阅读说明：本技术 制备热改性淀粉的方法 (Method for preparing thermally modified starch ) 是由 C·奎蒂尔 V·威兹 S·博克 J·罗格朗 于 2020-05-06 设计创作，主要内容包括：本发明涉及一种制备热改性淀粉的方法,该方法包括以下步骤：(i)制备干物质含量介于20重量％和45重量％之间,优选介于30重量％和40重量％之间的淀粉乳,并添加质量浓度介于25％和35％之间的碱剂,从而获得介于4mS/cm和7mS/cm之间的最终电导率；(ii)过滤该淀粉乳,以回收含水量介于30重量％和45重量％之间的淀粉饼,从而使过滤后以20重量％的干物质重悬的淀粉的电导率介于0.7mS/cm和2.5mS/cm之间；(iii)将该淀粉饼随着温度介于130℃和185℃之间的连续热空气流加入到干燥器中,以回收含水量介于8重量％和18重量％之间的干燥粉末；(iv)将该干燥粉末连续供给涡轮反应器,该涡轮反应器的内壁保持在介于180℃和240℃之间的温度,并且同时对该涡轮反应器的搅拌器的转速进行参数设置,以使离心加速度介于850m.s～(-2)和2100m.s～(-2)之间,以便将该干燥粉末连续离心并送入该涡轮反应器中,总持续时间介于3分钟和45分钟之间；(v)回收由此产生的热改性淀粉。(The invention relates to a method for preparing thermally modified starch, comprising the following steps: (i) preparing a starch milk with a dry matter content between 20 and 45 wt.%, preferably between 30 and 40 wt.%, and adding an alkaline agent with a mass concentration between 25 and 35% to obtain a final conductivity between 4 and 7 mS/cm; (ii) filtering the starch milk to recover a medium containing waterBetween 30 and 45% by weight of starch cake, such that the conductivity of the starch resuspended at 20% by weight of dry matter after filtration is between 0.7 and 2.5 mS/cm; (iii) feeding the starch cake to a dryer with a continuous stream of hot air at a temperature between 130 ℃ and 185 ℃ to recover a dried powder having a moisture content between 8% and 18% by weight; (iv) continuously feeding the dry powder to a turbo-reactor, the inner wall of which is maintained at a temperature between 180 ℃ and 240 ℃, and at the same time, the rotational speed of the stirrer of the turbo-reactor is parameterised such that the centrifugal acceleration is between 850m.s ‑2 And 2100m.s ‑2 So that the dry powder is continuously centrifuged and fed into the turbo-reactor for a total duration of between 3 and 45 minutes; (v) recovering the thermally modified starch thus produced.)

1. A method of preparing a thermally modified starch, the method comprising the steps of:

(i) preparing a starch milk with a dry matter content between 20 and 45 wt.%, preferably between 30 and 40 wt.%, and adding an alkaline agent with a mass concentration between 25 and 35% to obtain a final conductivity between 4 and 7 mS/cm;

(ii) filtering the starch milk to recover a starch cake having a water content of between 30 and 45 wt% such that the conductivity of the starch resuspended at 20 wt% dry matter after filtration is between 0.7 and 2.5 mS/cm;

(iii) feeding the starch cake into a dryer with a continuous flow of hot air at a temperature between 130 ℃ and 185 ℃ to recover a dry powder having a moisture content between 8% and 18% by weight;

(iv) continuously feeding the dry powder to a turbo-reactor, the inner wall of which is maintained at a temperature between 180 ℃ and 240 ℃, and at the same time, the rotational speed of the agitator of the turbo-reactor is parameterised in such a way that the centrifugal acceleration reaches 850 m.s.^-2To 2100m.s^-2So that the dry powder is continuously centrifuged and fed into the turbo-reactor for a total duration of between 3 and 45 minutes;

(v) recovering the thermally modified starch thus produced.

2. The method of claim 1, wherein the starch is derived from a source selected from the group consisting of corn, waxy corn, potato, tapioca, pea, and fava bean.

3. The process according to claim 1, characterized in that the alkaline agent is preferably selected from sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate and potassium hydroxide, alone or in combination, more preferably from sodium carbonate.

4. A thermally modified starch obtainable by the method according to any one of the preceding claims.

5. Use of a thermally modified starch produced by a method according to any one of claims 1 to 3 as a thickener or texturizer in food applications, in particular in soups, sauces, mayonnaises, desserts (such as yoghurt, yoghurt fruit preparations, stirred fermented milks, warm yoghurt, dessert cream), beverages, ready-to-eat food, meat or fish preparations (such as surimi).

Background

Biochemically synthesized starch is not only a source of carbohydrates, but also one of the most widely distributed organic materials in the plant kingdom, and can constitute the nutritional reserve required by the organism.

Starch has been used in the food industry not only as a nutritional ingredient, but also as a thickener, binder, stabilizer or gelling agent due to its technical characteristics.

For example, native starch may be used in formulations requiring cooking. In particular corn starch, can be used as a base material of pudding powder.

Because it is rich in amylose, it is easy to regenerate and has obvious gelling effect. After cooking and cooling, a firm pudding can be formed. It is also suitable for making cake cream.

However, these pastry creams cannot be used for pastry intended to be frozen, since the phenomenon of dehydration, when thawing, leads to the expulsion of water, thus destroying the creamy texture.

Thus, in the native state, the use of starch is limited by its syneresis, as well as other reasons including:

poor resistance to shear stress and heat treatment,

poor processability and, in particular,

low solubility in common organic solvents.

Therefore, in order to meet today's demanding technical requirements, the properties of starch must be optimized by various so-called "modification" methods.

These primary "modifications" are intended to adapt the starch to the technical limitations resulting from cooking as well as freezing/thawing, canning or sterilization, and to modern food processing means (e.g. microwave, ready-to-eat, "high temperature" cooking, etc.).

The modification of the starch is aimed at improving one or more of the above mentioned limitations, thereby increasing the versatility of the starch and meeting the needs of the consumer.

Starch modification techniques are broadly divided into four categories, namely physical modification, chemical modification, enzymatic modification and genetic modification, with the aim of producing various derivatives with optimised physicochemical properties.

Among them, the most popular modes of operation are chemical modification and physical modification.

Chemical treatment involves the introduction of functional groups into the starch, which can significantly alter the physicochemical properties of the starch. Such modifications to native granular starch can drastically alter the gelatinization, binding and retrogradation characteristics of the starch.

Typically, such modifications are made by chemical derivatization, such as esterification, etherification, crosslinking, or grafting.

However, although some modifications are considered safe and harmless, consumers are reluctant to perform chemical modifications in food applications (also considering environmental factors).

Thus, various physical modification methods have been developed, such as:

-Heat-Moisture Treatment (HMT, english term "Heat Moisture Treatment") comprising the Treatment of the starch for 16 hours under controlled Moisture levels between 22% and 27% and high temperature, to modify the structure and physicochemical properties of the starch;

"annealing" (the english term "annealing") consists in treating the starch with an excess of water at a temperature below the gelatinization temperature, so as to approach the glass transition temperature;

ultra-High Pressure treatment (or HPP, english term), by which the amorphous regions of the starch granules are hydrated, thus deforming the crystalline parts of the granules, promoting the penetration of said crystalline regions into the water;

glow discharge plasma treatment, generating energetic electrons and other highly reactive species at room temperature. When these actives are applied to starch, they excite chemical groups in the starch and cause significant crosslinking of the macromolecules;

osmotic pressure treatment (english acronym "OPT"), operating in high salt solution. The starch was suspended in sodium sulfate to produce a homogeneous suspension.

The starch is converted from type B to type A after being processed, so that the gelatinization temperature is obviously increased;

treatment by "thermal inhibition". Generally, thermal inhibition refers to the dehydration of starch until it reaches an anhydrous or substantially anhydrous state (i.e., moisture < 1%), followed by a heat treatment at a temperature in excess of 100 ℃ for a period of time until the starch is "inhibited" at which time the starch has the characteristics of a crosslinked starch. Before the deep dehydration step is carried out, the starch must also be subjected to conditions in which the pH profile is at least neutral, preferably alkaline.

An alternative method of treatment by "heat suppression" is proposed in the solvent phase, which consists in heating the non-pregelatinized granular starch in an alcoholic medium to a temperature of from 120 ℃ to 200 ℃ for a period of from 5 minutes to 2 hours in the presence of a base and a salt.

In any case, the heat-inhibiting process results in a starch paste exhibiting a high resistance to viscosity breakdown and a non-sticky texture.

The invention relates to the technical field of carrying out heat inhibition treatment on starch in the presence of anhydrous alcohol solvent.

In this particular technical field, reference may be made in detail to the document US 6.221.420, which describes a thermally inhibited starch obtained after dehydration and heat treatment.

The method mainly comprises the following steps:

-dehydrating starch at a temperature between 100 ℃ and 125 ℃ to a water content of less than 1%, followed by

-heat treating the dried starch thus obtained in a reaction fluidized bed at a temperature of about 140 ℃ for about 20 hours.

Preferably, before the starch dehydration step, it is advisable to carry out a starch alkalization step so that the pH of the starch suspension is between 7 and 10, preferably between 8 and 10.

In this stage, the moisture content of the starch (as exemplified) is between 8% and 10% before the actual dehydration step before the inhibition step.

Document US 2001/0017133 describes a similar process in which the starch is also dehydrated at a temperature below 125 ℃ (at a temperature above 100 ℃, preferably between 120 ℃ and 180 ℃, more preferably between 140 ℃ and 160 ℃) for a period of up to 20 hours, preferably between 3 hours 30 minutes and 4 hours 30 minutes before the start of the inhibition process.

A conventional alkalization step leads to a pH of the starch suspension of between 7.5 and 11.2, preferably between 8 and 9.5, and a water content of between 2% and 15% before the dehydration step is carried out.

A variant is proposed in patent application WO 2014/042537, which involves heating the alkaline starch to a temperature between 140 ℃ and 190 ℃ while ensuring that the inhibition process is started and carried out in the presence of a sufficient amount of water, i.e. an amount of water exceeding 1%.

In other words, the method suggests that no dehydration step is performed prior to heat-inhibiting the pre-alkalized starch.

The pH of the starch preparation or starch is thus adjusted to between 9.1 and 11.2, preferably about 10, and the moisture is adjusted to between 2% and 22%, preferably between 5% and 10%.

Subsequently, the powder or starch is directly heat-inhibited for 30 minutes at a temperature comprised between 140 ℃ and 190 ℃, preferably between 140 ℃ and 180 ℃.

From the above, it can be seen that the thermal inhibition method performed to stabilize the viscosity of starch requires the following operations:

-carrying out a long-term treatment, i.e. up to 20 hours, and

-controlling the moisture content of the starch to be treated, whether the moisture content value is less than 1% or between 2% and 22%, according to the methods proposed in the prior art.

Thus, there remains a need for an original method for inhibiting starch, thereby further reducing reaction time, and without the need to control the moisture content of the starch to be "thermally inhibited".

Detailed Description

Accordingly, the present invention relates to a process for producing thermally modified starch from starch milk, comprising the steps of:

(i) preparing a starch milk with a dry matter content between 20 and 45 wt.%, preferably between 30 and 40 wt.%, and adding an alkaline agent with a mass concentration between 25 and 35% to obtain a final conductivity between 4 and 7 mS/cm;

(ii) filtering the starch milk to recover a starch cake having a water content of between 30 and 45 wt% such that the conductivity of the starch resuspended at 20 wt% dry matter after filtration is between 0.7 and 2.5 mS/cm;

(iii) feeding the starch cake to a dryer with a continuous stream of hot air at a temperature between 130 ℃ and 185 ℃ to recover a dried powder having a moisture content between 8% and 18% by weight;

(iv) continuously feeding the dry powder to a turbo-reactor, the inner wall of which is maintained between 180 ℃ and 240 ℃And at the same time the rotational speed of the stirrer of the turbo-reactor is parameterised in such a way that the centrifugal acceleration is between 850m.s^-2And 2100m.s^-2So that the dry powder is continuously centrifuged and fed into the turbo-reactor for a total duration of between 3 and 45 minutes;

(v) recovering the thermally modified starch thus produced.

The starch used in the process of the invention may be any source of starch, for example corn starch, waxy corn starch, corn-like starch, wheat starch, waxy wheat starch, legume starch (such as pea starch and broad bean starch), potato starch, waxy potato starch, tapioca starch, waxy tapioca starch, rice starch, konjac starch, and the like.

Preferably, corn starch, in particular waxy corn starch (high amylopectin content), potato starch, tapioca starch, pea starch and broad bean starch are chosen, as will be exemplified below.

The alkaline agent is preferably selected from sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate and potassium hydroxide, alone or in combination, more preferably from sodium carbonate.

The method according to the invention first requires the preparation of a starch milk with a dry matter content between 20 and 45 wt.%, preferably between 30 and 40 wt.%, and the addition of an alkaline agent with a mass concentration between 25 and 35%, in order to obtain a final conductivity between 4 and 7 mS/cm.

The next step consists in controlling the alkaline impregnation of the starch by adding an alkaline agent in the form of a solution with a mass concentration of between 25% and 35%, preferably 30%, so that the conductivity of the starch milk is between 4mS/cm and 7 mS/cm.

The applicant company has in fact found:

the addition of alkaline agents, in particular sodium carbonate, directly to the starch in the milk stage makes it possible to achieve the desired high pH (between 10.2 and 10.8, preferably between 10.5 and 10.65) more effectively than spraying sodium carbonate on the starch in the drying stage, in other words makes it possible to achieve better migration of the carbonate into the starch granules than powder impregnation.

Furthermore, since the moisture of the starch needs to be adjusted to a higher value in the powder stage impregnation, part of the energy dedicated to the treatment of the product will be lost to ensure evaporation of the residual moisture.

Adding the alkaline agent to a solution with a mass concentration of between 25% and 35%, preferably 30%, so that the alkaline agent is completely dissolved in the starch milk and the pH can be adjusted more quickly and more precisely, while avoiding the deposition of solid alkaline agent on the bottom of the reactor when not dissolved.

The precision required for this high pH can be achieved by controlling the starch impregnation level by conductivity measurements.

The next step consists in filtering the starch milk to recover a starch cake with a water content between 30% and 45% by weight, so that the conductivity of the starch resuspended at 20% by weight of dry matter after filtration is between 0.7mS/cm and 2.5 mS/cm.

After this alkalization step, the starch is dried to reduce its moisture content.

The next step consists in feeding the starch cake obtained in the previous step into a dryer with a continuous flow of hot air at a temperature between 130 ℃ and 185 ℃ to recover a dry powder having a moisture content between 8% and 18% by weight.

This step can be accomplished in a flash dryer type dryer well known to those skilled in the art.

The dry powder is then continuously fed to a turbo-reactor, the inner wall of which is maintained at a temperature between 180 ℃ and 240 ℃ and, at the same time, the speed of rotation of the stirrer is parametrized so that the centrifugal acceleration is between 850 m.s.^-2And 2100m.s^-2So that the dry powder is continuously centrifuged and fed into the turbo-reactor for a total duration of between 3 and 45 minutes.

In this implementation step of the method according to the invention, the parameter setting of the rotational speed of the stirrer is determined by calculation, i.e. the centrifugal acceleration according to the invention is between 850m.s^-2And 2100m.s^-2In the meantime.

The calculation is carried out by setting the turbine reactor to be constituted by a stirring shaft equipped with blades having a specific orientation set by the manufacturer (in this case, a device sold by VOMM under the name ES350 may be used):

the centrifugal velocity is defined as the linear velocity "v" at the blade tip divided by the radius R (distance between the stirring shaft and the blade tip), thus in m.s^-2。

[Math.1]

The linear velocity of the blade tip is then defined as the constant pi multiplied by the diameter and speed of rotation (in rpm) of the stirring shaft and divided by 60.

[Math.2]

As follows: for VOMM model ES350 turbo-dryer, the linear velocity of the blade tip is easily calculated from the values given by the manufacturer:

-diameter: 0.35 m;

-rotational speed of the stirring shaft: 1000 rpm.

The mechanical action exerted by the rotor of the turbo-reactor thus provides a large amount of kinetic energy, which makes it possible to promote the intramolecular and intermolecular reactions of the polysaccharide-based chains of the starch, thus obtaining a higher degree of branching than the starting starch, putting it in a more "cross-linked" state.

In addition, the formation of a dynamic thin layer of starch circulating inside the turbo-reactor makes it possible to reduce the reaction time to between 3 and 40 minutes, which is reduced compared with the treatments of the prior art and is particularly suitable for continuous industrial applications.

According to a preferred mode, the heating jacket of the turbo-reactor is generally intended to pass a heating fluid (for example diathermic oil or steam).

Since the turbo-reactor has a double heating jacket, it is possible to ensure precise control of the temperature inside said turbo-reactor, so that the dynamic thin layer of starch is maintained within an optimal temperature range for carrying out a thorough mixing step that favours its physical transformation.

The last step is the recovery of the thermally modified starch thus obtained.

The invention also relates to a thermally modified starch obtainable according to the above-described process of the invention.

The thermally modified starch according to the invention can be advantageously used as a thickener and texturizer in a variety of food applications, in particular in soups, sauces, beverages and ready-to-eat foods, and desserts (such as yoghurt, stirred fermented milk and warm yoghurt) depending on their respective properties.

These thermally modified starches will also find wide application in the following fields by virtue of their texturizing and gelling properties:

-acid sauces and soups (pasteurization and sterilization),

-a pasta meat sauce,

desserts, such as yoghurt, stirred fermented milk, warm yoghurt, dessert cream,

-hot mayonnaise and savoury vinegar,

pie fillings, fruit or sweet/salty marinated or meat fillings, dinner dishes (instant food with short shelf life),

-pudding (dry mix to be cooked),

-baby canned/baby formula,

-a beverage, the beverage comprising a liquid,

ready-to-eat food, meat or fish based products, such as surimi.

-animal feed

The invention will be better understood from the following non-limiting examples.

Apparatus and method

Conductivity measurement

The method employed here is adapted from the european pharmacopoeia-current official version-conductivity (section 2.2.38).

Equipment:

the KNICK 703 electronic conductivity meter, which was also equipped with a measuring element, was verified according to the operating mode described in the related instruction manual.

The operation mode is as follows:

a solution was prepared containing 20g of the sample in powder form and 80g of distilled water having a resistivity greater than 500000ohms.

Measurements were made at 20 ℃ using a conductivity meter, with reference to the procedure indicated in the equipment instruction manual.

Values are expressed in units of microsiemens per centimeter (. mu.S/cm) or milliSiemens per centimeter (mS/cm).

Measurement of the viscosity of starch suspensions using a Rapid Viscometer Analyzer (RVA)

The measurements are carried out according to a suitable temperature/time analysis curve, at pH values acidic (between 2.5 and 3.5) and under defined concentration conditions.

Two buffers were prepared:

buffer solution A

In a 1L beaker with 500mL of deionized water, add

91.0g of citric acid monohydrate (> 99.5% purity) and mixed well,

33.0g of sodium chloride (purity > 99.5%), mixed until completely dissolved,

300.0g of 1N sodium hydroxide.

Poured into a 1L volumetric flask and made up to 1L with deionized water.

Buffer B

100g of buffer A were mixed with 334.0g of deionized water.

The product to be analyzed was prepared as follows:

the dry product to be analyzed thus obtained, having a mass of 1.37g, is added directly to the cup of the viscometer, and buffer B is added until a mass of 28.00. + -. 0.01g is reached. The mixture was mixed using a stirring blade of a rapid visco-analyzer (RVA-NewPort Scientific).

The time/temperature and velocity analysis curves in the RVA were then obtained as follows:

[ Table 1]

And (4) finishing the test: 00:20:05(hh: mm: ss)

Initial temperature: 50 ℃ plus or minus 0.5 DEG C

Data acquisition interval: 2 seconds

Sensitivity: low (low)

The measurements are in RVU (unit used to indicate the viscosity obtained on RVA), 1RVU unit being known as 12cpoises (cp).

Note that 1cP is 1 mpa.s.

Thus, the results will be expressed in mpa.s.

The viscosity will be measured when the "peak" is reached, i.e. the maximum viscosity value between 4 and 6 minutes; and measuring the viscosity at "drop", i.e. the difference between the peak viscosity value and the 17 minute measurement.

Examples

Example 1: preparation of thermally modified starch "A" from potato starch "

i) The alkalization of potato starch is carried out according to the following steps:

-preparing a suspension of potato starch at a Dry Matter (DM) weight ratio of 36.5%;

-preparing a sodium carbonate solution with a mass concentration of 30%, heating it to 40-50 ℃ to facilitate the dissolution of the carbonate;

-adding a sodium carbonate solution so that the conductivity of the starch milk is between 4mS/cm and 6 mS/cm;

-ensuring a contact time of 0.5 h;

ii) filtration with a horizontal dewatering machine with a scraper to separate water and starch and to bring the final conductivity of the starch resuspended at 20 wt% of dry matter to between 0.7mS and 1.1 mS;

iii) drying the starch in a flash dryer type dryer to a moisture content of 12% by weight, wherein the temperature of the gas stream is 150 ℃;

iv) heat treatment.

The product thus obtained is subjected to a thermal treatment in a VOMM-type continuous turbo reactor of the ES350 series, the centrifugal acceleration of which is adjusted to 1700m.s^-2The constant temperature is set to 210 ℃ and the air flow is set to 300Nm³h。

The VOMM type continuous turbo-reactor of the ES350 series is configured so that the total residence time of the product is between 30 and 45 minutes and the temperature difference between this constant temperature and the temperature of the product leaving the reactor is defined as Δ t, i.e. a value of about 20-22 ℃.

The process parameters are shown in the following table.

[ Table 2 ]]

RVA viscosity was measured and is shown in the table below.

Results

[ Table 3 ]]

Testing	RVA valley value (mPa.s)	RVA Peak (mPa.s)
			Potato alkaline starch	554	877
A-1	-226	654
			A-2	-382	451
A-3	-427	305

The thermally modified starches A-1, A-2, A-3 obtained with potato starch have an improved stability compared to native starch: less stickiness and retrogradation were observed with these inhibited starches. This can be demonstrated by drop measurements using an RVA viscometer: the smaller the fall, the greater the resistance of the inhibited starch to shear, medium acidity and heat treatment.

Example 2: preparation of thermally modified starch 'B' from tapioca starch "

i) The alkalization of the cassava starch is carried out according to the following steps:

-preparing a cassava starch suspension with a Dry Matter (DM) weight ratio of 36.5%;

-preparing a sodium carbonate solution with a mass concentration of 30%, heating it to 40-50 ℃ to facilitate the dissolution of the carbonate;

-adding a sodium carbonate solution so that the conductivity of the starch milk is between 4mS/cm and 6 mS/cm;

-ensuring a contact time of 0.5 h;

ii) filtration with a horizontal dewatering machine with a scraper to separate water and starch and to bring the final conductivity of the starch resuspended at 20 wt% of dry matter to between 0.7mS and 1.1 mS;

iii) drying the starch in a flash dryer type dryer to a moisture content of 10% by weight, wherein the temperature of the gas stream is 150 ℃;

iv) heat treatment.

The product thus obtained is subjected to a thermal treatment in a VOMM-type continuous turbo reactor of the ES350 series, the centrifugal acceleration of which is adjusted to 1700m.s^-2The constant temperature is set to 210 ℃ and the air flow is set to 300Nm³h. The VOMM type continuous turbine reactor is configured so that the total residence time of the product is between 17 and 32 minutes, and the temperature difference between this fixed value temperature and the temperature of this product leaving the reactor is defined as Δ t, i.e. a value of about 22-27 ℃.

The process parameters are shown in the following table.

[ Table 4 ]]

RVA viscosity was measured and is shown in the table below.

Results

[ Table 5 ]]

Testing	RVA valley value (mPa.s)	RVA Peak (mPa.s)
			Cassava alkaline starch	480	603
B-1	60	438
			B-2	-97	269
B-3	-155	147

Compared with natural starch, the thermally modified starch B-1, B-2 and B-3 obtained by utilizing the cassava starch has improved stability: less stickiness and retrogradation were observed with these inhibited starches.

Example 3: preparation of thermally modified starch "B" from pea starch "

i) The alkalization of pea starch is carried out according to the following steps:

-preparing a pea starch suspension with a Dry Matter (DM) weight ratio of 33%;

-preparing a sodium carbonate solution with a mass concentration of 30%, heating it to 40-50 ℃ to facilitate the dissolution of the carbonate;

-adding a sodium carbonate solution so that the conductivity of the starch milk is between 4mS/cm and 6 mS/cm;

-ensuring a contact time of 0.5 h;

ii) filtration with a horizontal dewatering machine with a scraper to separate water and starch and to bring the final conductivity of the starch resuspended at 20 wt% of dry matter to between 0.7mS and 1.1 mS;

iii) drying the starch in a flash dryer type dryer to a moisture content of 10% by weight, wherein the temperature of the gas stream is 135 ℃;

iii) heat treatment.

The product thus obtained is subjected to a thermal treatment in a VOMM-type continuous turbo reactor of the ES350 series, the centrifugal acceleration of which is adjusted to 1700m.s^-2The constant temperature is set to 210 ℃ and the air flow is set to 300Nm³h. The VOMM-type continuous turbine reactor is configured so that the total residence time of the product is between 6 and 21 minutes, and the temperature between the set point temperature and the temperature of the product leaving the reactorThe temperature difference is defined as Δ t, i.e., a value of about 23 ℃ to 24 ℃.

The process parameters are shown in the following table.

[ Table 6 ]]

RVA viscosity was measured and is shown in the table below.

Results

[ Table 7 ]]

Testing	RVA valley value (mPa.s)	RVA Peak (mPa.s)
			Pea alkali starch	76	285
C-1	-54	302
			C-2	-140	97
C-3	-132	60

Compared with natural starch, the thermal modified starch C-1, C-2 and C-3 has improved stability in use: less stickiness and retrogradation were observed with these inhibited starches.

Example 4: preparation of thermally modified starch 'D' from waxy maize starch "

i) The alkalization of the waxy corn starch is carried out according to the following steps:

-preparing a waxy corn starch suspension with a Dry Matter (DM) weight ratio of 36.5%;

-preparing a sodium carbonate solution with a mass concentration of 30%, heating it to 40-50 ℃ to facilitate the dissolution of the carbonate;

-adding a 30% by mass sodium carbonate solution to a conductivity of the starch milk of between 4mS/cmg and 7 mS/cm;

-ensuring a contact time of 0.5 h;

ii) filtration with a horizontal dewatering machine with a scraper to separate water and starch and to bring the final conductivity of the starch resuspended at 20 wt% of dry matter to between 1.75mS and 2 mS;

iii) drying the starch in a flash dryer type dryer to a moisture content of 11.8 wt%, wherein the gas stream temperature is 135 ℃;

iii) heat treatment.

The product thus obtained is subjected to a thermal treatment in a VOMM-type continuous turbo reactor of the ES350 series, the centrifugal acceleration of which is adjusted to 1700m.s^-2The constant temperature is set at 200 ℃ and the air flow is set at 300Nm³h. The VOMM type continuous turbine reactor is configured so that the total residence time of the product is between 15 and 35 minutes, and the temperature difference between the set temperature and the temperature of the product leaving the reactor is defined as Δ t, i.e. a value of about 17-20 ℃.

The process parameters are shown in the following table.

[ Table 8 ]]

RVA viscosity was measured and is shown in the table below.

Results

[ Table 9 ]]

Experiment of	RVA valley value (mPa.s)	RVA Peak (mPa.s)
			Waxy corn alkaline starch	914	1020
D-1	-66	441
			D-2	-127	284
D-3	-176	157

The thermally modified starches D-1, D-2, D-3 have an improved stability during use compared to native starches: less stickiness and retrogradation were observed with these inhibited starches.

Example 5: preparation of thermally modified starch 'E' from fava bean starch "

i) The small broad bean starch alkalization is carried out according to the following steps:

-preparing a small broad bean starch suspension with a Dry Matter (DM) weight ratio of 33%;

-preparing a sodium carbonate solution with a mass concentration of 30%, heating it to 40-50 ℃ to facilitate the dissolution of the carbonate;

-adding a sodium carbonate solution so that the conductivity of the starch milk is between 4mS/cm and 6 mS/cm;

-ensuring a contact time of 0.5 h;

ii) filtration with a horizontal dewatering machine with a scraper to separate water and starch and to bring the final conductivity of the starch resuspended at 20 wt% of dry matter to between 1.5mS and 2 mS;

iii) drying the starch in a flash dryer type dryer to a moisture content of 14% by weight, wherein the temperature of the gas stream is 135 ℃;

iii) heat treatment.

The product thus obtained is subjected to a thermal treatment in a VOMM type continuous turbine reactor, the centrifugal acceleration of which is adjusted to 1700m.s^-2The constant temperature is set to 210 ℃ and the air flow is set to 300Nm³h。

The continuous turbo-reactor of the VOMM type is configured so that the total residence time of the product is between 13 and 25 minutes and the temperature difference between the fixed temperature and the temperature of the product leaving the reactor is defined as Δ t, i.e. a value of about 23-24 ℃.

The process parameters are shown in the following table.

[ Table 10 ]]

RVA viscosity was measured and is shown in the table below.

Results

[ Table 11]

Testing	RVA valley value (mPa.s)	RVA Peak (mPa.s)
			Alkali starch of small broad beans	82	323
E-1	-79	229
			E-2	-47	45

The thermally modified starches E-1 and E-2 have an improved stability during use compared to native starches: less stickiness and retrogradation were observed with these inhibited starches.