Green preparation process of tapioca acid starch with baking expansibility

Abstract

The invention provides a green preparation process of tapioca sour starch with baking expansibility, and relates to the technical field of food preparation, the process comprises the following steps: (1) preparation of tapioca native starch, (2) fermentation and ultraviolet irradiation, and (3) drying. After the cassava raw starch is prepared, the cassava raw starch is subjected to denaturation treatment in a manner of combining fermentation with ultraviolet radiation, and then the drying process is combined, so that the finally obtained cassava sour starch has the characteristic of good baking expansibility.

Description

[Technical field]

[0001] The invention relates to the technical field of food preparation, and in particular to a green preparation process of tapioca starch with baking expansion properties. [Background technology]

[0002] Cassava (Manihot esculenta Crantz) is one of the three major tubers and six major food crops in the world. It is known as the "underground food" and the "king of starch" because of its rich starch content. It has been widely planted in tropical and subtropical regions of more than 100 countries in Africa, America and Asia. Cassava is the staple food of nearly one billion people in the world. In many countries such as Africa and South America, cassava is the third largest food source after rice and corn, making a huge contribution to food security and poverty alleviation. Cassava starch, like wheat, potato, corn and other starches, can provide rich carbohydrates for human diet and is a good starch-based raw material.

[0003] However, due to the poor solubility, stability, high temperature resistance, shear, and acid-base properties of cassava starch, the poor quality of cassava starch protein (low content and lack of structural amino acids), and the fact that it does not contain gluten protein, it cannot form a gluten network structure when used alone, and cannot form a dough with viscoelasticity and extensibility. It has poor plasticity and has certain limitations when directly used in the field of food processing.

[0004] Therefore, it is inevitable to develop modified starch with new functions or improve the original functions to broaden the application scope of cassava starch. [Summary of the invention]

[0005] In view of this, the purpose of the present invention is to provide a green preparation process of tapioca starch with baking expansion properties, which uses fermentation combined with ultraviolet irradiation to physically modify the native cassava starch, and combines the drying process of the present application to finally obtain tapioca starch with good baking expansion properties.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A green preparation process of tapioca starch with baking expansion property comprises the following steps:

[0008] (1) Preparation of cassava starch: peel fresh cassava, add water and beat into a slurry to obtain cassava pulp; add an extract to the slurry obtained by sieving the cassava pulp to obtain a composite slurry; send the composite slurry to a separator for separation treatment to obtain starch milk, and dehydrate and dry the starch milk to obtain cassava starch;

[0009] (2) fermentation: taking the cassava starch obtained in step (1), adding glucose powder, fermentation agent and water, mixing them thoroughly in a triangular flask, sealing the flask, fermenting, and then discarding the upper fermentation liquid to obtain a precipitated slurry for later use;

[0010] (3) Drying: Drying the precipitated slurry obtained in step (2) to obtain tapioca starch.

[0011] In the present invention, further, the extract is a liquorice extract, which is obtained by alcohol extraction of liquorice raw material.

[0012] In the present invention, further, the fermentation bacteria in step (2) is lactic acid bacteria, which is a composite bacteria, and the manufacturer of the lactic acid bacteria is DSM. When used, in order to make the fermentation more uniform, the whole package of bacteria can be dissolved in water, and then prepared into a lactic acid bacteria solution (the amount of water is adjusted as needed) and then used (the converted amount is 0.01%-0.05% of the mass of the original cassava starch).

[0013] In the present invention, further, in step (2), the added amount of the glucose powder accounts for 3%-6% of the mass of the original cassava starch, the added amount of the fermentation agent accounts for 0.01%-0.05% of the mass of the original cassava starch, and the water is distilled water, accounting for 150%-300% of the mass of the original cassava starch.

[0014] In the present invention, further, the fermentation in step (2) is placed in a constant temperature box at 30-40° C. and the fermentation process is carried out for 36-72 hours.

[0015] In the present invention, further, the following treatment is performed before drying in step (3): the precipitation slurry is placed under ultraviolet light with a wavelength of 254nm and irradiated for 6-12h, during which the precipitation slurry is stirred to ensure that the ultraviolet light irradiates different parts of the precipitation slurry; after the ultraviolet light irradiation, the precipitation slurry is dried with hot air.

[0016] In the present invention, further, the hot air drying is to place the precipitation slurry in a stainless steel plate and dry it in an electric heated blast drying oven at 45-65° C. for 20-30 hours until the water content is below 14%.

[0017] The present invention also provides a cassava modified starch with baking expansion property obtained by the green preparation process. The cassava modified starch can be used for preparing bread.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. The present invention proposes a green preparation process of tapioca starch with baking expansion properties, wherein the original cassava starch is denatured by fermentation combined with ultraviolet irradiation, and enzymatic physical denaturation is proposed to denature the cassava starch, which is greener and safer than chemical denaturation; specifically, in the fermentation process of cassava starch, different microbial flora appear, which are responsible for the synthesis of amylase and organic acid, causing the pH value of the fermentation liquid to drop to 3.2-4.2, and the organic acid produced will erode the surface morphology of starch particles, causing the surface of starch particles to have cracks or micropores. Under acidic conditions, the polymer chains depolymerize to form small linear fragments of starch molecules, which is conducive to the formation of a uniform and continuous gel network structure during baking. Under ultraviolet irradiation, the starch acidified by lactic acid bacteria is exposed to ultraviolet radiation catalysis, resulting in starch oxidation. The hydroxyl groups (-OH) on C2, C3 and C6 are oxidized to carbonyl groups (-C=O) and carboxyl groups (-COOH). The physical and chemical processing properties and multi-scale structures of starch are modified, resulting in a decrease in starch viscosity, DP≥36 long chain content, short-range order and molecular weight, and DP The 6-12 short chains increase, and these structural changes lead to changes in the gelatinization behavior of starch at the supramolecular level. At the same time, the starch has a low hydration capacity, is easier to swell and gelatinize, and is beneficial to gas retention and water dissipation during baking, resulting in high steam pressure and reduced expansion resistance, thereby increasing the baking expansion capacity; and then the cassava starch is treated with the extract and then hot-air dried to finally obtain a loose and porous cassava acid starch with good baking expansion properties; the entire preparation process of the present application is short in time, low in cost, and is green and environmentally friendly, the product quality is controllable, and is conducive to industrial production.

[0020] 2. During the experiment, the applicant found that the drying method has a great influence on the bulk density, and the bulk density can be used to know the looseness of the powder. When hot air drying is used, under the influence of long-term temperature and blast, the solute inside the starch continues to migrate to the surface with the water, resulting in surface crystallization and hardening. Therefore, conventional hot air drying will result in a large bulk density. In order to solve this problem, the applicant added licorice extract during the preparation of cassava starch. The original intention was to give cassava starch a health-care effect, but it was magically discovered that the addition of licorice extract can reduce the bulk density of the modified starch after drying, making the finished product looser. This may be because after the licorice is fermented by lactic acid bacteria, its internal components such as glycyrrhizic acid can act on starch, promote the bonding of starch molecules to become smaller, hinder the intermolecular association, and then combine with ultraviolet radiation, resulting in starch oxidation, thereby increasing the expansion performance. In addition, since ultraviolet radiation is performed before hot air drying, the efficiency of hot air drying will be greatly improved. Therefore, it only takes a short time to complete the drying and ensure the bulk density of the finished starch. [Specific implementation method]

[0021] The following embodiments may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

[0022] Example 1

[0023] The present embodiment provides a green preparation process of tapioca starch with baking expansion property, which specifically comprises the following steps:

[0024] (1) Preparation of cassava starch: peel fresh cassava, add water, and beat into a slurry to obtain cassava pulp; add liquorice extract to the slurry obtained by sieving the cassava pulp to obtain a composite slurry; send the composite slurry to a separator for separation treatment to obtain starch milk, and dehydrate and dry the starch milk to obtain cassava starch;

[0025] (2) fermentation: taking the cassava starch obtained in step (1), adding glucose powder, lactic acid bacteria and water, mixing them thoroughly in a triangular flask, sealing the flask, and placing it in a thermostat at 30° C. for fermentation for 72 hours, then pouring out the upper fermentation liquid to obtain a precipitated slurry for standby use; the amount of glucose powder added is 4% of the mass of the cassava starch, the amount of the fermentation agent added is 0.01% of the mass of the cassava starch, and the water is distilled water, accounting for 150% of the mass of the cassava starch;

[0026] (3) ultraviolet irradiation: the precipitated slurry obtained in step (2) is subjected to ultraviolet irradiation treatment, specifically, the precipitated slurry is placed under ultraviolet light with a wavelength of 254 nm for 6 hours, during which the precipitated slurry is stirred to ensure that the ultraviolet light irradiates different parts of the precipitated slurry;

[0027] (4) Drying: After ultraviolet irradiation, the precipitated slurry is subjected to hot air drying to obtain cassava starch; the hot air drying is to place the precipitated slurry in a stainless steel plate and dry it in an electric heated blast drying oven at 45° C. for 30 hours until the moisture content is below 14%.

[0028] Example 2

[0029] The present embodiment provides a green preparation process of tapioca starch with baking expansion property, which specifically comprises the following steps:

[0030] (1) Preparation of cassava starch: peel fresh cassava, add water, and beat into a slurry to obtain cassava pulp; add liquorice extract to the slurry obtained by sieving the cassava pulp to obtain a composite slurry; send the composite slurry to a separator for separation treatment to obtain starch milk, and dehydrate and dry the starch milk to obtain cassava starch;

[0031] (2) fermentation: taking the cassava starch obtained in step (1), adding glucose powder, lactic acid bacteria and water, mixing them thoroughly in a triangular flask, sealing the flask, and placing it in a thermostat at 35° C. for fermentation for 48 hours, then pouring out the upper fermentation liquid to obtain a precipitated slurry for standby use; the amount of the glucose powder added is 5% of the mass of the cassava starch, the amount of the fermentation agent added is 0.02% of the mass of the cassava starch, and the water is distilled water, accounting for 200% of the mass of the cassava starch;

[0032] (3) ultraviolet irradiation: the precipitated slurry obtained in step (2) is subjected to ultraviolet irradiation treatment, specifically, the precipitated slurry is placed under ultraviolet light with a wavelength of 254 nm for 10 hours, during which the precipitated slurry is stirred to ensure that the ultraviolet light irradiates different parts of the precipitated slurry;

[0033] (4) Drying: After ultraviolet irradiation, the precipitated slurry is subjected to hot air drying to obtain cassava starch; the hot air drying is to place the precipitated slurry in a stainless steel plate and dry it in an electric heated blast drying oven at 55° C. for 25 hours until the moisture content is below 14%.

[0034] Example 3

[0035] The present embodiment provides a green preparation process of tapioca starch with baking expansion property, which specifically comprises the following steps:

[0036] (1) Preparation of cassava starch: peel fresh cassava, add water, and beat into a slurry to obtain cassava pulp; add liquorice extract to the slurry obtained by sieving the cassava pulp to obtain a composite slurry; send the composite slurry to a separator for separation treatment to obtain starch milk, and dehydrate and dry the starch milk to obtain cassava starch;

[0037] (2) fermentation: taking the cassava starch obtained in step (1), adding glucose powder, lactic acid bacteria and water, mixing them thoroughly in a triangular flask, sealing the flask, and placing the flask in a constant temperature box at 40° C. for fermentation for 36 hours, then pouring out the upper fermentation liquid to obtain a precipitated slurry for standby use; the amount of glucose powder added is 6% of the mass of the cassava starch, the amount of the fermentation agent added is 0.05% of the mass of the cassava starch, and the water is distilled water, accounting for 300% of the mass of the cassava starch;

[0038] (3) ultraviolet light irradiation: the precipitated slurry obtained in step (2) is subjected to ultraviolet light irradiation, specifically, the precipitated slurry is placed under ultraviolet light with a wavelength of 254 nm for 12 hours, during which the precipitated slurry is stirred to ensure that the ultraviolet light irradiates different parts of the precipitated slurry;

[0039] (4) Drying: After ultraviolet irradiation, the precipitated slurry is subjected to hot air drying to obtain cassava starch; the hot air drying is to place the precipitated slurry in a stainless steel plate and dry it in an electric heated blast drying oven at 65° C. for 20 hours until the moisture content is below 14%.

[0040] Test example

[0041] In order to illustrate the practical value of this application, the applicant conducted the following comparative tests:

[0042] Test 1: Comparison of the bulk density of each group of tapioca starch, the specific groups are as follows:

[0043] Group A: tapioca starch obtained in the manner of Example 2;

[0044] Group B: except for the liquorice extract, the other methods were the same as those in Example 2;

[0045] Group C: except for the liquorice extract and ultraviolet irradiation, the other methods were the same as those in Example 2;

[0046] Group D: except for the liquorice extract and the ultraviolet irradiation, the drying method was sun drying, and the other methods were the same as in Example 2;

[0047] Group E: Drying method is sun drying, and other methods are the same as Example 2;

[0048] Group F: The fermentation step was removed, and the other methods were the same as Example 2.

[0049] Compare the bulk density of the tapioca starch obtained in the above groups. Bulk density determination: The bulk density of the sample was determined by the measuring cylinder filling method: take a measuring cylinder with a range of 10mL, weigh it and record it as m1, place the sample (tapioca starch) in the measuring cylinder and fill it to the 10mL scale, then weigh it and record the weight as m2, and calculate the bulk density according to the following formula.

[0050] Bulk density (g / mL) = (m2-m1) / 10, record each group of data as shown in Table 1:

[0051] Table 1 Tapioca starch bulk density

[0052] Bulk density (g / mL) Group A <![CDATA[0.70±0.03 d ]]> Group B <![CDATA[0.82±0.03 c ]]> Group C <![CDATA[0.88±0.01 ab ]]> Group D <![CDATA[0.85±0.02 bc ]]> Group E <![CDATA[0.73±0.02 d ]]> Group F <![CDATA[0.90±0.01 a ]]>

[0053] According to the data in Table 1, the tapioca starch prepared by the method of the present application has a relatively low bulk density, indicating that the product has a loose and porous structure and has good quality.

[0054] Experiment 2: The tapioca starch of the present application can be used for bread preparation. In order to illustrate the effect, the applicant compares the cross-sectional pore parameters and specific volume of bread obtained after using different tapioca flours (including tapioca starch and native tapioca starch) to prepare bread, that is, the following groups of tapioca flours are used as raw materials for bread preparation:

[0055] The first group: tapioca starch obtained in the manner of Example 2 of the present application;

[0056] Group 2: Remove the fermentation operation, and the other methods are the same as Group 1;

[0057] Group 3: Drying method is sun drying, other methods are the same as Group 1;

[0058] Group 4: Remove the UV treatment operation, and other methods are the same as Group 1;

[0059] Group 5: Drying method is vacuum freeze drying, other methods are the same as Group 1;

[0060] Group 6: native cassava starch obtained in the manner of step (1) of Example 2.

[0061] In this test, the preparation steps of bread are as follows: 5g high-gluten flour, 20g milk, 5g corn oil, 0.2g salt, 6g fine sugar and 12g egg liquid, stir evenly, put in a pot to boil, stir constantly to prevent the bottom from burning, until it becomes a semi-solid paste, remove from heat, add cassava flour immediately, stir until there is no dry powder, add 12g egg liquid, a little at a time, stir constantly after each addition, until it becomes an inverted triangle. Put it into a piping bag and squeeze it into a ball shape, and divide it into 3 equal parts. Put it in an oven with a top heat of 200℃ and a bottom heat of 160℃ and bake it for 15 minutes.

[0062] The cross-sectional pore parameters and specific volume of the bread were obtained after each group of baking.

[0063] Among them, the method for detecting the pore parameters of the bread cross section is: cut the bread into uniform slices, scan the bread cross section with a scanner, and repeat the measurement 6 times for each group of samples.

[0064] The method for determining the specific volume of bread is as follows: the mass of the bread product (g) was weighed using a balance, and the volume of the bread (mL) was determined using the rapeseed displacement method. Specific volume (mL / g) = volume (mL) / mass (g). Each group of samples was measured three times.

[0065] The cassava flour (including cassava acid starch and cassava native starch) is obtained in the above-listed groups. Except for the cassava flour, the other raw materials and processes used to prepare the bread are exactly the same. In this way, multiple groups of bread are obtained, and their cross-sectional pore parameters and specific volumes are compared, as shown in Table 2:

[0066] Table 2 Comparison of bread cross-section pore parameters and specific volume

[0067] <![CDATA[Average pore area (mm 2 )]]> <![CDATA[Stomatal density (number / m 2 )]]> Bread specific volume (mL / g) Group 1 <![CDATA[4.60±0.04 e ]]> <![CDATA[35.74±1.40 a ]]> <![CDATA[4.76±0.11 a ]]> Group 2 <![CDATA[9.05±0.09 b ]]> <![CDATA[18.61±0.82 e ]]> <![CDATA[2.61±0.16 d ]]> Group 3 <![CDATA[5.15±0.07 d ]]> <![CDATA[33.44±0.84 b ]]> <![CDATA[4.67±0.13 a ]]> Group 4 <![CDATA[8.01±0.11 c ]]> <![CDATA[23.47±0.91 d ]]> <![CDATA[2.98±0.13 c ]]> Group 5 <![CDATA[5.25±0.10 d ]]> <![CDATA[29.47±0.57 c ]]> <![CDATA[4.17±0.07 b ]]> Group 6 <![CDATA[11.41±0.18 a ]]> <![CDATA[15.71±1.06 f ]]> <![CDATA[2.21±0.08 e ]]>

[0068] According to the results in Table 2, the tapioca starch prepared by the method of the present application is used in the preparation of bread, and the obtained bread has good quality and good fluffiness, which indicates that the tapioca starch obtained by the method of the present application has baking expansion properties.

[0069] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A green preparation process of tapioca starch with baking expansion properties, characterized in that: The following steps are involved: (1) Preparation of cassava starch: peel fresh cassava, add water and beat into a slurry to obtain cassava pulp; add an extract to the slurry obtained by sieving the cassava pulp to obtain a composite slurry; send the composite slurry to a separator for separation treatment to obtain starch milk, and dehydrate and dry the starch milk to obtain cassava starch; (2) fermentation: taking the cassava starch obtained in step (1), adding glucose powder, fermentation agent and water, mixing them thoroughly in a triangular flask, sealing the flask, fermenting, and then discarding the upper fermentation liquid to obtain a precipitated slurry for later use; (3) Drying: Drying the precipitated slurry obtained in step (2) to obtain tapioca starch.

2. The process according to claim 1, characterized in that The extract is liquorice extract.

3. The process according to claim 1, characterized in that In the step (2), the fermentation bacteria is lactic acid bacteria.

4. The process according to claim 1, characterized in that In step (2), the added amount of the glucose powder accounts for 3%-6% of the mass of the original cassava starch, the added amount of the fermentation agent accounts for 0.01%-0.05% of the mass of the original cassava starch, and the water is distilled water, accounting for 150%-300% of the mass of the original cassava starch.

5. The process according to claim 1, characterized in that The fermentation in step (2) is carried out in a constant temperature box at 30-40°C for 36-72 hours.

6. The process according to claim 1, characterized in that In the step (3), the following treatment is also performed before drying: the precipitation slurry is placed under ultraviolet light with a wavelength of 254nm and irradiated for 6-12h, during which the precipitation slurry is stirred to ensure that the ultraviolet light irradiates different parts of the precipitation slurry; after the ultraviolet light irradiation, the precipitation slurry is dried with hot air.

7. The process according to claim 6, characterized in that The hot air drying is to place the precipitated slurry in a stainless steel plate and dry it in an electric heated blast drying oven at 45-65° C. for 20-30 hours.

8. A tapioca starch with baking expansion properties prepared by the process according to any one of claims 1 to 7.