No abstract

Among the fat fish species available from Eastern Quebec (Canada), whole Atlantic mackerel (Scomber scombrus) and herring (Clupea harengus) represent abundant fishery resources which are currently underutilized. They have relatively high contents of oil and coenzyme Q10 (CoQ10) in their tissues, which could be valuable for nutraceutical applications. Therefore, two low-temperature extraction processes were compared for the recovery of oil and CoQ10 from these resources, such as enzymatic hydrolysis using Protamex ™ and supercritical CO 2 (SCO 2 ) using fish lyophilizates. The results revealed that highest yields of oil and CoQ10 were obtained using the enzymatic hydrolysis process with mackerel. Whatever the process used, CoQ10 concentrations were higher in herring oil, due mainly to a more selective extraction of CoQ10 over that of the oil. The highest CoQ10 recovery rates (extraction efficiencies) were obtained using the enzymatic hydrolysis process with both types of fish, but also the SCO 2 process with herring under some conditions. For mackerel, the lower CoQ10 recovery rates obtained from the SCO 2 process were explained by its more important matrix effect. An economic assessment of both processes revealed that the enzymatic hydrolysis extraction process would be the most promising for up-scaling the recovery of oil and CoQ10 from these resources.

No abstract

Sequential acidic precipitation followed by a single chromatographic step (gel filtration) allowed the recovery of a collagenolytic fraction containing several proteases from by-products of snow crab (Chionoecetes opilio). The partial purification was particularly efficient to recover tryptic (purification fold = 1,352.5; yield = 110%) but also chymotryptic, elastolytic, and collagenolytic activities. A temperature of 40 °C and pH 8.0-8.5 were optimal for enzyme activity, which was stable for 2 h under these conditions. Calcium was not required for stability and thus activity. The isoelectric points of the protein components ranged from 3.7 to 4.6. Zymography revealed 29 and 48 kDa major components and others from 22 to 56 kDa. Enzymes were inhibited by PMSF and TLCK but were insensitive to TPCK. In view of these properties, the proteases likely belong to the serine collagenase group. Inhibition by EDTA could be due to a mechanism other than Ca(2+) chelation. Using a food system (ground fish), the fraction was more proteolytic than a commercial bacterial protease, suggesting potential applications in enzymatic hydrolysis processes.