnesium chloride respectively account for 1-8% and 0.15-0.45% of the total mass of the soybean milk;

when the combination of yoghourt, magnesium chloride and gluconolactone is adopted as a coagulant, the addition amount of the yoghourt, the addition amount of the magnesium chloride and the addition amount of the gluconolactone respectively account for 1-8%, 0.15-0.45% and 0.20-0.80% of the total mass of the soybean milk.

4. The preparation method according to any of claims 1-3, wherein the coagulant is added to the soy milk in portions;

preferably, half of the total amount of the coagulant is added within 30 seconds, the mixture is fed at a constant speed, the mixture is fully stirred until the instant flower breaking phenomenon appears, the rest coagulant is added within 3 minutes, the mixture is slowly stirred until the instant flower breaking phenomenon appears, the tofu pudding is filtered, squeezed and dehydrated, and formed to prepare the tofu.

5. The method of any one of , wherein the soybean is dehulled soybean;

preferably, the dehulling treatment comprises the steps of subjecting the soybeans to a centrifugal dehulling treatment, a milling dehulling treatment and a baking treatment;

more preferably, the peeling treatment comprises the steps of:

(1) performing bean skin crisping treatment on the soybeans;

(2) carrying out centrifugal peeling treatment on the soybeans subjected to the bean skin crisping treatment;

(3) performing times of soybean hull separation on the soybeans subjected to centrifugal peeling treatment;

(4) cooling the soybeans subjected to the bean hull separation for times;

(5) milling and peeling the cooled soybeans;

(6) carrying out secondary bean skin separation on the soybeans subjected to milling and peeling treatment;

(7) and (4) baking the soybeans subjected to the secondary soybean hull separation, and then soaking to complete the soybean peeling treatment.

6. The preparation method as claimed in claim 5, wherein the rotation speed of the centrifugal peeling treatment is 1000-2000 rpm.

7. The production method according to claim 5 or 6, wherein the milling dehulling treatment is performed by a dehulling apparatus based on the milling principle, and the soybeans are pressed and rubbed by a fixed-milling part and a movable-milling part of the dehulling apparatus.

8. The preparation method according to of any one of claims 5-7, wherein in step (7), the dehydration rate of the roasted soybeans is controlled to 1% -5%;

preferably, in the baking treatment, the bean paving adopts a mode of combining a quantitative hopper and a conveyor belt, and the thickness of the bean layer is 1-15 cm;

preferably, in the roasting process, the speed of the conveyor belt conveying the bean layer is 0.5-2 m/min;

preferably, in the baking treatment, the soybeans are heated by hot air, and the heating temperature is controlled to be 50-150 ℃;

preferably, the baking treatment time is 30 to 50 minutes.

9. The preparation method according to claim 5, wherein, in the step (1), the beancurd skin crisping treatment is performed in the following manner: heating the soybeans to the temperature of more than 80 ℃ within the time of 180 seconds of 120-; preferably, a fluidized bed is adopted for the bean curd skin crusting treatment;

preferably, the times of bean curd skin separation are carried out in a vertical blowing separation mode, and the secondary bean curd skin separation is carried out by vertical blowing and is matched with a vibrating screen;

preferably, in step (4), the cooling is to normal temperature or below 20 ℃, and cooling is preferably performed by cold air;

preferably, in the step (7), the soaking treatment is to soak the soybeans in an aqueous sodium bicarbonate solution at 80-95 ℃, wherein the pH value of the aqueous sodium bicarbonate solution is 8.0-8.5, and the soaking time is 5-35 minutes.

10. A tofu prepared by the method of any of the methods of claims 1-9.

Technical Field

The invention relates to bean curds prepared by using yoghourt as a coagulant and a preparation method thereof, belonging to the technical field of bean product preparation.

Background

In recent years, health consciousness of consumers has been increasing with the improvement of living standards, and natural plant raw material foods and foods having health functions have been favored, particularly foods related to soybeans as a raw material, soybeans contain various nutrients such as high-quality proteins, vitamin E, isoflavones, lecithin and vegetable linoleic acid, and contain no cholesterol as compared with animal-derived materials, and isoflavones , which is a soybean component, is a bioactive substance having physiological functions such as prevention of osteoporosis, alleviation of symptoms of menopausal syndrome, prevention of arteriosclerosis, and the like, and soybeans have attracted attention in the health food industry.

The bean curd is prepared with bean curd of kinds of Chinese medicinal materials and includes bittern, gypsum, calcium sulfate, silicic acid, aluminum hydroxide, sulfide and other metal ions, and features bitter taste, and inhibition of cardiovascular and nervous systems.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide kinds of bean curd and a preparation method thereof, and the bean curd which has yoghourt, bean flavor, smooth and tender taste and easy storage can be prepared by adopting a coagulant different from the traditional brine and gypsum and singly or by compounding the coagulant with the traditional coagulant.

In order to achieve the above objects, the present invention provides a method for preparing kinds of bean curd using yogurt as a coagulant, comprising the steps of:

preparing soybean into soybean milk, and adding a coagulant to prepare the bean curd;

the coagulant is yoghourt, the combination of yoghourt and magnesium chloride, or the combination of yoghourt, magnesium chloride and gluconolactone.

In the above preparation method, preferably, the yogurt is obtained by sterilizing milk, cooling, inoculating lactic acid bacteria, and fermenting. Wherein the sterilization temperature can be 95 ℃ and the sterilization time can be 300 s. The lactic acid bacteria used may include Streptococcus thermophilus and Lactobacillus bulgaricus. The pH value of the fermentation end point can be controlled to be 3.8-4.5; before inoculating lactobacillus, cooling the feed liquid to 42-43 deg.C. The storage temperature of the fermented yoghourt is less than or equal to 4 ℃.

In the preparation method, preferably, when yoghourt is used as a coagulant, the addition amount of the yoghourt accounts for 5-15% of the total mass of the soybean milk, when a combination of the yoghourt and magnesium chloride is used as the coagulant, the addition amount of the yoghourt and the addition amount of the magnesium chloride respectively account for 1-8% and 0.15-0.45% of the total mass of the soybean milk, when the yoghourt, the combination of the magnesium chloride and gluconolactone are used as the coagulant, the addition amount of the yoghourt, the addition amount of the magnesium chloride and the addition amount of the gluconolactone respectively account for 1-8%, 0.15-0.45% and 0.20-0.80% of the total mass of the soybean milk, and when the latter two combinations of coagulants are used, the obtained soybean curd has a more exquisite appearance and a changed flavor.

In the preparation method, the coagulant is preferably added into the soybean milk in batches, more preferably, half of the total amount of the coagulant is added within 30 seconds, the mixture is added at a constant speed in a flowing manner, the mixture is fully stirred until the instant flower breaking phenomenon appears, the rest of the coagulant is added within 3 minutes, the mixture is slowly stirred until the instant flower breaking phenomenon appears, the soybean flower is filtered, squeezed and dehydrated, and formed to prepare the bean curd.

In the preparation method, the soybeans can be used with skins or peeled, preferably, the soybeans are peeled soybeans, and the soybean milk prepared from the peeled soybeans is fine and smooth in tofu and good in taste; more preferably, the dehulling treatment comprises the steps of subjecting the soybeans to a centrifugal dehulling treatment, a milling dehulling treatment and a baking treatment.

The above peeling treatment preferably comprises the steps of:

(1) performing bean skin crisping treatment on the soybeans;

(2) carrying out centrifugal peeling treatment on the soybeans subjected to the bean skin crisping treatment;

(3) performing times of soybean hull separation on the soybeans subjected to centrifugal peeling treatment;

(4) cooling the soybeans subjected to the bean hull separation for times;

(5) milling and peeling the cooled soybeans;

(6) carrying out secondary bean skin separation on the soybeans subjected to milling and peeling treatment;

(7) and (4) baking the soybeans subjected to the secondary soybean hull separation, and then soaking to complete the soybean peeling treatment.

In the above-described peeling treatment, preferably, in the step (1), the soybean hull crisping treatment is performed in the following manner: heating the soybeans to more than 80 ℃ within the time of 180 seconds of 120-. The bean skin is easy to fall off after becoming crisp, and is convenient for subsequent treatment. The crusting treatment of the bean curd skin can be carried out by adopting a fluidized bed.

In the above-mentioned peeling treatment, it is preferable that in the step (2), the rotation speed of the centrifugal peeling treatment is 1000-2000 rpm. The centrifugal peeling treatment of the soybeans can be carried out by using a peeling device with a centrifugal collision principle, so that the soybeans are peeled for the first time. The centrifugal peeling treatment time is short, and peeling can be almost completed along with acceleration.

In the above peeling process, it is preferable that times of soybean hull separation are performed by vertical blowing separation in step (3), which is mainly used to separate the soybean hulls from the peeled soybeans, so that the primarily peeled soybeans enter a vertical suction system to separate the lighter soybean hulls, particles from the soybean material.

In the above-mentioned dehulling treatment, preferably, in the step (4), cooling means cooling the soybeans subjected to times of soybean hull separation to room temperature or 20 ℃ or lower, preferably with cold wind.

In the above-mentioned dehulling treatment, preferably, in step (5), the milling dehulling treatment is carried out by dehulling equipment based on the milling principle, and the soybeans are extruded and rubbed by fixed grinding parts and movable grinding parts of the dehulling equipment, the step (5) uses dehulling equipment based on the milling principle to carry out the second dehulling treatment of the soybeans, which is composed of fixed grinding parts, movable grinding parts and gap adjusters, wherein the fixed grinding parts and the movable grinding parts have proper tooth shapes to extrude and rub the soybeans, the soybean is crushed, and the soybean is rubbed to separate soybean hulls from kernels, after the soybeans are centrifugally dehulling for times, most of the soybeans are dehulling, the soybean petals and the soybean hulls are well separated, but 5-6% of the soybeans are still in a half-hull wrapping state, the soybean hulls are actually separated from the soybeans, the milling equipment is used to rub the surfaces of the half-wrapped soybeans by rotors (movable grinding parts) on internal rotating rollers, the soybean hulls and the soybean hulls are rubbed to achieve the effect of improving the yield of the half-wrapped soybeans by using a milling device (ZKG) operated under the milling principle of a zero-load operation speed adjusting device, such as a commercial milling machine (ZK 18).

In the peeling treatment, the secondary separation of the skin of beancurd refers to the separation of the skin of beancurd and the bean paste by blowing wind, preferably, in the step (6), the secondary separation of the skin of beancurd is performed by vertically blowing wind, and a vibrating screen is used in combination, and specifically, the following method can be adopted: the soybean to be separated is laid on a vibrating screen, the germ powder is firstly removed by vibration, and then the skin of beancurd and the bean cotyledon are separated by vertical blowing.

In the above-mentioned dehulling treatment, it is preferable that the dehydration rate of the soybeans subjected to the baking treatment in step (7) is controlled to 1% to 5%. The roasting process comprises bean spreading, conveying, roasting, cooling, detecting and the like. In the baking treatment, the bean spreading operation can adopt a mode of combining a quantitative hopper and a conveyor belt, and the thickness of the bean layer can be controlled to be 1-15 cm. The speed of the conveyor belt for conveying the bean layer is 0.5-2 m/min, and the speed of the conveyor belt can be controlled by a motor. During the baking process, the soybeans can be heated by hot air, and the heating temperature is controlled to be 50-150 ℃. The time of the baking treatment is preferably controlled to 30 to 50 minutes. And finally, cooling the soybeans by using cold air, reducing the temperature to be below 20 ℃, detecting the dehydration rate of the soybeans, and controlling the dehydration rate of the roasted soybeans to be 1-5%, namely, the moisture content is 6-9%.

In the above peeling treatment, preferably, in the step (7), the soaking treatment is to soak the soybeans in an aqueous sodium bicarbonate solution at 80 to 95 ℃, wherein the pH of the aqueous sodium bicarbonate solution is 8.0 to 8.5, and the soaking time is 5 to 35 minutes.

The invention also provides the bean curd prepared by using the yoghourt as the coagulant according to the method, which can be called yoghourt bean curd.

The packaging mode of the bean curd can adopt: (1) soft packaging: cutting the formed bean curd into blocks with proper size, and putting the blocks into a vacuum packaging device for vacuum packaging. (2) And (3) plastic box packaging: cutting the formed bean curd into blocks with proper size, putting the blocks into a plastic box, adding proper sterile water to remove air, and sealing with a plastic film. (3) Tetra Pak of tetra Pak: adding coagulator into the soybean milk after boiling, mixing, filling into a paper-plastic composite packaging box, and forming at 40-90 deg.C for 30-60min to obtain bean curd.

The invention relates to a bean curd which is prepared by using a yoghourt coagulant, the surface of the bean curd is white, tender and slightly tasty, the bean curd has yoghourt flavor, the bean curd expands into porous shape and has elasticity, the fragrance is strong, the mouth feel is smooth and tender, and the bean curd can be directly eaten without being cooked and matched with jam.

Detailed Description

The technical solutions of the present invention will be described in detail below in order to clearly understand the technical features, objects, and advantages of the present invention, but the present invention is not limited to the practical scope of the present invention.

The yoghourt tofu provided by the invention can be prepared according to the following specific steps:

1) soybean peeling:

s1: heating the soybeans to more than 80 ℃ within 180 seconds of 120-;

s2: carrying out centrifugal peeling treatment on the soybeans treated in the step S1 in a huller, and then feeding the soybeans into a vertical air suction duct to separate light particles from particulate materials;

s3, feeding the soybeans processed in the step S2 into a cooling bin, and cooling to obtain th dehulled soybeans;

s4, grinding and peeling the th time dehulled soybeans in a dehuller, separating light particles and broken beans from particulate materials by using a vibrating screen and a vertical air draft channel, and separating light impurities in the particulate materials by using an air draft device after the particulate materials are discharged out of the dehuller to obtain second time dehulled soybeans;

2) baking soybeans:

baking the second hulled soybean, wherein the baking process comprises bean spreading, conveying, baking, cooling and detecting;

s1: the bean paving step adopts a mode of combining a quantitative funnel and a conveyor belt, and the thickness of a bean layer is 1-15 cm;

s2: in the conveying step, the speed of a conveyor belt is controlled by a motor, and the speed of the conveyor belt for conveying the bean layer is 0.5-2 m/min;

s3: in the baking step, the soybeans are heated by hot air, the heating temperature is controlled to be 50-150 ℃, and the baking time is controlled to be 30-50 minutes;

s4: cooling the baked soybeans by using cold air, and cooling to below 20 ℃;

s5: the detection step is used for detecting the dehydration rate of the soybeans, and the dehydration rate of the baked soybeans is controlled to be 1% -5%.

S6: preparing soybean milk: after the roasting and cooling of the soybeans are finished, soaking the obtained roasted soybeans for 5 to 35 minutes by using hot water at the temperature of between 80 and 95 ℃ through an online pipeline, and controlling the pH value of soaking water to be between 8.0 and 8.5 by adding a sodium bicarbonate solution accounting for 0.15wt percent of the target soybean milk yield online; after soaking, grinding the soybeans into thick liquid, inactivating enzymes, removing residues and homogenizing to obtain soybean raw stock meeting the conditions.

3) And (3) yogurt fermentation:

s1: sterilization of base materials: heating milk to 95 deg.C, and sterilizing for 300 s;

s2: cooling the base material: cooling the milk processed by the S1 to 40-42 ℃ and transferring the cooled milk into a fermentation tank;

s3: inoculating and fermenting: inoculating lactobacillus (Streptococcus thermophilus and Lactobacillus bulgaricus) into the milk treated by S2 in sterile environment for 4-8h, and demulsifying for later use after fermentation is completed, wherein the storage temperature is less than or equal to 4 ℃.

4) Coagulant scheme:

(1) yogurt coagulant: adding the yogurt treated by the S3 in the yogurt fermentation step into the soybean milk treated by the S6 in the soybean baking step according to the addition amount of 5-15% (mass ratio).

(2) Yogurt coagulant and MgCl₂Compounding: adding the yogurt treated by the S3 in the yogurt fermentation step into the soybean milk treated by the S6 in the soybean baking step according to the addition amount of 1-8% (mass ratio), and adding MgCl₂Adding the soybean milk into the soybean milk treated by S6 in the soybean baking step according to the addition amount of 0.15-0.45% (mass ratio), and mixing the above materials.

(3) Yogurt coagulant, MgCl₂And delta-GDL (gluconolactone) compounding: adding the yogurt treated by the S3 in the yogurt fermentation step into the soybean milk treated by the S6 in the soybean baking step according to the addition amount of 1-8% (mass ratio), and adding MgCl₂Adding the delta-GDL into the soybean milk treated by the S6 in the soybean baking step according to the adding amount of 0.15-0.45% (mass ratio), adding the delta-GDL into the soybean milk treated by the S6 in the soybean baking step according to the adding amount of 0.20-0.80% (mass ratio), and uniformly mixing the above materials.