Changes in taste and textural properties of the foot of the Japanese cockle (Fulvia mutica) by cooking and during storage

Abstract

Physicochemical changes of Japanese cockle foot parts occurring during cooking and cold storage at 4°C for 10 days were examined. Raw samples decreased in weight by 27% during cooking at 85°C for 15 s. Both raw and cooked samples decreased in weight to the same extent of 22-23% during the 10-day cold storage. The levels of ATP and related compounds, as well as those of free amino acids, were higher in raw than in cooked samples, although the former were found by sensory evaluation to have a stronger fishy odor. Raw samples started to decrease in ATP content after 5 days of cold storage, showing K' values of 18 and 42% after 5 and 7 days, respectively. The L* value in the Hunter scale color evaluation increased during the cold storage of raw samples, revealing a gradual disappearance of its original purple-gray color. Meanwhile, the L* value of cooked samples remained constant during the cold storage. The tensile strength of cooked samples was significantly higher than those of both raw samples before and after the cold storage, indicating increased toughness by cooking.