CN115197333A

CN115197333A - Starch pasting device and method

Info

Publication number: CN115197333A
Application number: CN202210989268.7A
Authority: CN
Inventors: 张谦; 骞李鸽; 张珂; 张炳
Original assignee: Xinchang Xinhecheng Vitamin Co ltd; Zhejiang NHU Co Ltd
Current assignee: Xinchang Xinhecheng Vitamin Co ltd; Zhejiang NHU Co Ltd
Priority date: 2022-08-17
Filing date: 2022-08-17
Publication date: 2022-10-18
Anticipated expiration: 2042-08-17
Also published as: CN115197333B

Abstract

The invention discloses a starch pasting device and a starch pasting method. The invention carries out the pasting process of the starch in a special annular space pasting machine, and has the advantages of high pasting speed, good product uniformity, complete pasting and difficult shedding of ester groups when the modified starch (containing ester groups) is pasted.

Description

Starch pasting device and method

Technical Field

The invention relates to the technical field of food science, in particular to a starch pasting device and method.

Background

Starch is insoluble in water at normal temperature, but when the temperature of water rises to above 53 ℃, the physical properties of starch change obviously. The characteristic of starch that swells and splits at high temperature to form a homogeneous pasty solution is called gelatinization of starch.

The raw starch is heated in water until the micelle structure is completely collapsed, and starch molecules form single molecules and are surrounded by water to form a solution state. Since the starch molecules are chain-like or even branched and are dragged by each other, a viscous pasty solution is formed as a result, which is called gelatinization. The gelatinization temperature of starch must reach a certain degree, the gelatinization temperature of different starches is different, the particle size of the same starch is different, the gelatinization temperature is different, the gelatinization is carried out before the particle size is large, and the gelatinization is carried out after the particle size is small.

In 2016, fuyi Te (Shanghai) environmental protection science and technology Co Ltd, zheng applied for China Utility model patent of continuous material cooking device, authorization notice number CN 205676722U. A process for continuously cooking materials is disclosed, and the patent does not describe the solution of the problems of slow gelatinization speed and incomplete gelatinization of starch and the achieved technical effect.

In 2016, gui army force, a product of flavoring food, foshan Haitian, etc. applied for the invention of Chinese patent, a gelatinization method of modified starch, published under No. CN 105753996A. Discloses a gelatinization method of modified starch, which comprises the following steps: 1) Firstly preparing modified starch suspension at room temperature; 2) Then, primarily pasting the modified starch suspension at low temperature to form starch slurry; 3) Then, performing secondary gelatinization on the modified starch of the starch slurry at high temperature; 4) And finally, rapidly cooling the modified starch subjected to secondary gelatinization. However, the patent does not solve the problems of slow gelatinization speed and incomplete gelatinization of starch.

In summary, the following problems are common to the existing starch gelatinization methods:

1. the gelatinization speed is low;

2. gelatinization is not thorough;

3. the product uniformity is poor;

4. the ester group is easy to fall off when the modified starch (containing ester group) is gelatinized.

Disclosure of Invention

The invention aims to provide a starch pasting device and method, which can effectively improve the starch pasting degree and reduce the problem of ester group falling off during the pasting of modified starch.

The technical scheme of the invention is as follows:

a starch gelatinizing device comprises a mixer, an annular space gelatinizing device and a gelatinized starch receiving tank which are sequentially communicated;

the annular space gelatinizing device comprises a middle sleeve, an internal heating pipe penetrating the middle sleeve, an external heating pipe sleeved outside the middle sleeve and a spacing ring arranged between the middle sleeve and the internal heating pipe;

the top end of the middle sleeve is provided with a starch slurry inlet communicated with the mixer, and the side wall close to the bottom end is provided with a starch slurry outlet communicated with the gelatinized starch receiving tank;

the top end of the internal heating pipe is closed, and the pipe wall of the internal heating pipe and the middle sleeve form an annular starch slurry pasting channel.

By adopting the gelatinization device, starch slurry is violently mixed with steam under the impact action of high-temperature and high-pressure steam, and rapid mass transfer and heat transfer occur. The starch slurry was rapidly suspended in the steam in the form of tiny droplets and passed into an annular space gelatinizer. The mixture of starch slurry and steam entering the annular space gelatinizer is firstly distributed into an annular space between the internal heating pipe and the middle sleeve pipe through the top end of the heating pipe,at this time, if the inner heating pipe and the outer heating pipe are not supplied with heating steam,the starch slurry is gradually expanded in the descending process, has higher and higher viscosity, and is adhered to the outer wall of the internal heating pipe and the inner wall of the middle sleeve pipe due to the wall effect. The steam occupies the near-center section (near the middle diameter) of the annular gap gelatinizer with the minimum resistance due to high flow velocity, starch slurry adhered to the outer wall of the internal heating pipe and the inner wall of the middle sleeve pipe flows under the dragging action of the steam, and the temperature is gradually increased and is gradually gelatinized. Due to the viscosity of the starch slurry, a velocity distribution is formed in which the flow velocity of the starch slurry on the inner wall surface and the outer wall surface of the annular space is zero, and the flow velocity is larger as the distance from the center (near the intermediate diameter) of the annular space is closer. As starch is gradually gelatinized and has higher and higher viscosity, the flow in the whole annular space gelatinizer is close to laminar flow, and finally, starch slurry on two sides of a near-annular space central steam flow passage is formedThe residence time in the gelatinizer is shortest, and the residence time close to the annular space wall surface of the starch slurry is longest. The starch slurry with short retention time has insufficient gelatinization time and is not fully gelatinized. The modified starch (ester group) slurry with long residence time can cause hydrolysis of ester groups or decomposition of other substituent groups, and the quality of the modified starch is influenced.

When the slurry enters the annular space gelatinizing device, steam with the pressure higher than the gelatinizing steam (the temperature is higher) is introduced into the internal heating pipe and the external heating pipe for heating, the temperature of the outer surface of the internal heating pipe and the temperature of the inner surface of the middle sleeve are increased to reduce the viscosity of the starch slurry near the wall surface, and the speed gradient of the starch slurry near the wall surface is reduced. The starch slurry with the whole annular space section flows downwards at a basically consistent speed, so that the starch slurry is gelatinized in a mode close to plug flow, the uniformity of the product is improved, and the problems of nonuniform and incomplete gelatinization are solved.

Preferably, the closed top end of the internal heating pipe forms a conical distributor, the bottom of the internal heating pipe is provided with a steam condensate outlet, and a steam inlet is formed near the side wall of the bottom of the internal heating pipe. The tapered distributor may allow slurry to enter the annulus gelatinizer uniformly relative to other shapes.

Preferably, the number of the starch slurry outlets is 3-5, preferably 4, and the starch slurry outlets are radially and uniformly distributed along the side wall of the middle sleeve. 3-5 starch size outlets are radially and uniformly distributed at the bottom of the annular space, and each outlet is structurally ensured to have basically consistent flow resistance.

Preferably, the space ring comprises a circular ring and 4 partition plates which are radially and uniformly distributed on the outer wall of the circular ring and have the same length.

Preferably, the inner diameter of the circular ring is equal to the outer diameter of the internal heating pipe, and the diameter of the circle where the outer end face of the partition plate is located is equal to the inner diameter of the middle sleeve.

Preferably, the space ring is sleeved outside the internal heating pipe, the internal heating pipe and the space ring are inserted into the bottom of the middle sleeve together, and the position, close to the steam inlet at the bottom of the internal heating pipe, of the bottom surface of the middle sleeve is welded with the internal heating pipe into a whole.

Preferably, the upper part of the external heating pipe is provided with a steam inlet, the lower part of the external heating pipe is provided with a steam condensate outlet, and two ends of the external heating pipe and the outer wall of the middle sleeve are welded into a whole.

Preferably, the ratio of the inner diameter of the middle sleeve to the outer diameter of the inner heating pipe is 1.5-3.0: 1, the unit flow cross section area has a large wetting periphery, and the flowing uniformity and the heat transfer effect of starch slurry are improved. More preferably, the inner heating pipe has an outer diameter of 25 to 35mm.

The invention also provides a starch pasting method, which comprises the following steps:

(1) Uniformly mixing starch and water in a mixing tank to obtain starch slurry;

(2) And introducing the starch slurry and steam into a mixer of the gelatinizing device for mixing, then introducing the starch slurry and the steam into the annular space gelatinizing device for gelatinizing, and introducing the gelatinized starch obtained after gelatinizing into the gelatinized starch receiving tank.

Preferably, in the step (1), the mass ratio of starch to water is 1:1.2 to 1.6, and the mixing temperature is below 30 ℃. Too small a proportion of water causes too large viscosity of starch slurry in the gelatinizer and too long retention time of the starch slurry in the gelatinizer; too large a proportion of water will result in excessive steam consumption for subsequent drying and dewatering of the gelatinised starch.

In the step (1), the starch can be ordinary starch and modified starch, preferably, the starch is modified starch, especially modified starch containing ester groups.

Preferably, in the step (2), the pressure of the steam is 0.3 to 0.4MPa.

Preferably, in the step (2), the weight ratio of the starch size to the water vapor is 1:0.5 to 1.2.

In step (2), the mixer is similar to a Venturi nozzle, steam enters from the inlet of the nozzle, and the starch slurry is conveyed into the throat part of the nozzle through a conveying pump. The steam pressure and the steam flow entering the mixer need to meet the requirement of total energy balance, the larger the steam consumption is, the better the gelatinization effect is, but the subsequent drying and dehydration of gelatinized starch consumes excessive steam, which causes energy waste. When the annular space gelatinizer is adopted for gelatinizing, the weight ratio of starch slurry to water vapor is 1:0.5 to 1.2, can meet the requirement of fully gelatinizing the starch slurry.

Preferably, in the step (2), the steam pressure in the internal heating tube and the external heating tube is 0.5 to 0.6MPa. At this time, the viscosity of the starch slurry near the wall surface is reduced by increasing the temperature of the outer surface of the internal heating tube and the temperature of the inner surface of the middle sleeve, and the speed gradient of the starch slurry near the wall surface is reduced. The starch size with the whole annular space section flows downwards at a basically consistent speed, so that the starch size is gelatinized in a mode close to plug flow, and the uniformity of the product is improved.

Compared with the prior art, the invention has the beneficial effects that:

(1) By adopting the pasting device and the method, the starch pasting speed is high, the starch pasting is thorough, the uniformity of the pasted starch is good, and the performance of the pasted starch is improved;

(2) The pasting device and the method are more suitable for pasting modified starch (containing ester groups), and the ester groups are not easy to fall off compared with other pasting methods.

Drawings

FIG. 1 is a schematic flow diagram of a starch gelatinization process according to the present invention;

FIG. 2 is a cross-sectional view of an annulus gelatinizer in a starch gelatinizing process of the present invention;

FIG. 3 is a schematic structural view of a spacer;

FIG. 4 is a photograph of a polarized light microscope (magnified 100 times) with incomplete gelatinization;

FIG. 5 shows a polarized light microscope photograph (magnified 100 times) with complete gelatinization.

Wherein, marking a 1-starch feeding port; label 2-drinking water pipe; label 3-mix tank; label 4-delivery pump; mark 5-mixer steam tube; label 6-mixer; label 7-external heating tube steam tube; marking an 8-annulus gelatinizer; label 81-starch slurry inlet; mark 82-middle sleeve; mark 83-conical distributor; reference 84-internal heating tube; mark 85-space ring; marker 851-circle; mark 852-spacer; reference 86-external heating tube steam inlet; marker 87-external heating tube; mark 88-external heating pipe steam condensate outlet; mark 89-starch slurry outlet; label 810-internal heating tube steam inlet; label 811-internal heating tube steam condensate outlet; mark 9-internal heating tube steam tube; mark 10-gelatinized starch receiving tank.

Detailed Description

Embodiments of the present invention are further described below with reference to the accompanying drawings.

Fig. 1 is a schematic flow chart of the starch gelatinization method of the present invention, and as can be seen from fig. 1, the process of the method is as follows:

starch is added into a mixing tank 3 from a starch feeding port 1, meanwhile, drinking water is added into the mixing tank 3 from a drinking water pipe 2, and stirring and mixing are started to obtain starch slurry. Then a delivery pump 4 is started to input the starch slurry into a mixer 6, steam is input into the mixer 6 through a steam pipe 5 of the mixer, and the starch slurry is driven by the steam to be uniformly mixed by the mixer 6 and then enters an annular space gelatinizing device 8.

The detailed structure of the annular gap pasting device 8 is shown in fig. 2, and as can be seen from fig. 2, the annular gap pasting device 8 comprises an inner heating pipe 84, a middle sleeve 82 and an outer heating pipe 87 which are sequentially sleeved from inside to outside. The top end of the internal heating pipe 84 is closed to form the conical distributor 83, the side wall of the bottom is provided with a steam inlet 810, the bottom is provided with a steam condensate outlet 811, and heating steam enters from the steam inlet 810 (communicated with the steam pipe 9 of the internal heating pipe) to heat the pipe wall of the internal heating pipe 84. Be equipped with space ring 85 between internal heating pipe 84 and the middle part sleeve pipe 82, space ring 85 includes ring 851 and is 4 baffle 852 of radial evenly distributed isometric at the ring outer wall, the ring 851 internal diameter equals internal heating pipe 84 external diameter, the diameter of baffle 852 outer terminal surface place circle equals middle part sleeve pipe 82 internal diameter, space ring 85 has two, set up respectively in upper portion and lower part, can install internal heating pipe 84 and middle part sleeve pipe 82 together through space ring 85, the top of internal heating pipe 84 is equipped with starch thick liquids import 81, be equipped with starch thick liquids export 89 on the lateral wall near the bottom, starch thick liquids enter from top starch thick liquids import 81, evenly distributed is gone up in middle part sleeve pipe 82 and is gelatinized after toper distributor 83, then derive from starch thick liquids export 89, get into gelatinized starch receiving tank 10. The side wall of the top of the external heating pipe 87 is provided with a steam inlet 86, the side wall of the bottom is provided with a steam condensate outlet 88, heating steam enters the external heating pipe 87 from the steam inlet 86 (communicated with the steam pipe 7 of the external heating pipe) to heat the outer wall of the middle sleeve 82, and gelatinization is promoted.

The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

Example 1

Structural parameters of the annular space pasting device:

specification of internal heating tube:

specification of middle casing:

external heating tube specification:

total length of the annular space gelatinizer: 5.8m.

Preparation of starch slurry:

150kg of starch is added into a mixing tank, 200kg of drinking water is added, the temperature of starch slurry is controlled to be less than 30 ℃, and the starch slurry is stirred and mixed uniformly.

Pasting:

opening an annular space pasting device, externally heating pipe steam, and setting the steam pressure to be 0.55MPa; the steam is heated in the open-loop gelatinizer, and the steam pressure is set to be 0.55MPa. The steam pipe steam of the mixer is started, and the steam flow is set as follows: 200kg/h. And (5) starting a conveying pump to control the total conveying time to be about 1.0 hour, and conveying the starch slurry in the mixing tank to the mixer. The starch slurry is uniformly mixed by a mixer under the drive of steam and then enters an annular space gelatinizing device, and is gelatinized in the annular space gelatinizing device. Finally, the starch slurry is brought out from 4 starch slurry outlets of the annular space gelatinizer by steam and enters a gelatinized starch receiving tank. Taking the gelatinized starch in the gelatinized starch receiving tank, preparing a 10wt% starch water solution, and detecting the gelatinization condition of the starch on an XP-800P polarized light microscope. Firstly, zeroing the analyzer and the polarizer; then, adjusting the ocular lens multiple and finding out starch granules; and finally, rotating the polarizer by 45 degrees, and observing whether a polarized cross appears on a computer screen by adjusting the analyzer. The results are shown in fig. 5, with no particulate present, showing: the starch is completely gelatinized.

Example 2

Preparation of starch slurry:

150kg of octenyl succinic acid starch ester (degree of substitution: 2.55%, free OSA, 0.07%) was charged into a mixing tank, 200kg of drinking water was added thereto, the temperature of the starch slurry was controlled to be less than 30 ℃, and the mixture was stirred and mixed uniformly.

Pasting:

opening steam pipe steam of an external heating pipe of the annular space gelatinizing device, and setting the steam pressure to be 0.55MPa; the steam is heated in the open-loop gelatinizer, and the steam pressure is set to be 0.55MPa. Starting steam pipe steam of the mixer, setting steam flow: 200kg/h. And (5) starting a conveying pump to control the total conveying time to be about 1.5 hours, and conveying the starch slurry in the mixing tank to the mixer. The starch slurry is uniformly mixed by a mixer under the drive of steam and then enters an annular space pasting device, and pasting is carried out in the annular space pasting device. Finally, the starch is brought out by steam from 4 starch size outlets of the annular space gelatinizer and then enters a gelatinized starch receiving tank. And (3) detecting the gelatinized octenyl succinic acid starch ester in the gelatinized starch receiving tank on a polarized light microscope. The results show that: the starch is completely gelatinized. And (3) detecting the degree of substitution: degree of substitution: 2.51%, free OSA,0.10%.

Example 3

The experimental protocol and process parameters of example 3 were substantially the same as those of example 1, except that: the amount of drinking water added was: 220kg. After the gelatinization, the gelatinized starch in the gelatinized starch receiving tank is taken and detected on a polarized light microscope. The results show that: the starch is completely gelatinized.

Example 4

The experimental protocol and process parameters of example 4 were substantially the same as those of example 1, except that: setting the steam pressure of a steam pipe of an external heating pipe of the annular space gelatinizer to be 0.65MPa; the steam pressure of a heating pipe inside the annular space gelatinizing device is set to be 0.65MPa. After the gelatinization, the gelatinized starch in the gelatinized starch receiving tank is taken and detected on a polarized light microscope. The results show that: the starch is completely gelatinized.

Comparative example 1

The experimental protocol and process parameters of comparative example 1 were substantially the same as example 1, except that: the steam gage pressure of the internal heating pipe of the annular space gelatinizer is set to be 0.0MPa (namely, the steam is not introduced into the internal heating pipe, and only the steam is introduced into the external heating pipe). After the gelatinization, the gelatinized starch in the gelatinized starch receiving tank is taken and detected on a polarized light microscope. The results are shown in FIG. 4, where some particulate was present, indicating incomplete starch gelatinization.

Comparative example 2

The experimental protocol and process parameters of comparative example 2 are substantially the same as those of example 1, except that: the pasting is carried out by adopting a hollow pipe pasting device with the same diameter and length as the annular space pasting device. After gelatinization, the gelatinized starch in the gelatinized starch receiving tank is taken to be detected on a polarized light microscope. The results show that: starch gelatinization is incomplete.

Comparative example 3

The experimental protocol and process parameters of comparative example 3 are essentially the same as example 2, except that: the steam pressure of the internal heating pipe of the annular space gelatinizer is set to be 0.0MPa (namely, the steam is not introduced into the internal heating pipe, and only the steam is introduced into the external heating pipe). And (3) detecting the gelatinized octenyl succinic acid starch ester in the gelatinized starch receiving tank on a polarized light microscope. The results show that: starch gelatinization is incomplete. And (3) detecting the degree of substitution: degree of substitution: 2.46%, free OSA,0.13%.

Claims

1. The starch gelatinization device is characterized by comprising a mixer (6), an annular space gelatinization device (8) and a gelatinized starch receiving tank (10) which are sequentially communicated;

the annular space gelatinizing device (8) comprises a middle sleeve (82), an internal heating pipe (84) penetrating through the middle sleeve (82), an external heating pipe (87) sleeved outside the middle sleeve (82) and a space ring arranged between the middle sleeve (82) and the internal heating pipe (84);

the top end of the middle sleeve (82) is provided with a starch slurry inlet (81) communicated with the mixer (6), and the side wall close to the bottom end is provided with a starch slurry outlet (89) communicated with the gelatinized starch receiving tank (10);

the top end of the internal heating pipe (84) is closed, and the pipe wall and the middle sleeve (82) form an annular starch slurry pasting channel.

2. Gelatinizing apparatus according to claim 1, characterised in that the closed top end of the internal heating tube (84) forms a conical distributor (83), the bottom is provided with a steam condensate outlet and the side wall near the bottom is provided with a steam inlet.

3. The gelatinizing apparatus according to claim 1, wherein the number of the starch slurry outlets is 3 to 5, and the starch slurry outlets are uniformly distributed in a radial manner along the side wall of the middle sleeve (82).

4. The pasting device according to claim 1, characterized in that the spacer (85) comprises a ring (851) and 4 partitions (852) radially and uniformly distributed on the outer wall of the ring with equal length.

5. The pasting device according to claim 4, characterized in that the inner diameter of the ring is equal to the outer diameter of the inner heating tube (84), and the diameter of the circle on which the outer end face of the partition is located is equal to the inner diameter of the middle sleeve (82).

6. The pasting device according to claim 1, characterized in that the external heating pipe is provided with a steam inlet at its upper part and a steam condensate outlet at its lower part, both ends being welded with the outer wall of the middle sleeve (82) as one piece.

7. The gelatinizing apparatus as claimed in claim 1, wherein: the ratio of the inner diameter of the middle sleeve (82) to the outer diameter of the internal heating pipe (84) is 1.5-3.0: 1.

8. a method for gelatinizing starch, comprising:

(1) Uniformly mixing starch and water in a mixing tank to obtain starch slurry;

(2) Introducing starch slurry and steam into a mixer of the pasting device as claimed in any one of claims 1 to 7 for mixing, then introducing the starch slurry and the steam into the annular space pasting device for pasting, and introducing the pasted starch obtained after pasting into the pasted starch receiving tank.

9. The method for gelatinizing starch according to claim 8, wherein in the step (1), the mass ratio of starch to water is 1:1.2 to 1.6.

10. The method for gelatinizing starch according to claim 8, wherein in the step (2), the pressure of the steam is 0.3 to 0.4MPa.

11. The method for gelatinizing starch according to claim 8, wherein in the step (2), the mass ratio of starch slurry to water vapor is 1:0.5 to 1.2.

12. The method for gelatinizing starch according to claim 8, wherein in the step (2), the steam pressure in the internal heating tube and the external heating tube is 0.5 to 0.6MPa.