A process for treating cereal caryopses affected by the black-point phenomenon

Abstract

A process for treating cereal caryopses, in particular wheat caryopses, is described, the process comprising the steps of providing a mass of cereal caryopses comprising cereal caryopses affected by chromatic alterations due to the attack of microorganisms, exposing the cereal caryopses of said mass to at least one laser source, and subjecting said cereal caryopses whose surface layers are at least partially carbonized to a decortication treatment. The present invention also relates to a flour obtainable through the above-described process.

Description

[0001] A PROCESS FOR TREATING CEREAL CARYOPSES AFFECTED BY THE BLACK-POINT PHENOMENON

[0002] DESCRIPTION

[0003] Field of application

[0004] The present invention relates to the field of the food industry and, in particular, refers to the process for treating cereal caryopses, in particular wheat caryopses, more in particular caryopses of durum wheat (Triticum turgidum subsp. durum), and also to a flour obtained from said thereby treated cereal caryopses.

[0005] Prior art

[0006] Cereals (especially wheat, rice, corn, barley, oat, rye) are consumed all over the world as staple food, because they are a main carbohydrate source due to the high starch content contained in the endosperm, which is in the central part of the durum-wheat caryopsis and is the main constituent thereof.

[0007] With reference to Figure 1, the structure of the caryopsis, also known as “grain”, of durum wheat 101 is outlined. Examining the layers of durum-wheat caryopsis, the caryopsis bran is made of the following layers, from the outermost to the innermost: four (longitudinal, transverse, cross, and tube) cell layers which, together, constitute the pericarp 102 (3-6% by weight of the total weight of the caryopsis), then the integument 103, the nucellar layer (or hyaline layer) 104, and the aleurone 105, which together form the seed coating.

[0008] Externally, in the lower part of the durum-wheat caryopsis, there is the germ 107.

[0009] The inner part of the caryopsis consists of the endosperm 106.

[0010] The aleurone layer, constituting 5-7% by weight of the total weight of the caryopsis, consists of a large polygonal-cell layer in contact with the endosperm.

[0011] Semolina is the main product of the durum-wheat milling process, whose main purpose is to obtain an end product with a high degree of purity (sifted through plansifters). In particular, semolina is made of the innermost starchy parts of the caryopsis (endosperm) following the separation from the outermost parts of the caryopsis (namely the bran, constituting about 15% of the total content of caryopsis, and the germ, constituting about 3%) which are traditionally intended for animal feeding.

[0012] In this perspective, the modern industrial process for producing durum-wheat semolina aims at maximizing its efficiency of this separation through a series of multiple operations (cleaning, decortication, milling, sieving) to carry out the separation and the removal of bran from the parts of caryopsis endosperm which will constitute the final semolina.

[0013] The process of wheat treatment and processing normally comprises a series of predetermined and consecutive steps, as shown in Figure 2. The first step is pre-cleaning. Durum wheat reaches the mill by truck or train. Once the durum wheat has arrived, representative samples of the vehicle are inspected through product analyses. The analysis consists in verifying the salubrity of the durum wheat and the correspondence with the purchase specifications. The analyses comprise visual, olfactory, and instrumental controls. Visual analysis consists in searching for:

[0014] - wheat defects, such as black-point disease, germination, mealy, chalky, infested grains, grains attacked by bugs, Claviceps purpurea, etc.;

[0015] - extraneous seeds, such as vetch, corn, soybean, mustard, and other types of seeds;

[0016] - foreign bodies, such as stones, glass, wood, iron, etc.

[0017] The olfactory analysis verifies that the durum wheat is not moldy due to poor storage management.

[0018] Moreover, instrumental analysis is carried out, wherein the wheat is analyzed through instruments to assess its absolute weight, moisture, protein content, temperature, and hardness.

[0019] After the characterization of the durum wheat, the grain is received through mechanical transport means and, subsequently, it is treated through suction and sieving to remove the coarsest impurities that characterize this type of raw material, and it is then transferred into storage facilities.

[0020] The cleaning step follows, during which the grain is taken from the storage cells to be transferred through mechanical transport to suction and screening systems to remove all the light and coarse parts of the wheat. The wheat is then treated through the optical sorting machine which, through vision systems, distinguishes healthy grains from defective grains and, through air jets, separates them from the mass, and the seeds are then discarded.

[0021] The cleaned grain is finally treated through humidification systems and tempered in the storage cells.

[0022] Specifically, the typical processes for producing semolina and cereal flours involve a treatment of dampening of the caryopses, in particular of durum wheat, known as tempering, wherein the durum-wheat caryopses are dampened externally with water for a predetermined time, for example between 5 hours and 9 hours, so as to increase the moisture content thereof and, as a consequence, to soften them and facilitate carrying out the subsequent steps of decortication, abrasion, and also milling (purifiers).

[0023] Lastly, the conventional processes for producing cereal semolinas comprise a step of removal of the outer caryopsis layers through operations of friction and abrasion (decortication), followed by a step of milling the caryopsis fractions generally consisting of the endosperm only, which are obtained in the preceding step.

[0024] Specifically, the previously tempered wheat is taken from the storage cells and transferred through mechanical transport to the decorticators. The latter abrade the wheat grains through abrasive springs and remove the outer grain parts constituting the bran.

[0025] Finally, after the grain has been cleaned of all impurities, tempered and freed from most of the bran, it is sent to milling. The milling consists of three processing steps, one active and two passive. The active step consists in opening the grain and gradually separating the endosperm from the residual bran parts. This step is called rolling, which essentially consists in an operation of milling through suitably grooved or smooth rolls. The two following steps are the sifting and the cleaning of the semolina thereby obtained, the first being a sifting through plansifters and the second being carried out through purifiers. These processing steps, suitably combined with each other, constitute milling, whose purpose is also to separate the granulated endosperm (semolina) from the outer caryopsis integuments (middlings or “farinaccio” and coarse bran or “tritello”) .

[0026] Cereal caryopses and, among these, the durum-wheat caryopses, are not exempt from fungal attacks, which can already occur during cultivation. This problem is very common and in durum wheat, in particular, it results in a phenomenon called “black-point disease”, which gives the caryopsis a black or reddish-brown coloration following fungal attacks.

[0027] The black-point disease is a disease that affects caryopses, causing a black or reddish-brown mycelial spot to appear on the bearded end, in the scutellum area, or along the groove. Black-point disease is commonly caused by the fungal species Altemaria altemata, Bipolaris sorokiniana or Cochliobolus sativus, Fusarium proliferatum, Cladosporium cladosporioid.es, Pyrenophora tritici-repentis or Drechslera tritici-repentis.

[0028] The various mycetes are ubiquitous and characterized by weak parasitic abilities, being able to develop only on parts weakened by attacks from primary pathogens and aphids. The infections usually occur after ear emergence, are favored by frequent rainfall and high environmental humidity, especially in crops with high planting density and lodged plants.

[0029] The black-point phenomenon may be localized only in some areas of the outer surface of the caryopsis, typically at the ends and / or in the longitudinal groove thereof, or even on a significant part of its surface, with a potential partial aggression of the underlying layers and of the endosperm too.

[0030] This type of fungal attacks does not causes quantitative production losses but may significantly affect the technology quality, especially of the hard grains, since the semolina obtained from caryopses affected by blackpoint disease have necrotic residuals that alter the uniform coloration of pasta, thereby obtained.

[0031] Protection is obtained through agronomic actions intended to limit the causes of development of infections. Said actions are the adoption of optimum planting density suitable for reducing lodging, balanced fertilization, and the adoption of measures of protection against attacks by other fungal diseases and aphids.

[0032] However, said protection actions are not sufficient to prevent the blackpoint phenomenon.

[0033] Therefore, although through the most recent decortication techniques it is possible to remove, as already mentioned, a significant part of the outer caryopsis layers, part of them is still held back together with the endosperm and sent to the next milling steps, thereby causing an undesired coloration of pasta, and also potentially contributing to alterations of the product from the nutritional point of view.

[0034] In particular, when the wheat campaign provides durum wheat affected by black-point disease, which is a defect present in a varying percentage from 2 to 30%, the whole milling process cannot guarantee the desired quality of durum-wheat semolina, since the characteristic black discoloration deriving from the black-point disease compromise the appearance of the end product durum-wheat dried pasta.

[0035] As a consequence, during the step of durum-wheat cleaning, the mill must discard this black-point-disease-affected wheat through a massive use of optical sorting machines. This results in yield losses of semolina extraction that can be quantified as a loss of 0.75% of the overall yield for each percentage point of black-point-disease-affected wheat present. In the wheat campaigns where the black-point-disease defect is not extended to the whole available durum wheat, the firms are still forced to buy wheat exempt from or with the lowest level of defectiveness at a higher purchase price.

[0036] The publication “Changes in Particle Size Distribution of Bran and Flour from Vacuum Impregnated and Infrared Heated Wheat Grain” by Rydzac et al., 2017, concerns a process for the optimized conditioning of wheat grains, wherein the raw material undergoes a conditioning or vacuum impregnation phase, a heating phase using infrared rays, and a final grinding phase.

[0037] This document is silent about the treatment of caryopses affected by black-point disease.

[0038] US6887509B2 discloses the treatment of wheat grains by means of radiant heat, for example by means of an infrared heating device. In the final stage of grinding, the outer layers of the bran are separated from the endosperm.

[0039] This document is silent about the treatment of caryopses affected by black-point disease, as well.

[0040] Similar processes are disclosed in RU2324370C1, US4555409A, which relates to corn, CN107397136 and KR20110124049, which relates to generic cereals.

[0041] CN1 11149973 discloses the production of low-bacteria wheat flour by sterilizing wheat caryopses with ultraviolet radiation after a secondary peeling step. After the sterilization step, wheat is directly ground.

[0042] All these prior art documents are completely silent about the treatment of caryopses affected by black-point disease.

[0043] In other words, there is an urgent need for providing a technique to overcome the technical problems described above in relation to the undesired black-point phenomenon and that is compatible with the needs of an industrial production.

[0044] Ultimately, the technical problem underlying the present invention was to provide a process for treating cereal caryopses, in particular wheat caryopses, more in particular caryopses of durum wheat (Triticum turgidum subsp. Durum), affected by a fungal colonization that resulted in black-point disease, thereby obtaining a flour whose coloration is not significantly altered by the dark residuals characteristic of this phenomenon and, consistently, obtaining a flour in which the alterations of the product from the nutritional point of view are minimized.

[0045] Summary of the invention

[0046] Said technical problem has been solved, according to the invention, through a process for treating cereal caryopses involving the following steps:

[0047] a) providing a mass of cereal caryopses comprising cereal caryopses affected by chromatic alterations due to the attack of microorganisms, said microorganisms preferably being fungi and said caryopses being affected by the black-point phenomenon;

[0048] b) exposing the cereal caryopses of said mass to at least one infrared- or ultraviolet-ray source, irradiating said mass with at least one laser beam coming from said at least one source for a prefixed time until cereal caryopses, whose surface layers are at least partially carbonized, are obtained;

[0049] c) subjecting said cereal caryopses whose surface layers are at least partially carbonized to a decortication treatment, thus removing said at least partially carbonized surface layers and obtaining decorticated cereal caryopses.

[0050] According to the present invention, the term “black-point disease” means a chromatic alteration of the cereal grain or caryopsis, caused by a microorganism attack, said means microorganisms being specifically fungi, and wherein said attack causes a typical brownish, reddish, and / or black coloration, typically black.

[0051] In particular, said microorganisms may belong to fungal species selected in the group comprising Altemaria altemata, Bipolaris sorokiniana or Cochliobolus sativus, Fusarium proliferatum, Cladosporium cladosporioid.es, Pyrenophora tritici-repentis, or Drechslera tritici-repentis. As will be seen in relation to the detailed description, the irradiating step b) causes the combustion and subsequent carbonization of the surface layers of the caryopsis, in particular a partial carbonization of the latter takes place, grain by grain, depending on the duration of said prefixed time and on the caryopsis surface area exposed to said infrared- or ultraviolet-ray source.

[0052] Thanks to the treatment the caryopses underwent in the preceding irradiating step b) and during the subsequent step c), caryopsis decortication occurs in a simple and more efficient way compared to a conventional decortication treatment which, with reference to the prior art, typically occurs after a preliminary dampening.

[0053] In particular, according to a preferred embodiment of the invention, the cereal caryopses of the mass provided during step a) or treated during the process of the invention do not undergo any preliminary dampening treatment or dampening post-treatment.

[0054] Therefore, advantageously and during the irradiating step b), through the process of the invention it is possible to at least partially carbonize the surface layers of the caryopses and thus to destroy the area affected by black-point disease. Hence, the surface layers, that are thereby at least partially carbonized, can be better removed during the subsequent decortication step c).

[0055] Moreover, from a general point of view of the process for treating cereal caryopses and of the overall process of production of cereal flours, the capability of being able to deal with the black-point-disease defect, especially of the durum wheat, internally is a huge economic and competitive advantage for the firms of the field, thereby transforming a problem into an opportunity.

[0056] According to a preferred embodiment, during step b) the cereal caryopses of said mass are moved along a treatment path, along which said infrared- or ultraviolet-ray source is placed in a fixed way.

[0057] Preferably, during step b), the cereal caryopses of said mass are distributed on a spreading surface having an extension that is transverse to the direction of said at least one laser beam coming from said at least one infrared- or ultraviolet-ray source.

[0058] More preferably, said spreading surface is a conveyor belt or, alternatively, a vibrating belt or screen.

[0059] Advantageously, the use of a vibrating belt or screen enables the continuous stirring of the caryopses that are moving on it, thereby exposing the whole outer surface of the caryopses to the laser source and minimizing the risk that part of the areas affected by chromatic alterations, specifically to black-point disease, are not thermally destroyed and carbonized.

[0060] In any case, the process of the invention is particularly effective even in the absence of a continuous stirring of the caryopses, since the radiation is capable of passing through the black-point-free part of the grain since it is transparent to the selected light beam. Thereby, the radiation preferentially hits the parts affected by black-point disease and possibly placed on the grain side that is not directly exposed to the source. Said phenomenon was observed during the experimental tests reported below, and, thus, in particular in relation to the irradiating step b) carried out through infrared rays and by treating durum-wheat caryopses.

[0061] According to an alternative embodiment, during the irradiating step b) said at least one laser beam coming from said at least one infrared- or ultraviolet-ray source follows a scanning path so as to transversally hit the whole spreading surface.

[0062] According to a preferred embodiment, during the irradiating step b) the mass of cereal caryopses is hit by a jet of air or of inert gas and / or in the chamber, where said mass is stored, a suction mouth, through which the gaseous atmosphere above the mass is sucked, is present.

[0063] Advantageously, thanks to the latter embodiment, it is possible to remove the possible flue gases formed due to the partial carbonization of the cereal caryopses.

[0064] As a matter of fact, flue gas might cause an absorption of the radiation of the at least one laser beam, thereby modifying the process conditions and causing the treatment to be less effective.

[0065] Preferably, the moisture content of the cereal caryopses of the mass provided during step a) is between 8% and 35% by weight, more preferably between 8% and 17% by weight, of the total weight of the cereal caryopses.

[0066] According to an embodiment of the invention, the cereal caryopses of step a) are obtained following a preliminary tempering step, by increasing the moisture content of the cereal caryopses, preferably according to a variation of maximum moisture of 25% by weight, more preferably of 5% by weight.

[0067] In particular, the durum-wheat caryopses commonly have a moisture content between 8 and 13.5% by weight, and, through the above-mentioned preliminary tempering step, the moisture content can be increased up to a maximum of 35% by weight, preferably is between 8% and 17% by weight, of the total weight of the cereal caryopses.

[0068] According to an alternative embodiment of the invention, before the above-mentioned step a) the process for treating cereal caryopses comprises the following preliminary steps in the order indicated:

[0069] - subjecting a mass of cereal caryopses to a pre-cleaning or preliminary cleaning treatment, removing the coarsest impurities and / or the foreign bodies that are in said mass, preferably through suction and sieving; - subjecting said mass of cereal caryopses so obtained from the preceding step to a first cleaning treatment, during which the light and coarse parts of the wheat are removed through suction and screening means;

[0070] - subjecting said mass of cereal caryopses so obtained from the preceding step to a second cleaning treatment, during which an optical sorting machine using vision systems and air jets separates defective grains from said mass;

[0071] - optionally, carrying out a step of tempering the cereal caryopses of said mass, by increasing the moisture content of the cereal caryopses, preferably according to a variation of maximum moisture of 25% by weight, more preferably of 5% by weight.

[0072] In other words, during said tempering step the cereal caryopses are subjected to rehydration, by increasing the moisture content up to a maximum moisture content of 35% by weight, preferably up to a moisture content between 15 and 17% by weight.

[0073] Preferably, the cereal caryopses of the mass provided during step a) can be caryopses of wheat, rye, or barley caryopses.

[0074] More preferably, the cereal caryopses of the mass provided during step a) are wheat caryopses, even more preferably of soft wheat or durum wheat. According to an embodiment, the cereal caryopses of said mass are durum-wheat caryopses (Triticum turgidum var. durum, Desf.).

[0075] Preferably, during step b) the cereal caryopses of said mass are exposed to an infrared-ray source operating in the near infrared region, more preferably said infrared rays having a wavelength between 900 nm and 1100 nm, even more preferably between 960 nm and 985 nm..

[0076] Preferably, during step b) the cereal caryopses of said mass are exposed to an infrared-ray source, irradiating the mass with at least one infrared laser beam and said source being a continuous-wave infrared source (CW-IR laser).

[0077] Advantageously, as will be seen hereafter in connection with some preferred embodiments and with the examples, by exposing the cereal caryopses of the mass to an infrared-ray source it is possible to localize or anyway to concentrate the destruction of the tissues affected by the black-point phenomenon, namely that are affected by significant chromatic alterations and / or necrotic.

[0078] Indeed, since the tissues affected by the black-point phenomenon have a characteristic reddish-brown to black coloration, typically black, which is in any case considerably darker than the normal grain coloration and is localized in some specific areas of the grain, the areas affected by blackpoint disease absorb radiation more strongly, thereby making destruction and carbonization selective.

[0079] Once subjected to the decortication step c), the cereal caryopses so obtained are devoid of said surface layers, and the surface of the so-decorticated caryopses has drastically reduced blackened and / or carbonized areas, namely with a significantly reduced surface compared to the areas affected by the black-point phenomenon in the cereal caryopses of the original mass provided during step a) .

[0080] With reference to the examples, it was also observed that, in the context of the process of the invention and possibly after carrying out a preliminary step of tempering or rehydration preceding step a) of the present process, decortication of the caryopses occurs more efficiently compared to a conventional decortication treatment, that is in the absence of a laser treatment.

[0081] In particular, the decortication step c) may be carried out in a very efficient way in the absence of tempering or rehydration following the irradiating step b) and before the decortication step c).

[0082] Preferably, during the irradiating step b) said at least one laser beam is such that the mass of cereal caryopses is hit by it according to a spot size between 300 and 200000 gm, more preferably between 7000 and 13000 gm.

[0083] Preferably, during the irradiating step b) said at least one laser beam has a power between 100 and 1600 W, more preferably between 200 and 1300 W.

[0084] Preferably, during the irradiating step b) said prefixed time is between 40 ms and 10 s, more preferably between 60 ms and 1500 ms, even more preferably between 100 ms and 1000 ms.

[0085] Advantageously, as will be seen with reference to the detailed description and to the examples, when said mass is irradiated with at least one infrared laser beam, specifically with a continuous-wave infrared-ray source (CW-IR laser), which can be operated in a continuous or semi-continuous mode, and the prefixed time of step b) is controlled, selective carbonization of the outer surface of the caryopses is obtained, and a complete combustion thereof is prevented.

[0086] As a matter of fact, in the absence of a control of the energy density or fluence applied to the treated mass of cereal caryopses, the surface thereof absorbs an excessive amount of energy which results in excessive carbonization of the same, that is also surface parts not affected by chromatic alteration or black-point disease are carbonized.

[0087] Preferably, during the irradiating step b) the mass of cereal caryopses is subjected to an energy density or fluence between 60 J / cm2and 350 J / cm2, more preferably between 80 J / cm2and 350 J / cm2, even more preferably between 80 J / cm2and 240 J / cm2.

[0088] According to a first embodiment, during irradiating step b) the mass of cereal caryopses is subjected to an energy density or fluence between 60 J / cm2and 120 J / cm2.

[0089] According to an alternative embodiment, during the irradiating step b) the mass of cereal caryopses is subjected to an energy density or fluence between 120 J / cm2and 350 J / cm2.

[0090] Advantageously, by operating within the specified values of energy density or fluence it is possible to prevent that the treatment carried out during the irradiating step b) is inefficient or causes an excessive carbonization of the cereal caryopses.

[0091] Preferably, during the irradiating step b) the mass of cereal caryopses is subjected to a power density or irradiance between 80 W / cm2and 280 W / cm2, more preferably between 110 W / cm2and 230 W / cm2.

[0092] According to a preferred embodiment, during step b) the cereal caryopses of said mass are exposed to an infrared-ray source, irradiating the mass with at least one infrared laser beam and the source is used in a semi-continuous mode.

[0093] According to the present invention, the expression "in a quasi-continuous mode" refers to the fact that, during irradiation step b), the laser treatment is divided into a plurality of time intervals in which said at least one laser beam irradiates the mass, separated by respective pauses during which the mass of cereal kernels is not exposed to said at least one laser beam, the pulse power being lower than the maximum power allowed by said laser source.

[0094] In other words, during the irradiating step b) the laser treatment can be divided into at least two time intervals, preferably at least four or at least six time intervals, separated by respective pauses during which the mass of cereal caryopses is left to at least partially cool.

[0095] Advantageously, thanks to the latter embodiment, it is possible to administer to the mass of cereal caryopses the same energy density that would be administered without an interruption of the treatment as per the irradiating step b), but causing a smaller increase of the surface temperature of the caryopses. In other words, given the same energy density or fluence, it is possible to cause carbonization exclusively in the areas of the caryopsis surface that are most affected by chromatic alteration or black-point disease, namely - through this embodiment - an even more selective carbonization of the areas affected by black-point disease occurs.

[0096] According to a preferred embodiment, the process of the present invention comprises an optional step of tempering or rehydration which is carried out following the irradiating step b) and before the decortication step c).

[0097] In particular, said optional step of tempering or rehydration preceding the decortication step c) involves carrying out an operation of tempering the cereal caryopses whose surface layers are at least partially carbonized, so obtained from the irradiating step b), by increasing their moisture content, preferably according to a variation of maximum moisture of 10% by weight, more preferably of 5% by weight.

[0098] Advantageously, the optional tempering step preceding the decortication step c) is carried out in case the cereal caryopses treated during the irradiating step b) lose a considerable amount of moisture, especially in the outermost layers, due to the temperature increase.

[0099] Otherwise, in particular, the optional step of tempering is not carried out in case the cereal caryopses provided in step a) are obtained following a preliminary tempering step, thus increasing their moisture content, before the irradiating step b).

[0100] The process of the present invention also comprises an additional step d) of milling the decorticated cereal caryopses obtained during the decortication step c).

[0101] Preferably, the additional milling step d) comprises the following substeps:

[0102] i) milling the decorticated cereal caryopses, thereby detaching the endosperm from the residual bran parts and obtaining a mass comprising the endosperm in the milled form and residual bran parts and / or fractions thereof;

[0103] ii) separating the residual bran parts and / or fractions thereof from said mass.

[0104] In particular, during sub-step ii) of separation, an operation of sifting and cleaning of semolina takes place, the operation comprising a first treatment of sifting through plansifters and a second treatment carried out through purifiers.

[0105] The sub-steps i) and ii), suitably combined with each other, constitute milling, whose purpose is also to separate the granulated endosperm (semolina) from the outer caryopsis integuments (middlings and coarse bran) .

[0106] The present invention also refers to a cereal flour obtained through the above-described process of the invention.

[0107] In particular, said cereal flour has a moisture content between 8.0 and 16.0% by weight, preferably between 13 and 15% by weight, of its total weight.

[0108] More in particular, said flour is durum-wheat semolina or re-milled durum-wheat semolina.

[0109] Advantageously, the cereal flour according to the present invention does not have significant coloration alterations, and neither does it have significant alterations of the product from the nutritional point of view. In particular, the durum-wheat semolina of the invention is suitable for the production of pasta.

[0110] The present invention is further described below in the detailed description with reference to some exemplifying embodiments which are provided below by way of non-limiting illustration.

[0111] Brief description of the figures

[0112] Figure 1 schematically depicts a durum-wheat caryopsis.

[0113] Figure 2 schematically depicts a process for the production of a cereal flour according to the prior art.

[0114] Figure 3 schematically depicts a process for the production of cereals according to the present invention.

[0115] Figure 4 shows durum-wheat grains treated according to some different embodiments of the process according to the present invention (specifically the samples 1R44, 1R46, and 1R45), on the right, compared to the same grains before the treatment, on the left.

[0116] Figure 5 shows durum-wheat grains treated according to some further embodiments of the process according to the present invention (specifically the samples 1R50, 1R48, and 1R49), on the right, compared to the same grains before the treatment, on the left.

[0117] Figure 6 shows durum-wheat grains treated according to some further embodiments of the process according to the present invention (specifically the samples IR48, and IR45), on the right, compared to the same grains before the treatment, on the left.

[0118] Figure 7 shows durum-wheat grains treated according to some embodiments of the process according to the present invention and shown in Figures 4, 5, and 6 compared with each other, and also the conditions of the treatment applied.

[0119] Figure 8 shows durum-wheat grains treated according to some further embodiments of the process according to the present invention (specifically the samples BR05, and BR07), on the right, compared to the same grains before the treatment, on the left.

[0120] Figure 9 shows durum-wheat grains treated according to some further embodiments of the process according to the present invention.

[0121] Figure 10 shows durum-wheat grains treated according to the embodiments referred to in Figure 9, before and after the decortication post-treatment.

[0122] Detailed description

[0123] As already said, the process according to the present invention may involve a series of preliminary cleaning treatments to remove impurities in the durum wheat coming from the harvest in the field.

[0124] Consistently, Fig. 3 shows a flow diagram of a possible and totally optional embodiment of the process for treating cereal caryopses according to the present invention.

[0125] The process first comprises a step wherein a mass of cereal caryopses is subjected to a pre-cleaning cleaning treatment, removing the coarsest impurities and / or the foreign bodies that are in said mass, through suction and sieving.

[0126] Then, the mass of cereal caryopses thereby obtained is subjected to a cleaning step which may be divided into two sub-steps, one following the other.

[0127] A first cleaning treatment occurs, during which the light and coarse parts of the wheat are removed through suction and screening means, followed by a second cleaning treatment, during which the mass of cereal caryopses, through an optical sorting machine using vision systems and collimated air jets, defective grains are separated from the mass.

[0128] Optionally, a preliminary tempering step may be carried out, during which the cereal caryopses of said mass are rehydrated, thereby increasing the moisture content thereof.

[0129] Then, the laser treatment step follows, which will be better explained below in connection with the examples.

[0130] Once subjected to laser treatment, the cereal grains are subjected to a decortication step, separating the endosperm from the outermost surface layers of the caryopsis through operations of friction and abrasion.

[0131] The following step is milling the caryopsis fractions generally consisting solely of the endosperm. Said fractions were obtained through the preceding step and were possibly preliminarily subjected to additional separation steps, as it is previously described in connection with the summary (removal of bran, middlings, and coarse bran).

[0132] In the context of the following Examples 1-5, the step of laser treatment was carried out through an infrared laser beam according to the processing modes reported below in Table 1A. Instrument YLS- 1064- 1500 Mode of treatment Continuous or semi- continuous

[0133] Wavelength [nm] 1070

[0134] Nominal average output power [W] [200 to 1520]

[0135] Focal length [mm] 515

[0136] Spot size [pm] [1025 to 12010]

[0137]

[0138] Pitch [pm] 170

[0139] Table 1A

[0140] In the context of the following Example 6, instead, the step of laser treatment was carried out through an infrared laser beam according to the processing modes reported below in Table IB. _

[0141] Instrument DLS-1 1000-U-ECO

[0142] Mode of operation Continuous or semi- continuous

[0143] Wavelength [nm] 970

[0144] Optical power [W] 11000

[0145] Power tunability [%] 10-100

[0146] Laser illumination area [mm] up to 200 x 200 (adjustable)

[0147]

[0148] Wall Plug Efficiency [%](min. / typ.) 50 / 52

[0149] Table IB

[0150] With reference to the following examples, the tests were carried out on durum-wheat caryopses affected by chromatic alterations due to the attack of microorganisms, specifically being affected by the black-point phenomenon. The moisture content of the cereal caryopses of the mass provided during step a) was between 8% and 35% by weight, in particular between 8% and 17% by weight, of the total weight of the cereal caryopses.

[0151] In order to reach the moisture content indicated below, equal to 33% by weight or equal to 15% by weight, the so-provided grains were subjected to a preliminary step of tempering or re hydration.

[0152] For example, the tests were carried out varying the power density (Example 1), the energy density or fluence (Example 2 and Example 6), dividing or not the exposure time in several intervals (Example 3).

[0153] The equipment used during the tests was a laser machinery of the above-mentioned type, a sample support, placed at a certain distance from the laser gun, means adapted to hit the caryopses with a jet of air or of inert gas, a thermal camera for the detection of the temperature of the caryopses, and a camera.

[0154] For safety reasons, the whole equipment is placed in a box shielding it from the scattered laser radiation.

[0155] The wheat is fixed on a support and is exposed to a laser beam whose diameter may be varied by adjusting the focal length, namely the distance between the laser gun and the wheat, to operate in focusing or out-of-focus mode.

[0156] A nitrogen flow is directed above the wheat to prevent smoke accumulation, since smoke can partially absorb laser radiation, thereby modifying the process conditions.

[0157] A thermal camera is calibrated and focused onto the surface of the wheat grain to record the process temperature in real time. The error in the temperature reading is + / -1°C up to 90°C.

[0158] A camera is placed outside of the box to record the process.

[0159] In some cases, the grains were subjected to a preliminary tempering through water spraying.

[0160] The photographs detected by the camera at the end of the laser treatment are illustrated in Figures 4-8.

[0161] Examples

[0162] In general, with reference to Fig. 7, the photographs of the samples obtained according to Examples 1-3 are shown, so that an overview can be obtained.

[0163] As will be seen below, it will be clear that the fluence parameter significantly influences surface carbonization. In the case of Examples 1-4, below 120.0 J / cm2no noticeable effect was observed on the grains, whereas above 350 J / cm2, wheat showed signs of excessive carbonization.

[0164] Moreover, Example 4 was also carried out, varying the conditions of treatment-time interruption.

[0165] Furthermore, with reference to Example 6, it was possible to achieve significant carbonization even at fluence values below 120.0 J / cm2. Example 1

[0166] Figure 4 shows three samples of durum-wheat caryopses subjected to laser treatment using the above-described equipment and with reference to the process conditions indicated in Table 1A.

[0167] The following Table 2 shows the precise values of some of the process conditions reported in Table 1A in the form of a range and other parameters. Sample code IR44 IR46 IR45 Tmax [°C] >120 >120 >110 Spot size [pm] 12010 12010 12010 Power [W] 1520 1300 1000 Exposure time [ms] 100 100 100

[0168]

[0169] Initial moisture [% by weight] 33 33 33 Table 2

[0170] As can be seen in relation to Fig. 4, a selective carbonization is obtained in all the samples.

[0171] In any case, by reducing the power density with a fixed spot size, an effect of decreased carbonization and lower temperatures is obtained.

[0172] Example 2

[0173] Figure 5 shows three samples of durum-wheat caryopses subjected to laser treatment using the above-described equipment and with reference to the process conditions indicated in Table 1A.

[0174] The following Table 3 shows the precise values of some of the process conditions reported in Table 1A in the form of a range and other parameters. _

[0175] Sample code IR50 IR48 IR49 (not according to the invention) Tmax [°C] 94 >110 >120

[0176] Spot size [pm] 12010 12010 12010

[0177] Power [W] 200 200 200

[0178] Exposure time [ms] 500 1000 2000

[0179] Initial moisture [% by 33 33 33

[0180]

[0181] weight] Table 3

[0182] As can be seen in relation to Fig. 5, a selective carbonization is obtained in all the samples, except for the sample IR49 where carbonization extends over the whole caryopsis surface, destroying also healthy tissues that are not affected by black-point disease.

[0183] As a matter of fact, a treatment with very long exposure time burns the wheat, whereas a treatment with limited exposure time is not effective in terms of selective carbonization.

[0184] Example 3

[0185] Figure 6 shows two samples of durum-wheat caryopses subjected to laser treatment using the above-described equipment and with reference to the process conditions indicated in Table 1A.

[0186] The following Table 4 shows the precise values of some of the process conditions reported in Table 1A in the form of a range and other parameters. _

[0187] Sample code IR48 IR54

[0188] Tmax [°C] >110 68

[0189] Spot size [pm] 12010 12010

[0190] Power [W] 200 200

[0191] Exposure time [ms] 1000 4 x (250 on / 10000 off)

[0192] Initial moisture [% by weight] 33 33

[0193]

[0194] Table 4

[0195] As indicated in the row relative to the exposure time, sample IR54 was subjected to multiple exposures to the infrared laser beam with a rest time of 10 seconds between one exposure and the next one. As can be seen in relation to Fig. 6, a selective carbonization is obtained in all the samples.

[0196] This example showed that, in order to obtain a selective carbonization at a lower temperature, it is possible to administer the same fluence to the sample in several steps separated by several pauses.

[0197] Example 4

[0198] Figure 8 shows two samples of durum-wheat caryopses subjected to laser treatment using the above-described equipment and with reference to the process conditions indicated in Table 1A.

[0199] The following Table 5 shows the precise values of some of the process conditions reported in Table 1A in the form of a range and other parameters. _

[0200] Sample code BR_05 BR_07

[0201] Tmax [°C] 100 100

[0202] Fluence [J / cm2] 200 200

[0203] Power [W] 500 250

[0204] Exposure time [ms] 6 x (75 on / 250 off) 6 x (150 on / 250 off)

[0205] Initial moisture [% by weight] 15 15

[0206]

[0207] Table 5

[0208] As indicated in the row relative to the exposure time, both samples were subjected to multiple exposures to the infrared laser beam with a rest time between one exposure and the next one.

[0209] As can be seen in relation to Fig. 8, a selective carbonization is obtained in all the samples. The power and the exposure time may be adjusted together to adjust the outcome of the process.

[0210] It is possible to increase the power and decrease the exposure time, or vice versa, maintaining the fluence (power x exposure time) constant and a similar outcome.

[0211] Example 5

[0212] The process of the invention was then repeated on a scaled-up sample of about a hundred durum-wheat grains, evenly distributed on a support. The caryopses were then subjected to laser treatment, gradually hitting the mass with a beam according to a serpentine scanning path and with a scanning speed of 58.2 mm / s and a spot size of 12 mm.

[0213] The precise values of some of the process conditions reported in Table 1A in the form of a range and other parameters are indicated below.

[0214] Power: 250 W

[0215] Energy density (fluence): 45 J / cm2

[0216] Initial moisture: 15% by weight

[0217] The so-obtained caryopses subjected to laser treatment were subjected to a decortication step, capable of simulating the operating conditions in a mill for the production of durum-wheat semolina.

[0218] A post-treatment based on wheat abrasion with a metal brush was developed to quantitatively assess the amount of defective part removed through mechanical processing.

[0219] The developed equipment comprised the following components:

[0220] • two main cylindrical abrasive parts, a rotating internal steel brush, and a fixed external cylinder covered with sandpaper (Medium-Grit Sandpaper p-80), wherein the rotating internal brush is inserted inside the fixed cylinder and there in a gap between them, in which the grains receive the treatment;

[0221] • a motor rotating at 100 rpm to actuate the brush.

[0222] In particular, the gap was 2 mm, calculated between the abrasive elements.

[0223] A fixed amount of grain weight (namely, 1.3 g) was inserted and the decortication treatment through brush rotation was carried out for 1 minute. The processed grains were then analyzed (weighed and photographed to enable a quantitative and visual analysis) .

[0224] The test was carried out both with non-selected wheat and with the sample after laser treatment.

[0225] It has come to light that wheat treated with infrared laser is easily removed compared to non-treated wheat, and thus requires less energy (or less time) to obtain the same decortication rate.

[0226] In other words, it was observed that, in the context of the process of the invention and after a totally optional preliminary tempering step that precedes step a), depending on the moisture content on the raw material to be treated, caryopsis decortication occurs more efficiently than a conventional decortication treatment carried out in the absence of a laser treatment.

[0227] Example 6

[0228] With reference to Table IB, the machinery used for the present example was set up according to the precise values and other parameters indicated below.

[0229] Laser source:

[0230] Working distance: 500 mm Laser illumination area: 70 x 70 mm

[0231] Sample:

[0232] 10 g of durum-wheat caryopses, which had been not subjected to any wet pre-tempering pre-treatment nor preliminary decortication and on which darkened areas were evident, were treated. Said darkened areas were caused by the black-point phenomenon due to the attack of microorganisms. The caryopses were distributed evenly throughout the area of treatment so as to obtain a single layer of grains to be treated. Machinery:

[0233] An air knife is used to spread the vapors produced by combustion. An extractor is used to drain the process smoke to avoid beam absorption and scattering of smoke or air molecules.

[0234] The distance of the source from the sample, the area of treatment and the machinery power were kept constant, that is, the irradiance in the tests carried out in this example was constant and equal to 224 W / cm2. As will be seen below, the treatment times were modified instead, resulting in a gradually increasing fluence value.

[0235] The following Table 6 shows the precise values of some of the process conditions reported in Table IB in the form of a range and other parameters. _

[0236] Ex. 6 A Ex. 6B Ex. 6C Ex. 6D Tmax [°C] 78 96 >125 >125 Fluence [J / cm2] 60 89 112 224 Exposure time 270 400 500 1000

[0237] [ms]

[0238]

[0239] Irradiance 224 W / cm2224 W / cm2224 W / cm2224 W / cm2Table 6 As can be seen in relation to Fig. 9, a selective carbonization is obtained in all the samples 6B, 6C, and 6D. For sample 6A, the carbonization process is very weak and was not sufficient to involve all the areas of the grain surface affected by black-point disease.

[0240] At fixed irradiance, the temperature increase during treatment depends directly on fluence. In this regard, a threshold of optimum carbonization was observed for fluence values higher than about 89 J / cm2.

[0241] In any case, carbonization occurs only on the parts affected by darkening due to black-point disease: the larger the darkened area affected by black-point disease, the stronger the overall effect on the sample.

[0242] Moreover, an analysis of the protein content was carried out, comparing the caryopses before and after irradiation treatment. Said analysis revealed that laser treatment, even at high fluence, has no significant effect on protein and gluten content.

[0243] The so-obtained caryopses subjected to laser treatment were subjected to a decortication step, through a laboratory machinery having a cylindrical grindstone capable of simulating the decortication operating conditions of a mill for the production of durum-wheat semolina.

[0244] The conceptual design of this device follows the main elements of an industrial peeler machine but is adapted for small quantities (2 g).

[0245] The grains are inserted into the gap between two abrasive surfaces: a rotating grindstone and a metal mesh wall having a slight slope (12°). The slope acts as a funnel, accommodating different grain sizes. The minimal gap at the bottom of the setup is 1.5 mm.

[0246] A counterweight, connected to three springs, keeps the grains at the bottom while the grindstone rotates.

[0247] The machinery used had the following technical characteristics.

[0248] Grindstone Material: Diamond coated steel. Activated by a servo motor (50 RPM); Counter- surface: Inox steel grid (Mesh 20); Conical gap to accommodate size variability among the wheat grains: minimal gap is 1.5 mm; Counterweight: a press tool / tamper following the same conical profile.

[0249] Then, for each of the samples 6B, 6C, and 6D, 2 g of caryopses which had been previously subjected to irradiation were treated. The peeling step was repeated for 15 seconds and for four consecutive times, so as to assess mass loss and the quality of the end product from a visual point of view.

[0250] The same procedure was carried out on 2 g of a sample of caryopses that had not previously been subjected to any irradiation treatment (control). Evidences of the peeling tests carried out are shown in Figure 10 in the form of photographs of the treated material, with indication of the percentage mass loss (steps 1-4) in relation to the initial biomass weight after irradiation.

[0251] The following Table 7 shows percentage values of mass loss for each tested sample. _

[0252] Step 1 Step 2 Step 3 Step 4 Control 1.98% 3.91% 5.77% 8.10% Ex. 6B 2.43% 4.95% 7.08% 9.59% Ex. 6C 2.25% 4.29% 6.49% 8.93%

[0253]

[0254] Ex. 6D 4.09% 7.87% 11.45% 14.75%

[0255] Table 7

[0256] As can be seen, decortication efficiency increases as fluence increases, even considering the possible detachment of small seed portions due to breakage.

Claims

CLAIMS1. A process for treating cereal caryopses, comprising the following steps: a) providing a mass of cereal caryopses comprising cereal caryopses affected by chromatic alterations due to the attack of microorganisms, said microorganisms being fungi and said cereal caryopses being affected by the black-point phenomenon;b) exposing the cereal caryopses of said mass to at least one infrared-ray source, irradiating said mass with at least one laser beam coming from said at least one source for a prefixed time until cereal caryopses, whose surface layers are at least partially carbonized, are obtained;c) subjecting said cereal caryopses whose surface layers are at least partially carbonized to a decortication treatment, thus removing said at least partially carbonized surface layers and obtaining decorticated cereal caryopses.

2. The process for treating cereal caryopses according to claim 1, wherein said microorganisms belong to fungal species selected in the group comprising Altemaria altemata, Bipolaris sorokiniana or Cochliobolus sativus, Fusarium proliferatum, Cladosporium cladosporioid.es, Pyrenophora tritici-repentis, or Drechslera tritici-repentis.

3. The process for treating cereal caryopses according to claim 1 or 2, wherein the moisture content of the cereal caryopses of the mass provided during step a) is between 8% and 35% by weight, preferably between 8% and 17% by weight, of the total weight of the cereal caryopses.

4. The process for treating cereal caryopses according to any one of claims 1-3, wherein the cereal caryopses as per step a) are obtained following a preliminary tempering step, by increasing the moisture content of the cereal caryopses, preferably according to a variation of maximum moisture of 25% by weight, more preferably of 5% by weight.

5. The process for treating cereal caryopses according to any one of claims 1-4, wherein the cereal caryopses of the mass provided during step a) are wheat, rye, or barley caryopses.

6. The process for treating cereal caryopses according to claim 5, wherein the cereal caryopses of the mass provided during step a) are wheat caryopses, preferably of soft wheat or durum wheat, even more preferably of durum wheat.

7. The process for treating cereal caryopses according to any one of claims 1-6, wherein during step b) the cereal caryopses of said mass are exposed to an infrared-ray source, irradiating the mass with at least one infrared laser beam and said source being a continuous-wave infrared source.

8. The process for treating cereal caryopses according to claim 7, wherein during step b) the cereal caryopses of said mass are exposed to an infrared-ray source, irradiating the mass with at least one continuousmode or semi-continuous infrared laser beam.

9. The process for treating cereal caryopses according to any one of the preceding claims, wherein during said irradiating step b) said prefixed time is between 40 ms and 10 s, preferably between 60 ms and 1500 ms, more preferably between 100 ms and 1000 ms.

10. The process for treating cereal caryopses according to preceding claims, wherein during said irradiating step b) the mass of cereal caryopses is subjected to an energy density between 60 J / cm2and 350 J / cm2, preferably between 80 J / cm2and 350 J / cm2, more preferably between 80 J / cm2and 240 J / cm2.

11. The process for treating cereal caryopses according to any one of claims 8 to 10, wherein during said irradiating step b) the laser treatment is divided into at least two time intervals, preferably at least four or six time intervals, separated by respective pauses during which the mass of cereal caryopses is left to at least partially cool.

12. The process for treating cereal caryopses according to any one of claims 1 to 11, further comprising an additional step d) of milling said decorticated cereal caryopses obtained during decortication step c) .

13. The process for treating cereal caryopses according to claim 12, wherein said additional milling step d) comprises the following sub-steps: i) milling the decorticated cereal caryopses, thereby detaching the endosperm from the residual bran parts and obtaining a mass comprising the endosperm in the milled form and residual bran parts and / or fractions thereof;ii) separating the residual bran parts and / or fractions thereof from said mass.

14. The process for treating cereal caryopses according to any one of claims 1 to 13, wherein during said irradiating step b) said mass of cereal caryopses is hit by a jet of air or of inert gas and / or in the chamber, where said mass is stored, a suction mouth, through which the gaseous atmosphere above the mass is sucked, is present.

15. A cereal flour obtained through the process for treating cereal caryopses according to any one of claims 1 to 14, preferably said cereal flour having a moisture content between 8.0 and 16.0% by weight, more preferably 13.0 -15.0 % by weight, of its total weight.

16. The cereal flour according to claim 15, wherein said flour is durum-wheat semolina or re-milled durum-wheat semolina.

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