Study of rheological properties of gels based on Thorny Skate cartilage broth (Raja radiata) in the technology of natural fish culinary products -aspic fish, in jelly, fish jellies and potions

The paper deals with methodological approaches to study the rheological properties of gelatin gels based on the thorny skate cartilage broth ( Raja radiate ), which is an aqueous extract of chondroitin sulfate, depending on the manufacturing technology. It is shown that the use of modern instrumental methods for studying the rheological properties of gels and methodological approaches typical of physical and colloidal chemistry allows to obtain the most complete and objective information about the mechanisms of formation of key consumer properties of fish products and the main directions of improving the technology of its manufacture. The influence of gelatin concentration in the range from 0.5 to 5.0 % in chondroitin sulfate-containing broths from the thorny skate cartilage on kinematic and dynamic viscosity of broths, as well as on the strength, melting point and shear stress indices of gels based on these broths was studied. As control samples, aqueous solutions of gelatin in concentrations from 0.5 to 5.0 % and gels based on them were used in the studies. The analysis of the results of the study showed that the broths prepared on the basis of the thorny skate cartilage have increased relative to the control samples the values of kinematic and dynamic viscosity, the increase in indicators is characterized by a directly proportional dependence on the concentration of gelatin in the broth. Gelatin gels based on chondroitin sulfate-containing broths made from the thorny skate cartilage have increased strength, which has a positive effect on the organoleptic evaluation and consumer properties of the finished culinary products.

Echeneibothrium canadensis n.sp. (Tetraphyllidea: Phyllobothriidae) in the spiral intestine of the thorny skate (Raja radiata) from the Canadian Atlantic Ocean

From a study of 124 skates (Raja radiata Donovan, 1808) in the Canadian Atlantic Ocean, Echeneibothrium canadensis n.sp., is described, and the nomenclatural confusion of this species with E. variabile Van Beneden, 1849 is discussed. Echeneibothrium canadensis n.sp. is most closely related to E. variabile and other members of the genus with a large, robust myzorhynchus but is differentiated by possessing 12 distinct loculi within each bothridium, a large robust myzorhynchus, 18–26 testes per proglottis, and an armed cirrus and vitellaria extending posterior to the ovary.

Blood protozoans of fish from the Davis Strait in the northwestern Atlantic Ocean

A study was carried out to determine the occurrence and prevalence of blood protozoans in benthic marine fish from the Davis Strait, an area between Baffin Island and Greenland (61–70°N, 53–63°W) in the northwestern Atlantic Ocean. Parasites were seen in all 17 species offish examined; piroplasms were most prevalent (78% of 413), infecting all fish species. Prevalences of infection were substantially lower for trypanosomes (23%) and haemogregarines (4%), both of which infected only 10 and 6 of the fish species, respectively. Prevalences were greater in 5 of the fish species examined, Reinhardtius hippoglossoides, Hippoglossoides platessoides, Lycodes lavalaei, Macrourus berglax, and Raja radiata, than in the other 12 species. Though the prevalence of trypanosomes decreased considerably in the most northerly of three areas, no differences were apparent for piroplasms. Prevalences noted in this paper are comparable to those observed in fish taken off the coast of Labrador but considerably greater than those of the Grand Banks or in areas south of latitude 50°N. Based on occurrence and prevalence, it is likely that fish haematozoans and their leech vectors originated in the northern latitudes and radiated southwards.