Comparative study on proteolysis of two species of bigeye snapper, Priacanthus macracanthus and Priacanthus tayenus

Abstract

Proteolytic activity in muscle from two species of bigeye snapper (Priacanthus macracanthus and Priacanthus tayenus) was studied. Autolysis of mince and washed mince at 50 and 60 • C was compared. Higher degradation of myosin heavy chain was observed in both mince and washed mince from P macracanthus than in those from P tayenus, especially when the incubation time was increased. Autolysis of washed mince from both species was inhibited by soybean trypsin inhibitor, suggesting that myofibril-associated proteases were serine proteases. When sarcoplasmic proteolytic activity in P macracanthus muscle was studied, two activity peaks with an optimum temperature of 60 • C were observed at pH 6.5 and 8.5. The activities of both peaks were mostly inhibited by soybean trypsin inhibitor, suggesting that the major protease was a serine protease. Major sarcoplasmic proteolytic activity in P macracanthus muscle was found at M r 62 000 on sodium dodecyl sulphate substrate gel. For P tayenus sarcoplasmic proteolytic activity, two activity peaks with an optimum temperature of 60 • C were found at pH 5.0 and 8.5. The pH 5.0 peak activity was effectively inhibited by pepstatin A, while the pH 8.5 peak activity was inhibited by several inhibitors. The results indicated that various sarcoplasmic proteases were present in P tayenus muscle. The two species contained different sarcoplasmic proteases in terms of composition and activity level. P macracanthus muscle generally had higher sarcoplasmic proteolytic activities than P tayenus muscle.

Identification of antioxidative oligopeptides derived from autolysis hydrolysates of sea cucumber (Stichopus japonicus) guts

“…The autolysis of sea cucumber guts needs a similar incubation temperature than that needed for shrimp head (50°C) [34], but a lower temperature of incubation than that of various fishes (60-65°C) [37][38][39]. Moreover, Benjakul et al [40] reported that heat-activated alkaline proteases in bigeye snapper and lizardfish (Saurida tumbil) played an important role in degradation of muscle protein, especially at 60-65°C. Both acid and alkaline proteinases were involved in autolysis of Japanese sandfish [41].…”

Gel‐forming properties of surimi produced from bigeye snapper, Priacanthus tayenus and P macracanthus, stored in ice

“…P macracanthus muscle displayed higher proteolytic activity than P tayenus muscle, as shown by autolytic activity assay. 31 The results suggested that pretreatment of P macracanthus by beheading and evisceration effectively protected myosin from degradation.…”

Heat-activated proteolysis in lizardfish (Saurida tumbil) muscle

“…Nevertheless, the proteinases associated with myofibrils still remained and resulted in the degradation as shown in Fig 1B. Approximately one-fifth of the proteinase activity in Pacific whiting was removed by the washing and dewatering steps (Morrissey et al, 1995). Benjakul et al (2003aBenjakul et al ( , 2003b also found that washing could decrease the degradation of MHC in bigeye snapper muscle at 50 and 60 C. Therefore, the proper washing is a means to reduce the proteolytic activity, especially sarcoplasmic proteinases. The degradation of muscle protein in surimi gel during heating was associated with the weakening of gel called 'modori' (Jiang, 2000).…”

“…Sarcoplamic proteinases can be removed to some extent during washing process, while myofibril associated proteinases still remain in surimi, resulting in gel weakening (modori) (Benjakul, Seymour, Morrissey, & An, 1996;Benjakul et al, 2003a;Morrissey, Hartley, & An, 1995). Myofibril associated serine proteinase in lizardfish (Saurida wanieso) with a molecular weight of 60 kDa hydrolyzed myosin heavy chain at 55-60 C (Cao, Osatomi, Hara, & Ishihara, 2000).…”

“…Gel softening varies with species, but is generally caused by two major groups of proteinase, cathepsin and heat-stable alkaline proteinases (An, Peters, & Seymour, 1996). Different proteolytic activities between two species of bigeye snapper were associated with the differences in gelling properties (Benjakul, Leelapongwattana, & Visessangaun, 2003a). Most of myosin heavy chain (MHC) in Pacific whiting muscle was degraded when incubated at 60 C for 30 min, prior to cooking at 90 C and surimi did not form the gel (Morrissey, Wu, Lin, & An, 1993).…”