Development of the Design of Plate with Variable Diameters of Holes and Its Impact on Meat-Grinding Quality and Efficiency

Abstract

Meat-grinder plates are critical for efficiently processing meat, significantly influencing the grinding process. This study aimed to develop a meat-grinder plate with variable diameter holes and assess its impact on ground meat quality and processing efficiency. Various meat types (beef, horse meat, mutton, chicken, and pork) were processed using both plate designs: a control plate with a constant hole diameter of 12 mm and a developed plate with featured holes increasing in diameter from periphery to center (8 mm–12 mm–16 mm). The results demonstrate that the developed plate significantly improves the WBC of minced meat, with notable increases in beef (58.3% vs. 57.7%), horse meat (61.8% vs. 56.2%), chicken (51.0% vs. 49.1%), and pork (46.1% vs. 43.6%), indicating a more homogeneous particle size distribution. Yield stress, a critical factor influencing the rheological properties of minced meat, also showed substantial improvements, particularly in poultry (18.9% increase) and pork (31.3% increase). The variable hole design produced a higher proportion of intermediate-sized particles, contributing to a more cohesive texture and potentially enhancing the binding properties of processed meat products. Theoretical calculations based on the Hagen–Poiseuille equation and empirical data confirmed that the new plate design increases the grinder’s productivity by 50%, with average throughput rising from 150 kg/h to 225 kg/h. Additionally, the developed plate reduced power consumption by up to 7.3%, particularly in horse meat processing, highlighting its cost effectiveness for industrial applications. These findings suggest that the variable diameter hole plate design offers substantial improvements in ground meat quality and processing efficiency, with potential implications for industrial meat-processing operations.

1. Introduction

Intensification of technological processes is one of the main directions of technological progress in the meat industry. Along with significantly increasing the volume of meat products, the industry must also improve the quality and diversity of its product range while ensuring the most efficient and rational use of raw materials. Cutting processes are widely applied to the production of sausages and semi-finished products, which significantly affect the quality of both raw materials and finished products [1].

Industrial meat grinders are among the most basic types of equipment designed to produce minced meat. The complexity of processes occurring in the transporting and cutting mechanism spaces of these grinders significantly affects the kinetics of the grinding process. Studying the changes in the structural and mechanical characteristics of minced meat as well as the technological parameters of the grinding process forms the basis for improving meat-grinding techniques [2,3]. One possible solution to the challenges faced by meat-processing enterprises is the development and creation of technological machines with improved cutting mechanisms that provide better quality grinding of raw materials. Specifically, the plate, a component of the cutting mechanism in meat grinders, plays a crucial role. The impact of the plate’s design parameters on the process of grinding meat in meat grinders is an important scientific problem that warrants further investigation [4].

The main and most important part of the grinder is the cutting mechanism. The working principle of a meat grinder can be described as a system in which meat is conveyed through a cutting mechanism by a rotating screw, resulting in the meat being cut or minced. The productivity of all known types of meat grinders is determined by the level of pressure of the screw on the meat and the speed of the minced meat passing through the plate of the grinder, i.e., the speed of release of the “knife–plate” zone [5,6]. Effective meat processing depends greatly on the role of meat-grinder plates. The plate’s design and the holes it contains play a crucial part in the grinding process. The plate is an integral part of the cutting mechanism of a meat grinder. It is divided into undercutting and cutting plates. The undercutting plate is a disk with radially arranged or sickle-shaped blades. The undercutting plate is placed in the screw housing first, in the direction of raw material flow. It serves for cutting and preliminary coarse shredding. Cutting plates are made in the form of a disk with round holes, which are arranged spirally or staggered or on a circle or the contour of a square or triangle. Such plates are designed to grind food raw materials of the desired particle size [7].

The holes in the plates are designed to regulate the passage of ground meat and the degree of chopping; they are also paired cutting parts. The plate area should be used as much as possible for the holes while maintaining the required strength with the maximum permissible wearing of the grate. The level of utilization of the plate area for holes also depends on the rational arrangement of holes (e.g., staggered arrangement), their diameter, and the full utilization of the entire plate surface for holes [8,9]. A more detailed analysis of the plates for meat grinders is presented in the Supplementary File (Table S1).

Known types of meat grinders are equipped with a traditional “knife–plate” cutting pair with holes for the passage of minced meat, located perpendicular to the end surface of the plate. Such a design of the “knife–plate” cutting pair does not yield high-quality minced meat due to the destruction of the structure of the meat and the tearing and compression of fibers. In addition, the processing of large volumes is accompanied by the heating of minced meat, and as a result, the quality of meat protein deteriorates [10,11]. With this in mind, the aim of the study was to develop a plate for the cutting mechanism of the meat grinder, which allows for improving the cutting process, reducing technological losses, and increasing productivity while maintaining the quality of the ground meat.

The purpose of this work was to design a plate for a meat grinder with variable diameters of holes and determine its effect on the quality parameters of minced meat. The novelty of this research focuses on developing and evaluating a meat-grinder plate with variable hole diameters. A mathematical model was developed to optimize the grinding process, leading to improved meat homogeneity, water retention, and texture. By optimizing plate design, the research enhances minced meat quality while increasing productivity and reducing energy consumption, potentially transforming industrial meat processing efficiency and output.

2. Materials and Methods

2.1. Meat Samples

Meat (beef, horse, mutton, chicken, and pork) was purchased from meat pavilions of Semey City (Kazakhstan): 5 kg of each type. After transportation to the sausage shop, the meat was deboned and cut into large pieces (up to 100 × 100 mm) and frozen to −18 °C until the experiments.

2.2. Description of the Experimental Meat Grinder

An experimental meat grinder was designed and developed to produce minced meat (Figure 1). The meat grinder was designed for fine grinding of meat and meat–bone raw materials, hard confiscates, a mixture of hard and soft confiscates, as well as thawed blocks of frozen meat [12].

The meat grinder consists of a frame, screw, gearbox, electric motor, V-belt drive, housing, safety interlock, and hopper. The main working component of the meat grinder is the grinding part, which is a set of plates and knives alternating in a specific order: a plate with large triangular holes, a knife, a plate with small triangular holes, and a plate with round holes (Figure 2). The plates are installed in the attachment and fixed with stops. The knives are installed on the front part of the screw. Pieces of meat up to 100 mm in size are loaded into the hopper, where they are caught by the screw and moved to the grinding mechanism. The meat is ground between the stationary plates and rotating knives. The screw is driven by an electric motor through a V-belt drive and gearbox.

The advancement of the product within the working chamber, its delivery to the knife, and its pushing through the knife plates are facilitated by a rotating screw with a uniform pitch. A notable characteristic of the screw’s operation is its generation of sufficient pressure to push the product through the cutting mechanism without expressing the liquid phase contained in the meat.

The cutting mechanism of the grinder comprises stationary plates and rotating knives. The stationary plates are constructed as discs with circular and trapezoidal holes, functioning as paired cutting elements in conjunction with the rotating knives.

The meat grinder is equipped with four plates featuring hole diameters of 5, 8, 16, and 25 mm and three sectoral plates and one trimming plate (Supplementary File Figure S1) as well as three cruciform and two double-bladed knives (Supplementary File Figure S2).

The knives and plates are mounted on a steel pin with parallel flats, which is screwed into the front face of the screw. The central aperture of the knife shares the same profile as the external contour of the screw pin, thereby enabling the rotation of the latter to be transmitted to the knife. The plates are fitted loosely onto the screw pin and are prevented from rotating by a key rigidly affixed to the grinder housing. The tight contact between the working surfaces of the knives and plates is ensured by a pressure nut.

The cruciform knives of traditional design are four-bladed with axially positioned cutting edges, the front portion of which presents a rectangular plane perpendicular to the cutting edge.

2.3. Scheme of Experiments

To determine the rational modes of meat grinding, complex studies were carried out under laboratory conditions on a meat grinder.

The object of the experiments was to select meat from different types of animals and poultry. The change of water-binding capacity and yield stress of minced meat depending on the design of the cutting mechanism was determined. Two sets of cutting mechanisms were used (Figure 2):

-1 set (control, traditional)-receiving plate, cross-shaped knife, and plate with a diameter of holes 12 mm;

-2 set (developed)-receiving plate, cross-shaped knife, and plate with variable hole diameters.

• Determination of Chemical Composition

The chemical composition of the samples was determined through a series of analytical procedures. Moisture content was assessed using the method described by Antipova et al. (2001) [13], which involved drying the sample at 150 °C until a constant weight was achieved. Following moisture determination, the dried samples were subjected to fat content analysis using the Soxhlet method, in accordance with the GOST 23042-86 standard [14]. Ash content was measured by calcining the samples in a muffle furnace at temperatures ranging from 500 to 600 °C [13]. Protein content analysis was conducted following the GOST 25011-81 standard [15].

• Determination of Water-Binding Capacity

The method used for determination of the water-binding capacity was based on the release by the test sample with light pressing, sorption of the released water with filter paper (Whatman, qualitative grade 1, 150 mm), and determination of the amount of separated moisture by the size of the spot area left by it on the filtered paper [16].

• Determination of Yield Stress

A texture analyzer ST-1 (company “Radius”, Moscow, Russia), a tapered indenter with an angle of 60°, and a special container for the product were used to determine the yield stress of minced meat [17]. On each sample, the yield stress was determined at three different points at a temperature of 25 ± 2 °C.

The yield stress θ₀ (in Pa) was determined by the depth of cone immersion and calculated by Equation (1):

$$Q_0=K·{\displaystyle \frac{F}{h^2}}$$

(1)

where F—loading value (N);

h—total immersion depth of the cone (m);

K—cone constant, which is dependent on the cone angle α at the apex.

• Determination of Meat-Grinder Energy Characteristics

To conduct the meat-grinding process economically, it is imperative to consider the total energy consumption over the time required to achieve the specified degree of grinding. During meat grinding, the total energy expenditure is contingent upon multiple factors (such as the type of blades, structural/mechanical characteristics of the minced meat, etc.). To determine the energy characteristics of the meat grinder, a measurement stand was constructed.

The measurement stand (Figure 3) consists of a voltmeter 1, ammeter 2, and phase meter 3 (an instrument for measuring “cosφ”). All instruments are integrated into the electrical control circuit of the grinder’s drive motors. To determine the energy characteristics of the experimental setup, a methodology was developed, the essence of which lies in finding the power determined by the values of current, voltage, and cosφ, which were directly measured using these instruments [18].

To measure the current, voltage, and cosφ, meat was loaded into the grinder’s hopper. Then the electric motor was switched on. The corresponding values of electrical quantities on the instruments were recorded using a WEB camera connected to a computer. Subsequently, the measurement results were processed on the computer.

• Determination of Particle Size Distribution

To determine the quantitative residue of muscle tissue and to conduct further analysis of the particle size distribution, the meat particles were sorted by size. In this process, the particles were categorized based on their degree of grinding within ranges of <5, 5, 8, 12, and >12 mm. For this purpose, ground meat was weighed on analytical scales with a precision of 0.01 g and placed on the top of the sieve. The set of sieves was shaken for a specified time.

Particle content in % was determined by Equation (2):

$$x_2=m_1\cdot 100/m_0$$

(2)

where m₀—total weight of the sample, g;

m₁—the mass of minced meat particles by size, g.

• Calculation of the Flow Capacity of a Meat-Grinder Plate Based on the Hagen–Poiseuille Equation

The known methods of engineering calculation of industrial meat grinders are based on the so-called cutting capacity of the knife mechanism [19,20]. In this case, the plates are considered only as paired parts to cross-shaped or other knives, and in calculations, the role of the grids is evaluated by the utilization factor φ.

This factor is the ratio of the total area of the holes in the plate to the area of the plate itself (Equation (3)).

$$\phi ={\displaystyle \frac{z·f_o}{f}}={\displaystyle \frac{z{·d}^2}{D^2}}$$

(3)

where φ—utilization factor;

f₀, f—the area of one hole in the plate and the area of the plate itself, m²;

z—number of holes in the given plate, pcs;

d—diameter of holes in the plate, m;

D—plate diameter, m.

Even though this coefficient has no dimension, the physical meaning of the utilization factor is that it represents the relative area of the plate intended for the minced meat passage. Since the cutting unit includes several plates in different configurations, each of them has its utilization factor.

These coefficients have different values. The highest utilization factor is for the intake plate installed first in the product flow, while the other plates have a decreasing utilization factor toward the output. The last grate usually has the lowest utilization factor.

This circumstance is one of the reasons for the so-called reverse flows of minced meat back into the receiving hopper of the meat grinder. In general, the reason for the occurrence of backflows of minced meat into the hopper is that the cutting capacity of the meat grinder and the conveying capacity of the feed screw do not match or are not equal.

Backflow occurs when the conveying capacity is greater than the cutting capacity. In addition, reverse flows are affected by the gap between the screw and the cylinder, which should be no more than 2 mm. However, the role of plates in the throughput and operation of the cutting mechanism as well as in the occurrence of reverse flows has not been given due attention. Therefore, in this paper, plates with different diameter holes were considered. At the same time, the utilization factor of such a plate is higher than that of the output plate with the smallest hole diameters.

The theoretical capacity or throughput of a meat-grinder plate, based on the operating conditions of the working element, can be determined by the Hagen–Poiseuille equation. It is known from hydraulics that this equation describes the relationship between the flow rate of a fluid and its pressure. Under the influence of this pressure, the liquid flows out of the hole or several holes, depending on their design parameters, particularly the radius or diameter and length of the holes, as well as the viscous properties of the liquid itself.

Although the working mechanism of a meat grinder propels meat rather than liquid under the pressure exerted by the screw, it is conceivable, with certain assumptions, to employ the Hagen–Poiseuille equation for the theoretical assessment of the throughput capacity of the meat grinder’s perforated plates.

In computational and experimental research practices, depending on the known parameters, one determines the flow rate given a known pressure (Equation (4)):

$$Q={\displaystyle \frac{\pi ·d^4}{128·l}}·{\displaystyle \frac{P}{{\eta }_{ЭФ}}}={\displaystyle \frac{\pi R^4}{8·l}}·{\displaystyle \frac{P}{{\eta }_{ЭФ}}}{,m}^3/s$$

(4)

where

Q—flow rate, m³/s

D—hole diameter;

R—radius, m;

P—pressure, Pa;

η_ЭФ—effective viscosity, Pa∙s;

l—hole length, m.

Alternatively, given a known flow rate, the Hagen–Poiseuille equation can be utilized to determine the pressure or pressure differential at which the product is expelled through the holes.

$$P=\mathsf{\Delta }P={\displaystyle \frac{8{\eta }_{ЭФ}·l·Q}{\pi R^4}}={\displaystyle \frac{128{\eta }_{ЭФ}·l·Q}{\pi D^4}},\mathrm{P}\mathrm{a}$$

(5)

where R—hole radius, m.

By transforming this equation, it is possible to identify the geometric coefficient that characterizes the opening of the plate of the meat grinder. For a plate with equal diameters of holes, the geometric coefficient can be determined:

$$k_{г}={\displaystyle \frac{\pi ·R^4}{8·l}}={\displaystyle \frac{\pi ·d^4}{128·l}},{\mathrm{m}}^3$$

(6)

where d, R—diameter or radius of holes in the plate, m;

l—length of holes in the grate, m.

The geometric parameter of the plate characterizes its constructional features more accurately and comprehensively than the utilization coefficient, as it incorporates not only the diameters of the plate’s holes but also the length or, more precisely, the thickness of the plate. Furthermore, the geometric parameter has the dimension of volume, which elucidates its physical significance as the plate’s capacity to transmit a certain volume of product through its holes.

To calculate the theoretical throughput of the plate, the following dependence derived from the Hagen–Poiseuille equation is used:

$$M=k_{г}z\rho {\displaystyle \frac{P}{{\eta }_{эф}}}$$

(7)

where k_Г—geometric parameter of the circular hole, m³;

z—the number of holes in the grid;

ρ—the density of the meat in the holes in the plate, kg/m³;

η_ЭФ—effective viscosity of minced meat, Pa∙s;

P—pressure created by the screw of the meat grinder, Pa.

• Statistics

Each measurement was conducted three times, and the results are presented as the average value along with its corresponding standard error. Data analysis was carried out using Microsoft Excel 2016 and Statistica 12 PL (StatSoft, Inc., Tulsa, OK, USA). To determine if there were significant differences between samples, a one-way analysis of variance (ANOVA) was employed. Statistical significance was established at a p-value less than 0.05.

3. Results

3.1. Design and Calculation of the Throughput Capacity of a Meat-Grinder Plate

The Hagen–Poiseuille equation was used for the calculation of the throughput capacity of the plate of the meat grinder. In addition, the choice of such a distribution of hole diameters on the grid (Figure 4 and Figure 5) is associated with the need to obtain the maximum possible value of the coefficient ϕ: the coefficient of the utilization of the cutting capacity of the mechanism.

For meat grinders, as continuous-operation machines, productivity is determined by cutting capacity. Consequently, a coefficient of cutting capacity utilization (ϕ) was established for both existing and proposed plates. This coefficient is calculated using the following Equation (8) [19]:

$$\phi ={\displaystyle \frac{F_h}{F_p}}$$

(8)

where $F_h$—single hole area, m²;

$F_p$—area of plate, m².

The total area of the holes is determined by the following Equation (9) for the designed plate:

$$F_{\mathrm{o}тв.}={\displaystyle \frac{\pi ·d_1^2}{4}}·z_1+{\displaystyle \frac{\pi ·d_2^2}{4}}·z_2+{\displaystyle \frac{\pi ·d_3^2}{4}}·z_3$$

(9)

where $d_1^2$, $d_2^2$, and $d_3^2$—hole diameters, m;

z₁, z₂, and z₃—number of holes.

The area of the plate is determined by the Equation (10):

$$F_p={\displaystyle \frac{\pi ·D^2}{4}}$$

(10)

where D²—diameter of plate, m.

Let us determine the theoretical productivity of the plate by the recommendations of Prof. Ivashov VI. He determined the theoretical productivity of the machine by the Hagen–Poiseuille Equation (11) [19].

$$Q={\displaystyle \frac{\pi \cdot d^4}{128}}\cdot {\displaystyle \frac{P}{{\eta }_{ЭФ}\cdot l}},$$

(11)

where d—hole diameter, m;

P—pressure, Pa;

η_ef—effective viscosity, Pa∙s;

l—hole length, m.

Here is the formula for volumetric capacity. The dimensionality of Q is m³/s. To convert to (kg/s), it is necessary to multiply this equation by the density of the product, ρ (kg/m³).

However, by transforming this equation, the so-called geometric coefficient is distinguished from it [19]. The geometric parameter is a very important coefficient. It shows two constructive parameters of the plate: the diameter of the holes and the length of the holes or the thickness of the plate. The geometric coefficient of holes is calculated by Equation (6).

Ivashov VI transferred the length of the hole from the second fraction to the first fraction. This resulted in a parameter characterizing the plate. Ideally, all three plates of the meat grinder, despite the different number and diameter of holes, should have the same or at least close parameters. Let us transform Equation (6) concerning the developed plate with different hole diameters to Equation (12):

$$k_{г}={\displaystyle \frac{\pi \cdot (d_1^4+d_2^4+d_3^4)}{128\cdot l}}$$

(12)

Equation (7) is applied to calculate the productivity M.

The results of calculations of the theoretical capacity of the plate are given in

Table 1. The results of calculations of the theoretical capacity of the plate.

Indicator	Plate
	d—8 mm	d—12 mm	d—16 mm	d—16, 12, and 8 mm	d—8, 12, and 16 mm
z—the number of holes in the plate	132	72	46	78 (14; 24; 40)	72 (24; 24; 24)
ϕ—cutting capacity utilization factor	0.33	0.37	0.46	0.40	0.38
M—production capacity (kg/s)	0.24	0.67	1.4	0.80	0.76

.

According to the data given in Table 1, it was determined that the most cost-effective plate is a plate with variable diameters of holes decreasing towards the periphery.

From Figure 6, a plate for grinding meat and meat–bone raw materials with increased productivity was developed.

The technical result of using the developed plate was obtaining monodisperse ground meat. This was achieved because the meat grinder contains a fixed receiving, intermediate, and output plate, having holes with a variable diameter increasing from the periphery to the center.

In the improvement of the design of plates of meat grinders, the essential point was given to studying of technological parameters of processes occurring in the cutting mechanism of a meat grinder at fine grinding of meat raw material and its quality.

3.2. Studying the Chemical Composition of Meat

Studies of the chemical composition of meat were carried out. Beef, horsemeat, chicken, mutton, and pork, raised in the Semey region of the eastern Kazakhstan region, were taken. Determining meat’s chemical composition before grinding is crucial for optimizing the process and ensuring product quality. Moisture content significantly affects the meat’s rheological properties and flow characteristics during grinding. Fat content analysis is vital, as excessive fat can impede proper grinding and cause localized temperature increases. Understanding the basic chemical composition helps predict and control minced meat quality, allowing for adjustments in processing parameters [21,22]. During the research, the results were obtained and are shown in

Table 2. Chemical composition of different types of meat, %.

Meat Type	Mass Fraction Content, %
	Water	Fat	Ash	Protein
Beef	63.9 ± 1.02	16.0 ± 0.24	1.3 ± 0.02	18.8 ± 0.31
Horse	71.0 ± 1.06	8.7 ± 0.16	2.2 ± 0.03	18.1 ± 0.30
Chicken	71.4 ± 1.63	6.1 ± 0.10	1.0 ± 0.02	21.5 ± 0.41
Mutton	61.5 ± 0.77	20.5 ± 0.22	1.6 ± 0.03	16.4 ± 0.18
Pork	53.7 ± 0.59	21.7 ± 0.17	1.4 ± 0.03	23.2 ± 0.32

.

The chemical composition of meat is characterized by the content of moisture, fat, ash, and protein. The high content of fat and protein makes meat a suitable raw material for a variety of products. At the same time, the high moisture content of meat forces it to be processed immediately after receipt or stored under conditions that exclude or inhibit putrefactive decomposition processes at temperatures between 2 °C and 6 °C for no more than 24 h, at −12 °C for 1 month, and at −18 °C for no more than 2 months.

Table 2 shows that the fat and protein content of mutton and pork exceeds other types of meat. Thus, the conducted studies allowed us to determine the chemical composition of various meats, which, after appropriate processing, can be used as the main raw material for the production of meat products enriched with necessary and healthy elements for humans.

3.3. Investigation of the Effect of the Developed Plate on the Change of Water-Binding Capacity of Minced Meat

The most important factors determining the quality and yield of sausage products are the degree of meat grinding and the properly controlled water content of minced meat. Grinding is necessary for the destruction of tissue structure [23,24]. Depending on the type and grade of sausage products and cold treatment of meat, the degree of grinding varies from relatively large pieces of 16–25 mm (coarse grinding) to almost complete homogeneity (fine grinding). Grinding increases the surface area of particles, which contributes to an increase in the amount of adsorption-bound moisture [25].

When improving the design of the meat-grinder grate, a significant place is given to the study of the technological parameters of the meat-grinding process and its quality. The quality was established based on the study of the WBC (water-binding capacity) of the ground meat.

The water-binding capacity (WBC) of ground meat, an essential factor affecting the juiciness and texture of meat products, was found to be higher in samples processed using the developed plate compared to the factory plate [26,27]. This increase in WBC was observed across all types of meat tested. Compared to the control samples, the experimental minced meat yielded higher WBC values (p < 0.05) for beef (58.3% vs. 57.7%), horse meat (61.8% vs. 56.2%), chicken (51.0% vs. 49.1%), and pork (46.1% vs. 43.6%); however, for mutton (57.6% vs. 57.3%), the result was not significant (Figure 7). This explains that the varying hole diameters effectively enhance the meat’s ability to retain water, likely due to the more homogeneous particle size distribution achieved during grinding.

The requirements for the minced meat obtained in the process of grinding are different depending on the type of end products of the meat industry. For the production of cooked sausages, minced meat should be a strong structure, with maximum water-binding capacity, giving the highest yield of ready sausages, including by reducing mass loss in the process of heat treatment. For raw smoked sausage minced meat, it is necessary to obtain a structure with the lowest toughness and water-binding capacity during the grinding process, which ensures the acceleration of the drying process [28,29].

During the grinding process, the mechanical disruption of the meat’s structural integrity results in the formation of free active sites capable of binding water molecules. Consequently, the essential conditions for hydration-based water binding by meat proteins are twofold: the absence of intermolecular bonds between water molecules and the presence of unoccupied active sites within the protein structure of the meat [30]. The former can be achieved through cavitation treatment of water without a significant increase in temperature, while the latter can be accomplished through comminution. Therefore, the water-binding capacity of meat is primarily determined by two parameters: protein content and the degree of dispersion achieved during grinding [31,32].

3.4. The Impact of Grinder Plate Design on Changes in the Yield Stress of Minced Meat

The most critical factor influencing the rheological parameters of minced meat is yield stress. The yield stress of minced meat significantly affects processing parameters and the quality of finished products. Two types of grinder plates were employed in this study: a traditional design and a newly developed one. Yield stress is a measure of the force required to initiate flow in ground meat, influencing its texture and how it behaves during cooking and processing [33,34,35]. The yield stress of ground meat using the developed plate was higher for all meat types, indicating a denser and more cohesive product. For beef, the yield stress increased from 39.22 Pa (control) to 42.18 Pa (experimental), representing a 7.5% increase. Horse meat exhibited a more substantial improvement, with yield stress rising from 46.61 Pa to 52.48 Pa, a 12.6% increase. The most notable enhancement was observed in poultry meat, where the yield stress increased from 49.09 Pa to 58.36 Pa, marking an 18.9% improvement. Lamb and pork samples also showed significant increases, with lamb yield stress rising from 43.47 Pa to 56.12 Pa (29.1% increase) and pork from 37.15 Pa to 48.79 Pa (31.3% increase) (Figure 8).

When processed with the traditional cutting mechanism, the yield stress values did not reach their extreme levels, with chicken minced meat exhibiting the highest yield stress. Minced meat produced by the newly developed cutting mechanism achieved high yield stress values, also peaking with chicken minced meat. The angular velocity of the screw did not significantly influence the change in yield stress values of the minced meat; therefore, the screw’s rotational speed was kept constant. Consequently, when utilizing the newly developed cutting mechanism, which incorporates a plate with variable diameter holes, the yield stress of various types of minced meat demonstrated higher rational values compared to the traditional cutting mechanism.

This increase in yield stress could contribute to better structural integrity and stability of the ground meat, potentially benefiting applications such as sausage production or meat patty formation [36,37].

3.5. Effect of Cutting Mechanism Design on Changes in the Particle Size Distribution of Minced Meat

Samples of minced meat ground using the traditional (receiving plate, cross-shaped knife, and plate with a hole diameter of 12 mm) and developed (receiving plate, cross-shaped knife, and plate with variable hole diameters) cutting mechanisms were sorted by size. The particles were divided depending on the degree of grinding within the range from 3 to 14 mm [38]. The graphs of particle size distribution depending on the cutting mechanism design are plotted in Figure 9, Figure 10, Figure 11, Figure 12 and Figure 13.

From Figure 9, Figure 10, Figure 11, Figure 12 and Figure 13, showing the particle size distribution of minced meat, it can be seen that in the distribution of particles by size, depending on the design of the cutting mechanism, the most preferable for grinding different types of meat is the developed cutting mechanism, which has a plate with variable diameters of holes.

The developed plate produced a higher proportion of intermediate-sized particles of minced meat. There was a notable increase in 5 mm particles and 8 mm particles, while larger particles (12 mm and 14 mm) showed a decrease in all types of meat. Thus, the design of the developed plate, with increasing hole diameters from the periphery to the center (8 mm–12 mm–16 mm), appears to effectively optimize the grinding process. The higher percentage of mid-sized particles (5 mm and 8 mm) suggests that larger meat pieces are indeed being more effectively crushed by the smaller peripheral holes. This mechanism likely contributes to a more efficient grinding process, potentially reducing energy consumption and processing time. The higher proportion of mid-sized particles could contribute to a more cohesive texture, potentially improving binding properties in processed meat products while maintaining a desirable mouthfeel.

3.6. Effect of Plate Design on the Variation of Meat-Grinder Performance

The productivity of the meat grinder was evaluated by measuring the time required to process a fixed volume of meat. Based on the results of these time measurements, a graph depicting the meat grinder’s productivity was plotted (Figure 14). The developed plate demonstrated a substantial increase in production capacity, particularly for beef (84.4%) and horse meat (74.3%). This improvement is likely due to the optimized flow of meat through the grinder, facilitated by the larger central holes reducing resistance and preventing clogging.

The diagram illustrating the meat grinder’s productivity variation demonstrates that, depending on the type of meat and the design of the grinding plate, the grinder’s productivity is higher when using the newly developed plate, averaging 225 kg/h. In contrast, the productivity when using the traditional plate averaged 150 kg/h. Consequently, it can be inferred that the developed plate with variable diameter holes proves to be the most advantageous in terms of productivity for grinding various types of meat.

This suggests that the use of the developed plate not only improves the quality of the ground meat but also enhances the efficiency of the grinding process. This improved efficiency can be attributed to the variable hole design facilitating better flow and processing of the meat.

3.7. Effect of Plate Design on the Variation of Power Consumption of a Meat Grinder

The energy characteristics of the meat-grinding process were determined by the power consumed by the cutting mechanism to overcome the forces of cutting, pressure, and friction [39,40]. It is known that the electric power consumed by the electric motor is converted into mechanical power. This power represents the active power. In the initial period of grinding, the active power of electric motors is maximum. As the load increases, the active power increases. In the steady-state grinding mode, the power N can be determined by Equation (13) [41]:

$$N=\sqrt{3\cdot }U\cdot I\cdot \cos \varphi$$

(13)

where U—voltage is shown by the voltmeter, V;

I—current intensity is shown by the ammeter, A;

cosφ—power factor.

The change in the power of the meat grinder depending on the type of meat and the design of the plate is shown in accordance with Figure 15.

From the diagram of the change of power of the meat grinder, it can be seen that for grinding, depending on the type of meat and on the design of the plate, the least energy-consuming was the use of the developed grate with variable diameters of holes. The experimental plate resulted in lower power consumption for all meat types, with the most significant reduction observed in horse meat (7.3%). This reduction can be attributed to the decreased mechanical resistance and improved efficiency of the grinding process due to the optimized hole configuration. This reduction in power consumption could lead to potential energy savings and cost efficiency in large-scale meat-processing facilities.

4. Conclusions

The development of a meat-grinder plate with variable hole diameters significantly enhances both the quality and efficiency of the grinding process. The Hagen–Poiseuille equation was employed to calculate the theoretical throughput capacity, revealing that the plate with variable hole diameters decreasing towards the periphery is the most cost-effective design. The water-binding capacity (WBC) of ground meat increased significantly for most meat types, with improvements ranging from 0.6% to 5.6%. Yield stress also showed substantial increases, particularly in poultry (18.9%), lamb (29.1%), and pork (31.3%). Particle size distribution analysis revealed a higher proportion of intermediate-sized particles (5 mm and 8 mm) and fewer large particles (12 mm and 14 mm), indicating more efficient and uniform grinding. These enhancements suggest improved structural integrity and potential benefits for processed meat products. The grinder’s productivity rose by 50% to 225 kg/h, and power consumption decreased, notably in horse meat processing (7.3%). This new plate design has the potential to greatly improve the meat-processing industry by providing better quality of ground meat and reducing costs. Future research should concentrate on assessing the plate’s long-lasting strength and testing its suitability for use in extensive industrial operations.