Abstract
During the food process of the sea urchin, Strongylocentrotus intermedius, alum solution of the artificial seawater (ASW) base is used to prevent the collapse of gonads and to extend preservation period, but it enhances endemic bitterness when used in higher concentrations. In this experiment, bacterial features, tasteand outlook of gonads were compared after treated with four kinds of alum solutions; 0.2, 0.5 and 1.0% on the base of deep seawater (DSW, pipelined from a depthof 218 m off Rausu) and 1.0% on the base of ASW (traditionally used). Each unit (120 g) of gonads were kept in a refrigerator (5°C) after the alum treatments for ten minutes. Number of general bacteria (NGB) in the gonads was kept under10, 000/g in all blocks for ten days though the highest value 23, 000/g appeared on ASW block on the fifteenth day. Occurrence of coliform bacteria (CB) was negativein all blocks. These bacterial features cleared the criteria for raw fish andshellfish materials (less than 100, 000/g in NGB and negative in CB) ruled in Japanese Food Hygiene Law. In the sensory test, practiced on the fourth day, all ofDSW blocks (particularly with lower concentration of alum) got higher scores in taste, outlook and total evaluations than the ASW block. Therefore, use of DSW can eliminate the elaboration of preparing ASW and improve the taste of gonads bylowering the alum concentration.
