Cathepsin Degradation of Pacific Whiting Surimi Proteins

Abstract

MATERL4LS & METHODSCathepsin B was the most active cysteine protease in Pacific whiting fish fillets; cathepsin L was predominant in surimi. Cathepsin L showed highest activity at SY'C in both fish fillets and surimi, indicating its function in myosin degradation during conventional heating of fillers and surimi gels. Washing during surimi processing removed cathepsin B and H but not cathepsin L. Myosin heavy chain was the primary substrate during autolysis of surimi paste and actin and myosin light chain showed limited hydrolysis during 2 hr incubation. Purified Pacific whiting cathepsin L hydrolyzed myofibrils, myosin and native and heat-denatured collagen. The degradation pattern of myofibrils by the protease was the same as the autolytic pattern of surimi. Fish and surimi samplesPacific whiting (A4erlucciusproductu.s) were harvested off the Oregon coast, stored on-board in aerated slush ice, and off-loaded within 24 hr of capture. The round fish were mechanically "butterfly-cut" in a local surimi processing plant and transferred in ice to the Oregon State University Seafood Laboratory. The fish were hand-filleted, vacuum-packed, and kept frozen at -20°C until use before 6 mo. Pacific whiting surimi without additives was obtained from a local surimi processing plant. Washed mince was collected from the processing line, kept in ice, and transferred to the OS&Seafood Laboratory. Samples were used on the day received unless otherwise specified.

Preparo e caracterização de proteínas miofibrilares de tilápia-do-nilo para elaboração de biofilmes

“…A identificação das bandas foi praticamente a mesma, com a única diferença que esses autores não separaram a troponina e a tropomiosina em suas subunidades. As figuras de SDS-PAGE apresentadas por An et al (1994) trabalhando com amostras de surimi de merluza (Merluccius productus), mostram também um perfil eletroforético muito parecido, com a diferença de que não foram observadas as bandas relativas à a-actinina e as troponinas C e I. As diferenças devem-se principalmente às diferentes concentrações do gel utilizadas, gradiente de 3,2-17,4% por Cuq et al (1995), 10% no trabalho de An et al (1994) e gradiente de 6-15% no presente trabalho.…”

Preventing Soft Texture Fish Fillets through Brine Injection Technology

“…Evaluations were conducted as described by An et al [13]. Samples were extracted with 1% brij and were evaluated for both cathepsin L activity and protein content.…”

“…Those two factors synergistically and detrimentally influence both the raw and cooked fillets texture of Pacific whiting. The most active cysteine proteinase in raw fillets of Pacific whiting was identified as cathepsin B while the degradation of myosin in fillets and surimi gels during conventional heating was caused by cathepsin L [13]. These proteinases impact Pacific whiting's commercial value and limit the prospective market for Pacific whiting in a fillet form.…”

Degradation of myofibrils in cultured yellowtail Seriola quinqueradiata burnt meat: effects of a myofibril-bound EDTA-sensitive protease

“…Several studies have shown that the different types of endogenous protease, such as cathepsins [12][13][14][15][16], aspartic acid proteases [17] or serine proteinases [18,19], especially the myofibril-bound serine proteinases [20,21], led to the degradation of myofibrillar proteins in fish meat.…”