Pet food

Abstract

To provide a pet food that is more easily crunched while holding a satisfactory chewing feel, so that the palatability is improved.SOLUTION: A pet food has pores 1. When the pet food is projected in a first direction, a first surface C1 has a pore area ratio of 10% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to pet foods. [Background technology]

[0002] Pet food can be divided into staple foods and snacks depending on the occasion for feeding. Pet food used as a staple food is called a "complete nutritional food" and is made so that pets can get all the nutrients they need by simply giving them the food and water. On the other hand, "snacks" are pet foods that are intended to be given in limited amounts for training, exercise, or as a reward. They are classified by purpose into "complete nutritional foods," "snacks," "therapeutic foods," and "foods for other purposes" that do not fall into any of the above categories.

[0003] In addition, pet food is broadly classified by moisture content into dry food with a moisture content of about 10% (12% or less), soft food with a moisture content of about 25-35% and foamed, semi-moist food with a moisture content of about 25-35%, and wet food with a moisture content of about 75%. Of these, demand for dry pet food has been increasing in recent years due to its ease of handling and good storage properties.

[0004] Dry pet food is generally hard, not only harder than other types of pet food, but also harder than most foods eaten by humans. Dogs and cats are originally carnivores, and their teeth evolved primarily for holding prey or cutting meat, and are not suited to crushing hard foods with their molars. For these reasons, traditional hard dry pet food is not easy for dogs and cats to eat. Easy-to-chew kibble makes it easy to eat, and easy-to-eat kibble means high palatability.

[0005] Although it is not a dry type pet food, Patent Document 1 discloses an aerated pet treat that is a low-calorie, low-fat treat that is easy to chew and has less than about 5 kilocalories per gram of weight. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2016-515808 Summary of the Invention [Problem to be solved by the invention]

[0007] Although ease of chewing leads to improved palatability, pet food with a chewy texture also improves palatability. In other words, simply improving the chewability of pet food by whipping the pet food, for example, as in the pet food described in Patent Document 1, results in a decrease in chewiness. As a result, this does not lead to improved palatability. Furthermore, the pet food described in Patent Document 1 requires air to be mixed in and whipped, which limits the ingredients that can be included.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pet food that is easy to chew while maintaining chewiness, thereby improving palatability. [Means for solving the problem]

[0009] The present invention has the following aspects. [1] A pet food having openings, wherein the opening area ratio of a first surface of the pet food projected in a first direction is 10% or more. [2] The pet food according to [1], wherein the open area ratio of the surface of the pet food projected in a direction other than the first direction is 8% or less. [3] The pet food according to [1] or [2], wherein, when the surface of the pet food projected onto side A of a second direction intersecting the first direction is defined as the second surface, and the surface of the pet food projected onto side B of the second direction is defined as the third surface, the open area ratio of at least one of the second surface and the third surface is 10% or more. [4] The pet food according to [3], wherein the open area ratio of both the second surface and the third surface is 10% or more. [5] The pet food according to any one of [1] to [4], wherein the ratio of the open area ratio on the first surface to the open area ratio on a cross section when the pet food is cut perpendicular to the first direction (open area ratio on the first surface / open area ratio on the cross section) is 0.4 to 2. [6] The pet food according to any one of [1] to [5], wherein the ratio of the open area ratio on the first surface to the open area ratio on a cross section when the pet food is cut so as to divide the first surface equally (open area ratio on the first surface / open area ratio on the cross section) is 0.4 to 2. [Effects of the Invention]

[0010] According to the present invention, pet food with improved palatability can be obtained by making the food easier to chew while maintaining chewiness. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic view showing a pet food according to a first embodiment of the present invention. [Figure 2] 2A to 2C are schematic diagrams illustrating projection surfaces of the pet food according to the first embodiment of the present invention projected in various directions. [Figure 3] FIG. 3 is a schematic view showing a pet food according to a second embodiment of the present invention. [Figure 4] 5A to 5C are schematic diagrams illustrating projection surfaces of pet food according to a second embodiment of the present invention projected in various directions. [Figure 5] FIG. 2 is a schematic diagram for explaining the method for producing the pet food of the present embodiment. [Figure 6]1 shows an image of the first surface of a pet food product of an example, and an image taken when the open pore area ratio of the first surface was measured. [Figure 7] 1 shows an image of the third surface of the pet food of an example, and an image taken when the open pore area ratio of the third surface was measured. [Figure 8] 1 shows an image of the fifth surface of the pet food of an example, and an image taken when the open pore area ratio of the fifth surface was measured. [Figure 9] 1 shows an image of the first surface of a pet food product of an example when the open pore area ratio was measured, and an image of the cross section when the open pore area ratio was measured. [Figure 10] 1 shows an image of the third surface of the pet food of an example when the open pore area ratio was measured, and an image of the cross section when the open pore area ratio was measured. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification, the term "pet" refers to an animal kept by a human. In a narrower sense, a pet is an animal kept as a pet by its owner. Furthermore, the term "pet food" refers to feed for pets. The pet food of the present invention can be sold as "animal feed" or "animal food."

[0013] In this specification, "palatability" is an index of whether a food is enjoyed by pets and is determined by texture, taste, smell, and the like.

[0014] In this specification, the value of moisture content is the value obtained by the "loss on drying method". The loss on drying method involves heating and drying a sample by infrared irradiation, and determining the amount of moisture in the sample from the change in mass due to evaporation of the moisture contained therein. The moisture content can be measured using a known device. For example, the moisture content can be measured using an Infrared Moisture Analyzer FD-720 (manufactured by Kett Electric Laboratory).

[0015] In this specification, the size of the pet food refers to the diameter if the pet food is spherical, and refers to the longest diameter if the pet food is shaped other than spherical (cylindrical, polygonal pillar, plate-like, etc.).

[0016] (Pet food) The pet food of this embodiment is a pet food having openings. In this specification, "open holes" refer to minute holes present on the surface and inside of the pet food. The holes may be interconnected as communicating holes, with a plurality of holes being connected together. On the other hand, for example, holes that penetrate from the front surface of pet food to the corresponding back surface, such as in donut-shaped pet food, are not included in the definition of "holes" because they do not have the effect of making the food easier to chew while maintaining its chewiness.

[0017] The pet food according to this embodiment may consist solely of the pet food according to this embodiment, or may be a mixture of the pet food according to this embodiment with another pet food. The other pet food is not particularly limited, and examples include dry pet foods, ingredients, flakes, etc. other than the pet food according to this embodiment. In a mixture of the pet food according to this embodiment and another pet food, the pet food according to this embodiment may be contained in an amount of 1% or more of the total amount of the mixture.

[0018] More specifically, "open pores" means pores having a circle-equivalent diameter of 50 to 5000 μm, for example. When the openings are communicating holes, the equivalent circle diameter refers to the equivalent circle diameter when the surface of the pet food is viewed from above. More specifically, it refers to the value obtained by taking an image of the surface of the pet food using, for example, a digital microscope (product name "VHX-7000", manufactured by Keyence Corporation) and using the image to measure the equivalent circle diameter of the openings (communicating holes) with the measurement and scale tool of the digital microscope.

[0019] <Open area ratio of the first surface> In the pet food of this embodiment, the open area ratio of a first surface when the pet food is projected in a first direction is 10% or more. The first direction may be any direction. For example, if the pet food of this embodiment is placed on the measurement stage of the digital microscope and an image of the surface (top surface) opposite to the surface on which the pet food is placed is captured, the direction from the digital microscope toward the top surface of the pet food is the first direction. Furthermore, the image of the top surface of the pet food captured by the digital microscope is the first surface onto which the pet food is projected.

[0020] The open area ratio of the first surface of the pet food of this embodiment is 10% or more, preferably 12% or more, more preferably 16% or more, even more preferably 20% or more, and particularly preferably 25% or more. If the open area ratio of the pet food is 10% or more, the pet food becomes easier to chew and is more palatable. Furthermore, if the open area ratio of the pet food is equal to or greater than the above-mentioned preferred value, the pet food becomes easier to chew, and the palatability is further improved.

[0021] On the other hand, the open area ratio of the first surface of the pet food of this embodiment is preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. When the open area ratio of the pet food is equal to or less than the above-mentioned preferable value, the chewing texture of the pet food is improved, and the palatability is further improved.

[0022] For example, the open area ratio of the first surface of the pet food of this embodiment is preferably 10% or more and 60% or less, more preferably 12% or more and 60% or less, even more preferably 16% or more and 55% or less, particularly preferably 20% or more and 50% or less, and most preferably 25% or more and 50% or less.

[0023] In this specification, the term "open pore area ratio" refers to the value obtained by taking an image of the surface of the pet food using a digital microscope (product name "VHX-7000", manufactured by Keyence Corporation) and using the image to measure the open pore area ratio using the automatic area measurement (particle count) function of the measurement and scale tool of the digital microscope, excluding particles with a circle equivalent diameter of less than 50 μm. More specific operation procedures are as follows:

[0024] (i) Set the magnification of the digital microscope so that the first surface of the pet food placed on the measurement table is entirely reflected (for example, set to 20x). (ii) The setting value for the epi-illumination is set to a value between 100 and 255 at which the aperture is most visible. (iii) In the digital microscope's measurement and scale tool, automatic area measurement (particle counting), set the extraction method to "brightness (standard)." Next, set the extraction area for the first surface of the pet food. (iv) By excluding particles with a circle equivalent diameter of less than 50 μm and performing automatic area measurement (particle counting) using the measurement and scale tool of a digital microscope, the open area ratio of the first surface of the pet food can be measured.

[0025] <Open area ratio of other surfaces> The pet food of this embodiment preferably has an open pore area ratio of a surface of the pet food projected in a direction other than the first direction (hereinafter also referred to as "other surface") of 8% or less. In other words, the pet food of this embodiment preferably has a surface that includes a mixture of areas with a large number of open pores and areas with a small number of open pores. The pet food of this embodiment has a first surface with an open area ratio of 10% or more and another surface with an open area ratio of 8% or less, which allows the pet food to be enjoyed with multiple textures when chewed, thereby further improving its palatability.

[0026] The open area ratio of the other surface of the pet food of this embodiment is preferably 8% or less, more preferably 4% or less, even more preferably 2% or less, and may be 0%. If the open area ratio of the other surfaces of the pet food of this embodiment is not more than the above-mentioned preferred value, the difference between the open area ratio of the first surface of the pet food and the open area ratio of the other surfaces will be greater, allowing for a greater variety of textures to be enjoyed, further improving palatability.

[0027] <Open area ratio of the second and third surfaces> In the pet food of this embodiment, in addition to the first surface described above, if the surface of the pet food projected to side A (which can also be referred to as the + side, the first side, or one side) of a second direction intersecting the first direction is defined as the second surface, and the surface of the pet food projected to side B (which can also be referred to as the - side, the second side, or the other side) of the second direction is defined as the third surface, it is preferable that at least one of the second surface and the third surface has an open pore area ratio of 10% or more. In other words, it is preferable that the pet food of this embodiment has multiple areas on its surface with a large number of open pores.

[0028] Here, the second direction typically means a direction that is "perpendicular" to the first direction, but is not limited to a direction that is perpendicular to the first direction, and may also mean a specified direction that intersects the first direction and is perpendicular to the surface of the pet food. For example, as a specific example where the second direction is not a direction perpendicular to the first direction, if the pet food of this embodiment is tetrahedral and the bottom surface is the first surface, the second direction would be a direction perpendicular to the side surface of the tetrahedral pet food. Furthermore, when the pet food of this embodiment has a shape such as a sphere or a cylinder that cannot be expressed by a surface, the second direction means a direction "perpendicular" to the first direction.

[0029] The preferred ranges of the open area ratios of the second and third surfaces are the same as the preferred range of the open area ratio of the first surface described above. If the open area ratio of at least one of the second and third surfaces of the pet food of this embodiment is equal to or greater than the above-mentioned preferred value, the pet food becomes easier to chew and its palatability is further improved. Furthermore, if the open area ratio of at least one of the second and third surfaces of the pet food of this embodiment is equal to or less than the above-mentioned preferred value, the chewiness of the pet food is further improved and its palatability is further improved.

[0030] In the pet food of the present embodiment, in addition to the above-described first side of the pet food, the open area ratio of the second side and the third side of the pet food is preferably all 10% or more. If the open area ratios of the second and third sides of the pet food of this embodiment are equal to or greater than the above-mentioned preferred values, the pet food will be easier to chew and will have better palatability. If the open area ratios of the second and third sides of the pet food of this embodiment are equal to or less than the above-mentioned preferred values, the pet food will have better chewing texture and will have better palatability.

[0031] In the pet food of this embodiment, it is preferable that the open area ratio of the first, second and third surfaces is all 10% or more, and that the open area ratio of at least one surface other than the first, second and third surfaces is 8% or less.

[0032] More specifically, in the pet food of this embodiment, the open area ratios of the first, second and third surfaces are all preferably 10% or more and 60% or less, and at least one surface other than the first, second and third surfaces is preferably 8% or less; more preferably the open area ratios of the first, second and third surfaces are all 12% or more and 60% or less, and at least one surface other than the first, second and third surfaces is preferably 4% or less; and the open area ratios of the first, second and third surfaces are all 16% or more and 55% or less, and at least one surface other than the first, second and third surfaces is preferably 4% or less. It is more preferable that the open area ratios of the first, second and third surfaces are all 20% or more and 50% or less, and that the open area ratio of at least one surface other than the first, second and third surfaces is 4% or less, even more preferable that the open area ratios of the first, second and third surfaces are all 25% or more and 50% or less, and that the open area ratio of at least one surface other than the first, second and third surfaces is 4% or less, and it is particularly preferable that the open area ratios of the first, second and third surfaces are all 25% or more and 50% or less, and that the open area ratio of at least one surface other than the first, second and third surfaces is 4% or less, and it is most preferable that the open area ratios of the first, second and third surfaces are all 25% or more and 50% or less, and that the open area ratio of at least one surface other than the first, second and third surfaces is 2% or less. Furthermore, in the above pet food, "at least one surface other than the first, second and third surfaces" is preferably "two surfaces other than the first, second and third surfaces."

[0033] <Ratio of the open area ratio of the first surface to the open area ratio of the cross section> In the pet food of the present embodiment, the ratio of the open area ratio in the first surface to the open area ratio in a cross section (hereinafter referred to as cross section A) when the pet food is cut perpendicular to the first direction (open area ratio in first surface / open area ratio in cross section A) is preferably 0.3 to 3. In other words, from the perspective of further improving palatability, the pet food of the present embodiment preferably has open pores not only on the surface of the pet food but also inside the pet food.

[0034] In the pet food of this embodiment, the ratio of the open area ratio of the first surface to the open area ratio of the cross section A is preferably 0.3-3, more preferably 0.35-2.5, and even more preferably 0.4-2. If the ratio of the open area ratio of the first surface to the open area ratio of cross section A is within the above preferred range, the pet food is easier to chew and has an improved chewability, further improving palatability.

[0035] In the pet food of this embodiment, the ratio of the open area ratio on the first surface to the open area ratio on a cross section (hereinafter referred to as cross section B) when the pet food is cut in the first direction so as to equally divide the first surface (open area ratio on first surface / open area ratio on cross section B) is preferably 0.3 to 3. In other words, from the perspective of further improving palatability, the pet food of this embodiment preferably has open pores not only on the surface of the pet food but also inside the pet food.

[0036] In the pet food of this embodiment, the ratio of the open area ratio of the first surface to the open area ratio of cross section B is preferably 0.3-3, more preferably 0.35-2.5, and even more preferably 0.4-2. If the ratio of the open area ratio of the first surface to the open area ratio of cross section B is within the above-mentioned preferred range, the pet food is easier to chew and has an improved chewability, thereby further improving palatability.

[0037] In the pet food of this embodiment, the ratio of the open area ratio of the first surface to the open area ratio of cross section A or cross section B is preferably 0.3 to 3, more preferably 0.35 to 2.5, and even more preferably 0.4 to 2. In the pet food of this embodiment, the ratio of the open area ratio of the first surface to the open area ratio of cross section A and cross section B is preferably 0.3 to 3, more preferably 0.35 to 2.5, and even more preferably 0.4 to 2.

[0038] <Pet food particle density> The pet food of this embodiment preferably has a granule density of 600 g / L or less, more preferably 500 g / L or less, and even more preferably 400 g / L or less. If the granule density of the pet food of this embodiment is equal to or less than the above-mentioned preferred value, the pet food becomes easier to chew and its palatability is further improved. Furthermore, if the granule density is equal to or less than the above-mentioned preferred value, the mass per unit volume can be reduced while maintaining an appropriate chewiness, and a feeling of fullness can be easily obtained, thereby further improving the diet effect.

[0039] The granule density of pet food is calculated using the following formulas (1) and (2). Grain volume (L) = Grain volume (mm 3 ) / 1,000,000···(1) Grain density (g / L) = Grain mass (g) / Grain volume (L) (2)

[0040] The particle mass in the above formula (2) can be measured by the following procedure. (Step 1A) Select one pet food to be measured. (Step 2A) The mass of one grain is measured using an electronic balance.

[0041] The particle volume in the above formula (2) can be measured by the following procedure. (Step 1B) Select one pet food to be measured. (Step 2B) The grain volume is calculated using an X-ray CT device (for example, CosmoScan FX (manufactured by Rigaku Corporation)).

[0042] In this embodiment, the CT images in step 2B are taken under the following conditions. (CT image shooting conditions) Tube voltage: 90kV Tube current: 88μA Irradiation time: 2 minutes Resolution: 50μm FOV (Field of View): 25.6mm x 25.6mm x 25.6mm matrix:512×512×512

[0043] In the above step 2B, the area of ​​the entire grain (grain area) in each CT cross-sectional image is calculated by the following procedure. (ib) Using image analysis software (e.g., Fiji), the X-ray CT images are binarized (maximum entropy method). For each grain cross-sectional image, the background value is subtracted to calculate the grain area. (iib) In each CT cross-sectional image, the area of ​​the entire grain (grain area) is calculated by filling in the holes using Fill holes and Dilate / Erode processing and subtracting the background value. Under the above conditions, the CT image is measured by dividing the FOV (Field of View) into 512 equal parts, so one CT cross-sectional image can be considered to be 50 μm thick. Therefore, multiplying the grain area of ​​one CT cross-sectional image by the thickness of 50 μm gives the grain volume of one CT cross-sectional image, and adding up the grain volumes of all the CT cross-sectional images makes it possible to calculate the grain volume of one food grain being measured.

[0044] ≪Shape≫ The shape of the pet food of this embodiment is not particularly limited as long as it is a shape suitable for pets to eat. For example, any shape can be applied, such as a sphere, an ellipsoid (go stone shape), a pellet, a cylinder, a polygonal prism, a hexahedron (plate shape), a cloverleaf shape, a heart shape, a star shape, a cross shape, etc. Among these, from the viewpoint of more easily achieving the effects of the present invention, a cylinder, a polygonal prism or a hexahedron shape is preferred, and a hexahedron shape is more preferred.

[0045] <Size> The size of the pet food of this embodiment may be small enough for a pet to eat in one bite, or large enough for a pet to bite into multiple times, but the longest diameter of the pet food is preferably 1 to 200 mm, more preferably 1 to 150 mm, and even more preferably 3 to 40 mm. Furthermore, the shortest diameter of the pet food is preferably 1 to 100 mm, more preferably 1 to 50 mm, and even more preferably 3 to 30 mm.

[0046] ≪Moisture content≫ The water content of the pet food of this embodiment is preferably from 1 to 50% by mass, more preferably from 3 to 30% by mass, and even more preferably from 3 to 12% by mass. From the viewpoint of more easily achieving the effects of the present invention, the pet food of this embodiment is preferably a dry food with a moisture content of about 10% or less, and more preferably a dry food with a moisture content of 5 to 12%.

[0047] <Hardness> The hardness of the pet food of this embodiment is preferably 60N or less, more preferably 50N or less, and even more preferably 40N or less. If the hardness of the pet food is equal to or less than the above-mentioned preferred value, the pet food becomes easier to chew and is more palatable.

[0048] On the other hand, the hardness of the pet food of this embodiment is preferably 6N or more, more preferably 8N or more, and even more preferably 10N or more. If the hardness of the pet food is equal to or greater than the above-mentioned preferred value, the chewing texture of the pet food will be improved, and the palatability will be further improved.

[0049] In this specification, the hardness of pet food is a value obtained by the following measurement method. Using a compression tester (Texture Analyzer, Model No. EZ-SX, manufactured by Shimadzu Corporation), the breaking force is measured when the pet food is compressed at a constant compression speed. Specifically, one pet food to be measured is placed on a tray, and the test force is measured while pressing the plunger vertically from directly above at a constant speed. The peak value (maximum value) of the test force is read as the breaking force. The measurement is repeated for 10 pet foods, and the average value is calculated. The breaking force (unit: kgw) measured by the compression tester is multiplied by 9.8 to convert the unit into Newtons (N). The measurement conditions are as follows. Plunger: Width 10mm, length 20mm, tip 1mm thick, wedge-shaped plunger Platform: 100mm diameter flat tray Compression speed: 60 mm / min The lowest point of the plunger: Set it so that it is pushed in 70-90% of the thickness (height) of the pet food. Measurement temperature: 25℃

[0050] In the pet food of this embodiment, the hardness of the first surface preferably has the above-mentioned preferred hardness value. That is, in the method for measuring the hardness of pet food described above, the value (hardness) of the test force measured while pressing a plunger against the first surface of the pet food of this embodiment is preferably 6 N or more and 60 N or less, more preferably 8 N or more and 50 N or less, and even more preferably 10 N or more and 40 N or less.

[0051] Furthermore, when the pet food of this embodiment has another surface with an open area ratio of 8% or less, the value (hardness) of the test force measured while pressing a plunger against the other surface of the pet food of this embodiment is preferably 15 N or more and 70 N or less, more preferably 20 N or more and 60 N or less, and even more preferably 25 N or more and 50 N or less.

[0052] ≪Water absorption rate≫ The pet food of this embodiment has an open area ratio of the first surface of 10% or more and a large specific surface area, resulting in a pet food with a higher water absorption rate than conventional pet foods. Furthermore, because of its high water absorption rate, the hardness of the pet food can be easily adjusted in a short time to suit the pet's preference by soaking it in water. Furthermore, since the higher the open pore area ratio, the larger the specific surface area and the higher the water absorption rate, the high open pore area ratio of the pet food of this embodiment can also be expressed in terms of water absorption rate.

[0053] 5-second water absorption rate The 5-second water absorption rate of the pet food of this embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 80% by mass or more, particularly preferably 100% by mass or more, and most preferably 130% by mass or more. As used herein, the "5-second water absorption rate" refers to the ratio of the increase in mass of a pet food when the pet food is immersed in water for 5 seconds at a constant temperature to the original mass of the pet food.

[0054] In this specification, the temperature of water when measuring water absorption typically means a value measured in water at 20°C, but may also be a value measured in water at, for example, 5 to 60°C, or 15 to 30°C. Since the lower the temperature, the lower the water absorption, so if the 5-second water absorption measured in water at a lower temperature is equal to or higher than the above-mentioned preferred value, it can be said that the pet food has higher water absorption.

[0055] Water absorption rate for 30 seconds The 30-second water absorption rate of the pet food of this embodiment is preferably 40% by mass or more, more preferably 60% by mass or more, even more preferably 100% by mass or more, particularly preferably 120% by mass or more, and most preferably 150% by mass or more. In this specification, the "30-second water absorption rate" is the ratio of the increase in mass of the pet food when the pet food is immersed in water for 30 seconds at the above-mentioned temperature to the original mass of the pet food.

[0056] 60-second water absorption rate The 60-second water absorption rate of the pet food of this embodiment is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 120% by mass or more, particularly preferably 140% by mass or more, and most preferably 160% by mass or more. In this specification, the "60-second water absorption rate" refers to the ratio of the increase in mass of the pet food when the pet food is immersed in water for 60 seconds at the above-mentioned temperature to the original mass of the pet food.

[0057] For example, the pet food of this embodiment is preferably a pet food in which the open area ratio of the first side is 10% or more and the 5-second water absorption rate measured in water at 20°C is equal to or greater than the above-mentioned preferred value. Furthermore, the pet food of this embodiment is preferably one in which the open area ratio of the first side is 10% or more and the 30-second water absorption rate measured in water at 20°C is equal to or greater than the above-mentioned preferred value. Furthermore, the pet food of this embodiment is preferably one in which the open area ratio of the first side is 10% or more and the water absorption rate for 60 seconds measured in water at 20°C is equal to or greater than the above-mentioned preferred value.

[0058] <Water absorption measurement method> 5-second water absorption rate The 5-second water absorption rate is a value determined by the following method. (Step 1) First, a predetermined amount of pet food granules is placed in a container filled with water, and the pet food granules are immersed in the water. (Step 2) After the pet food granules have been immersed in the water for 5 seconds, immediately remove the pet food granules from the container and drain the water. In step 2, the method for draining the water is not particularly limited as long as it is a known method. For example, a method in which the collected pet food granules are left to stand on Kimtowel (manufactured by Nippon Paper Crecia Co., Ltd.) for 3 seconds is recommended, but a method in which the collected pet food granules are sandwiched between a mesh or the like and shaken for about 1 to 10 seconds is also acceptable.

[0059] The 5-second water absorption rate can be calculated by subtracting the mass of the pet food in (step 1) from the mass of the pet food after (step 2), and dividing the result by the mass of the pet food in (step 1), according to the following formula (1). 5-second water absorption rate (mass%) = (mass (g) of pet food after (process 2) - mass (g) of pet food in (process 1)) / mass (g) of pet food in (process 1) × 100 (1)

[0060] The predetermined amount in (Step 1) is, for example, 20 g.

[0061] 30-second and 60-second water absorption rates The 30-second water absorption rate and the 60-second water absorption rate were determined in the same manner as the above-described method for measuring the 5-second water absorption rate, except that the immersion time in water in step 2 for the 5-second water absorption rate was changed to 30 seconds or 60 seconds, respectively.

[0062] ≪Water activity≫ The water activity of the pet food of this embodiment is preferably less than 0.65. Pet food spoilage occurs primarily when proteins are broken down by bacteria and mold. Depending on the type of microorganisms that grow, they can cause food poisoning. For microorganisms to grow, in addition to the presence of nutrients and an appropriate temperature, the presence of an appropriate amount of water is essential. However, microorganisms can only utilize the water in pet food, which is called "free water." The moisture in pet food can be broadly divided into "bound water" and "free water" depending on its state of existence.

[0063] "Bound water" is water that is bound to other components in pet food (proteins, carbohydrates, etc.) by hydrogen bonds, restricting molecular movement. For this reason, "bound water" does not freeze even at 0°C, does not evaporate easily even at high temperatures, and is not available to microorganisms. On the other hand, "free water" is water whose molecules can move freely, and is expressed as an index called water activity. "Water activity" is the value obtained by dividing the water vapor pressure of a food product by the water vapor pressure of pure water under the same conditions. Water activity has a significant impact on lipid oxidation and the growth of microorganisms present in pet food. Water activity (Aw)=P / P0 P: Water vapor pressure of pet food P0: Water vapor pressure of pure water

[0064] <Hardness of pet food granules> - Hardness of pet food pellets after soaking in water for 5 seconds In this embodiment, the hardness of the pet food granules after immersion in water for 5 seconds is preferably 50N or less, more preferably 40N or less, even more preferably 30N or less, particularly preferably 20N or less, and most preferably 10N or less. In this specification, "hardness of pet food granules immersed in water for 5 seconds" means the value of the hardness of the pet food after immersing the pet food in water for 5 seconds, determined using the method described above.

[0065] - Hardness of pet food pellets soaked in water for 30 seconds In this embodiment, the hardness of the pet food granules after immersion in water for 30 seconds is preferably 30N or less, more preferably 25N or less, even more preferably 15N or less, particularly preferably 10N or less, and most preferably 5N or less. In this specification, "hardness of pet food granules immersed in water for 30 seconds" means the value of the hardness of the pet food after immersing the pet food in water for 30 seconds, determined using the method described above.

[0066] - Hardness of pet food pellets soaked in water for 60 seconds In this embodiment, the hardness of the pet food granules after immersion in water for 60 seconds is preferably 20N or less, more preferably 15N or less, even more preferably 10N or less, particularly preferably 5N or less, and most preferably 4N or less. In this specification, "hardness of pet food granules immersed in water for 60 seconds" means the value of the hardness of the pet food after immersing the pet food in water for 60 seconds, determined using the method described above.

[0067] Pet food soaked in water to have hardness after immersion for 5 seconds, 30 seconds, and 60 seconds can be obtained by the same steps as (Step 1) and (Step 2) above. Furthermore, the hardness of the pet food granules immersed in water for 5 seconds, 30 seconds, or 60 seconds is the hardness of the pet food measured within 20 seconds (preferably within 10 seconds) after draining the water in step 2 above.

[0068] The pet food of this embodiment has an open area ratio of 10% or more on the first surface, making it easy to chew while maintaining a chewy texture, and highly palatable. However, pet preferences may vary depending on factors such as health and growth conditions, and preferences for pet food hardness may also vary. The pet food of this embodiment has an open area ratio of the first surface of 10% or more and a large specific surface area, so it also has a high water absorption rate, and by immersing the pet food of this embodiment in water, the hardness of the pet food can be softened in a short period of time. Therefore, the pet food of this embodiment has the excellent properties of being easy to chew while maintaining a chewy texture, and can be easily adjusted to the desired hardness by soaking it in water.

[0069] ≪Raw materials≫ As ingredients for the pet food of this embodiment, powder ingredients and liquid ingredients known in the manufacture of pet food can be used, and the following pet food ingredients may be used alone or in combination of two or more.

[0070] Specific examples of powdered and liquid raw materials include grains (corn, grain sorghum, wheat, barley, brown rice, oats, rye, wheat flour, rice flour, corn flour, wheat bran, rice, wheat germ, wheat gluten, corn gluten feed, corn gluten meal, breadcrumbs, etc.); potatoes (sweet potatoes, potatoes, etc.); pulses (soybeans, broad beans, adzuki beans, peas, defatted soybeans, soybean meal, soybean flour, soybean flour, soy protein, okara, etc.); and starch. Flours (cornstarch, potato starch, tapioca starch, wheat starch, rice starch, potato starch, sweet potato starch, sago starch, etc.); meats (beef, pork, lamb, mutton, chicken, turkey, poultry, etc., liver and other organs, meat extract powders and liquids, processed products such as pork meal, chicken meal, beef meal, and mixed meals of these); seafood (tuna, bonito, salmon, cod, horse mackerel, sardines, etc.) Crustaceans such as shrimp and crab, shellfish, processed fish meal, fish extract powder and liquid, dried bonito flakes, etc.; eggs (chicken eggs (whole eggs, dried whole eggs, egg yolks, egg whites), etc.); vegetables (carrots, cabbage, green peas, pumpkin, beet pulp, etc.), nuts and seeds; mushrooms; sugars (sugar, glucose, fructose, isomerized sugar, oligosaccharides, starch syrup, syrup, molasses, honey, etc.); dairy products (whole milk, skim milk, whole milk powder, skim milk powder, whey, cheese, butter, cream cream, etc.); oils and fats (animal fats (beef tallow, lard, chicken fat, fish oil, etc.); vegetable fats and oils (soybean oil, sesame oil, germ oil, palm oil, corn oil, olive oil, coconut oil, etc.), fatty acids, etc.); dried yeast and its extract powder and liquid; dietary fiber (cellulose, etc.); herbs; vitamins; minerals; amino acids; sweeteners; coloring agents; preservatives; thickening agents; modified starch; antioxidants; pH adjusters; seasonings; emulsifiers; leavening agents; flavorings, etc.

[0071] Of the above, the pet food of the present embodiment preferably contains grains and meat. The content of grains in the pet food of this embodiment is preferably 10 to 90 mass %, more preferably 15 to 80 mass %, and even more preferably 20 to 70 mass %, relative to the total mass of the pet food.

[0072] The meat content in the pet food of this embodiment is preferably 1 to 40 mass %, more preferably 3 to 30 mass %, and even more preferably 5 to 20 mass %, relative to the total mass of the pet food.

[0073] The pet food of this embodiment is preferably a mixture of (a) grains, (b) beans, (c) meat, (d) seafood, (e) dietary fiber, (f) dry yeast or its extract powder or liquid, (g) vegetables, (h) vitamins and minerals, and (i) fats and oils, among the above. The mixture may contain coloring agents, antioxidants, and seasonings as needed.

[0074] The pet food of this embodiment may be a mixture of (a) grains, (b) beans, (c) meat, (d) seafood, (e) dietary fiber, (f) dry yeast or its extract powder or liquid, (g) vegetables, (h) vitamins and minerals, (i) oils and fats, (j) starches, (k) eggs, (l) sugars, and (m) milk. The mixture may contain coloring agents, preservatives, thickening stabilizers, antioxidants, pH adjusters, seasonings, emulsifiers, and flavorings, as needed.

[0075] An example of the composition of pet food (dry food) for a complete nutritional diet is shown below. The ingredients are adjusted to contain grains (10 to 90% by mass), beans (0 to 40% by mass), meat (0 to 40% by mass), seafood (0 to 40% by mass), dietary fiber (0 to 20% by mass), dried yeast and its extract powder or liquid (0 to 10% by mass), vegetables (0 to 20% by mass), vitamins and minerals (0 to 10% by mass), oils and fats (0 to 20% by mass), coloring agents (0 to 5% by mass), antioxidants (0 to 5% by mass), and seasonings (0 to 5% by mass).

[0076] As specific aspects of the pet food according to this embodiment, pet foods according to first and second embodiments will be described in detail below with reference to the drawings.

[0077] In the following explanation, an X, Y, Z Cartesian coordinate system will be used as necessary. In this case, the Z direction indicates the height direction (direction of gravity). The two directions perpendicular to the Z direction are the X and Y directions. In the drawings, the arrow side is the plus (+) side, and the opposite side to the arrow is the minus (-) side. For example, the +Z side corresponds to the upper side in the height direction, and the -Z side corresponds to the lower side in the height direction.

[0078] (Pet food according to the first embodiment of the present invention) Pet food C10 according to a first embodiment of the present invention will be described in detail with reference to FIG. Pet food C10 is a hexahedral pet food. In pet food C10, the four side surfaces (peripheral side surfaces) of pet food C10 have more openings 1 than the top surface and bottom surface.

[0079] 1, the first direction corresponds to the X direction, the second direction corresponds to the Y direction, and the third direction corresponds to the Z direction. That is, the two directions perpendicular to the first direction are the second direction and the third direction. Pet food C10 is a hexahedral pet food, and the two directions perpendicular to the first direction are the second direction and the third direction, so the first surface C1 projected onto side A (+X side) of the first direction coincides with the side surface of pet food C10 on side A of the first direction.

[0080] In the pet food C10, the open area ratio of the first surface C1 when the pet food C10 is projected on the A side (+X side) in the first direction is 10% or more.

[0081] In pet food C10, the surface of pet food C10 projected onto side A (+X side) in the first direction is the first surface C1. Furthermore, the surface of pet food C10 projected onto side B (-X side) in the first direction is the fourth surface C4. In pet food C10, the surface of pet food C10 projected on side A (+Y side) in a second direction perpendicular to the first direction is the second surface C2. Furthermore, the surface of pet food C10 projected on side B (-Y side) in the second direction perpendicular to the first direction is the third surface C3. In pet food C10, the surface obtained by projecting pet food C10 onto side A (+Z side) in a third direction perpendicular to the first direction is a fifth surface C5. Furthermore, the surface obtained by projecting pet food C10 onto side B (-Z side) in the third direction perpendicular to the first direction is a sixth surface C6.

[0082] FIG. 2 is a diagram showing the surfaces of the pet food C10 projected in each direction, ie, the first surface C1 to the sixth surface C6. In pet food C10, the first to fourth surfaces C1 to C4 have an open area ratio of 10% or more, and the fifth and sixth surfaces C5 and C6 have an open area ratio of 8% or less.

[0083] The preferred ranges of the open area ratios of the first surface C1 to the fourth surface C4 in pet food C10 are as described above, and are, for example, preferably 10% or more and 60% or less, more preferably 12% or more and 60% or less, even more preferably 16% or more and 55% or less, particularly preferably 20% or more and 50% or less, and most preferably 25% or more and 50% or less.

[0084] The open area ratio of the fifth surface C5 and the sixth surface C6 of pet food C10 is preferably 8% or less, more preferably 4% or less, and even more preferably 2% or less, and may be 0%.

[0085] Furthermore, as described above, in pet food C10, the projected first surface C1 coincides with the side surface of pet food C10 on side A in the first direction, so it can also be said that pet food C10 has a bottom and top surface with an open area ratio of 8% or less, and all four side surfaces with an open area ratio of 10% or more.

[0086] Pet food C10 has a ratio of the open hole area ratio on the first surface C1 to the open hole area ratio on a cross section (A-A' cross section: a surface parallel to the first surface C1) when pet food C10 is cut perpendicular to the first direction (open hole area ratio on the first surface C1 / open hole area ratio on cross section) of 0.4 to 2.0. The preferred range of the open hole area ratio ratio is as described above.

[0087] The preferred particle density, size, moisture content, hardness, and ingredients of pet food C10 are as described above.

[0088] The pet food C10 described above has a surface with a high open pore area ratio, and is therefore easy to chew while maintaining a chewy texture. In addition, because pet food C10 has both a surface with a high open pore area ratio and a surface with a low open pore area ratio, multiple textures can be enjoyed, making it more palatable.

[0089] In pet food C10, the first to fourth surfaces C1 to C4 have an open area ratio of 10% or more, and the fifth and sixth surfaces C5 and C6 have an open area ratio of 8% or less, but the fourth surface C4 and the second or third surface C2 or C3 may have an open area ratio of 8% or less. Alternatively, the fifth surface C5 or the sixth surface C6 may have an open area ratio of 10% or more.

[0090] As described above, when the shape of the pet food according to this embodiment is hexahedral and the two directions perpendicular to the first direction are the second direction and the third direction, the surface of the pet food projected onto side A (+X side) of the first direction coincides with the side surface of pet food C10 on side A of the first direction. That is, the present invention has the following aspects.

[0091] "1" Pet food product in the shape of a hexahedron having openings, and having an A-side with an open area ratio of 10% or more. [2] The pet food according to [1], further having a side B having an open pore area ratio of 8% or less. [3] The pet food according to [1] or [2], wherein at least one of the four surfaces adjacent to surface A has an open area ratio of 10% or more. [4] The pet food according to [1] or [2], wherein at least two of the four surfaces adjacent to surface A have an open area ratio of 10% or more. "5" The pet food according to any one of "1" to "4", wherein, when the pet food is cut so as to create a surface parallel to the A surface and a cross section is prepared, the ratio of the open area rate on the A surface to the open area rate on the cross section (open area rate on the A surface / open area rate on the cross section) is 0.4 to 2.0. "6" Pet food in a hexahedral shape with openings, wherein the opening area ratio of the bottom and top surfaces of the pet food is 8% or less, and the opening area ratio of each of the side surfaces (all four surfaces) is 10% or more.

[0092] (Pet food according to a second embodiment of the present invention) Pet food D10 according to a second embodiment of the present invention will be described in detail with reference to FIG. Pet food D10 is a cylindrical pet food. In pet food D10, the lateral peripheral surface has many openings 2, and the top and bottom surfaces of pet food D10 have few openings 2.

[0093] 3 and 4, the first direction corresponds to the X direction, the second direction corresponds to the Y direction, and the third direction corresponds to the Z direction. That is, the two directions perpendicular to the first direction are the second direction and the third direction.

[0094] Pet food D10 has an open area ratio of 10% or more on a first surface D10 when pet food D10 is projected on side A (+X side) in the first direction.

[0095] In pet food D10, the surface of pet food D10 projected onto side A (+X side) in the first direction is the first surface D1. Furthermore, the surface of pet food D10 projected onto side B (-X side) in the first direction is the fourth surface D4. In pet food D10, the surface of pet food D10 projected on side A (+Y side) in a second direction perpendicular to the first direction is second surface D2. Furthermore, the surface of pet food D10 projected on side B (-Y side) in the second direction perpendicular to the first direction is third surface D3. In pet food D10, the surface obtained by projecting pet food D10 onto side A (+Z side) in a third direction perpendicular to the first direction is fifth surface D5. Furthermore, the surface obtained by projecting pet food D10 onto side B (-Z side) in the third direction perpendicular to the first direction is sixth surface D6.

[0096] Since the pet food D10 is cylindrical, only the fifth surface D5 and the top surface of the pet food D10 and the sixth surface D6 and the bottom surface of the pet food D10 coincide with each other.

[0097] FIG. 4 is a diagram showing the surfaces of the pet food D10 projected in each direction, that is, the first surface D1 to the sixth surface D6. In pet food D10, first surface D1 to fourth surface D4 have an open area ratio of 10% or more, and fifth surface D5 and sixth surface D6 have an open area ratio of 8% or less.

[0098] The preferred ranges of the open area ratios of the first surface D1 to the fourth surface D4 in pet food D10 are as described above, and are, for example, preferably 10% or more and 60% or less, more preferably 12% or more and 60% or less, even more preferably 16% or more and 55% or less, particularly preferably 20% or more and 50% or less, and most preferably 25% or more and 50% or less.

[0099] The open area ratio of the fifth surface D5 and the sixth surface D6 of pet food D10 is preferably 8% or less, more preferably 4% or less, and even more preferably 2% or less, and may be 0%.

[0100] Furthermore, as described above, in pet food D10, only the fifth surface D5 and the top surface of pet food D10, and the sixth surface D6 and the bottom surface of pet food D10 coincide, so it can also be said that pet food D10 has an open area ratio of 8% or less on the bottom and top surfaces, and an open area ratio of 10% or more on the side surfaces.

[0101] Pet food D10 has a ratio of the open hole area ratio on the first surface D1 to the open hole area ratio on a cross section (cross section B-B') when pet food D10 is cut perpendicular to the first direction (open hole area ratio on first surface D1 / open hole area ratio on cross section) of 0.4 to 2.0. The preferred range of the open hole area ratio ratio is as described above.

[0102] The preferred particle density, size, moisture content, hardness, and ingredients of pet food D10 are as described above.

[0103] Pet food D10 described above has a surface with a high open pore area ratio, and is therefore easy to chew while maintaining a chewy texture. In addition, pet food D10 has both a surface with a high open pore area ratio and a surface with a low open pore area ratio, allowing multiple textures to be enjoyed and making it more palatable.

[0104] In pet food D10, the first surface D1 to the fourth surface D4 have an open area ratio of 10% or more, and the fifth surface D5 and the sixth surface D6 have an open area ratio of 8% or less, but the fourth surface D4 and the second surface D2 or the third surface D3 may have an open area ratio of 8% or less. That is, pet food D10 may have open holes not over the entire side peripheral surface, but only part of the side peripheral surface. Furthermore, the fifth surface D5 or the sixth surface D6 may have an open area ratio of 10% or more. That is, the bottom surface or the top surface of pet food D10 may have an open area ratio of 10% or more.

[0105] (Pet food manufacturing method) The method for producing pet food of this embodiment may include, for example, a method for producing pet food that includes an expansion step in which a kneaded raw material mixture is extruded from an extruder to expand it and obtain a expanded dough, a porous step in which the expanded dough is made porous and obtain a porous dough, and a cutting step in which the porous dough is cut.

[0106] As a specific example of the pet food manufacturing method of this embodiment, a pet food manufacturing method 100 will be described in detail with reference to FIG. As shown in Figure 5, the raw material mixture is kneaded in an extruder 101 and then extruded from the extruder to obtain a puffed dough sd. The obtained puffed dough sd is transported by a belt conveyor 102. The transported puffed dough sd is cooled by a cooler 103 to make it porous, and a porous dough pd is obtained. The obtained porous dough pd is cut with a cutter 104 to obtain the pet food PF of this embodiment.

[0107] [Puffing process] The puffing step is a step in which the raw material mixture kneaded in the extruder 101 is puffed by extruding it from the extruder to obtain puffed dough sd. The extruder 101 is not particularly limited, and a known single-screw or twin-screw extruder or the like can be used.

[0108] The temperature of the raw material mixture when kneading it in the extruder 101 is, for example, preferably 75 to 140°C, more preferably 80 to 135°C, and even more preferably 85 to 130°C.

[0109] [Porous process] The porous forming step is a step of forming porous dough pd by forming porous dough sd. Specifically, the porous forming step includes a step of placing the puffed dough sd under atmospheric pressure and cooling the puffed dough sd with a cooler 103.

[0110] The cooler 103 is not particularly limited, and a known spot cooler or the like can be used.

[0111] [Cutting process] The cutting step is a step of cutting the porous dough pd with a cutter 104. When cutting the porous dough pd with the cutter 104, the porous dough pd may be cut from the MD, from the CD, or from either the MD or the CD. Here, the MD (machine direction) is the flow direction of the porous dough pd (which can also be said to be the flow direction of the puffed dough sd extruded from the extruder). The CD (cross direction) is the direction perpendicular to the flow direction of the porous dough pd.

[0112] The temperature of the porous material pd when it is cut by the cutter 104 is preferably, for example, 70° C. or less.

[0113] By the above method, it is possible to obtain pet food having openings, in which the opening area ratio of the first surface of the pet food projected in the first direction is 10% or more.

[0114] The pet food manufacturing method described above includes a porosity-inducing step, and therefore can easily produce the above-described pet food. Specifically, in conventional pet food manufacturing methods, as described in, for example, "Small Animal Clinical Nutrition, 5th Edition" (edited by Michael S. Hand, Craig D. Thatcher, Rebecca L. Remillard, Philip Roudebusg, and Bruce J. Novotny, published by Mark Morris Associates; 2014; pp. 209-215), a cutter is provided at the outlet of an extruder, and the raw material mixture is generally cut with the cutter immediately after being extruded from the extruder. On the other hand, in the pet food manufacturing method of this embodiment, the raw material mixture is extruded from the extruder, and a time is allowed to pass before being cut with the cutter, thereby making the pet food porous. Therefore, the pet food manufacturing method of this embodiment can easily produce the above-described pet food.

[0115] In the porosity-forming step in the pet food production method 100, cooling by the cooler 103 may be carried out batchwise by transferring the puffed dough extruded from the extruder outside the line. Furthermore, in the porosity-forming step in pet food manufacturing method 100, the puffed dough sd is cooled by cooler 103, but cooler 103 does not have to be used. That is, the step may involve increasing the length of belt conveyor 102 to cool the puffed dough sd at room temperature. For example, the length of belt conveyor 102 can be adjusted so that the puffed dough sd is kept at room temperature (25°C) for, for example, one minute or more from the time it is extruded from the extruder until it is cut.

[0116] <Other manufacturing methods> The pet food of this embodiment may be produced by a method other than the above-described method, and may be produced, for example, by using an ingredient that generates gas when heated. Specific examples of ingredients that generate gas include sodium bicarbonate. [Example]

[0117] The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[0118] (Production of pet food with openings 1) Example 1 The ingredients constituting the pet food were mixed according to the formulation shown in Table 1 to obtain a raw material mixture. Water was added to the raw material mixture in a preconditioner in an amount of 12 to 25 parts by mass per 100 parts by mass of the total raw material mixture, and the mixture was mixed while heating at 70 to 100°C for 5 seconds to 3 minutes. The heated raw material mixture was then placed in an extruder and kneaded while being heat-treated at 80 to 125°C for 10 seconds to 2 minutes to gelatinize the starch component. The mixture was then extruded to obtain a puffed dough. The resulting dough was cooled in a cooler so that the surface temperature of the dough was 70°C or below, resulting in a porous dough. The resulting dough was then cut into hexahedrons in the MD and CD directions using a cutter, yielding the pet food of Example 1 having hexahedral openings (8 mm long (X direction) × 8 mm wide (Y direction) × 11.5 mm high (thickness) (Z direction)). The pet food of Example 1 has the same configuration as pet food C10 shown in Figure 1, and the surface cut with the cutter is the circumferential side surface. The first surface of the pet food of Example 1 coincides with the first surface C1 of pet food C10 shown in Figure 1, the third surface of the pet food of Example 1 coincides with the third surface C3 of pet food C10 shown in Figure 1, and the fifth surface of the pet food of Example 1 coincides with the fifth surface C5 of pet food C10 shown in Figure 1. The moisture content of the pet food of Example 1, determined by the "loss on drying method" described above, was 8.4%.

[0119] [Table 1]

[0120] (Preparation of pet food with apertures) <Comparative Examples 1 to 7> As the pet foods of Comparative Examples 1 to 7, seven types of commercially available pet foods (commercial products A to G) were prepared.

[0121] <Evaluation of open area ratio> Surface measurement Using a digital microscope (product name "VHX-7000", manufactured by Keyence Corporation), images of the surface of the pet food of each example were taken, and the images were used to measure the open pore area ratio of the first side of the pet food of each example using the automatic area measurement (particle count) of the measurement and scale tool of the digital microscope, excluding particles with a circle equivalent diameter of less than 50 μm. Note that for the pet food of Example 1, the open pore area ratio was measured not only for the first side, but also for the third and fifth sides. The specific method is as follows.

[0122] (i) The magnification of the digital microscope was set to 20x so that the entire specific surface of each example of pet food placed on the measurement table could be captured. (ii) The setting value for the epi-illumination was set to a value between 100 and 255 that made the aperture most visible. (iii) In the automatic area measurement (particle count) of the digital microscope's measurement and scale tool, the extraction method was set to "brightness (standard)." Next, the extraction area of ​​the first surface of the pet food was set. (iv) Excluding particles with a circle equivalent diameter of less than 50 μm, the open area ratio was measured using the automatic area measurement (particle count) function of the measurement and scale tool of a digital microscope. The results are shown in Table 2 as "surface open pore area ratio (%)."

[0123] Figure 6 shows an image of the first side of the pet food of Example 1 and an image taken when the open hole area ratio of the first side was measured. Figure 6a is an image of the first side, and Figure 6b is an image taken when the open hole area ratio was measured. In Figure 6b, the colored areas represent the open holes (the same applies below).

[0124] Fig. 7 shows an image of the third surface of the pet food of Example 1 and an image taken when the open hole area ratio of the third surface was measured. Fig. 7a is an image of the third surface, and Fig. 7b is an image taken when the open hole area ratio was measured.

[0125] Fig. 8 shows an image of the fifth surface of the pet food of Example 1 and an image taken when the open hole area ratio of the fifth surface was measured. Fig. 8a is an image of the fifth surface, and Fig. 8b is an image taken when the open hole area ratio was measured.

[0126] Cross-section measurement The pet food of each example was cut with a cutter perpendicular to the first direction to divide the pet food of each example into equal parts. The open area ratio of the cross section of the cut pet food of each example was measured using the same method as in the "Surface measurement" above. For the pet food of Example 1, the pet food of Example 1 was prepared separately, cut with a cutter perpendicular to the second direction to divide the pet food into equal parts, and the open area ratio of the cross section (plane parallel to the third surface) of the pet food was measured using the same method as in the "Surface measurement" above. The results are shown in Table 2 as "cross-sectional open area ratio (%)."

[0127] ·Open hole area ratio calculation For each example of pet food, the ratio of the open hole area ratio on the first side (the open hole area ratio measured in the above "surface measurement") to the open hole area ratio on the cross section (the open hole area ratio measured in the above "cross section measurement") (open hole area ratio on the first side / open hole area ratio on the cross section) was determined. Note that for the pet food of Example 1, the ratio of the open hole area ratio on the third side to the open hole area ratio on the cross section (a surface parallel to the third side) (open hole area ratio on the third side / open hole area ratio on the cross section) was also determined using the same method. The results are shown in Table 2 as "open pore area ratio."

[0128] [Table 2]

[0129] As shown in Table 2, the pet food of Example 1 had a higher open area ratio of the first side (open area ratio of the third side) than the pet foods of Comparative Examples 1 to 7. Furthermore, none of the commercially available pet foods of Comparative Examples 1 to 7 had an open area ratio of the first side of 10% or more.

[0130] FIG. 9 shows an image of the first surface of the pet food of Example 1 when the open pore area ratio was measured, and an image of the cross section (plane parallel to the first surface) when the open pore area ratio was measured. FIG. 10 shows an image of the pet food of Example 1 when the open pore area ratio of the third surface was measured, and an image of the cross section (plane parallel to the third surface) when the open pore area ratio was measured. As shown in Figures 9 and 10, it can be seen that the distribution of openings on the first surface and cross section (plane parallel to the first surface) of the pet food of Example 1, and on the third surface and cross section (plane parallel to the third surface) are similar to each other.

[0131] Furthermore, as shown in Table 2, the pet food of Example 1 had an open hole area ratio of the first surface (open hole area ratio of the third surface) closer to 1 compared to the pet foods of Comparative Examples 1 to 7. This confirmed that the pet food of Example 1 had open holes more evenly distributed on the surface and inside compared to the pet foods of Comparative Examples 1 to 7.

[0132] <Hardness evaluation> The hardness of the first, third and fifth sides of the pet food of Example 1 was measured by the following method.

[0133] In this specification, the hardness of pet food is a value obtained by the following measurement method. Using a compression tester (Texture Analyzer, model number: EZ-SX, manufactured by Shimadzu Corporation), the breaking force was measured when the pet food was compressed at a constant compression speed. Specifically, one pet food product of Example 1 was placed on a tray, and the test force was measured while pressing the plunger vertically from directly above at a constant speed. The pet food product was placed so that the surface in contact with the plunger was the first, third, or fifth surface, and measurements were repeated for 10 pieces of each product, and the average value was calculated. The breaking force (unit: kgw) measured by the compression tester was multiplied by 9.8 to convert the unit into Newton (N). The measurement conditions are as follows. Plunger: Width 10mm, length 20mm, tip 1mm thick, wedge-shaped plunger Platform: 100mm diameter flat tray Compression speed: 60 mm / min Lowest point of plunger: 1st and 3rd faces: 6 mm, 5th face: 10 mm Measurement temperature: 25℃ The results are shown in Table 3.

[0134] [Table 3]

[0135] As shown in Table 3, the pet food of Example 1 had different hardness on different sides, and it was confirmed that the pet food could be chewed to enjoy a variety of textures.

[0136] <Evaluation of water absorption rate> Using the same method as for the 5-, 30-, and 60-second water absorption rates described above, the water absorption rates of the pet food of Example 1 were measured for 5, 30, and 60 seconds when the water temperature was 20° C. The results are shown in Table 4.

[0137] [Table 4]

[0138] As shown in Table 4, the pet food of Example 1 had a high water absorption rate.

[0139] <Hardness evaluation> The hardness of the pet food granules of Example 1, which had been immersed in water at 20°C, was measured after immersion for 5, 30, or 60 seconds in the same manner as in the hardness of the pet food granules immersed in water for 5, 30, or 60 seconds described above (hardness after immersion for 5 seconds, hardness after immersion for 30 seconds, and hardness after immersion for 60 seconds). The results are shown in Table 5. Note that the hardness after immersion for 0 seconds in Table 5 is the same as the hardness of the fifth side shown in the <Evaluation of hardness> described above.

[0140] [Table 5]

[0141] As shown in Table 5, the hardness of the pet food of Example 1 changed when it was immersed in water for just a few seconds.

[0142] <Evaluation of palatability> (Production of pet food with openings 2) The pet foods of Examples 2 and 3 and Reference Example 1 were produced in a hexahedral shape (length 8 mm (X direction) × width 8 mm (Y direction) × height (thickness) 11.5 mm (Z direction)) using the same method as in Example 1. The specific production method is as follows. In the following description and in Table 4, a "surface having openings" refers to a surface having an open pore area ratio of 10% or more as measured by the method described above. A "surface without openings" refers to a surface having an open pore area ratio of less than 10% as measured by the method described above.

[0143] Pet food of Example 2 The pet food of Example 2 was obtained in a hexahedral shape (8 mm long (X direction) × 8 mm wide (Y direction) × 11.5 mm high (thickness) (Z direction)) in the same manner as in Example 1 described above, except that the extruder die plate was changed and the porous dough was cut with a cutter only from the CD. The cut surface becomes the surface with perforations, and therefore the pet food of Example 2 has two surfaces with perforations. The perforation area ratio of the surfaces with perforations in the pet food of Example 2 was approximately the same as the perforation area ratios of the first and third surfaces of the pet food of Example 1, respectively, and the perforation area ratio of the surface without perforations in the pet food of Example 2 was approximately the same as the perforation area ratio of the fifth surface of the pet food of Example 1.

[0144] Pet food of Example 3 The die plate of the extruder was changed, and a hexahedral pet food slightly larger than the pet food of Example 1 was obtained in the same manner as in Example 1. The surfaces of the pet food that were not cut (the surfaces corresponding to the fifth and sixth surfaces of the pet food of Example 1) were each cut with a cutter, to obtain the pet food of Example 3 in a hexahedral shape (length 8 mm (X direction) × width 8 mm (Y direction) × height (thickness) 11.5 mm (Z direction)) with perforations all around. Because the cut surfaces are the surfaces with perforations, the pet food of Example 3 has six surfaces with perforations. The open area ratio of the surfaces with perforations of the pet food of Example 3 was similar to the open area ratios of the first and third surfaces of the pet food of Example 1.

[0145] Pet food for reference example 1 Except for changing the die plate of the extruder and cutting the raw material mixture with a cutter immediately after it was discharged from the extruder, a hexahedral (length 8 mm (X direction) × width 8 mm (Y direction) × height (thickness) 11.5 mm (Z direction)) pet food of Reference Example 1 was obtained in the same manner as in Example 1. The pet food of Reference Example 1 did not have a surface with open holes.

[0146] · Palatability test 100 g of each of the pet foods from Examples 1 to 3 and Reference Example 1 was placed in a dish for fasting dogs (weighing 5 kg or less), and the amount of each pet food remaining was measured after 5 minutes, and the palatability was evaluated according to the following criteria. The results are shown in Table 6. A: Less than 5g B: 5g or more but less than 25g C: 25g or more

[0147] [Table 6]

[0148] From the above, it was confirmed that the pet food of the Example has a surface with an open area ratio of 10% or more, and therefore is easier to chew while maintaining a chewy texture compared to the pet food of the Reference Example, making it more palatable. Furthermore, among the Examples, the pet food of Example 1, which had four surfaces with perforations and two surfaces without perforations, was the most palatable. [Explanation of symbols]

[0149] C10...pet food, C1...1st side, C2...2nd side, C3...3rd side, C4...4th side, C5...5th side, C6...6th side, 1...opening D10: Pet food, D1: First surface, D2: Second surface, D3: Third surface, D4: Fourth surface, D5: Fifth surface, D6: Sixth surface, 2: Opening 101: Extruder, 102: Belt conveyor, 103: Cooler, 104: Cutter

Claims

1. It is a hexahedral pet food, a first surface C1 on which the pet food is projected on side A (+X side) of a first direction, a fourth surface C4 on which the pet food is projected on side B (-X side) of the first direction, a second surface C2 on which the pet food is projected on side A (+Y side) of a second direction perpendicular to the first direction, a third surface C3 on which the pet food is projected on side B (-Y side) of the second direction perpendicular to the first direction, a fifth surface C5 on which the pet food is projected on side A (+Z side) of a third direction perpendicular to the first direction, and a sixth surface C6 on which the pet food is projected on side B (-Z side) of the third direction perpendicular to the first direction The pet food, wherein the first surface (C1) to the fourth surface (C4) have an open area ratio of 10% or more, and the fifth surface (C5) and the sixth surface (C6) have an open area ratio of 8% or less.

2. It is a cylindrical pet food, The cylindrical pet food has a side peripheral surface with an open area ratio of 10% or more, The pet food product has a cylindrical shape, and the top and bottom surfaces of the pet food product have an open area ratio of 8% or less.

3. 3. The pet food according to claim 1, wherein the ratio of the open area ratio in the surface with an open area ratio of 10% or more to the open area ratio in a cross section when the pet food is cut so as to equally divide the surface with an open area ratio of 10% or more (open area ratio in the surface with an open area ratio of 10% or more / open area ratio in cross section) is 0.4 to 2.

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