The proteolytic enzymes in the muscle fluid of Pacific whiting
(Merluccius productus) were studied and compared to those found in muscle
fluid of true cod (Gadus macrocephalus). Preliminary studies indicated
three pH optima of activity for whiting, pH 3.5-3.9, 4.3-4.6 and 7.1-7.2.
Only two pH optima were found for the...
The optimum conditions for the proteolytic solubilization of
trash fish and processing carcass waste in a simple shell-in-tube
heat exchange system was investigated. The nutritional and chemical
effects of processing variables were evaluated.
An exogenous source of proteolytic enzymes (albacore tuna
viscera, Thunnus alalunga) yielded a linear increase in the...
Feasibility of ohmic heating to overcome gel-weakening in Pacific whiting surimi
was investigated. An ohmic heating apparatus was developed using two rhodium-coated
stainless steel electrodes inside a polyvinyl chloride (PVC) tube, a variable transformer,
and voltage and current transducers. Rapid heating associated with the ohmic process
quickly inactivated endogenous proteinase(s),...
Kinetic properties of the two proteases, causing textural degradation of Pacific
whiting (Merluccius productus) during heating, were compared and characterized with the
synthetic substrate, Z-Phe-Arg-NMec. Pacific whiting P-I and P-II showed the highest
specificity on Z-Phe-Arg-NMec, specific substrate for cathepsin L. The K [subscript m] of
preactivated P-I and P-II...
The effect of salt (0, 0.9, 1.7, 2.5%) and pH (range 4
to 10) on surimi gels made from Pacific Whiting (Merluccius
productus) was investigated. Gel-forming ability was measured
by the torsion test. In general, surimi gels
increased in gel strength with increased pH. Breaking shear
stress increased to a...
Cryoprotection in stabilized mince from Pacific whiting (Merluccius productus) was investigated by monitoring changes in physical and chemical properties during 32 weeks of frozen storage. The effects of 4 different cryoprotectants were evaluated by torsion test, color analysis, extractability of salt soluble proteins, and formation of dimethylamine (DMA) and 2-thiobarbituric...
The major portion of Pacific whiting (PW) is commercialized in the form of frozen surimi. Alternative products for PW were investigated focusing on fresh surimi and texturized meat from PW mince. Fresh surimi is made without additives and kept refrigerated instead of frozen. Texturized meat is a meat-like product made...
The ability of salmon plasma protein (SPP) obtained from Chinook salmon at the Klaskanine Fish Hatchery (Astoria, OR) to inhibit protease enzymes found in Pacific whiting (PW) surimi and salmon mince as well as the effect of SPP on the gelation properties of PW surimi under various heating conditions was...
Cathepsin B was the most active cysteine proteinase in the Pacific whiting
(Merluccius productus) fish fillet, and cathepsin L in surimi when the activities of the
most active cysteine proteinases (cathepsin L, B, and H) were compared. Cathepsin L
showed maximum activity at 55°C in both fish fillet and surimi,...