Gallo feed additive and preparation method thereof

Abstract

The invention provides a gallo feed additive and a preparation method thereof, and belongs to the technical field of livestock feed breeding. Fresh galls are subjected to steam treatment and then added into a twin-screw extruder to obtain broken galls, then premixed oxidized cassava starch, carboxymethyl cellulose and glycerol are added into the twin-screw extruder to be mixed with the broken galls to prepare expanded galls, lac coating liquid is sprayed after fluidization and granulation, and the expanded galls are prepared. The tannic acid is mixed in the bio-based material and shielded by the acid-resistant and water-resistant shellac resin, so that the prepared feed additive has good palatability, relatively high stability and relatively low hygroscopicity, maximum utilization of resources is realized by taking the fresh galls as the raw material, no waste is generated, and the feed additive is suitable for industrial production. Moreover, the preparation process is simple, the tedious process of extracting tannic acid is reduced, reference is provided for application of the gallo as a feed additive, and the gallo feed additive has important significance for development of the livestock and poultry breeding industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of livestock feed breeding, and particularly relates to a gallnut feed additive and a preparation method thereof. Background Art

[0002] After piglets are weaned, various factors can cause diarrhea in piglets and even a large number of deaths. In the actual feeding process, the stress response of piglets is mainly reduced by adding antibiotics or high-dose ZnO. However, the use of antibiotics will bring problems of drug resistance, and long-term use of high-dose zinc oxide will cause a series of problems such as piglet poisoning and heavy metal pollution in feces. Therefore, in the context of the development of antibiotic replacement and zinc reduction, finding safe and green alternative products has become a research hotspot in the livestock field.

[0003] Tannic acid has functions such as anti-stress and improving animal immunity. However, directly using tannic acid as a feed additive faces many difficulties. First, the extraction and refining process of tannic acid is long and energy-consuming; second, tannic acid is easily oxidized and has high hygroscopicity. When directly mixed into feed, it is difficult to avoid its oxidation and denaturation, and tannic acid is extremely easy to contaminate feed after absorbing moisture; the most crucial is that tannic acid has a bitter and astringent taste and poor palatability, which affects the feeding of animals. Usually, tannic acid used as a feed additive must be coated to shield the astringent taste and prevent moisture, so as to improve its palatability and stability. At present, the coating of tannic acid used as a feed additive is generally completed through processes such as granulation, shot blasting, drying, screening, and coating. The process is relatively cumbersome and requires adding a large amount of auxiliary materials such as starch, oil, and fatty acids, resulting in a low effective content of tannic acid in the final product, high cost, and insufficient market competitiveness. Summary of the Invention

[0004] Aiming at the problems of the existing tannic acid as a feed additive, such as cumbersome extraction process, high cost, and poor palatability, the present invention provides a gallnut feed additive and a preparation method thereof, which directly uses fresh gallnuts rich in tannic acid as raw materials, and prepares the gallnut feed additive by extrusion and puffing followed by coating.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A preparation method of a gallnut feed additive, comprising the following steps:

[0008] After steam-treating fresh gallnuts, adding them to a twin-screw extruder to obtain gallnut fragments, and then adding pre-mixed oxidized tapioca starch, carboxymethyl cellulose, and glycerol to the twin-screw extruder to mix with the gallnut fragments to obtain gallnut expanded material;

[0009] Fluidized granulating the gallnut expanded material and spraying shellac coating solution to obtain the gallnut feed additive.

[0010] Tannic acid is mainly distributed inside cells. To increase the dissolution rate of tannic acid, it is necessary to destroy the cell wall. Therefore, the present invention uses fresh galls with a high content of tannic acid (usually 50 - 70%) as raw materials to prepare feed additives. The galls are sheared and extruded by a twin-screw extruder, and then oxidized cassava starch, carboxymethyl cellulose, and glycerol are incorporated and fluidized into pellets, and then coated with shellac resin. The gall feed additive prepared by this method has good palatability, high stability, and low hygroscopicity because the tannic acid is mixed in the bio-based material and shielded by the acid- and water-resistant shellac coating solution.

[0011] Furthermore, the sleeve temperature of the twin-screw extruder is 110 - 170 °C, and the rotation speed is 40 - 200 r / min.

[0012] Even further, the sleeve temperatures of the 1st, 2nd, and 3rd zones of the twin-screw extruder are 110 °C, and the sleeve temperatures of the 4th, 5th, and 6th zones are 130 - 170 °C, with a rotation speed of 40 - 200 r / min; preferably, the sleeve temperatures of the 1st, 2nd, and 3rd zones of the twin-screw extruder are 110 °C, the sleeve temperatures of the 4th, 5th, and 6th zones are 150 °C, and the rotation speed is 120 r / min.

[0013] In the twin-screw extruder, the extrusion expansion technology is adopted to destroy the biological structure of the galls, turning the tannic acid in the galls from cell contents into a cellulose lignin - tannic acid mixture, and improving the dissolution rate of tannic acid in the pellets.

[0014] Furthermore, the shellac coating solution, by weight, includes: 25 parts of shellac resin and 1 part of glycerol.

[0015] Even further, the preparation method of the shellac coating solution is: weigh the shellac resin and glycerol by weight, dissolve the shellac resin in ethanol, and add glycerol after dissolution to obtain a mixture, where the mass concentration of the shellac resin in ethanol is 5 - 50%.

[0016] The present invention uses the shellac coating solution to perform enteric coating on the gall expanded material, which has the functions of airtightness, moisture-proofing, and shielding the astringent taste, and the formed coating is acid-resistant, thereby reducing the dissolution and release of the functional ingredient tannic acid in the additive in the stomach; after the tannic acid additive enters the duodenum, under the action of bile and the like, the additive coating swells and disintegrates, and the tannic acid in the additive can be quickly dissolved and act on the intestinal mucosa, improving the bioavailability of tannic acid.

[0017] Furthermore, the temperature for spraying the shellac coating solution is 45 °C, the spraying flow rate is 100 kg / h, and the spraying time is 2 h.

[0018] Further, the mass ratio of the oxidized tapioca starch, carboxymethyl cellulose, and glycerol is 30:20:10.

[0019] Further, the moisture content of fresh galls after steam treatment is < 50%.

[0020] Further, the steam pressure of the steam treatment is 0.3 MPa.

[0021] Further, the gall puffed material is fluidized and granulated to a particle size of 5 - 60 mesh.

[0022] In a specific embodiment of the present invention, the preparation method of the gall feed additive specifically includes the following steps:

[0023] (1) Place fresh galls in high-temperature steam with a steam pressure of 0.3 MPa for inactivation treatment to make the moisture content of fresh galls < 50%;

[0024] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110°C, the sleeve temperatures of zones 4, 5, and 6 to 130 - 170°C, and the rotation speed to 40 - 200 r / min. Put the galls obtained in step (1) into the feed port of zone 1 at the head of the twin-screw extruder. The galls are sheared, extruded, and mixed under the action of the screw to obtain gall crushed materials. Then, the pre-mixed oxidized tapioca starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feed port of zone 6 at the end of the twin-screw extruder and mixed with the gall crushed materials. After shearing, extruding, mixing, and puffing, gall puffed materials are obtained;

[0025] (3) Weigh 25 parts of shellac resin and 1 part of glycerol by weight. Dissolve the shellac resin in ethanol, and add glycerol after dissolution to obtain a shellac coating solution;

[0026] (4) Put the gall puffed materials into a fluidized granulator to make them fluidized. Spray the shellac coating solution into the upper part of the fluidized granulator. The air flow temperature is 45°C. After drying and film formation, discharge to obtain the gall feed additive.

[0027] The second technical solution of the present invention:

[0028] A gall feed additive prepared by the above preparation method.

[0029] The third technical solution of the present invention:

[0030] Use of the gall feed additive in the preparation of animal feed.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects:

[0032] (1) The present invention uses fresh Chinese gallnuts with a high tannic acid content (50 - 70%) as raw materials to prepare a feed additive. The Chinese gallnuts are sheared and extruded by an extruder, and after adding oxidized cassava starch and carboxymethyl cellulose, they are puffed and granulated, and then coated with shellac resin. The prepared feed additive has good palatability, high stability and low hygroscopicity because the tannic acid is mixed in the bio-based material and shielded by the acid-resistant and water-resistant shellac resin.

[0033] (2) The present invention directly uses fresh Chinese gallnuts as raw materials to directly prepare a feed additive, realizing the maximum utilization of resources, with high resource utilization rate, no waste generation, and a simple preparation process, which simplifies the cumbersome process of extracting tannic acid, provides a reference for the application of Chinese gallnuts as a feed additive, and is of great significance to the development of the livestock and poultry breeding industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0035] Figure 1 It is the scanning electron micrograph of the fresh Chinese gallnuts used in Example 1;

[0036] Figure 2 It is the result of the tannic acid dissolution rate of the puffed Chinese gallnuts and Chinese gallnut granules prepared in Example 1;

[0037] Figure 3 It is the SEM image of the raw Chinese gallnuts in Example 2;

[0038] Figure 4 It is the SEM image of the puffed Chinese gallnuts prepared in Example 2;

[0039] Figure 5 It is the SEM image of the Chinese gallnut feed additive prepared in Example 11;

[0040] Figure 6 It is the flow chart for evaluating the effect of the in vitro release test of the Chinese gallnut feed additive;

[0041] Figure 7 It is the result of the determination of the tannic acid release rate of the puffed Chinese gallnuts (puffed material) prepared in Example 2 and the Chinese gallnut feed additive (shielded material) prepared in Example 11 in the simulated in vitro release. DETAILED DESCRIPTION OF THE INVENTION

[0042] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0043] It should be understood that the terms used in this invention are only for describing specific embodiments and are not intended to limit the invention. Additionally, for the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0044] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0045] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of this invention are obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0046] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0047] An embodiment of this invention provides a preparation method of a gallnut feed additive, comprising the following steps:

[0048] After subjecting fresh gallnuts to steam treatment, they are added to a twin-screw extruder to obtain gallnut fragments. Then, pre-mixed oxidized tapioca starch, carboxymethyl cellulose, and glycerol are added to the twin-screw extruder to be mixed with the gallnut expanded material to prepare a gallnut expanded feed;

[0049] The gallnut expanded feed is fluidized granulated and then sprayed with shellac coating solution to obtain the gallnut feed additive.

[0050] As a natural raw material, gallons not only contain tannic acid (the main component is gallic acid tannin), but also are rich in natural ingredients such as polyphenols and flavonoids. These ingredients work synergistically with tannic acid to produce physiological functions that single tannic acid cannot achieve (such as anti-oxidation, antibacterial, regulating intestinal flora, etc.). Directly adding tannic acid (usually chemically extracted or synthesized) is only a single component, and its function is relatively limited. Fresh gallons are steam treated (water content reduced to <50%) and puffed by twin-screw extrusion (high temperature and high pressure shearing), which can destroy some anti-nutritional factors in gallons (such as fiber binding in cell wall structure), reduce the negative impact on animal feeding behavior, and release the active sites of tannic acid to improve its bioavailability. The high-temperature puffing treatment of the twin-screw extruder (sleeve temperature 110-170℃, speed 40-200r / min) makes the gallon crushed material form a porous fluffy structure, increase the release path of tannic acid, and improve the release rate of tannic acid. The premixed oxidized cassava starch and carboxymethyl cellulose (CMC) are used as polymer carriers to encapsulate tannic acid through coating to form a sustained-release system, thereby avoiding the instantaneous release of tannic acid in the oral cavity and further improving the taste. Therefore, the embodiment of the present invention utilizes the synergistic effect of the natural ingredients of the gall to achieve functional enhancement, which has significant technical advantages over directly adding tannic acid.

[0051] In a preferred embodiment of the present invention, the barrel temperature of the twin-screw extruder is 110-170° C., and the rotation speed is 40-200 r / min.

[0052] In a preferred embodiment of the present invention, the sleeve temperature of zones 1, 2 and 3 of the twin-screw extruder is 110°C, the sleeve temperature of zones 4, 5 and 6 is 130-170°C, and the rotation speed is 40-200r / min; preferably, the sleeve temperature of zones 1, 2 and 3 of the twin-screw extruder is 110°C, the sleeve temperature of zones 4, 5 and 6 is 150°C, and the rotation speed is 120r / min.

[0053] In a preferred embodiment of the present invention, the shellac coating liquid comprises, by weight, 25 parts of shellac resin and 1 part of glycerol; the preparation method of the shellac coating liquid is as follows: weigh the shellac resin and glycerol by weight, dissolve the shellac resin in ethanol, add glycerol after dissolution, and mix, wherein the mass concentration of the shellac resin in the ethanol is 5-50%.

[0054] The pH value of piglet gastric juice is usually between 1 and 2. However, due to the addition of pancreatic juice and bile in the duodenum, the pH value will rise to near neutral or slightly alkaline, about 6.8. Under simulated gastric juice conditions, the cumulative release rate of shellac resin increases with time. But in simulated intestinal juice (pH 6.8), the release rate of shellac resin will significantly accelerate. Therefore, in the present invention, shellac coating solution is used to perform enteric coating on gallnut expanded feed, which has the functions of airtightness, moisture-proof, and astringency masking, and the formed coating is acid-resistant, reducing the dissolution and release of the additive functional ingredient tannic acid in the stomach. After the tannic acid additive enters the duodenum, under the action of bile, etc., the additive coating swells and disintegrates, and the tannic acid in the additive can be quickly dissolved and act on the intestinal mucosa, improving the bioavailability of tannic acid.

[0055] In a preferred embodiment of the present invention, the temperature for spraying the shellac coating solution is 45 °C, the spraying flow rate is 100 kg / h, and the spraying time is 2 h.

[0056] In a preferred embodiment of the present invention, the mass ratio of oxidized cassava starch, carboxymethyl cellulose, and glycerol is 30∶20∶10; however, it includes but is not limited to oxidized cassava starch and carboxymethyl cellulose, and also includes edible natural polymers such as corn starch, chitosan, and arabic gum.

[0057] In a preferred embodiment of the present invention, the moisture content of fresh gallnuts after steam treatment is <50%.

[0058] In a preferred embodiment of the present invention, the steam pressure of the steam treatment is 0.3 MPa.

[0059] In a preferred embodiment of the present invention, the gallnut expanded feed is fluidized and granulated to a particle size of 5 - 60 mesh.

[0060] An embodiment of the present invention also provides a gallnut feed additive prepared by the above preparation method.

[0061] In the embodiments of the present invention, "parts" represents "parts by weight" unless otherwise specified.

[0062] The applicable raw materials of the method in the embodiments of the present invention are not limited to fresh gallnuts, and also include other plants containing tannins such as tara, acorn cup, and larch.

[0063] The fresh gallnuts used in the embodiments of the present invention are purchased from Wufeng Chicheng Biotechnology Co., Ltd., and the tannic acid content is 63%; the shellac resin is purchased from Anning Daike Fine Chemical Co., Ltd., and the rest of the raw materials are obtained by purchasing on the market.

[0064] The technical solutions of the present invention are further described below through examples.

[0065] Example 1

[0066] (1) Place the fresh galls in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 minutes for inactivation, so that the moisture content of the fresh galls < 50%;

[0067] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotation speed to 40 r / min. Put the galls obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The galls are sheared, extruded, and mixed under the action of the screw to obtain gall fragments. Then, premixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feeding port of zone 6 at the end of the twin-screw extruder and mixed with the gall fragments. After shearing, extrusion, mixing, and puffing, gall expanded material is prepared.

[0068] Example 2

[0069] Same as Example 1, the only difference is that the rotation speed of the twin-screw extruder is set to 80 r / min, specifically:

[0070] (1) Place the fresh galls in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 minutes for inactivation, so that the moisture content of the fresh galls < 50%;

[0071] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotation speed to 80 r / min. Put the galls obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The galls are sheared, extruded, and mixed under the action of the screw to obtain gall fragments. Then, premixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feeding port of zone 6 at the end of the twin-screw extruder and mixed with the gall fragments. After shearing, extrusion, mixing, and puffing, gall expanded material is prepared.

[0072] Example 3

[0073] Same as Example 1, the only difference is that the rotation speed of the twin-screw extruder is set to 120 r / min, specifically:

[0074] (1) Place the fresh galls in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 minutes for inactivation, so that the moisture content of the fresh galls < 50%;

[0075] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotation speed to 120 r / min. Put the galls obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The galls are sheared, extruded, and mixed under the action of the screw to obtain gall fragments. Then, the pre-mixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio of 30:20:10) are added to the feeding port of zone 6 at the tail end of the twin-screw extruder, mixed with the gall fragments, and after shearing, extrusion, mixing, and puffing, gall expanded material is prepared.

[0076] Example 4

[0077] Same as Example 1, the only difference is that the rotation speed of the twin-screw extruder is set to 160 r / min. Specifically:

[0078] (1) Place the fresh galls in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh galls < 50%;

[0079] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotation speed to 160 r / min. Put the galls obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The galls are sheared, extruded, and mixed under the action of the screw to obtain gall fragments. Then, the pre-mixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio of 30:20:10) are added to the feeding port of zone 6 at the tail end of the twin-screw extruder, mixed with the gall fragments, and after shearing, extrusion, mixing, and puffing, gall expanded material is prepared.

[0080] Example 5

[0081] Same as Example 1, the only difference is that the rotation speed of the twin-screw extruder is set to 200 r / min. Specifically:

[0082] (1) Place the fresh galls in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh galls < 50%;

[0083] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotation speed to 200 r / min. Put the gallnuts obtained in step (1) into the feed port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screw to obtain gallnut fragments. Then, the pre-mixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feed port of zone 6 at the tail end of the twin-screw extruder, mixed with the gallnut fragments, and after shearing, extrusion, mixing, and puffing, gallnut puffed material is prepared.

[0084] Use an ultraviolet spectrophotometer to measure the absorbance at 276 nm, and measure the tannic acid content in the gallnut puffed material prepared at different screw rotation speeds in Examples 1-5. The results are shown in Table 1.

[0085] Table 1 Tannic acid content in the gallnut puffed material prepared in Examples 1-5

[0086] Rotational speed / r / min 40 80 120 160 200 Tannic acid content / % 44.31 45.69 46.29 45.19 43.98

[0087] Example 6

[0088] (1) Place fresh gallnuts in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh gallnuts < 50%;

[0089] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 130 °C, and the rotation speed to 120 r / min. Put the gallnuts obtained in step (1) into the feed port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screw to obtain gallnut fragments. Then, the pre-mixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feed port of zone 6 at the tail end of the twin-screw extruder, mixed with the gallnut fragments, and after shearing, extrusion, mixing, and puffing, gallnut puffed material is prepared.

[0090] Example 7

[0091] Same as Example 6, the only difference is that the sleeve temperatures of zones 4, 5, and 6 are changed to 140 °C (i.e., the same as Example 3):

[0092] (1) Place fresh gallnuts in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh gallnuts < 50%;

[0093] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 140 °C, and the rotational speed to 120 r / min. Feed the gallnuts obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screw to obtain gallnut fragments. Then, premixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feeding port of zone 6 at the tail end of the twin-screw extruder and mixed with the gallnut fragments. After shearing, extruding, mixing, and puffing, gallnut puffing material is prepared.

[0094] Example 8

[0095] Same as Example 6, except that the sleeve temperatures of zones 4, 5, and 6 are changed to 150 °C:

[0096] (1) Place fresh gallnuts in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh gallnuts < 50%;

[0097] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 150 °C, and the rotational speed to 120 r / min. Feed the gallnuts obtained in step (1) into the feeding port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screw to obtain gallnut fragments. Then, premixed oxidized cassava starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added to the feeding port of zone 6 at the tail end of the twin-screw extruder and mixed with the gallnut fragments. After shearing, extruding, mixing, and puffing, gallnut puffing material is prepared.

[0098] Example 9

[0099] Same as Example 6, except that the sleeve temperatures of zones 4, 5, and 6 are changed to 160 °C:

[0100] (1) Place fresh gallnuts in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh gallnuts < 50%;

[0101] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 160 °C, and the rotational speed to 120 r / min. Feed the gallnuts obtained in step (1) into the feed port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screws to obtain gallnut fragments. Then, premixed oxidized tapioca starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added into the feed port of zone 6 at the tail end of the twin-screw extruder, and are mixed with the gallnut fragments. After shearing, extrusion, mixing, and puffing, gallnut puffed materials are prepared.

[0102] Example 10

[0103] Same as Example 6, except that the sleeve temperatures of zones 4, 5, and 6 are changed to 170 °C:

[0104] (1) Place fresh gallnuts in high-temperature steam at 133 °C with a steam pressure of 0.3 MPa for 2 min for inactivation, so that the moisture content of the fresh gallnuts < 50%;

[0105] (2) Set the sleeve temperatures of zones 1, 2, and 3 of the twin-screw extruder to 110 °C, the sleeve temperatures of zones 4, 5, and 6 to 170 °C, and the rotational speed to 120 r / min. Feed the gallnuts obtained in step (1) into the feed port of zone 1 at the head end of the twin-screw extruder. The gallnuts are sheared, extruded, and mixed under the action of the screws to obtain gallnut fragments. Then, premixed oxidized tapioca starch, carboxymethyl cellulose, and glycerol (mass ratio 30:20:10) are added into the feed port of zone 6 at the tail end of the twin-screw extruder, and are mixed with the gallnut fragments. After shearing, extrusion, mixing, and puffing, gallnut puffed materials are prepared.

[0106] Use an ultraviolet spectrophotometer to measure the absorbance at 276 nm, and measure the tannic acid content in the gallnut puffed materials prepared at different temperatures in Examples 6 - 10. The results are shown in Table 2.

[0107] Table 2 Tannic acid content in the gallnut puffed materials prepared in Examples 6 - 10

[0108] Temperature / °C 130 140 150 160 170 Tannic acid content / % 44.19 45.29 46.68 43.08 41.54

[0109] Note: The tannic acid content in Tables 1 - 2 is the tannic acid content in the gallnut puffed materials. Since tapioca starch, carboxymethyl cellulose, and shellac resin are added during the preparation process, it is reasonable that the tannic acid content is lower than that in fresh gallnuts.

[0110] It can be seen from the data in Tables 1 and 2 that the dissolution rate of tannic acid in the gallon puffed material is increased by using the extrusion puffing technology in the twin-screw extruder. This may be because the extrusion puffing technology destroys the biological structure of the gallon, and changes the tannic acid in the gallon from the cell content to the cellulose lignin-tannic acid mixture, thereby increasing the dissolution rate of tannic acid and the tannic acid content. Under the conditions of the screw speed of 120r / min and the sleeve temperature of the 4th, 5th and 6th zones being 150℃, the prepared puffed material has the highest tannic acid content and the best physical and chemical properties of the gallon puffing.

[0111] The scanning electron microscope image of the fresh gallnut used in Example 1 is shown in Figure 1 It can be seen that after dyeing, tannic acid appears as crystalline particles in the cells. Tannic acid is mainly distributed in the cells. To release the tannic acid well, it is necessary to destroy the cell wall, so extrusion, shearing and puffing can release the tannic acid faster.

[0112] The dissolution rate of tannic acid in the expanded galloup material (fluidized granulation to 5-60 mesh) and galloup granules (fresh galloup was placed in 133°C high-temperature steam with a steam pressure of 0.3 MPa for 2 minutes to inactivate it, so that the moisture content of the fresh galloup was less than 50%, and then crushed to a particle size of 5-60 mesh) prepared in Example 1 was measured. The results are shown in Table 1. Figure 2 It can be seen that the release rate of tannic acid in the expanded gallon material is significantly increased compared with that in the gallon granules. It takes 4.5 hours for the gallon granules to completely release tannic acid, while the gallon expanded material only takes 3 hours, an increase of 33.3%. Therefore, extrusion puffing significantly increases the release rate of tannic acid.

[0113] Embodiment 11

[0114] (1) dissolving 25 g of shellac resin in 100 mL of 95% ethanol, adding 1 g of glycerol after the dissolution, and mixing to obtain a shellac coating solution;

[0115] (2) The puffed gallon material prepared in Example 2 was put into a fluidized granulator and fluidized into granules of 5-60 mesh. The shellac coating liquid was sprayed into the fluidized granulator from the top with the air flow temperature of 45°C. After drying and film formation, the material was discharged to obtain a gallon feed additive.

[0116] The SEM images of the raw material gallon of Example 2, the gallon puffed material prepared in Example 2, and the gallon feed additive prepared in Example 11 are shown in FIG. Figures 3 - 5 It can be seen that the gallnut itself is relatively dense, and has obvious holes after extrusion and expansion, which increases the release pathway of tannic acid. After coating, the surface has a coating agent to form a smooth film.

[0117] Taking Example 2 as an example, the invention inactivates, extrudes, puffs and granulates gallnuts to obtain granular gallnut puffed materials, and coats them to obtain coated granular gallnut feed additives, and conducts a simulated in vitro release test to evaluate the effects (see the flowchart in Figure 6 ), and the specific evaluation process is as follows:

[0118] (1) Preparation of buffer solution

[0119] Gastric buffer solution (pH = 2.0): Weigh 5.18 g of NaCl and 0.5 g of KCl and put them into a beaker, dissolve them with water, adjust the pH to 2.0, and finally make up the volume to 1 L for standby.

[0120] Small intestine buffer solution (pH = 7.0): Weigh 26.22 g of Na2HPO4·12H2O and 66.84 g of Na2HPO4·2H2O and put them into a 1 L beaker, dissolve them with water, adjust the pH to 7.0, and finally make up the volume to 1 L for standby.

[0121] (2) Preparation of gastric and intestinal juices

[0122] Simulated gastric juice: Weigh 36.875 g of pepsin and dissolve it in gastric buffer solution with pH = 2.0. After dissolution, make up the volume to 500 mL and use it immediately.

[0123] Simulated intestinal juice: Weigh 55.35 g of amylase, 265.65 mg of trypsin and 5.45 mg of chymotrypsin, dissolve them with small intestine buffer solution and make up the volume to 500 mL, and use it immediately.

[0124] (3) In vitro simulated digestion

[0125] Weigh 1 g of the gallnut puffed material prepared in Example 2 (recorded as: puffed material) and 1 g of the gallnut feed additive prepared in Example 11 (recorded as: shielded material) samples and place them in a 50 mL conical flask. Add 40 mL of simulated gastric juice to the conical flask, place the conical flask in a 38 °C thermostatic shaker and oscillate it at a constant temperature of 100 r / min for 4 h. Take 5 mL of the digestive juice every 1 h and soak it in hot water at 90 °C for 5 min, then centrifuge it at 8000 r / min for 10 min, and finally filter it through a 0.22 μm filter membrane and detect the tannic acid content.

[0126] At the end of the gastric simulated digestion, clean up the gastric simulated solution, then add 40 mL of simulated small intestine juice to the conical flask, and oscillate it at a constant temperature for 8 h. Take samples every 2 h, and measure the tannic acid content by the same treatment method. Do 3 parallel tests, and the results are shown in Figure 7 .

[0127] From Figure 7It can be seen that after in vitro simulated gastric (4 h) and intestinal (8 h) release, the tannic acid release of the expanded feed in the gastric stage is 30.4%, and the release amount reaches 68.2% in the intestinal stage, with a total release of 98.6%; the tannic acid release of the shielded feed in the gastric stage is 4.2%, and the release amount reaches 92.6% in the intestinal stage, indicating that the secondary coating reduces the release of tannic acid in the stomach and increases the release amount in the intestine, with a total release of 96.8%. This is because the gallotannic acid has a good controlled release rate in the intestine after being coated with shellac resin, and the shellac resin coating can significantly increase the release amount of tannic acid in the intestine.

[0128] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a gallnut feed additive, characterized in that, The following steps are involved: After the fresh pallets are treated with steam, they are added into a twin-screw extruder to obtain pallet crushed material, and then the pre-mixed oxidized cassava starch, carboxymethyl cellulose and glycerol are added into the twin-screw extruder to mix with the pallet crushed material to obtain pallet expanded material; The gallon puffed material is fluidized and granulated and then sprayed with shellac coating liquid to obtain the gallon feed additive.

2. The preparation method of the gallnut feed additive according to claim 1, characterized in that, The barrel temperature of the twin-screw extruder is 110-170° C., and the rotation speed is 40-200 r / min.

3. The preparation method of the gallnut feed additive according to claim 2, wherein, The sleeve temperatures of zones 1, 2 and 3 of the twin-screw extruder are all 110° C., the sleeve temperatures of zones 4, 5 and 6 are all 130-170° C., and the rotation speeds of zones 1-6 are all 40-200 r / min.

4. The preparation method of the gallnut feed additive according to claim 3, characterized in that The sleeve temperature of the twin-screw extruder in zones 1, 2 and 3 is 110° C., the sleeve temperature of zones 4, 5 and 6 is 150° C., and the rotation speed is 120 r / min.

5. The preparation method of the gallnut feed additive according to claim 1, characterized in that, The shellac coating liquid comprises, by weight, 25 parts of shellac resin and 1 part of glycerol.

6. The preparation method of the gallnut feed additive according to claim 1, characterized in that, The temperature of the sprayed shellac coating liquid is 45° C., the spraying flow rate is 100 kg / h, and the spraying time is 2 hours.

7. The preparation method of the gallnut feed additive according to claim 1, characterized in that, The mass ratio of the oxidized cassava starch, carboxymethyl cellulose and glycerol is 30:20:

10.

8. The preparation method of the gallnut feed additive according to claim 1, characterized in that, After steam treatment, the moisture content of fresh gallnuts is less than 50%.

9. A galloate feed additive prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the galloate feed additive according to claim 9 in preparing animal feed.

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