Animal bones, particularly from cattle after slaughter, are commonly discarded, posing environmental challenges and highlighting the need for sustainable valorization. This study investigated the effect of enzyme and organic acid treatment on physicochemical properties, particle size, microstructure and safety of meat-bone paste (MBP). Two samples were prepared: a control (MBP-C) without enzyme treatment and an experimental sample (MBP-E) treated with pepsin and ascorbic acid. Results showed that the enzyme reaction rate increased from 0.004 mmol/min at 60 min to 0.014 mmol/min at 120–180 min before declining to 0.006 mmol/min at 480 min, suggesting substrate depletion or product inhibition. Temperature greatly influenced reaction rates, peaking at 0.0129 mmol/min at 30 °C, with significant declines at higher temperatures due to enzyme denaturation. The enzyme’s kinetic performance was proportional to the pepsin concentration, demonstrating enhanced catalytic efficiency at higher enzyme concentrations. Particle size analysis revealed that enzyme treatment significantly reduced bone particle size, with 86.33% of particles measuring between 0.05 and 0.2 mm, compared to 86.4% between 0.25 and 0.75 mm in the untreated sample. Microscopy confirmed these findings, showing an average particle size reduction from 0.21 mm to 0.052 mm after enzyme treatment. Physicochemical analysis revealed no significant differences in chemical composition between the two samples. However, enzyme-treated MBP-E exhibited a lower pH (5.9) compared to MBP-C (7.02), attributed to the addition of ascorbic acid. Water-binding capacity significantly increased in MBP-E (82.54% vs. 77.28%), indicating enhanced hydration and collagen loosening during enzymatic action. Enzyme treatment significantly reduced the total viable count and eliminated pathogenic bacteria (E. coli, Listeria, Salmonella), improving MBP safety. These findings highlight the potential of this approach for valorizing animal bones as a valuable food ingredient while promoting sustainable waste management practices.

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.

The growing demand for cost-effective, high-quality protein ingredients in the meat industry highlights the need for advanced processing methods capable of producing uniform, functional meat–bone pastes from poultry by-products. This study investigates the optimization of colloid milling parameters for the fine grinding of chicken meat–bone by-products, with a focus on improving particle size distribution, rheological properties, and processing efficiency. A modified rotor–stator system with teeth inclined at 20° and a reduced pitch (0.5 mm) was compared to a conventional configuration (45° inclination, 1.5 mm pitch). Experiments were conducted at rotor speeds ranging from 1000 to 4000 rpm, with a fixed clearance of 0.1 mm. The results showed that the modified design significantly enhanced grinding efficiency, reducing the proportion of bone fragments > 1 mm and yielding over 70% of particles under 0.1 mm at 3000 rpm. Viscosity and shear stress measurements indicated that grinding at 3000 rpm yielded a dynamic viscosity of 71,507 Pa·s and a shear stress of 43,531 mPa·s, values that were significantly lower (p < 0.05) than those observed at other tested speeds, thereby producing a paste consistency with the most favorable balance of elasticity and flowability. At 4000 rpm, the temperature rise (up to 32 °C) led to partial denaturation of muscle proteins, accompanied by emulsion destabilization and disruption of the protein gel matrix, resulting in reductions in the viscosity and water-binding capacity of the paste. Comparative analysis confirmed that tool geometry and rotor speed have critical effects on grinding quality, energy use, and thermal load. The optimal operating parameters, 3000 rpm with modified rotor–stator teeth, achieve the finest, most homogeneous bone paste while preserving protein functionality and minimizing energy losses. These findings support the development of energy-efficient grinding equipment for the valorization of poultry by-products in emulsified meat formulations.

The poultry industry generates large amounts of protein- and mineral-rich by-products that remain underutilized. This study investigated the use of chicken skin protein hydrolysate and chicken bone protein–mineral mass (PMM) as functional ingredients in emulsified poultry sausages. The hydrolysate was characterized by a high protein content (52.25%) and high water- and fat-binding capacity (142% and 125%, respectively), while the PMM served as a source of protein and minerals with stable physicochemical and rheological characteristics. These ingredients were incorporated into sausage formulations at different substitution levels. Partial replacement of poultry meat increased protein and mineral content and affected key technological properties, including water-binding capacity, emulsion stability, cooking loss, and shear force. Moderate inclusion levels were associated with a more cohesive protein matrix, lower cooking losses, and improved structural stability, whereas excessive substitution resulted in increased firmness and less favorable sensory characteristics. Among the tested formulations, the combination of 18% PMM and 4% protein hydrolysate showed the most balanced technological and sensory performance. The findings suggest that poultry by-products processed into functional ingredients may have potential for application in value-added sausage formulations.