An innovative method for cooking chicken meatballs: Ohmic heating

This study was conducted to investigate the effects of ohmic heating technology on the cooking process of chicken meatballs. Ohmic heating is a modern heating method that provides volumetric and homogeneous heat production by directly passing electric current through food products. In the study, meatballs prepared using chicken breast meat were cooked at three different voltage gradients (7, 11 and 15 V/cm) and heating was applied until the product's center temperature reached 75 °C in each process. Parameters such as cooking time, temperature increase rate, temperature distribution (with thermal camera and T-type thermocouple), electrical conductivity (EC) and textural changes, and Salmonella inactivation were evaluated in detail. The ohmic cooking time of chicken meatballs for 7 V/cm, 11 V/cm and 15 V/cm voltage gradients was determined as 390±5 s, 149±10 s, 86±2 s, respectively. The highest value of the temperature increase rate was observed at 0.77 °C/s at 14 V/cm voltage gradient, while the lowest value was determined at 0.17 °C/s at 7 V/cm ohmic cooking process. During the ohmic cooking process, the EC value of the chicken meatballs was determined to be in the range of 0.54-2.49 S/m, 0.85-2.81 S/m and 0.81-2.91 S/m for 7, 11 and 15 V/cm voltage gradients, respectively. The hardness values obtained by the ohmic heating process applied to the chicken meatball samples at 7, 11 and 15 V/cm voltage gradients were determined as 12.91±0.84, 13.92±0.85 and 17.26±0.59 N, respectively. It was determined that the external adhesiveness value decreased with the increase in the hardness value. When the L* brightness values of the ohmic cooked chicken meatballs were examined, it was determined that they were 56.00±0.67, 72.70±3.75, 75.70±0.93, 80.17±0.72 in the control, 7, 11 and 15 voltage gradients, respectively. It was observed that different voltage gradients in the ohmic cooking process did not have any effect on important color values, especially Hue angle and chroma. The initial concentration of Salmonella spp. in the samples cultivated before the ohmic process was 7.19 ± 0.075 log cfu/g, and depending on the voltage gradients, it was counted as 6.04 ± 0.12 log cfu/g, 5.45 ± 0.22 log cfu/g and 5.20 ± 0.33 log cfu/g in the 7, 11 and 15 V/cm voltage gradients, respectively. As a result, the current thesis data demonstrate the applicability of the ohmic heating method in cooking chicken meatballs. It has been noted that the ohmic method provides a fast and energy-efficient cooking process, especially in high voltage gradients. It has also been determined that Salmonella species that pose a risk to food safety can be inactivated by the ohmic cooking process. Based on this, it can be stated that the usability in industrial food production can be increased by optimizing the cooking process with the ohmic heating method. In this respect, it is thought that the current thesis study will make a significant contribution to the limited number of ohmic heating applications in the literature, specific to chicken meatballs.