Title: Process and plant for the production of animal meals with improved amino acid availability

DESCRIPTION

Field of application The present invention relates to the field of the food and cattle industry and, in particular, it concerns a process for treating animal meals to obtain products characterized by an improved amino acid availability.

Prior art

The production of animal meals for the production of high protein content feeds for animal feeding is known. Such meals are generally prepared according to conventional cooking and pulverization techniques, followed by a drying step, to impart them with the characteristics typical of meals.

Such animal meals are mainly obtained from starting materials such as fish, plumes, feathers or other sources rich in proteins or other desirable nutrients.

They are not suitable for human consumption, as the conventional processes give rise to meals that conserve the odor - in these cases unpleasant - of the initial substrate, making their use and their marketing difficult within the context of food for human consumption.

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From the nutritional standpoint, moreover, such meals can be quite poor or present nutrients, such as proteins, in forms that are not entirely or easily assimilated by the animal they are intended for.

Patent WO 90/01023 discloses a method for solubilizing keratin-rich materials, such as feathers, hairs and wool, in highly diluted hydrogen peroxide alkaline solutions. The method gives rise to products containing hydrolyzed peptides especially rich in cysteine derivatives and they are suitable for integration into animal feeds.

Several processes are known for obtaining animal meals suitable for human consumption; for example, patent CN 1411751 describes a process for the production of a powder based on fish-product manufacture waste products. Such process comprises the steps of pulverization, washing, drying, cooking and addition of flavorings, scents, coagulants and stabilizers. This results in fish products that are rich in amino acids, proteins and minerals suitable for human consumption.

Patent JP62087075 describes a method for the production of a food in the form of powder obtained starting from a main product of the fish type together with a secondary product of the starch type, with flavorings, comprising the steps of extrusion at 150-200 ⁰ C, pulverization of the resulting material and drying.

However, these are products that use a combination of known methods for obtaining products suitable for limited and specific uses depending on the starting materials. Moreover, such meals have a nutritional profile that is not better in quality than that of the starting materials or they exhibit such organoleptic properties that their use in the context of products intended for human consumption is very limited or even discouraged.

The Applicant is not aware of animal meals being available, exhibiting improved amino acid availability and at the same time, such organoleptic properties as to be suitable for a wide variety of applications for both human and animal consumption, whether as such or in addition to other foodstuffs.

Summary of the invention

An object of the present invention is to provide an animal meal with improved amino acid availability which is suitable for both human and animal consumption.

Such an object is achieved, according to the invention, by a process for treating animal meals of animal origin, comprising the steps of:

feeding a continuous flow of animal meal to a turbo-reactor comprising a horizontal-axis cylindrical tubular body, provided with at least one opening for introducing reactants and for discharging the treated

product, a heating jacket for bringing the inner wall of the tubular body to a predetermined temperature, a bladed rotor, rotatably supported in the cylindrical tubular body where it is put into rotation at peripheral speeds comprised between 20 and 40 m/s, so as to disperse said continuous animal meal flow into an animal meal particle flow,

feeding into said turbo-reactor, cocurrently with said animal meal flow, a continuous and finely divided flow of a reactant consisting of a concentrated aqueous hydrogen peroxide solution,

centrifuging said animal meal particles and said reactant against the inner wall of the turbo-reactor, heated at a temperature of at least 100 ⁰ C, with formation of a thin, dynamic, highly turbulent tubular fluid layer wherein the animal meal particles and said reactant are mechanically kept in close contact by the blades of said bladed rotor,

reacting said animal meal and said reactant into said thin layer while progressing in substantial contact with said inner wall of the turbo- reactor towards the discharge opening,

continuously discharging a flow of treated animal meal, having a humidity content of 30-50%,

sending said flow of treated animal meal on to a maturation step for a time varying between 30 minutes and 20 h, at a temperature of 60-

9O ⁰ C, and to a subsequent drying step to bring the humidity content to

the values typical of the starting animal meal, that is, 5-10%.

The treated animal meal exiting the turbo-reactor generally has a temperature of about 60-90 ⁰ C.

The above-mentioned concentrated hydrogen peroxide solution preferably consists of an aqueous solution of hydrogen peroxide of at least 40-volumes and, advantageously, of about 120-140 volumes.

When 120-140 V hydrogen peroxide is used, the weight ratio of hydrogen peroxide to animal meal generally varies between 1:4 and 1:20.

The concentrated aqueous hydrogen peroxide solution can be introduced into the turbo-reactor right at the inlet, since in that case the bladed rotor carries out an effective nebulization and centrifugation thereof, thus ensuring its introduction into the turbulent dynamic thin layer of animal meal particles to be treated in a highly dispersed condition.

In this way, the closest possible contact between the particles and the hydrogen peroxide is promoted, and this considerably increases the efficacy of the treatment.

As an alternative or in addition to the above-mentioned introduction through an inlet opening, the introduction of the hydrogen peroxide may

also be carried out through openings for the nebulization of hydrogen peroxide at different levels along the length of the cylindrical tubular body.

It can sometimes be advantageous to introduce a steam flow into the turbo-reactor, cocurrently with the above-mentioned animal meal flow.

The mean residence time of the animal meal flow inside the turbo- reactor is of about 0.5-5 minutes.

The preferred temperature ranges for the turbo-reactor inner wall are 140-160°C, if the animal meal to be treated is based on high keratin content materials, such as feathers or plumes, and 110-130 ⁰ C, if the animal meal to be treated is based on fish or other materials susceptible to racemization.

The above-mentioned maturation step at 60-90 ⁰ C can be carried out in static conditions, for example inside heating silos with plate-type heat exchangers such as those manufactured by the Bulkflow Technologies Inc. (Canada) company.

Alternatively, and preferably, the maturation at 60-90 ⁰ C is carried out under dynamic conditions, in order to prevent undesirable agglomeration and increase the homogeneity of the end product, for example by means of a slow continuous stirrer or a screw apparatus. This latter apparatus advantageously consists of a horizontal-axis

cylindrical tubular body, provided with inlet and discharge openings, a heating jacket for bringing the inner wall of the tubular body to a predetermined temperature, and a screw supported in the cylindrical tubular body where it is put into rotation at low speeds.

The drying step mentioned above can be carried out using any apparatus commonly used for drying powdery substances but it is preferably carried out with the aid of a turbo-dryer, which is an apparatus structurally similar to the above-described turbo-reactor, also comprising a horizontal-axis cylindrical tubular body, provided with inlet and outlet openings, with heating jacket and with a bladed rotor rotatably and coaxially mounted inside the cylindrical tubular body.

When such an apparatus is used, the temperature of the heating wall is of about 140-180 ⁰ C and, cocurrently with the flow of treated animal meal entering the turbo-dryer, a hot and dry air flow is optionally fed at a temperature of 140-180 ⁰ C. The mean residence time of the treated animal meal inside the turbo-dryer is of about 1-5 minutes.

The expression "animal meal" includes any meal of animal origin suitable for human and/ or animal consumption. In particular, fish, feather and plume meals.

Following the treatment with hydrogen peroxide carried out according to the process of the present invention, the resulting animal meal exhibits

a better ammoniacal nitrogen to total nitrogen ratio, an indication of the greater availability of the amino acids contained therein. According to a non-binding hypothesis, this is due to the interaction of the hydrogen peroxide with the peptide bonds in the protein molecules.

The animal meal treated according to the present invention further exhibits an improved solubility, even ten times greater than the starting animal meal, a high digestibility degree and a low texturization level. Moreover, it is virtually free from unpleasant odors and free from pathogenic micro-organisms.

The resulting food therefore exhibits an improved nutritional profile compared to the starting material and it can be used for the manufacture of products intended for human consumption, both as such and in addition to others.

The main use of the animal meals obtained with the process according to the present invention is in the field of food supplements, for example in energy bars, energy drinks or other applications in which an immediate release of amino acids is required upon consumption, for certain categories of consumers such as athletes or children.

Another use of the animal meals obtained with the process according to the present invention is as additives to be added to the standard flours to improve their nutritional profile.

Finally, another use of the animal meals obtained with the process according to the present invention is as feed for animal consumption.

In another aspect thereof, the present invention relates to a plant for carrying out the process illustrated above, comprising a turbo-reactor of the above-described type, a screw apparatus for the maturation of the treated animal meal as described above, and a dryer, preferably a turbo- dryer.

The advantages and features of this invention will appear more clearly from the description of an embodiment of a process for treating animal meal in order to produce animal meals with improved amino acid availability, hereinafter provided with reference to the annexed drawing, given for illustrative and non-limiting purposes.

Brief description of the drawings

Figure 1 schematically shows a plant for the treatment of animal meals having improved amino acid availability according to the process of the invention.

Detailed description of a preferred embodiment

With reference to figure 1, the turbo-reactor A essentially consists of a cylindrical tubular body 1, closed at the opposed ends by end walls 2, 3 and coaxially provided with a heating jacket 4 intended to be run through by a fluid, for example diathermic oil, for keeping the inner wall

of body 1 at a predetermined temperature.

The tubular body 1 is provided with inlet openings 5, 6 for the animal meal to be treated and for the concentrated aqueous hydrogen peroxide solution , respectively, as well as a discharge opening 7 for the treated animal meal.

Inside the tubular body 1, is rotatably supported a bladed rotor 8, the blades 9 of which are helically arranged and are oriented for centrifuging and concurrently conveying the animal meal subjected to treatment towards the outlet.

A motor M is provided for driving the bladed rotor at peripheral speeds varying between 20 and 40 meters per second.

Openings 10 are provided in the inner wall of the cylindrical tubular body 1 for introducing concentrated aqueous hydrogen peroxide solution in nebulized form.

A plant for producing animal meals having improved amino acid availability according to the process of the invention comprises, in addition to the turbo-reactor A, a maturation apparatus B and a turbo- dryer C.

The maturation apparatus B, shown in a very schematic manner, comprises a cylindrical tubular body 21, closed at the opposed ends by

end walls 22, 23 and coaxially provided with a heating jacket 24 intended to be run through by a fluid, for example diathermic oil, for keeping the inner wall of the body 1 at a predetermined temperature.

The tubular body 21 is provided with an inlet opening 25 for the animal meal coming from the turbo-reactor A and with a discharge opening 27 for the animal meal at the end of the maturation step.

A screw 28 is rotatably supported in the tubular body 21, driven in rotation at low speed by a motor N and intended for conveying the animal meal subjected to maturation towards the outlet.

Finally, the turbo-dryer C is not described in detail as it has a structure totally similar to that of turbo-reactor A, except for the absence of openings for the introduction of liquid reactants. The components of turbo-dryer C that are the same as those of the turbo-reactor A are indicated with same reference numerals increased by 100.

EXAMPLE 1

In a turbo-reactor A wherein the bladed rotor is made to rotate at a peripheral speed of about 30 m/s and wherein the inner wall is kept at 150 ⁰ C, a flow of feather-based animal meal (humidity content of about 7%) is continuously fed, at a flow rate of 100 kg/ hour. At the same time, 50 I/hour of a 130-V hydrogen peroxide solution are continuously fed through opening 6 and openings 10.

Right at the inlet of the turbo-reactor A, the animal meal flow is mechanically dispersed into very small particles, which are immediately centrifuged against the inner wall of the turbo-reactor itself, where they form a dynamic tubular thin layer.

At the same time, the aqueous hydrogen peroxide solution entering through opening 6 is mechanically finely nebulized by the blades 9 of the rotor 8, which also readily centrifuge the very small droplets obtained. These are thus introduced into the dynamic tubular thin layer of animal meal particles with which they can interact.

The hydrogen peroxide solution introduced in nebulized form through the openings 10 further increases the interaction of the hydrogen peroxide with the animal meal particles.

After a residence time of about 2 minutes inside the turbo-reactor A, a treated animal meal is continuously discharged from opening 7 with a humidity content of about 40% and a temperature of about 70 ⁰ C.

The flow of treated animal meal exiting the turbo-reactor A is continuously fed to the maturation device B, through the inlet opening 25. The animal meal is made to slowly progress up to the discharge opening 27 by the slowly rotating screw 28, after a mean residence time of about 2 hours at a temperature of about 70° C (which is also the temperature at which the inner wall is stabilized by the heating jacket

24).

At this point, the animal meal flow coming out of maturation device B is continuously fed into the turbo-dryer C, through the inlet opening 105, along with a cocurrent air flow at about 160 ⁰ C. After a mean residence time of about 1 minute inside the turbo-dryer, in which the bladed rotor 108 is put into rotation at a peripheral speed of 30 m/s and the heating jacket 104 stabilizes the temperature of the inner wall at about 160°C, the animal meal is discharged through the discharge opening 107.

The resulting animal meal has a humidity content of about 7% and when analyzed, it exhibits a total nitrogen to ammoniacal nitrogen ratio of 60 against a starting value of 133, the quantity of total nitrogen as compared to the starting meal remaining substantially unchanged.

The meal is substantially odorless and sterilized from the microbiological standpoint.

The ratio of total nitrogen to ammoniacal nitrogen therefore indicates a considerable decrease and a subsequent analysis of the primary amine according to the Van Slyke method has shown that the treatment frees the essential amino acids constituting the protein chain.

EXAMPLE 2

In a turbo-reactor A in which the bladed rotor is made to rotate at a

peripheral speed of about 30 m/s and in which the inner wall is kept at 130 ⁰ C, a fish-based animal meal (humidity content of about 7%) is continuously fed, at a flow rate of 100 kg/hour. At the same time, 50 I/hour of a 130-V hydrogen peroxide solution are continuously fed through opening 6 and openings 10.

The subsequent steps of the method have been carried out as described in the Example 1, above.

The resulting animal meal has a humidity content of about 7% and when analyzed, it exhibits a total nitrogen to ammoniacal nitrogen ratio of 35 against a starting value of 60, the quantity of total nitrogen as compared to the starting meal remaining substantially unchanged.

The meal is substantially odorless and sterilized from the microbiological standpoint.

The ratio of total nitrogen to ammoniacal nitrogen therefore indicates a considerable decrease and a subsequent analysis of the primary amine according to the Van Slyke method has shown that the treatment frees the essential amino acids constituting the protein chain.