PROBLEM TO BE SOLVED: To provide a professional-use quick freezing apparatus with which an extremely low temperature set to -50°C or the like unsuitable for large-sized food materials such as tuna in conventional supercool freezing processing can be applied to the food materials, so that the food materials maintain their favorable freshness with less discoloration and deterioration when thawed.SOLUTION: The quick freezing apparatus includes conductive shelf boards 11 each of which placing a thick food material thereon, a food material-loading carriage 10 having insulators 12 electrically insulating the shelf boards 11, electrodes 20 each inserted and disposed into the vicinity of the center of the thick food material and an electric field-forming device 30 applying alternate high-voltage electric field on the food material-loading carriage 10 and the electrodes 20. In the apparatus, the thick food materials are each frozen sequentially from its outer peripheral side toward its center part in a freezer while the electric field-forming device 30 applies the alternate high-voltage electric field on the thick food materials to perform the supercool freezing processing. The alternate high-voltage electric field is applied to each of the thick food materials even after a freeze-up region is generated at the outer peripheral side of the thick food material because each of the electrodes 20 is located at an unfrozen portion inside the thick food material, so that the supercool freezing processing to the unfrozen portion is continued.COPYRIGHT: (C)2012,JPO&INPIT【課題】 従来の過冷却冷凍処理ではマグロ等の大型食材に不向きであった温度設定-50℃などの超低温であっても適用でき、解凍時に変色や劣化の少ない良好な鮮度に維持することができる業務用の急速冷凍装置を提供する。【解決手段】 肉厚食材を載せ置く導電体の棚板11と、棚板11を電気的に絶縁する絶縁体12を備えた食材載荷台10と、肉厚食材の中心付近に差し込んで配設する電極棒20と、食材載荷台10と電極棒20に対して交番高圧電場を印加する電場形成装置30を備える。電場形成装置30により肉厚食材に交番高圧電場を印加して過冷却冷凍を行いつつ、冷凍庫内において肉厚食材を外周側から中心部に向かって順次凍結させる。肉厚食材の外周側に氷結帯が生じた後も、肉厚食材の内側の未凍結部位に電極棒20が位置しているので内側から交番高圧電場が印加されるので、未凍結部位への過冷却冷凍処理が継続される。【選択図】 図4
