Process for producing a heat-modified starch

Description

[0001] The invention relates to the production of thermally modified starch, starch whose viscosity is stabilized following this heat treatment. Such thermally modified starches then find use as texturizing and thickening agents in numerous food applications, in particular in soups, sauces, in desserts such as yogurts, stirred fermented milks, thermized yogurts, dessert creams, but also drinks, ready meals, meat or fish-based preparations, such as surimi.

[0002] The invention also relates to the use of these thermally modified starches, in association with dextrins, as a coating agent for the preparation of transparent coating of vegetables (potato fries), meat products or even doughs for pizzas, doughnuts or pie bases, snacks, croquettes, cereals or breading agents. Background to the invention

[0003] Biochemically synthesized, a source of carbohydrates, starch is one of the most widespread organic materials in the plant world, where it constitutes the nutritional reserve of organisms.

[0004] Starches have always been used in the food industry, not only as a nutritional ingredient but also for their technological properties, as a thickening, binding, stabilizing or gelling agent.

[0005] For example, native starches are used in preparations requiring cooking. Corn starch, in particular, is the basis of "custard powders."

[0006] As it is rich in amylose, it retrogrades and therefore gels strongly. It allows for firm flans after baking and cooling. It is also suitable for pastry creams.

[0007] But these cannot be used in pastries intended for freezing because, when defrosting, the phenomenon of syneresis, which results in the expulsion of water, destroys the texture of the cream.

[0008] Thus, in its native state, starch is of limited application due to syneresis, but also due to: its low resistance to shear stresses and heat treatments, its low processability and its low solubility in common organic solvents.

[0009] Therefore, to meet today's demanding technological needs, the properties of starch must be optimized by various so-called "modification" methods.

[0010] These main modifications then aim to adapt the starch to the technological constraints resulting from cooking, but also from freezing / thawing, canning or sterilization, and to make it compatible with modern food (microwaves, instant preparations, "high temperatures"...).

[0011] Starch modification then aims to correct one or some of the defects mentioned above, thus improving its versatility and satisfying consumer demand.

[0012] Starch modification techniques have been broadly classified into four categories: physical, chemical, enzymatic and genetic, with the aim of producing various derivatives with optimized physicochemical properties.

[0013] Chemical and physical modifications are the most commonly implemented.

[0014] Chemical processing involves introducing functional groups into starch, which significantly alters its physicochemical properties. Such modifications of native granular starches profoundly alter gelatinization, sticking, and retrogradation behavior.

[0015] Typically, these modifications are achieved by chemical derivatization, such as esterification, etherification, crosslinking, or grafting.

[0016] However, chemical modifications are less sought after by consumers in food applications (also for environmental reasons), even though some modifications are considered safe.

[0017] Various physical modifications are therefore proposed, for example: Heat Moisture Treatment (HMT), which involves treating starch at controlled humidity levels (22-27%) and at high temperatures for 16 hours to alter the structure and physicochemical properties of the starch; Annealing, which involves treating starch with excess water at temperatures below the gelatinization temperature to approach the glass transition temperature; High Pressure Processing (HPP), which involves hydrating the amorphous regions of the starch granule, leading to distortion of the crystalline portions of the granule and promoting the accessibility of said crystalline regions to water; glow discharge plasma treatment, which generates, at room temperature, high-energy electrons and other highly active species.When applied to starch, these active species excite the chemical groups of the starch and cause significant crosslinking of the macromolecules; osmotic pressure treatment (OPT), carried out in the presence of high salt solutions. The starch is suspended in sodium sulfate to produce a uniform suspension.

[0018] The starch changes from type B to type A after treatment, thus acquiring a gelatinization temperature that increases significantly; treatment by "thermal inhibition". In general, thermal inhibition means the dehydration of a starch until it reaches an anhydrous or substantially anhydrous state (i.e. < 1% humidity), then a heat treatment at more than 100°C for a period of time sufficient to "inhibit" the starch, in this case to give it crosslinked starch properties. It is also necessary to place the starch in pH conditions that are at least neutral to preferably alkaline before proceeding with the advanced dehydration step.

[0019] An alternative treatment by "thermal inhibition" has been proposed in the solvent phase, which consists of heating a non-pregelatinized granular starch in an alcoholic medium, in the presence of a base and salts, at a temperature of 120° to 200°C, for 5 minutes to 2 hours.

[0020] In any case, the thermal inhibition process then leads to obtaining a starch paste with properties of increased resistance to viscosity breakage, and a non-cohesive texture.

[0021] The technical field to which the invention relates is that of the treatment by thermal inhibition of starch, without hydro-alcoholic solvent.

[0022] In this particular technical field, we can cite more particularly US 6,221,420 which describes a thermally inhibited starch, obtained by dehydration then heat treatment.

[0023] The main steps are: the dehydration of the starch to a water content of less than 1% carried out at a temperature between 100 and 125°C, then the heat treatment of the dry starch thus obtained, at approximately 140°C, in a reaction fluidized bed, for a period of around 20 hours.

[0024] Preferably, before the starch dehydration step, it is recommended to carry out a starch alkalization step, making it possible to bring the pH of the starch suspension to a value between 7 and 10, preferably between 8 and 10.

[0025] At this stage, before the actual dehydration step which precedes the inhibition step, the water content of the starch (as exemplified) is then between 8 and 10%.

[0026] US 2001 / 0017133 describes a similar process, in which the starch is also dehydrated below 125°C before the inhibition process is started (at a temperature of more than 100°C, preferably between 120 and 180°C, more preferably between 140 and 160°C) for a period of up to 20 hours, preferably between 3 and 4 hours 30 minutes.

[0027] Before the dehydration step, the conventional alkalization step results in a starch suspension having a pH value of between 7.5 and 11.2, preferably between 8 and 9.5%, and a water content of between 2 and 15%.

[0028] A variant has been proposed in patent application WO 2014 / 042537, a variant which relates to heating an alkaline starch to temperatures between 140 and 190°C, ensuring that the inhibition process is initiated and carried out in the presence of sufficient water, i.e. more than 1% water.

[0029] In other words, this process recommends thermally inhibiting a previously alkalized starch without carrying out a dehydration step.

[0030] The starch preparation or starch is thus brought to a pH between 9.1 and 11.2, preferably to a value of the order of 10, and the humidity is adjusted between 2 and 22%, preferably between 5 and 10%.

[0031] Thermal inhibition is then carried out directly on this powder or starch, at a temperature between 140 and 190°C, preferably between 140 and 180°C, for a period of 30 minutes.

[0032] From all of the above, it can be seen that the thermal inhibition processes used to stabilize the viscosity of starches involve processes that require: the implementation of long treatment times, i.e. up to 20 hours, and the control of the water content of the starches to be treated, depending on the processes proposed in the state of the art, whether at values ​​of less than 1% or on the contrary between 2 and 22%.

[0033] There therefore remains a need for an original process for inhibiting starch, allowing the reaction time to be further reduced, and without it being necessary to control the water content of the starch to be "thermally inhibited". Description of the invention

[0034] Thus, the invention relates to a method for producing a thermally modified starch from a starch milk comprising the steps of: (i) preparing a starch milk having a dry matter content of between 30 and 40%, preferably between 35 and 37% by weight, (ii) adding a solution of an alkaline agent at a mass concentration of between 25 and 35%, preferably 30% so as to obtain a conductivity on the milk of between 4 and 7 mS / cm, (iii) ensuring a contact time of between 0.5 and 2 hours, (iv) filtering and drying the starch milk so that the conductivity of the dried starch resuspended at 20% dry matter is between 0.7 and 2.5 mS / cm, (v) heating said dried starch so as to bring it to a temperature of more than 180°C for a residence time of between 10 and 40 minutes, more preferably still between 15 and 35 minutes.

[0035] The starch to be used in the process of the invention may be of any origin, for example corn, waxy corn, amylocorn, wheat, waxy wheat, legumes such as peas and faba beans, potato, waxy potato, tapioca, waxy tapioca, rice, konjac, etc.

[0036] By "fava bean" is meant the group of annual plants of the species Vicia faba, belonging to the group of legumes of the family of Fabaceae, subfamily of Faboideae, tribe of Fabeae. Minor and Major varieties are distinguished. In the present invention, wild varieties and those obtained through genetic engineering or varietal selection are all excellent sources.

[0037] Preferably, corn starch will be chosen, more particularly waxy corn starch (with a high amylopectin content), potato starch, cassava, pea and field bean, as will be exemplified below.

[0038] The alkaline agent is preferably selected from the group consisting of sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate, and potassium hydroxide taken alone or in combination, more preferably still sodium carbonate.

[0039] The process according to the invention first requires the preparation of a starch milk with a dry matter content of between 30 and 40%, preferably between 35 and 37% by weight. As will be exemplified below, the dry matter content is set at 36.5% by weight.

[0040] The next step then consists of controlling the alkaline impregnation of the starch by adding the alkaline agent in the form of a solution at a mass concentration of between 25 and 35%, preferably 30% to obtain a conductivity, on the milk, of between 4 and 7 mS / cm.

[0041] The Applicant company has in fact found that: the addition of the alkaline agent, more particularly sodium carbonate directly onto the starch in the milk phase, makes it possible to achieve the desired high pH values ​​more effectively (between 10.2 and 10.8, preferably between 10.5 and 10.65) than spraying sodium carbonate onto the starch in the dry phase, in the sense that the addition in the milk phase allows better migration of the carbonate inside the starch granules compared to powder impregnation.

[0042] Furthermore, since powder phase impregnation requires adjusting the starch humidity to high values, part of the energy dedicated to the treatment of the product will therefore be lost to ensure the evaporation of residual water. the addition of the alkaline agent in solution from a solution at a mass concentration of between 25 and 35%, preferably 30% allows total dissolution of the alkaline agent in the starch milk, faster and finer pH adjustment, and avoids deposition of solid alkaline agent in the bottom of the reactor in the event of non-solubilization.

[0043] The most important technical effect here is to achieve a contact time of between 0.5 and 2 hours. Controlling the level of starch impregnation via conductivity measurements allows achieving the precision required for said high pH values.

[0044] The next step involves filtering and drying the starch milk so that the conductivity of the dried and resuspended starch at 20% dry matter is between 0.7 and 2.5 mS / cm.

[0045] The final step consists of heating the dry starch thus obtained so as to bring it to a temperature of more than 180°C for a residence time of between 10 and 40 minutes, more preferably between 15 and 35 minutes.

[0046] The temperature increase during step (v) of the dry starch obtained in step (iv) is preferably carried out in continuous turbojet type devices, for which the set temperature is fixed at more than 190°C, preferably between 195 and 240°C, and the delta T, defined as the temperature difference between the set temperature and the temperature of the product at the outlet of the reactor, is between 15 and 25°C.

[0047] The invention also relates to a thermally modified starch capable of being obtained according to the process described above.

[0048] The thermally modified starches according to the invention will be advantageously used, depending on their respective properties, as a thickening agent or texturizing agent in food applications, in particular in soups, sauces, drinks and prepared dishes and in desserts such as yogurts and stirred fermented milks and thermalized yogurts.

[0049] Due to their texturizing and gelling properties, they will also find numerous applications in fields as varied as: Acidic sauces and soups (pasteurized and sterilized), pasta sauces with meat juice, desserts such as yogurts, fruit preparations for yogurts, fermented stirred milks, thermized yogurts, puddings, mayonnaise and hot salad dressings, pie filling, fruit or meat filling or meat stable and sweet or savory, dinners (ready meals with short shelf life), pudding (dry cooking mix), baby food / infant formula, drinks, ready meals, preparations based on meat or fish, such as surimi. Animal feed preparation for transparent coating of vegetables, such as for example potato chips, meat products or even dough for pizzas, doughnuts or pie bases, snacks, croquettes, cereals or coating agents.

[0050] For this last application, these coatings (the technical term for "coatings") or transparent coatings (the technical term for "clearcoating") are designed to improve the preservation and crispness of fries after cooking.

[0051] Classic coating recipes include a plurality of more or less complex constituents, including: a flour, in particular rice a chemically modified starch of the highly crosslinked starch phosphate type (crosslinking agent: sodium trimetaphosphate) with a degree of substitution of 0.4% maximum a native starch a dextrin.

[0052] A recipe such as that proposed by the Applicant company in its patent EP 1,557,093 may be chosen, where these components, chemically modified starch, native starch and dextrin, are derived from legumes, in particular peas.

[0053] The invention will be better understood with the aid of the following examples, which are intended to be illustrative and not limiting. Materials and methods Conductivity measurement

[0054] The method implemented here is adapted from the European Pharmacopoeia - official edition in force - Conductivity (§ 2.2.38). Materials:

[0055] KNICK 703 electronic conductivity meter also equipped with its measuring cell and checked according to the operating procedure described in the relevant instruction manual. Operating mode:

[0056] A solution is prepared containing 20 g of sample in powder form and 80 g of distilled water with a resistivity greater than 500,000 ohms.cm.

[0057] The measurement is carried out at 20°C using the conductivity meter, referring to the operating procedure indicated in the device's user manual.

[0058] Values ​​are expressed in microSiemens / cm (µS / cm) or miliSiemens / cm (mS / cm). Measuring the viscosity of a starch suspension using the Rapid Viscosimeter Analyzer (RVA)

[0059] This measurement is carried out at acid pH (between 2.5 and 3.5) under specific concentration conditions and following an adapted temperature / time analysis profile.

[0060] Two buffer solutions are prepared: Stamp A

[0061] In a 1 liter beaker, containing 500 ml of demineralized water, add 91.0 g of citric acid monohydrate (purity > 99.5%) and homogenize, 33.0 g of sodium chloride (purity > 99.5%), and homogenize until completely dissolved, 300.0 g of 1N sodium hydroxide. Transfer to a 1 L graduated flask and fill with demineralized water to 1 L. Buffer B

[0062] 100 g of Buffer A are mixed with 334.0 g of demineralized water.

[0063] The product to be analyzed is prepared as follows: A mass of 1.37 g of the dry product to be analyzed thus obtained is introduced directly into the bowl of the viscometer, and Buffer B solution is introduced until a mass equal to 28.00 ± 0.01 g is obtained. Homogenization is carried out using the stirring blade of the Rapid Visco Analyzer (RVA-NewPort Scientific).

[0064] The time / temperature and speed analysis profile in the RVA is then carried out as follows: [Table 1] Time hh:mm:ss Temperature °C Rotation speed RPM 00:00:00 50 100 00:00:10 50 500 00:00:20 50 960 00:00:30 50 160 00:01:00 50 160 00:05:00 92 160 00:17:00 92 160 00:20:00 50 160 End of test: 00:20:05 (hh:mm:ss) Initial temperature: 50°C ± 0.5°C Data acquisition interval: 2 seconds Sensitivity: low

[0065] The measurement results are given in RVU (unit used to express the viscosity obtained on the RVA), knowing that 1 RVU unit = 12 cPoises (cP).

[0066] As a reminder, 1 cP = 1 mPa.s.

[0067] The results will therefore be presented in mPa.s.

[0068] The viscosity measurements will be taken “at peak”, i.e. the maximum viscosity value between 4 and 6 minutes, and “at drop”, i.e. the difference between the viscosity value at peak and that measured at 17 minutes. Examples Example 1 : Preparation of thermally modified starches « A » from waxy corn starch .

[0069] 1) The alkalization of waxy corn starch is carried out according to the following steps: Prepare a waxy corn starch milk at 36.5% by weight of dry matter (DM) Prepare a sodium carbonate solution at 30% mass concentration and heat to around 40-50°C to promote the dissolution of the carbonate; Add the sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm; Ensure a contact time of 0.5h; Filter and dry the starch so that the final conductivity on the powder resuspended at 20% by weight of DM is 1.9 mS / cm. 2) Heat treatment

[0070] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 200°C and configured to subject the product to a residence time of 20 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 17°C.

[0071] Process parameters [Table 2] Exp Conductivity on product after impregnation returned to 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) A 1,9 11,8 17 200 20

[0072] RVA viscosity measurements are performed and are presented in the table below. Results

[0073] [Table 3] Exp RVA Peak (mPa.s) RVA Drop (mPa.s) A 530 93 Example 2 : Preparation of thermally modified starches “C” from waxy corn starch .

[0074] 1) The alkalization of waxy corn starch is carried out according to the following steps: Prepare a waxy corn starch milk at 36.5% by weight of dry matter (DM) Prepare a sodium carbonate solution at 30% mass concentration and heat to around 40-50°C to promote the dissolution of the carbonate; Add the sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm; Ensure a contact time of 0.5h; Filter and dry the starch so that the final conductivity on the powder resuspended at 20% by weight of DM is 1.4 mS / cm 2) Heat treatment

[0075] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 200°C and configured to subject the product to a residence time of 25 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 23°C. Process parameters

[0076] [Table 4] Exp Conductivity on product after impregnation returned to 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) C 1,4 11,6 23 200 25

[0077] RVA viscosity measurements are performed and are presented in the table below. Results

[0078] [Table 5] Exp RVA Peak (mPa.s) RVA Drop (mPa.s) C 914 -70 Example 3: Preparation of thermally modified starches “G” from pea starch .

[0079] 1) The alkalization of pea starch is carried out according to the following steps: Prepare a pea starch milk at 33% by weight of dry matter (DM) Prepare a sodium carbonate solution at 30% mass concentration and heat to around 40-50°C to promote the dissolution of the carbonate; Add the sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 6 mS / cm; Ensure a contact time of 0.5 hours; Filter and dry the starch so that the final conductivity on the powder resuspended at 20% by weight of DM is 0.9 mS / cm 2) Heat treatment

[0080] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 200°C and configured to subject the product to a residence time of 20 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 20°C. Process parameters

[0081] [Table 6] Exp Conductivity on product after impregnation returned to 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) G 0,9 10,5 20 200 20

[0082] RVA viscosity measurements are performed and are presented in the table below. Results

[0083] [Table 7] Exp RVA Peak (mPa.s) RVA Drop (mPa.s) G 60 -132 Example 4: Preparation of thermally modified starches “H-1” and “H-2” from faba bean starch.

[0084] 1) The alkalization of fava bean starch is carried out according to the following steps: Prepare a fava bean starch milk at 33% by weight of dry matter (DM); Prepare a sodium carbonate solution at 30% mass concentration and heat to around 40-50°C to promote the dissolution of the carbonate; Add the sodium carbonate solution at 30% by weight of mass concentration to the starch milk, so as to obtain a conductivity on the milk of between 4 and 6 mS / cm; Ensure a contact time of 0.5h; Filter and dry the starch so that the final conductivity on the powder resuspended at 20% by weight of DM is between 1.5 and 2mS 2) Heat treatment

[0085] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 210°C and configured to subject the product to a residence time of the order of 13 - 25 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 21-25°C. Process parameters

[0086] [Table 8] Exp Conductivity on product after impregnation resuspended at 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) Fava bean starch base 0,133 8 0 0 0 H-1 1,9 14 24 210 13 H-2 1,9 14 23.5 210 25

[0087] RVA viscosity measurements are performed and are presented in the table below. Results :

[0088] [Table 9] Tests RVA Drop (mPa.s) RVA Peak (mPa.s) Fava bean starch base 82 323 H-1 -79 229 H-2 -47 45

[0089] Thermally modified starches prepared from H-1 and H-2 faba bean starch exhibit improved stability during the use process compared to native starch: fewer viscosity and retrogradation phenomena are observed when using these thermally modified starches. Example 5: Preparation of thermally modified starches “I-1” and “I-2” » from potato starch

[0090] 1) The alkalization of potato starch is carried out according to the following steps: Prepare a potato starch milk at 36.5% by weight of dry matter (DM) Prepare a sodium carbonate solution at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm. Ensure a contact time of 0.5h Filter and dry the potato starch so that the final conductivity on the powder resuspended at 20% by weight of DM is 1.1mS 2) Heat treatment

[0091] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 210°C and configured to subject the product to a residence time of the order of 30 to 48 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 19-21°C. Process parameters

[0092] [Table 10] Exp Conductivity on product after impregnation resuspended at 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) Potato starch base 0.,15 16,8 0 0 0 I-1 1,1 13 21 210 30 I-2 1,1 13 19,5 210 48

[0093] RVA viscosity measurements are performed and are presented in the table below. Results :

[0094] [Table 11] Tests RVA Drop (mPa.s) RVA Peak (mPa.s) Potato starch base 545 887 I-1 -270 583 I-2 -400 167

[0095] Thermally modified starches prepared from I-1 and I-2 starch exhibit improved stability during the use process compared to native potato starch: less viscosity gain and retrogradation phenomena are observed when using these thermally modified starches. Example 6: Preparation of thermally modified starches “J-1” and “J-2” from cassava starch

[0096] 1) The alkalization of cassava starch is carried out according to the following steps: Prepare a suspension of cassava starch at 36.5% by weight of dry matter (DM) Prepare a solution of sodium carbonate at 30% mass concentration so as to obtain a conductivity on the milk of between 4 and 7 mS / cm. Ensure a contact time of 0.5h Filter and dry the cassava starch so that the final conductivity on the powder resuspended at 20% by weight of DM is 1mS 2) Heat treatment

[0097] The product thus obtained is heat treated in continuous turbojets of the VOMM type in series, whose set temperature is fixed at 210°C and configured to subject the product to a residence time of the order of 20 to 35 min, and in such a way that the temperature difference between the set point and the temperature of the product at the outlet of the reactor, which is called Delta T, is of a value of the order of 22-27°C. Process parameters

[0098] [Table 12] Exp Conductivity on product after impregnation resuspended at 20% by weight MS in mS / cm Product humidity before heat treatment in % Delta T Set temperature Stay time (min) Cassava starch base 0,10 14 0 0 0 J-1 1 11 27 210 20 J-2 1 11 22 210 35

[0099] RVA viscosity measurements are performed and are presented in the table below. Results :

[0100] [Table 14] Tests RVA Drop (mPa.s) RVA Peak (mPa.s) Cassava starch base 470 610 J-1 10 350 J-2 -195 95

[0101] Thermally modified starches prepared from J-1 and J-2 starch exhibit improved stability during the use process compared to native cassava starch: fewer viscosity and retrogradation phenomena are observed when using these thermally modified starches. Example 7: Use of thermally modified starches “G” and “I-2” in transparent coating (term “clearcoating”) of potato fries.

[0102] To obtain crispy and tasty products that stay warm for longer, the products are coated with a starch-based recipe.

[0103] The formula tested is as follows: [Table 15] Ingredients Quantity (%) Starch tested 61,1 TACKIDEX ®< C760 (pea dextrin) marketed by the Applicant company 12 Rice flour ML100 (Rickmers) 20 NaCl 5 Sodium bicarbonate 0,9 Disodium pyrophosphate 0,9 Xanthan gum F80 0.,1

[0104] In tested starch, it is understood: Thermally modified starch “I-2” according to example 5 Thermally modified starch “G” according to example 3 Chemically stabilized crosslinked pea starch CLEARAM ®< LI 4000 marketed by the Applicant company Native potato starch Di-Phosphate potato starch PERFECTAMYL ®< FFC from AVEBE Native pea starch N-735 marketed by the Applicant company Commercial thermally inhibited starch.

[0105] The clearcoating preparation process is as follows : Batter preparation Homogenization of powders Mix powder and water using a "kitchen aid" equipped with a K paddle, speed 1 for 10 min Dilution mass ratio (1 / 1.5) = 1 part powder and 1.5 parts water (temperature 6-8°C) Coating of fries Drying of blanched cut potatoes Coating and draining Excess batter is removed using a blower Frying 50 s at 180°C Draining Freezing 1 hour and storage at -18°C Final frying Frying 2 min 30 to 3 min 30 at 180°C

[0106] The evaluation of the different “clear-coated” fries is carried out by the following measures: 1) Pick-up

[0107] This measurement is part of the routine analyses carried out on this type of application. It consists of evaluating the amount of batter fixed around the potato after coating. The target value should be between 10 and 12%. 2) Viscosity measurement

[0108] This measurement is also part of routine analyses. It consists of measuring the batter's viscosity, as viscosity is directly related to pick-up. A thicker batter generally results in higher pick-up values.

[0109] This measurement is carried out using a T828 flow cup, diameter 4mm, capacity 100mL. The target value is around 54-55s. 3) Fat measurement

[0110] Since clear coating has a direct impact on the exchanges between the substrate and the oil, the measurements of fat and dry matter are an indicator of the performance of the clear coating. Two repetitions are carried out 4) Measurement of dry matter

[0111] This measurement is carried out using a Sartorius balance under atmospheric pressure (MA 40 moisture analyser device). 5 Sensory characterization

[0112] Sensory characterizations are subjective assessments and comments in terms of visual and texture (touch / mouth) were carried out with an internal panel, previously trained to evaluate the crispness of fries.

[0113] The results obtained show that replacing chemically stabilized crosslinked pea starch with thermally modified starch according to the invention results in a remarkably equivalent clear coating of fries.

Claims

1. A method for producing a heat-modified starch, comprising the steps consisting in: (i) preparing a starch milk having a solids content of between 30 and 40%, preferably between 35 and 37% by weight, (ii) adding a solution of an alkaline agent at a weight concentration of between 25 and 35%, preferably of 30% so as to obtain a conductivity on the milk of between 4 and 7 mS / cm, (iii) ensuring a contact time of between 0.5 and 2 hours, (iv) filtering and drying the starch milk such that the conductivity of the dried starch resuspended at 20% by weight of solids is between 0.7 and 2.5 mS / cm, (v) heating said dried starch so as to bring it to a temperature of more than 180°C for a residence time of between 10 and 40 minutes, even more preferentially between 15 and 35 minutes, the conductivity being mesured with a KNICK 703 electronic conductivity meter.

2. The method according to claim 1, characterized in that the origin of the starch is selected from the group consisting of corn, waxy corn, potato, cassava and leguminous plants such as pea and faba bean, more preferentially waxy corn, pea and faba bean.

3. The method according to claim 1, characterized in that the alkaline agent is preferentially selected from the group consisting of sodium hydroxide, sodium carbonate, tetrasodium pyrophosphate, ammonium orthophosphate, disodium orthophosphate, trisodium phosphate, calcium carbonate, calcium hydroxide, potassium carbonate, and potassium hydroxide, taken alone or in combination, and even more preferentially sodium carbonate.

4. The method according to claim 3, characterized in that the rise in temperature of the dry starch obtained in step (v) is carried out in devices of the continuous turbodryer type, for which the setpoint temperature is set at more than 190°C, preferably between 195 and 240°C, and the delta T, defined as the temperature difference between the setpoint temperature and the temperature of the product at the outlet of the dryer, is between 15 and 25°C.

5. A heat-modified starch obtainable by the method according to any of the preceding claims.

6. Use of a heat-modified starch produced by the method according to any one of claims 1 to 4, as a thickening agent or texturizing agent in food applications.

7. Use of a heat-modified starch according to claim 6, as a thickening agent or texturizing agent in soups, sauces, mayonnaises, in desserts such as yogurts, fruit preparations for yogurts, stirred fermented milks, thermized yogurts, dessert creams, beverages, ready meals, preparations based on meat or fish, such as surimi.

8. Use of a heat-modified starch produced by the method according to claim 6, as a glazing agent for preparing a transparent coating for vegetables, for example potato fries, meat products, or even pizza doughs, donuts or pie bases, snacks, croquettes, cereals or crumb-coating agents.