The potential of ohmic heating as an alternative to steam for heat processing shrimps

- OH reduced the cooking times of shrimps by ≈ 50% and provided a more uniform treatment.
- Ohmically cooked shrimps showed less colour differences vs. steam cooked.
- Ohmically treated shrimps (1-7 g) had comparable cook loss to steam.
- No textural differences were observed between shrimps cooked with steam vs. OH.
- Ohmic heating is a potentially viable alternative to steam cooking for shrimp.

The potential application of Ohmic Heating as an alternative to the conventional steam cooking for shrimps is examined in this study. Defrosted unpeeled shrimps (Pandalus borealis) were cooked either in a steamer or ohmically up to a 72 °C core-temperature. The head, body and tail of steam-heated shrimps cooked at different rates whereas the OH treatment was more uniform and faster. The impact of shrimp size on heating rate was also evaluated, with an overall cooking time of 38 s and 59 s for steam-cooked small and large shrimps, respectively, while only 40 s where needed for OH regardless of shrimp size and measured anatomical location. No differences were found for cook loss and texture (WBSF and Kramer methods) between cooking methods. However, shrimp size seemed to determine the effect of OH on colour differences (ΔE), with greater differences observed in large vs. small shrimps, although overall ohmically-cooked shrimps showed less colour differences compared to those cooked conventionally with steam.Industrial relevanceTraditional heating processes such as boiling or steaming are used in industrial cooking of shrimps. However, the low rate of heat penetration to the thermal centre of shrimps leads to heterogeneous treatments resulting in overcooking which may reduce yield. Ohmic heating technology offers a potential alternative over conventional heat treatments as heat is generated volumetrically inside the food. This form of heat generation results in more uniform temperature distribution which leads to shorter processing times and potentially higher yields while still maintaining the colour and nutritional value of food. This paper hence exploits the potential of Ohmic heating technology as an alternative to conventional steam processing for the cooking of shrimps.