Changes in meat texture of three varieties of squid in the early stage of cold storage

ABSTRACT: The present study examined the changes in texture and protein components during cold storage of different squid varieties. Raw oval squid, Japanese common squid and arrow squid were sliced fresh and the muscles were stored at 4°C for 0, 4, 8, 12, 18, 24, 48 and 120 h. The rheological measurements, protein components and amounts of collagen were examined. The adhesiveness of each squid increased significantly in the early stage of cold storage. In all varieties, penetration decreased at 4 h, which is considered to be rigor mortis, then increased. The amounts of total collagen, 20°C water-soluble collagen and 70°C water-soluble collagen did not change significantly in each variety during cold storage. Sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE) pattern showed that the 580 kDa component gradually disappeared up to 48 h. The correlations between the amounts of 580 kDa component and adhesiveness or firmness were high. Models of fit based on chemical kinetics accurately expressed the behavior of adhesiveness, firmness and penetration showing that 63.2% of adhesiveness changes occurred in 13–19 h and that 63.2% of firmness changes occurred in 18–24 h.     

Evidence of homing of black rockfish Sebastes inermis using biotelemetry

ABSTRACT: The black rockfish Sebastes inermis is one of the most important fishery species along the coast from southern Hokkaido to Kyushu, Japan and is often found in rocks and Zostera areas. We conducted biotelemetry using coded ultrasonic transmitters to clarify the movement of the black rockfish that inhabited the seawall of the Kansai International Airport. We released 25 black rockfish at two points. One was the airport seawall and the other was side shallows off the Sensyu district. Seventeen black rockfish returned to their capture site after release. We used the V -test to determine whether the direction of movement was random or orientated. The black rockfish moved at random along the seawall within some hours after release ( P  > 0.05). Four hours after release, they moved to their home site intentionally ( P  < 0.0025).     

Exclusion of NEU1 and PPGB from candidate genes for a lysosomal storage disease in Japanese Black cattle

A case of lysosomal storage disease has been reported in a calf of Japanese Black cattle. Lysosomal storage diseases are hereditary diseases caused by deficiency of lysosomal hydrolases. The clinical and pathological features and accumulated substrates of the affected animal indicated a possibility of sialidosis or galactosialidosis caused by deficiency of neuraminidase (NEU1) or protective protein for β-galactosidase (PPGB). In the present study, we investigated nucleotide sequences of the genes encoding these two proteins to evaluate whether mutation of these genes is involved in this disease. We determined cattle genomic sequences of these two genes by using bovine EST sequences and the nucleotide sequences of all exons of these genes were compared between affected and normal animals. The results showed several nucleotide substitutions, but none of them was a functional mutation or specific to the affected animal. Furthermore, genotyping of the microsatellite markers in the vicinity of these two genes revealed no homozygosity of the chromosomal regions including these genes in the affected animal. These findings indicated that neither NEU1 nor PPGB gene is responsible for the lysosomal storage disease of Japanese Black cattle and therefore the disease is neither sialidosis nor galactosialidosis.     

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

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.