Ohmic Heating Application on Pork Burger Processing

This study evaluates ohmic heating (OH) at varying electric field strengths (OH10: 5 V/cm, OH12.5: 6.3 V/cm, OH15: 7.5 V/cm) compared to conventional grilling (CONV) in pork burger processing, focusing on microbial inactivation, physicochemical and rheological properties, and in vitro bioactivity. CONV required 7 min to reach 75°C (heating rate: 11.15°C/min). OH required substantially longer times: 17 min (OH15), 36 min (OH12.5), and 82 min (OH10)-a trade-off between energy efficiency and throughput that must be considered for industrial application. Regarding energy performance, CONV consumed 996 ± 6 kJ/kg, while OH15 consumed 594 ± 17 kJ/kg-a 40% reduction that was statistically significant (P = 0.0097). OH15 significantly reduced total aerobic mesophilic bacteria (1.7 log CFU/mL) compared to CONV (3.6 log CFU/mL; P < 0.05), with Enterobacteriaceae undetectable in all heated samples. OH maintained macronutrient profiles but reduced water-holding capacity and increased firmness (76-96 kPa vs. 36 kPa for CONV), indicating textural changes. OH enhanced in vitro bioactivity (DPPH inhibition: 0.51% for OH15 vs. 0.29% for CONV; ACE inhibition: 0.40% vs. 0.15%) and vitamin B12 retention (0.14 vs. 0.11 µg/100 g; P < 0.05). However, these bioactivity values represent very low absolute levels and do not support claims that OH-processed burgers are a source of antioxidant, antihypertensive, or antidiabetic activity. Despite its energy efficiency and microbial inactivation benefits, OH's longer processing time-particularly at lower voltages-presents a challenge for industrial scale-up. Future work should focus on optimizing electric field strength to balance energy savings, processing time, and product quality. PRACTICAL APPLICATIONS: This research demonstrates that ohmic heating (OH) offers a more energy-efficient alternative to conventional grilling for pork burger processing, achieving up to 40% energy savings. By applying electrical current directly through the food, OH provides uniform volumetric heating that effectively inactivates spoilage microorganisms. However, this energy advantage comes with a trade-off in processing time. Nevertheless, a mathematical projection of OH at equivalent CONV electrical power showed that applying the same peak power (635 W) to OH in a realistic scenario for industrial equipment, it would yield a projected processing time of 3 min (57% faster than CONV's 7 min) while delivering the same total energy (0.03 kWh). This projection reinforces that higher-power OH systems could overcome current processing time limitations. Claims of global sustainability benefits would require supporting life cycle assessment (LCA) data, which was beyond the present scope. Future pilot-scale studies are needed to evaluate real-world throughput, assess consumer acceptance through sensory analysis, and incorporate LCA to quantify environmental trade-offs. These findings provide a data-driven foundation for the food industry to weigh the benefits and limitations of OH processing.