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The aim of the study was to perform histological differentiation of dorsal and ventral musculature of fresh and frozen/thawed carps (Cyprinus carpio). Histological findings of muscle fibres (Myofibra striata) of fresh carps did not show any changes. Single freezing at –10 ºС resulted in extracellular gaps in the central part of some of fibres. After single freezing at –18 ºС, muscle fibres with cell de-struction in the central part were identified while the periphery remained intact. Completely destruc-tured and deformed areas of muscle fibres were demonstrated after single freezing at –27 ºС. Double freezing at –10 ºС resulted in shrinkage, extracellular gaps and fragmentation of fibres, while muscle fibres double-frozen at –18 ºС were impaired, degraded and with visible defects. The histological findings in carp muscle, double-frozen at –27 ºС comprised severely deformed muscle fibres with increased extracellular gaps from degraded muscle tissue. On the basis of findings, it could be con-cluded that double freezing of carps was not an appropriate method of storage and shelf-life exten-sion.

The aim of the study was to perform histological differentiation of dorsal and ventral musculature of fresh and frozen/thawed carps (Cyprinus carpio). Histological findings of muscle fibres (Myofibra striata) of fresh carps did not show any changes. Single freezing at -10 °C resulted in extracellular gaps in the central part of some of fibres. After single freezing at -18 °C, muscle fibres with cell destruction in the central part were identified while the periphery remained intact. Completely destructured and deformed areas of muscle fibres were demonstrated after single freezing at -27 °C. Double freezing at -10 °C resulted in shrinkage, extracellular gaps and fragmentation of fibres, while muscle fibres double-frozen at -18 °C were impaired, degraded and with visible defects. The histological findings in carp muscle, double-frozen at -27 °C comprised severely deformed muscle fibres with increased extracellular gaps from degraded muscle tissue. On the basis of findings, it could be concluded that double freezing of carps was not an appropriate method of storage and shelf-life extension. [ABSTRACT FROM AUTHOR]

Chinese red pepper (Zanthoxylum bungeanum Maxim.) leaf (ZML) extract was added to salted silver carp. The effect of ZML extract on volatile compounds formation of both dorsal and ventral muscle of salted fish was investigated. Lipid oxidation of salted fish with ZML extract was alleviated with lower peroxide value (PV) and thiobarbituric acid reactive substance (TBARS) values than that of the control. Therefore, the contents of some volatile compounds formed mainly by oxidation such as benzene, methylbenzene, 1‐octene‐3‐ol, hexanal, and methyl ketone, which attributed off‐odor of salted fish, were reduced. Principal component analysis results showed that the first principal component (PC1) and the second principal component (PC2) explained 62% and 31% of total variance, respectively, and volatile compounds of the dorsal and ventral of control group differentiated from treatment group. These results showed that ZML extract can be a source of natural antioxidants and food additives for improving flavor of salted fish. [ABSTRACT FROM AUTHOR]

Chinese red pepper ( Zanthoxylum bungeanum Maxim.) leaf (ZML) extract contains high amounts of phenolic compounds possessing high total antioxidant capacity and hydroxyl, 1, 1-dipheny-2-picrylhydrazyl (DPPH) free radical scavenging activity. ZML extract was investigated as a natural antioxidant for the lipid stability of salted silver carp ( Hypophthalmichthys molitrix ) throughout salting and drying. Both dorsal and ventral muscles were examined for differences in moisture content, salt content, total lipid content, and degree of lipid oxidation. The hexanal content, Thiobarbituric acid reactive substances (TBARS) value, and lipoxygenase (LOX) activity in the ventral muscle were significantly higher than those of the dorsal muscle ( p < 0.05). In the treatments with ZML extract, the hexanal content, the TBARS value, and the LOX activity were significantly lower ( p < 0.05) during processing both in the dorsal and ventral muscles. The sensory qualities of processed salted fish could be improved with the amount of 0.030% extract in the dorsal muscle and 0.045% extract in the ventral muscle. These results showed that ZML extract can be a source of natural antioxidants and used as a food additive. [ABSTRACT FROM AUTHOR]

Anisakiasis is a gastrointestinal disease caused by parasitic anisakid nematodes, mainly Anisakis simplex sensu stricto (A. simplex). Anisakiasis is prevalent in Japan and approximately 40% of anisakiasis cases in Tokyo occur through the consumption of raw or marinated mackerel. However, in 2018, there was a sudden increase in the number of the food poisoning cases in Tokyo caused by consumption of skipjack tuna (Katsuwonus pelamis). Therefore, we investigated anisakiasis cases resulting from ingestion of skipjack tuna in Tokyo, and surveyed the presence of Anisakis larvae in skipjack tuna in 2018 and 2019. Nineteen samples from 15 patients (13 in 2018 and 2 in 2019) with anisakiasis surely caused by ingestion of skipjack tuna were all identified as A. simplex. The higher mean abundance of Anisakis simplex larvae in skipjack tuna muscle in May 2018 (1.30; 13 larvae/10 fishes) compared to that in the other periods was regarded as a contributing factor in the increase in anisakiasis cases by ingesting skipjack tuna in 2018. To verify whether Anisakis larvae migrate from the visceral organs to the muscle during the period from fishing on the boat until processing for sale, the number of Anisakis larvae in skipjack tuna caught from August to November 2018 was investigated by removing the visceral organs at three different timings, i.e., immediately after catching, after landing, and after transport to the laboratory. Anisakis larvae were detected in the muscle irrespective of the timings at which visceral organs were removed. All larvae from the muscle were detected only from the ventral part and were identified as A. simplex. We thus consider that avoiding raw consumption of the ventral muscle should be an effective measure to prevent anisakiasis. • All Anisakis larvae from patients with a history of ingesting skipjack tuna were identified as A. simplex sensu stricto. • A. simplex sensu stricto migrated to the muscle in live skipjack tunas before capture. • A. simplex sensu stricto was detected in the ventral muscle of skipjack tunas. • Removal of the ventral muscle from skipjack tuna could prevent human anisakiasis. [ABSTRACT FROM AUTHOR]