CN116848149A

CN116848149A - Thermally modified starch

Info

Publication number: CN116848149A
Application number: CN202280012743.3A
Authority: CN
Inventors: S·博克; J·罗格朗
Original assignee: Roquette Co
Current assignee: Roquette Co
Priority date: 2021-02-04
Filing date: 2022-02-04
Publication date: 2023-10-03

Abstract

The invention relates to a thermally modified starch produced by an acid process, characterized in that the starch has a free citrate content of less than 0.05% and a fixed citrate content of between 0.05% and 0.15%, that the starch granules obtained by a 2-17 minute analysis using rapid RVA have a maximum swelling temperature of more than 100 ℃, preferably between 100 ℃ and 140 ℃, and/or a sediment volume of between 20mL and 65mL, preferably between 25mL and 40 mL.

Description

Thermally modified starch

The invention relates to a heat modified starch produced by an acid method, which is characterized in that the starch has unique free and fixed citrate content, maximum swelling temperature of starch granules and precipitation level.

The invention also relates to a thermally modified starch produced by the acid process, the colour of said starch [ expressed in L x (brightness) and Yie (yellowness) ] being comparable to that of natural starch.

The invention also relates to a special process for producing these heat-modified starches at acidic pH, the viscosity of which is stabilized after heat treatment.

The acid treatment refers to the treatment of milk-phase starch with sodium citrate powder and citric acid powder at a pH between 4 and 6.

These heat modified starches are useful as setting agents and thickening agents for a variety of food products.

Background

Starch synthesized by biochemical means is not only a source of carbohydrates, but also one of the most widely distributed organic materials in the plant kingdom, and can constitute a nutrient reserve required by organisms.

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 properties.

For example, natural starch may be used in formulations that require 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 gel effect. After cooking and cooling, a firm pudding may be formed. It is also suitable for making cake cream.

However, these pastry creams cannot be used for pastries intended to be frozen, because, on thawing, the dehydration phenomenon causes the water to be expelled, thus destroying the creaminess.

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

poor resistance to shear stress and heat treatment,

poor processability, and

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 imposed by cooking and freezing/thawing, canning or sterilization, and to adapt it to modern food processing modes (e.g., microwave, ready-to-eat, "high temperature" cooking, etc.).

Modification of starch aims to ameliorate one or more of the above limitations, thereby increasing the versatility of starch and meeting consumer needs.

Starch modification techniques are largely 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 the most popular modes of operation are chemical and physical modifications.

Chemical treatments involve the introduction of functional groups into the starch, which can significantly alter the physicochemical properties of the starch. The above modification of the native granular starch can thoroughly alter the gelatinization, adhesion and retrogradation characteristics of the starch.

Typically, such modification is performed by chemical derivatization, such as esterification, etherification, crosslinking, or grafting.

However, while some modifications are considered safe and harmless, consumers are still reluctant to chemically modify (also in view of environmental considerations) in food applications.

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

-wet heat treatment (english term "Heat Moisture Treatment" or HMT) comprising treating the starch at a controlled humidity level between 22% and 27% and at high temperature for 16 hours, in order to modify the structure and physicochemical properties of the starch;

"annealing" includes treating starch with excess water at a temperature below the gelatinization temperature to approach the glass transition temperature;

-an ultra-high pressure treatment (english term "High Pressure Processing" or HPP), by which amorphous regions of starch granules are hydrated, thereby deforming the crystalline portions of the granules, promoting the infiltration of said crystalline regions into the water;

glow discharge plasma treatment, producing 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 cross-linking of macromolecules;

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

The starch is converted from form B to form a after processing, thereby obtaining a significantly elevated gelatinization temperature;

-treatment by "heat inhibition". In general, heat inhibition refers to the dehydration of starch until an anhydrous or substantially anhydrous state (i.e., humidity < 1%) is reached, followed by heat treatment at a temperature in excess of 100 ℃ for a period of time until the starch is "inhibited" at which point the starch has cross-linked starch properties. Before the deep-dewatering step is carried out, the starch must also be subjected to conditions with a pH attribute of at least neutral, preferably alkaline.

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

In any case, the heat inhibition process results in a starch paste exhibiting higher resistance to adhesive break properties and non-adhesive properties.

The invention relates to the technical field of heat inhibition treatment of starch without using absolute alcohol solvent.

In this particular technical field, reference may be made in detail to US 6.221.420 document describing a heat-inhibited starch obtained after dewatering and heat treatment.

The method mainly comprises the following steps:

-dewatering starch at a temperature between 100 ℃ and 125 ℃ to a moisture content below 1%, followed by

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

Preferably, before the starch dewatering step, a starch alkalization step is recommended, 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% prior to the actual dewatering step preceding the inhibition step.

Document US2001/0017133 describes a similar process in which the starch is also dehydrated at a temperature lower than 125 ℃ before the start of the inhibition process (at a temperature higher than 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.

Prior to the dewatering step, a conventional alkalization step results in a starch suspension having a pH between 7.5 and 11.2, preferably between 8 and 9.5, and a moisture content between 2% and 15%.

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

In other words, the method suggests not to perform a dewatering step before the heat inhibition of the pre-alkalized starch.

Thus, in the starch preparation, the pH of the starch is adjusted to between 9.1 and 11.2, preferably 10, and the moisture content 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 between 140 ℃ and 190 ℃, preferably between 140 ℃ and 180 ℃.

In contrast, in another alternative embodiment, the pH of the treated starch is reduced prior to the heat-inhibiting treatment. The main disadvantage is that high pH tends to increase the browning of the starch during the heating step.

Thus, patent application WO2020/139997 describes a starch preparation step comprising in succession:

-the preparation of a starch milk,

the pH of the starch milk prepared in this way is adjusted to between 5 and 6.5, neutralization is carried out if necessary,

-adding an acid buffer

-adjusting the pH value.

The actual heat treatment steps, including the dehydration step and the heat inhibition step, are then performed.

In this patent application, it is first necessary to bring the pH of the starch milk between 5 and 6.5. Either the starch already has this pH (which is considered to be its natural pH), or a "neutralization" step (by addition of acid or base) is performed to reach this pH range. This may take 24 hours.

Next, citric acid or citric acid pH buffer is added to bring the pH of the starch milk to between 4 and 6. This step may take 24 hours.

Finally, in order to produce heat inhibited starch, the present patent application teaches that we dewater and heat inhibit starch milk treated by this method. This step may require a reaction time of 4 hours.

Finally, it has been determined that this process makes it possible to obtain a heat-inhibited starch which is whiter and has a better mouthfeel than heat-inhibited starches prepared by conventional methods, i.e. after alkaline impregnation.

However, there is still room for improvement in this method of preparing heat inhibited starch. In fact, from the point of view of the process used, it has the disadvantage that the starch milk must be immersed in an acidic medium after fine control of the initial pH of the starch.

This type of treatment then results in the production of a heat inhibited starch with high levels of fixed citrate (exceeding 0.2%) reflecting a high degree of functionalization, as shown below.

For the above reasons, there remains a need for an original starch inhibition process that further shortens the reaction time by directly carrying out the impregnation on the starch and by reducing the heat inhibition time itself, so as to reduce the citrate content to values well below 0.2%, reflecting a sufficient degree of functionalization to meet the intended application.

Detailed Description

The invention therefore relates to a thermally modified starch produced by the acid process, characterized in that the starch has a free citrate content of less than 0.05% and a fixed citrate content of between 0.05% and 0.15%.

Advantageously, the thermally modified starch according to the invention has:

the maximum expansion temperature of the starch granules obtained by analysis using RVA for 2 to 17 minutes is higher than 100 ℃, preferably between 100 and 140 ℃,

and/or the volume of sediment is between 20mL and 65mL, preferably between 25mL-

Between 40 mL.

More specifically, the colour (L-value) of the thermally modified starch is between 90 and 98, preferably between 94 and 98, and/or the colour (Yie-value) of the starch is between 6 and 25, preferably between 6 and 15, more preferably between 6 and 9.

The citrate of the heat-modified starch of the invention was determined by HPLC on the wash and hydrolysis products under the following conditions.

Measurement of free citrate can verify the use of heat modified starch in "clean labels", while measurement of immobilized citrate can determine the degree of functionalization of the heat acid reaction product on the starch.

The free citrate content of the product according to the invention is less than 0.05%, lower than that of the similar products of the prior art (such as the products sold in the art or in the market according to the teachings of the international patent application WO 2020/139997), the latter being measured between 0.07% and 0.09%.

To have a free citrate content of less than 0.01% a large amount of washing is required.

As regards the determination of the fixed citrate obtained after washing and hydrolysis, the fixed citrate content of the thermally modified starch according to the invention is comprised between 0.05% and 0.15%, whereas the values of the similar products of the prior art, such as those obtained according to the process taught in international patent application WO2020/139997 or those marketed, are comprised between 0.24% and 0.39%.

The viscosity measurements according to the invention on the thermally modified starch were carried out on RVA4800 equipment, and the measurement results indicated that the burst temperature of the starch granules at the viscosity peak was changed.

The highest swelling temperature of the starch granules obtained by analysis using RVA for 2-17 minutes is higher than 100℃and even higher than 140 ℃.

The heat modified starches according to the invention also have a sedimentation capacity.

The test is carried out in a test tube, the smaller the sedimentation volume, the higher the degree of functionalization.

Thus, sedimentation volume:

-more than 70mL: indicating a low degree of functionality/low resistance of the product,

-between 60mL and 70mL: moderate functionality/moderate resistance,

-between 40mL and 60 mL: high functionality/resistance

-less than 40mL: high functionality or high resistance.

According to the invention, the sedimentation volume of the product is between 25mL and 40mL, which reflects a high level of crosslinking, rendering it highly functional and resistant.

Finally, the colour of the thermally modified starch according to the invention is identical to that of the native starch on which it is made.

This is reflected in a value L of between 90 and 98, preferably between 94 and 98, more preferably between 96 and 98, and/or a value Yie of between 6 and 25, preferably between 6 and 15, more preferably between 6 and 9.

The heat modified starch may be obtained by a process comprising the steps of:

(i) Starch milk is prepared with a dry matter of between 30 and 40% by weight, preferably between 35 and 37% by weight,

(ii) Directly adding sodium citrate and citric acid powder into starch milk to make pH value between 4 and 6,

(iii) The rest stability may be chosen to be at least 30 minutes,

(iv) Filtering and drying until the equilibrium moisture content is not more than 13%,

(v) Heated to at least 160 ℃, preferably between 170 ℃ and 210 ℃.

(vi) The resulting thermally modified starch is resuspended, pH adjusted, washed and re-dried.

The starch used in the process of the present invention may be of any origin, 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, konjak starch, etc.

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

The process according to the invention first requires the preparation of a starch milk having a dry matter of between 30% and 40% by weight, preferably between 35% and 37% by weight. As will be exemplified below, the dry matter is set to 36.5 wt%.

The second stage of the process according to the invention comprises adding a mixture of sodium citrate and citric acid powder to the starch milk so that the pH of the starch milk is between 4 and 6, as described below.

The mixture was then allowed to stabilize for at least 30 minutes and the pH and conductivity of the suspension were measured.

After filtration, the preparation is dried to an equilibrium starch moisture content of 13% or less.

Drying can be carried out in a laboratory Retsch dryer at 60 ℃, in a fume hood naturally vented at room temperature, or in a pilot/industrial dryer above 100 ℃.

After drying and grinding at 60 ℃, actual heat treatment was performed.

The heat treatment temperature is at least 160 ℃, preferably between 170 ℃ and 210 ℃, and the reaction time is 0.5 hours to 3 hours, as described below. These kinetics make it possible to vary the degree of functionalization of the thermally modified starch (the higher the degree of functionalization of the starch, the greater the resistance to the conditions of limited use, such as acidic pH, high shear, high temperature).

The heating may be carried out in a vented oven or in pilot or industrial equipment such as turbo-dryers, reaction fluidized beds or blade roasting ovens.

After heat treatment, the product was resuspended at 36% dry matter weight. The pH is adjusted to between 5.5 and 6 with sodium hydroxide, and finally filtered, dried and ground.

The heat-modified starches thus obtained can be used as thickeners or texturizers in food applications depending on their respective characteristics.

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

Apparatus and method

Substrate

Waxy corn starch produced by applicant company at its Beinheim production baseAnd (5) brand sales.

The method is characterized by comprising the following steps:

-water content: 12.4%

-pH value: 5.4

-conductivity: 223 mu S

-chromaticity: l=97.6; yie =8.11

Pea starch sold by applicant company under the trade name N735.

The method is characterized by comprising the following steps:

-water content: 11.73%

-pH value: 6.87

-conductivity: 455 mu S

-chromaticity: l=97.79; yie =4.27

The following are two products for pH 4 buffer.

Conductivity and pH measurements

Conductivity of

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

Apparatus and method for controlling the operation of a device：

The KNICK 703 electronic conductivity meter is also equipped with measuring elements and verified according to the modes of operation described in the relevant instruction manual.

Mode of operation：

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

The reference device uses the operating method indicated in the manual at 20 c, and the measurement is performed using a conductivity meter.

Values are expressed in units of microsiemens/centimeter (μS/cm) or millisiemens/centimeter (mS/cm).

pH value of

The method employed here was adapted from the European pharmacopoeia-current official edition-pH value (section 2.2.3).

A20% (w/w) suspension of the sample to be analyzed was prepared, the pH was determined using a laboratory pH meter, and reference was made to the instructions in the instruction manual. The pH is expressed in the nearest 0.01 unit.

Measurement of citrate by high performance liquid chromatography

Determination of citrate was performed:

directly after heat treatment, the washed and dried product (free citrate is measured),

After hydrolysis (measurement of immobilized citrate), the following method was used.

Measurement method

After ion exchange chromatography, citrate ions were detected by conductivity. Quantification was performed using an internal calibration method.

The equipment used is a set of high performance liquid chromatography device, comprising:

-a thermosusher ICS 2100 system;

-an injector (TSP AS-AP type) to keep the sample at 10 ℃;

-AERS 500-super-suppressor;

-Thermo AS11 HC 250 x 4mm chromatographic column with AG11-HC 4 x 50mm pre-column.

Ion chromatography filter-IC 0.45 μm-Pall.

The reagent used is as follows:

high performance liquid chromatography pure water

Sodium citrate trihydrate (manufactured by Sigma Co., ltd.)

Trifluoroacetic acid (Sigma Co., ltd.)

-internal standard solution: 400mg/L trifluoroacetic acid solution

-2N hydrochloric acid (Merck Co., ltd.)

EGC-KOH cartridge (Thermo company containing)

The operation method is as follows:

-solvent a: HPLC grade water, having a high-pressure concentration,

elution procedure:

sample introduction amount: 25 mu L

Column temperature: 36 DEG C

Analysis time: 77 minutes

Sample temperature: 10 DEG C

-ASRS：193mA

Calibration of

6 curve points are prepared.

Weighing x mg sodium citrate, i.e. x is between 10mg and 250mg, adding water to 500mL. Shaking up.

0.5mL of the internal standard solution was added and adjusted to 20mL with 1mM sodium hydroxide solution.

Filtration and feeding.

Calculate the weight of chloride standard (weight of sodium chloride (molecular weight of ion/molecular weight of salt)).

Drawing a calibration curve: peak height ratio (=chloride standard weight/internal standard weight).

Sample of

100mg of sample+0.5 mL of internal standard solution was weighed to 20mL of water. And (5) filtering. And (5) sample injection.

Washing and drying

About 20g of the sample to be analyzed and 200mL of deionized water were placed in a 250mL beaker. The watch glass was covered and shaken with a magnetic stirrer for 20 minutes. The filtrate was then filtered through a 150mm diameter buchner funnel fitted with a 150mm diameter duriux n 111 white band filter or equivalent.

The filtrate was placed back into a 250mL beaker, dispersed in 200mL deionized water, and stirred for 20 minutes. Again filtered and rinsed with 200mL deionized water.

The filtered product was dried overnight in a laboratory oven and then crushed to avoid caking.

Hydrolysis

To a 250mL flat bottom glass flask was added an accurately weighed test amount P of sample to be analyzed. Distilled water corresponding to (100-P), 100mL of 2N hydrochloric acid, and some boiling regulator (granular pumice) were added. Placed in an electrically heated sleeve under a reflux condenser for 45 minutes from boiling. Cooled and neutralized to pH 7 with 40% sodium hydroxide solution.

Test results：

The citrate ion content (%) is determined by the following formula:

Q/P×100

wherein:

q = amount of citrate read from curve (mg)

P=sample weight (mg)

Measurement of viscosity of starch suspensions using a Rapid Viscosimeter Analyzer (RVA) 4800

At a pH of 4 and under defined concentration conditions, measurements were made according to a suitable temperature/time analysis curve.

Preparation of citrate buffer with pH 4

-preparing 800mL of distilled water,

9.838g of sodium citrate is added,

12.782g of citric acid are added,

adjusting the pH of the solution to 4 with NaOH or HCl,

make up to 1 liter with distilled water.

The product to be analyzed was prepared as follows:

the dry product to be analyzed, having a mass of 1.37g, was directly added to the cup of the viscometer, and citrate buffer, having a pH of 4, was added until a mass of 28.00.+ -. 0.01g was reached.

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

TABLE 1]

Ending the test: 00:38:05 (hh: mm: ss)

Initial temperature: 30 ℃ +/-0.5 DEG C

Data acquisition interval: 2 seconds

Sensitivity: low (Low)

The measurement results are in RVU (unit for representing the viscosity obtained on RVA), 1RVU unit=12 cPoises (cP) is known.

Note that 1 cp=1 mpa.s.

In the graph, the results are expressed in cPoises.

The temperature of the swelling peak between 2 minutes and 17 minutes was added to the analytical curve.

Sedimentation test

The product was dispersed in an aqueous medium and the sedimentation volume was measured.

Solution A

-zinc chloride: 10g

-ammonium chloride: 26g

Distilled water: qsp 100mL of

A sample of 1.0g of the anhydrous product to be analyzed was placed in a 250mL jar. 100mL of solution A was added, capped, homogenized and placed in a water bath for 10 minutes. Cooled in a cold water bath, homogenized again, transferred to a 100mL tube and after 24 hours the pour volume was measured.

The pouring volume is given in mL and is given by the following formula:

starch pour volume/total volume) ×100

Conductivity measurement

The colorimetric measurements are based on the opponent color theory, which states that the response of cones (the cells responsible for color vision on the retina of the human eye) to the three colors red, green, and blue recombine into "black-white", "red-green", and "yellow-blue" opposites signals as they pass into the brain via the optic nerve.

The measurement method is based on the widely used color codes in the food and polymer industries, namely CIELAB L, a and b color codes.

The L, a, and b color scales are defined as follows:

-L x axis (luminance): 0 represents black, 100 represents white

-a x axis (red-green): positive values are red, negative values are green, and 0 is neutral.

-b x axis (yellow-blue): positive values are yellow, negative values are blue, and 0 is neutral.

Thus, the "L" index has a value between 0 and 100, while the "b" and "a" indices have no numerical limitation. The measuring instrument is typically a Colorflex EZ spectrophotometer, following the manufacturer's specifications (handbook version 1.2, month 8 of 2013, applicable to CFEZ firmware 1.07 and higher—see pages 17 and 38).

The measurement was performed in a 64mm glass sample pan, and the sample was placed in the glass sample pan so as to fill half of the glass sample pan so that there was enough material to cover the surface that was in contact with the radiation (measurement uniformity).

Yie (yellowness index), a number calculated from spectrophotometric data, describes the change in color of a sample being measured from "clear or white" to "yellow", as is well known to those skilled in the art.

Examples

Example 1: preparation of thermally modified starch "D" from waxy corn starch "

Preparation of milk-based

Will beCorn starch was added to a 1000mL beaker and then suspended in deionized water to bring the total dry Matter (MS) to 36.5% (weight percent). Sodium citrate and citric acid were added directly to the powdered starch milk to give a pH of 4.

At least 30 minutes wait for it to stabilize and then the pH and conductivity of the suspension are measured.

The suspension was filtered through a sintering machine with a porosity of 3.

Dried on a Retsch fluid bed dryer at 60 ℃ to an equilibrium moisture content of around 13%.

Starch was ground in a Thermomix mill to break it up and prevent the formation of aggregates.

Measurement: moisture content, pH, conductivity, colour (L. And Yie)

Heat treatment of

40g of the sample was weighed and placed in an aluminum pan of a METLERLJ 16 balance (moisture measuring balance).

The aluminum pan was placed in a memmerert vented oven previously heated to 170 ℃. Once the sample cup is placed, the balance begins timing and the sample cup is removed according to the reaction kinetics selected.

Washing and pH adjustment of the reacted product by re-suspension

Resuspend a 36% ms sample in deionized water,

adjusting the pH to between 5.5 and 6 with NaOH,

filtering by a sintering machine with a porosity of 3,

the filter cake was dried overnight in a fume hood at room temperature,

grinding (IKA) to break up the powder and homogenize the sample.

Measurement: moisture content, pH, conductivity, color (L and Yie), viscosity RVA4800 of the water wash product and sedimentation test.

Results

Physicochemical measurements

When the reaction was carried out at 170 ℃, the following measurements were carried out on the samples before washing:

-moisture content

pH value

Conductivity (μS)

-chromaticity

The formulation is shown in table 1 below:

TABLE 1

We observed during the reaction with citrate buffer (pH 4) directly powdered in waxy corn starch milk:

after 3 hours of reaction at 170℃the pH value is increased from 4.2 to 5.

The conductivity drops by about 50. Mu.S at the beginning of the reaction, and stabilizes at about 250. Mu.S after 1 hour of reaction.

After 3 hours of reaction at 170 ℃, the color slightly increased, yie (yellowness) from 8.6 to 12.7.

Washing the product after the reaction

The washed product was measured according to the protocol described above and the results are shown in tables 2 and 3 below.

TABLE 2

TABLE 3 Table 3

The pH value of the washed product is between 4.6 and 6.5, and the conductivity is between 176 mu S and 336 mu S.

Yie chromaticity (yellowness) is between 6.4 and 11.7. In contrast, the Yie value of the natural waxy base was 8.11.

RVA4800 viscosity determination of Water washed products at 140 ℃

The results are shown in FIG. 1 below.

Treatment of a pH 4 impregnated waxy corn starch in a citric acid/citric acid medium at 170 c appears to result in a change in the burst temperature of the starch granules at the peak viscosity.

Fig. 2 shows the measurement of the peak burst temperature between 2 and 17 minutes, and it can be observed that after 1 hour of reaction at 170 c, the maximum temperatures of the products produced are 140 c.

Thus, within the meaning of the present invention, thermally modified starches of high functionality or high heat resistance can be obtained by reaction at 170℃for 1 hour.

Sedimentation test

The results are shown in Table 4 and FIG. 3 below.

TABLE 4 Table 4

After 1 hour of reaction, a very resistant product was obtained.

Determination of citrate

The results are shown in Table 5 below (comparing the free citrate and the fixed citrate content of the product sold by TATE & LYLE company and produced according to patent application WO 2020/139997).

TABLE 5

It should be noted that the free citrate content of 0.18% in the waxy starch base represents the citrate content of the impregnated starch and to be used in the heat treatment reaction.

The fixed amount of citrate after the reaction of the heat modified starch of the invention at 170 ℃ is 0.09-0.11, which is far lower than the level of inhibited starch obtained according to the prior art process.

Example 2: preparation of thermally modified starch in VOMM turbo-dryer。

Preparation of milk phase base material

Preparation of deionized water with a dry Matter (MS) content of 36.5%Corn starch suspension;

-adding a mixture of sodium citrate and citric acid directly to the powdered starch milk to bring the pH to 6;

waiting for stabilization, then measuring the pH and conductivity of the suspension

By DorrThe wringer extrudes the starch milk and checks the pH and conductivity

Drying the product on a flash dryer with a moisture content of 10% -12%

Instead of adding sodium citrate and citric acid powder, the following method may be used:

-preparing an upstream solution of sodium citrate and citric acid in demineralized water

-adding the solution directly to starch milk. This will stabilize the pH and conductivity faster and ensure that the salt dissolves in the water when added.

Heat treatment of

The obtained product was subjected to a heat treatment in a VOMM-type continuous turbojet, the constant temperature of which was set at 210 ℃, the residence time of the product was set at 20 to 35 minutes, and the temperature difference between the constant temperature and the temperature of the product leaving the reactor was defined as Δt, i.e. the value was about 22 ℃.

Three tests were performed according to the three working conditions selected. They are trials 034, 035 and 036.

Measurement results of changes of pH value and conductivity of product along with process parameters

TABLE 6

Washing and pH adjustment of the reacted product by re-suspension

Re-suspending 36.5% ms heat treated product in demineralised water,

adjusting the pH between 4.5 and 6 with NaOH,

filtration is carried out by means of a sintering machine with a porosity of 3,

drying the filter cake on a Retsch dryer,

grinding (IKA) to break up the powder and homogenize the sample.

Moisture content, pH, conductivity, colour (L and Yie), RVA4800 viscosity of the water wash product and sedimentation tests were measured.

TABLE 7

The pH value of the washed product is between 4.5 and 6, and the conductivity is lower than 200 mu S.

Yie chromaticity (yellowness) is between 11.34 and 22.02.

In contrast, native waxy corn starch has a Yie value of 8.11.

Results

Figures 4 and 5 show RVA4800 viscosity results for water wash products at 140 ℃.

Treatment of a pH 6 impregnated waxy corn starch in a citric acid/citric acid medium at 210 c appears to result in a change in the burst temperature of the starch granules at the peak of viscosity.

FIG. 4 shows measurements of burst peak temperatures between 2 minutes and 17 minutes, and it can be observed that after 20 minutes of reaction at 210℃the resulting product temperatures are all higher than 100℃and at least 35 minutes of reaction is required to obtain a product with a maximum temperature of 140 ℃.

Sedimentation test

The results of the sedimentation test are shown in the following table.

TABLE 8

After 20 minutes of heat treatment, a medium functional product is obtained, after 25 minutes, a high functional product is obtained, and after 35 minutes, the high functional product is obtained.

Determination of citrate

The results are shown in the following Table (comparing the free citrate and fixed citrate levels of commercial products of TATE & LYLE and INGREDION).

TABLE 9

Example 3: in a reaction fluidized bedIn the preparation of thermally modified starches

Preparation of milk phase base material

-preparing dry Matter (MS) content with deionized waterCorn starch suspension.

-adding a mixture of sodium citrate and citric acid directly to the powdered starch milk to bring the pH to 6.

If necessary, the pH is adjusted using NaOH or HCl (in this case pH 6).

By means of orr-The juice extractor extrudes the starch milk and checks the pH and conductivity.

-drying the product on a flash dryer with a moisture content of 10% -12%.

Sodium citrate and citric acid powder may not be added, but:

preparing sodium citrate and citric acid solutions in demineralised water,

Heat treatment of

The product thus obtained was subjected to a heat treatment in a fluidized reaction bed (LFR manufactured by SCHWING corporation) with an anhydrous use of about 9 kg and a gas velocity (50/50 air+nitrogen mixture) of 10 cm/sec to 12 cm/sec, set at 160 ℃. Once the desired temperature is reached, the T0 point of the reaction is determined.

At T ₀ Kinetic point sampling at 160 ℃, followed by sampling at 1.5H, 2H, 3H and 4H.

The results of the analysis at each kinetic point are shown in the following table.

Table 10

Washing and pH adjustment of the reacted product by re-suspension

Re-suspending the MS 36% heat treated product in demineralised water.

-adjusting the pH between 5.5 and 6 with hydrochloric acid if necessary.

Filtration through a sintering machine with a porosity of 3.

Drying the filter cake on a Retsch dryer.

Grinding (Thermomix).

TABLE 11

The pH value of the washed product is between 5.8 and 6.3, and the conductivity is lower than 200 mu S.

Yie chromaticity (yellowness) chromaticity is between 10 and 15. In contrast, the Yie value of the native WAXILYS corn starch base was 8.1.

Results

RVA4800 viscosity of the water-washed product was measured at 140 ℃.

RVA4800 viscosity curves are shown in figure 6.

Heat treatment of an impregnated waxy corn starch at pH 6 in a citric acid/citric acid medium at 160 c results in a change in the burst temperature of the starch granules at the peak viscosity.

Fig. 7 shows the measurement results of the burst peak temperature from 2 minutes to 17 minutes. It can be observed that during the thermal reaction at 160℃the burst temperature at PIC (between 2 minutes and 17 minutes) increases and after 3 hours of reaction at 160℃the maximum temperature of 140℃is reached.

Sedimentation test

The results and curves of the sedimentation test are shown in table 12 below and fig. 8.

Table 12

The heat treatment time is not more than 2 hours, and the product with moderate functionality can be obtained. After 3 hours and 4 hours, the product has high functionality.

Determination of citrate

The results are shown in the following table (comparing the free and fixed citrate levels of the products sold by TATE & LYLE and INGREDION).

TABLE 13

Note that the free citrate content of 0.17% in the waxy starch base refers to the citrate content of the impregnated starch that will be used in the heat treatment reaction. The amount of citrate fixed after the reaction of the heat-modified starch according to the invention at 160 ℃ is 0.08% lower than the level of inhibited starch obtained according to the prior art process.

Example 4: preparation of thermally modified starch (supplied by ANDRITZGOUDA Co.) in a PADLE dryer

Preparation of milk phase base material

Preparation of deionized water with a dry Matter (MS) content of 36.5%Corn starch suspension.

-adding 40% sodium citrate and citric acid solution to the starch milk to bring the pH to 6.

-stabilization for about 30 minutes, measurement of pH and conductivity of the suspension.

If necessary, the pH is adjusted using NaOH or HCl (in this case pH 6).

Extruding the starch milk through a filter press.

-drying the product on a flash dryer with a moisture content of 10% -12%.

Heat treatment of

The product obtained was subjected to a heat treatment in a PADLE dryer (ANDRITZ GOUDA) with a steam temperature set at 185℃and a feed rate of 60kg/h. At this flow rate, the contact time in the machine was about 30 minutes. The product outlet temperature was 183 ℃.

Sample analysis：

TABLE 14

Washing and pH adjustment of the reacted product by re-suspension

Re-suspending the MS 36% heat treated product in demineralised water.

-adjusting the pH between 5.5 and 6 with hydrochloric acid if necessary.

Filtration through a sintering machine with a porosity of 3.

Drying the filter cake on a Retsch dryer.

Grinding (Thermomix).

The washed product was measured: moisture content, pH, conductivity, color (L and Yie), RVA4800 viscosity and sedimentation tests.

TABLE 15

Table 16

The pH value of the washed product is between 5.5 and 6, and the conductivity is lower than 200 mu S.

Yie the chroma (yellowness) is 9.7. In contrast, naturalThe Yie value of the corn starch base was 8.1.

Results

RVA 48000 viscosity of the water-washed product was measured at 140 ℃.

The results are shown in FIG. 9 below.

Peak burst temperature was measured between 2 minutes and 17 minutes.

TABLE 17

Reference numerals	Peak temperature (. Degree. C.)
		Citrate prepreg base material	91
E14-20-10	106

Heat treatment of a pH 6 impregnated waxy corn starch in a citric acid/citric acid medium at 185 ℃ results in a change in the burst temperature of the starch granules at the peak viscosity.

Sedimentation test

The following table lists the results and curves of the sedimentation test.

Product(s)	Reaction	Sedimentation volume mL
			Citrate prepreg base material	T0	100
E14-20-10(PE：CL)	About 30 minutes	70

After heat treatment at 185 ℃ for about 30 minutes, a moderately functional product is obtained.

Determination of citrate

TABLE 18

The free citrate content in the waxy starch base was 0.14%, representing the amount of citrate that was impregnated in the starch and would be used in the heat treatment reaction. The fixed amount of citrate after reaction of the heat modified starch of the invention at 185 ℃ is 0.08% lower than the level of inhibitory starch obtained according to the prior art process.

Example 5: application of heat-treated starch in preparation of oyster sauce according to the invention

In this example, the heat modified starches obtained in example 2, namely test 034, test 035 and test 036, will be evaluated in the preparation of oyster sauce by comparing the color, swelling capacity and freeze-thaw stability.

The following are control groups

-the applicant toCR3010 is a commercially available chemically modified waxy corn starch, commonly used for texturing of sauces,

a thermally modified starch made from waxy corn starch treated by alkaline impregnation, sold by the applicant company under the name FC20 starch,

sold by the company INGREDION0100，

By TATE&Sold by LYLE companyELITE。

These three products were used by both companies as CLEAN LABEL starch and were prepared thermally after acid impregnation.

Exemplary formulation

TABLE 19

Application method

Weighing the required oyster juice, sealing the container with a plastic film, and soaking in boiling water for 10 minutes;

-preparing a starch slurry of 20% and mixing well;

weighing the rest materials and water, adding oyster juice and stirring uniformly;

heating the mixture to 80-90 ℃ using a 300W induction cooker, then slowly adding the starch slurry and stirring to prevent starch clumping;

heating to slightly boil the mixture, adjusting the power of the electromagnetic oven to 120W, covering the cover, preserving the heat for 30 minutes, and uncovering and stirring once every 2 minutes to prevent the pot from sticking;

after the heat preservation is finished, subpackaging into sterilized bottles, and accurately weighing 260g of each bottle;

the samples were stored at room temperature (25 ℃) and 50℃respectively, and stability was observed.

Test method

Texture analyzer

Reference document: an SMS texture analyzer is provided which,

the texture analyzer can digitally express the physical properties of the sample, and is an accurate sensory quantification. It is a measuring instrument for quality control of various foods.

Parameters (parameters)：

-a probe: A/BE-d35

-mode: compression mode

-speed: 1.00mm/s;

-a target mode: distance of

Distance: 50.00mm;

viscometer RVA

Brookfield DV2TRVTJ type 0

Parameters (parameters)：

-a main shaft: #5

-rotational speed: 50rpm

Full scale range: 8000cp

Rotation time: 2min

Sample temperature: 23 ℃ -24 ℃ (room temperature)

-container/quantity: glass beaker/50 mL

Sensory characteristics

Sensory characterization was used to evaluate the properties of starch and oyster sauce, including color, reflow and physical feel.

Table 20

Recombination

Results

Brookfield viscosity

The results of measurements of Brookfield viscosity and starch paste stability (viscosity measurement of 6% dry matter after 60 minutes at 95 ℃) are shown in FIG. 10.

Regarding the change in viscosity and stability of the starch paste, all starches were identical, stable during cooking for 1 hour, and the viscosity increased with cooking.

Freeze thawing stability

The results are shown in FIG. 11 below.

It appears that3010 is most stable to freeze-thaw cycles and other starches perform quite well.

Damage analysis

Texture and consistency measurements were performed at 25 ℃ (room temperature).

The results are shown in fig. 12 (hardness measurement) and fig. 13 (consistency measurement).

The hardness and consistency of oyster sauce can be evaluated numerically by using a texture analyzer. As can be seen from fig. 12 and 13, at 25 c, from 1 week to 4 weeks,CR3010 had the highest hardness and consistency among all groups, followed by tests 034 and 035 and FC20 starches according to the present invention.0100 is the lowest hardness and consistency. Test 036 stability and +.>ELITE approaches.

Stability of viscosity over time

The results are shown in FIG. 14 below.

Regarding the viscosity of oyster sauce at room temperature, the viscosities of test 035 and test 034 were close to the viscosity of CR3010, the others were slightly lower, including0100。

In summary, all products according to the invention perform at least as well as chemically modified starches in this application and as well as or better than commercial products.

Example 6: preparation of thermally modified starch from pea starch

Preparation of milk-based

N735 pea starch was added to a 1000mL beaker and then suspended in deionized water to bring the total dry Matter (MS) to 36.5% (weight percent). Sodium citrate and citric acid were added directly to the powdered starch milk to give a pH of 4.

The suspension was filtered through a sintering machine with a porosity of 3.

Dried on a Retsch dryer at 60 ℃ to an equilibrium moisture content of around 13%.

Heat treatment of

40g of the sample was weighed and placed in an aluminum pan of a METTER LJ16 balance (moisture measuring balance).

The aluminum pan was placed in a memmerert vented oven previously heated to 170 ℃. Once the sample cup is placed, the timer is started. Depending on the reaction kinetics chosen, in this example, the pans are removed after 45 minutes, 1 hour and 2 hours of heat treatment.

Washing and pH adjustment of the reacted product by re-suspension

Resuspending the sample with an MS value of 36.5% in deionized water,

adjusting the pH to between 5.5 and 6 with NaOH,

filtering by a sintering machine with a porosity of 3,

the filter cake was dried overnight in a fume hood at room temperature,

grinding (IKA) to break up the powder and homogenize the sample.

Results

Physicochemical measurements

-moisture content

pH value

Conductivity (μS)

-chromaticity

The formulation is shown in table 21 below:

table 21

The pH value of the washed product is between 5 and 6.5, and the conductivity is between 95 and 111 mu S.

Chromaticity Yie (yellowness) is between 7.87 and 26.48. In contrast, the Yie value of the natural pea base was 5.82.

RVA4800 viscosity determination of Water washed products at 140 ℃

The results are shown in FIG. 15 below.

A control group was added: sold by applicant companyLI4000 crosslinked pea starch with a crosslinking rate expressed as immobilized phosphorus of up to 0.4%.

Treatment of the impregnated pea starch at pH 4 in a citric acid/citric acid medium at 170 ℃ appears to result in a change in the bursting temperature of the starch granules at the peak of viscosity. FIG. 16 shows the measurement of the burst peak temperature between 2 minutes and 17 minutes, it being observed that after 2 hours of reaction at 170℃the maximum temperature of the product formed is 140℃corresponding toLI4000 chemically modified pea starch.

Sedimentation test

The results are shown in the following table.

Table 23

After 45 minutes of reaction, a very resistant product was obtained.

The results of waxy corn starch base of example 1 are discussed.

It can be seen that the pea starch base is very sensitive to heat treatment and reacts faster than waxy corn starch because the sedimentation volume of pea starch is lower than waxy corn starch during the same heat treatment time. Furthermore, the unimpregnated pea starch also reacts to the heat treatment, since after 2 reactions we have obtained a product with a sedimentation volume of 50. Thus, impregnation with citric acid buffer increases the conversion rate and limits the color.

Determination of citrate

The results are shown in Table 24 below:

table 24

Note that the free citrate content of 0.16% in the pea starch base refers to the citrate content that is impregnated in the starch and will be used for the heat treatment reaction.

The fixed citrate content of the pea starch base material heat treatment modified starch of the invention is 0.11-0.13% after the reaction at 170 ℃.

Example 7: the sedimentation, colour and viscosity values of the starches thermally modified according to the invention are the same as those of the same classes Comparison of commercial products

The following table lists tests 011A, 011B and 011E in example 1 and tests 071GL and Taley (Tate) in example 3&Lyle) company sellsPLUS、ELITE and->Results of the ESSENTIAL comparison.

The process of the present invention makes it possible to develop a range of products, some of which perform equivalent or even better than commercial products.

Claims

1. The heat modified starch produced by the acid method is characterized in that the free citrate content of the starch is lower than 0.05 percent, and the fixed citrate content is between 0.05 and 0.15 percent.

2. The thermally modified starch of claim 1, wherein the starch has:

-and/or the sediment volume is between 20mL-65mL, preferably between 25mL-40 mL.

3. Thermally modified starch according to claim 1 or 2, characterized in that the colour (L-value) of the starch is between 90-98, preferably between 94-98, and/or the colour (Yie value) of the starch is between 6-25, preferably between 6-15, more preferably between 6-9.

4. A thermally modified starch according to any one of claims 1 to 3, wherein the plant source of the starch is selected from the group consisting of corn, waxy corn, starch corn, wheat, waxy wheat, peas, pea seeds, peas, peanuts and peanuts, waxy wheat, peas, broad beans, potatoes, waxy potatoes, tapioca, waxy tapioca, rice, konjak, alone or in combination, especially waxy corn and pea starch.

5. Process for the preparation of a thermally modified starch according to any of the preceding claims, characterized in that it comprises the following steps:

(iii) The mixture is stable for at least 30 minutes,

(iv) Drying until the equilibrium moisture content is not more than 13%,

(v) Heated to at least 160 c, preferably between 170 c and 210 c,

6. The process according to claim 5, wherein the vegetable source of starch is selected from the group consisting of corn, waxy corn, starch, wheat, waxy wheat, pea, broad bean, potato, waxy potato, tapioca, waxy tapioca, rice, konjak, especially waxy corn, used alone or in combination.

7. Use of the thermally modified starch of any one of claims 1 to 4 or producible according to any one of claims 5 and 6 as a thickener or texturizing agent in food applications.

8. Use according to claim 7 as a thickener in sauce applications, in particular in oyster sauce.