Structure, Microbiology and Sensorial Evaluation of Bologna-Style Sausages in a Kilohertz Ohmic Heating Process

Ohmic heating (OH) is a sustainable heating technology with a high potential in terms of energy and time efficiency. However, its industrial application for solid or semi-solid foods is not widespread yet. This study evaluates the pilot-scale production of Bologna-style sausages (2.3 kg weight) via conventional heating (COV) and OH at an electrical frequency of 10 kHz. Sausages with a diameter of 110 mm heated via OH were produced in approximately 5% of the time (i.e., 10 min) needed to produce sausages heated via COV. OH-treated samples showed a higher moisture content and an increased water holding capacity. A texture profile analysis revealed OH sausages as possessing a lower hardness, springiness, and chewiness. The microbiological load of the samples was identical, regardless of the heating technology. Color measurements (L*a*b* values) showed OH-treated samples to be less red. However, this difference could not be confirmed during sensorial evaluation. Temporal sensation of dominance and descriptive sensory analyses were conducted and revealed a decreased solid consistency but an increased meat taste when sausages were heated via OH. The gel network structures obtained via scanning microscopic analysis showed an increased size of fat globules within OH-treated samples. The results indicated that OH can be used as an alternative heating method to produce Bologna-style sausages.