Combination Effects of Microbial Transglutaminase, Reducing Agent, and Protease Inhibitor on the Quality of Hairtail Surimi

A combination of microbial transglutaminase (MTGase), reducing agent and protease inhibitor was employed to improve the quality of underutilized fish surimi. SDS-PAGE indicated that cross-linking of myosin heavy chain (MHC) occurred in MTGase-contained samples, while MHC of samples without MTGase disappeared after 120 min incubation at 45°C. Although the gel-forming ability increased with MTGase added up to 0.6 unit/g, it was still too low to be commercially acceptable. However, the combined use of 0.1% NaHSO₃, 0.01 mM transepoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64) and 0.35 units MTGase/g substantially improved the quality of hairtail surimi. Based on this result, the combined use of E-64, MTGase and NaHSO₃ seemed to be a better way to improve gel-forming ability of hairtail surimi.     

Microbial Transglutaminase and Recombinant Cystatin Effects on Improving the Quality of Mackerel Surimi

ABSTRACT: Effects of microbial transglutaminase (MTGase), recombinant cystatin, or their combination on the gel properties of mackerel surimi were investigated. The addition of MTGase caused the cross-linking of myosin heavy chain (MHC) and substantially increased the gel strength (from 536.6 to 2012.4 g × cm), while the recombinant cystatin could effectively prevent the MHC degradation and gel softening during the production of mackerel surimi-based products. Combined use of MTGase and recombinant cystatin revealed synergistic effectiveness on improving the quality of mackerel surimi (increased from 435 to 2438 g × cm, set at 45 °C for 20 min).     

Purified NADPH-Sulfite Reductase from Saccharomyces cerevisiae Effects on Quality of Ozonated Mackerel Surimi

The NADPH-sulfite reductase from Saccharomyces cerevisiae was purified to electrophoretic homogeneity by ammonium sulfate fractionation, DEAE Sephacel, Sephacryl S-300 and DEAE Sephadex A-50 chromatography. Optimal pH was 7.3 and temperature 25°C. It was inhibited by IAA, PCMPS, PMSF, NEM, PCMB, cyanide and most divalent metal ions. For the ozonated mackerel surimi ground with purified reductase, the reactive SH increased from 2.29∞10⁵ to 4.46∞10⁵mole/g and gel strength from 256.7 to 360.5g·cm. According to SDS-PAGE, the recovery of myosin heavy chain was observed on the ozonated mackerel surimi with addition of NADPH-sulfite reductase.     

Gel Strength Enhancement by Addition of Microbial Transglutaminase during Onshore Surimi Manufacture

Surimi from Alaska pollock flesh was manufactured onshore with Microbial transglutaminase (MTGase). Effect of MTGase was investigated by evaluating breaking strength and deformation of gels from MTGase-treated surimi with and without setting at 30°C. Quantitative analysis of ε-(γ-glutamyl)lysine (GL) crosslink was also carried out to monitor the MTGase reaction. In set gels, breaking strength and GL crosslink increased, and myosin heavy chain decreased correspondingly with MTGase concentration. These changes were smaller in gels prepared without setting. Results suggest that surimi gel could be improved through the formation of GL crosslinks by added MTGase in surimi.     

鸡蛋清蛋白对微生物转谷氨酰胺酶诱导鲢鱼鱼糜凝胶形成的影响

通过对鲢鱼鱼糜凝胶特性和溶解率的测定及SDS-PAGE检测研究鸡蛋清蛋白改善鱼糜凝胶特性的机理及其对微生物转谷氨酰胺酶(MTGase)诱导鱼糜凝胶形成的影响。结果表明：鸡蛋清蛋白(EA)和MTGase均能显著提高鱼糜凝胶特性。EA会降低MTGase诱导鱼糜凝胶的形成,显著降低MTGase诱导鱼糜凝胶的凝胶强度和破断强度,但不阻碍MTGase对肌球蛋白重链(MHC)的交联。     

Effect of microbial transglutaminase on autolysis and gelation of lizardfish surimi

In the absence of microbial transglutaminase (MTGase), the textural properties of lizardfish surimi (Saurida spp) improved when pre‐incubated at 4 and 25 °C for 24 and 4 h, respectively. MTGase optimally catalyzed incorporation of monodansylcadaverine (MDC) into surimi at 40 °C. Addition of MTGase appeared to reduce autolytic activity at 25 and 40 °C, but had no effect on autolytic activity at 65 °C. Breaking force and deformation of lizardfish surimi significantly improved when 0.1 unit MTGase g^?1 surimi (1.8 g kg^?1) was added and pre‐incubated at either 25 or 40 °C. Textural properties improved concomitant with cross‐linked polymers of myosin heavy chain and tropomyosin, but not actin. Addition of MTGase also improved the storage modulus (G′). The gel network of surimi mixed with MTGase and pre‐incubated at 40 °C readily formed during the pre‐incubation period, while formation of the gel network began at 48.1 °C in the absence of MTGase. Copyright © 2005 Society of Chemical Industry     

Comparative study on protein cross-linking and gel enhancing effect of microbial transglutaminase on surimi from different fish

BACKGROUND: Microbial transglutaminase (MTGase) has been used to increase the gel strength of surimi. Nevertheless, its effectiveness varies with fish species. The aim of this study was to elucidate the effect of MTGase at different levels on protein cross‐linking and gel property of surimi from threadfin bream, Indian mackerel and sardine in the presence and absence of endogenous transglutaminase. RESULT: Breaking force of all surimi gels increased as MTGase levels (0–0.6 U g^?1) increased except for threadfin bream surimi gel, where the breaking force decreased at 0.6 U g^?1 (P < 0.05). In the presence of EDTA, the gel strengthening effect was lower, suggesting the combined effect of endogenous transglutaminase with MTGase. With the addition of MTGase, the gel with the highest increase in breaking force showed highest decrease in myosin heavy chain. When cross‐linking activity of MTGase on natural actomyosin (NAM) was determined, the highest decreasing rate in ε‐amino group content with the concomitant increased formation of cross‐linked proteins was found in NAM from threadfin bream. The reactivity of muscle proteins toward MTGase‐induced cross‐linking was in agreement with surimi gel strengthening. CONCLUSION: The composition and properties of muscle proteins of varying fish species more likely determined protein cross‐linking induced by MTGase, thereby affecting their gel properties. Copyright © 2011 Society of Chemical Industry     

Microbial Transglutaminase Affects Gel Properties of Golden Threadfin-bream and Pollack Surimi

ABSTRACT: The properties of surimi gels from threadfin-bream and pollack surimi set at 30 °C or 45 °C with microbial transglutaminase (MTGase) from Streptoverticillium ladakanum were determined. The optimal amounts of MTGase and setting conditions were: 0.3 unit/g surimi either at 30 °C for 90 min or at 45 °C for 20 min for threadfin-bream, and 0.2 unit/g surimi at 30 °C for 60 min for pollack. The strength of golden threadfin-bream surimi gels with 0.35 unit MTGase set at 30 °C for 90 min or 45 °C for 20 min was 3400 g cm, almost 3-fold of the control. SDS-PAGE analyses indicated that inter- and/or intramolecular cross-linking formed in the myosin heavy chain of MTGase-containing surimi gels.     

Microbial Transglutaminase and ε-(γ-Glutamyl)lysine Crosslink Effects on Elastic Properties of Kamaboko Gels

Kamaboko gels from Alaska pollock surimi (SA? and 2nd? grades) were prepared by setting at 10 or 45°C with Microbial transglutaminase (MTGase) and its effect on gel properties was investigated. At 10 and 45°C, gels from 2nd? grade surimi paste showed increases in breaking strength, without decline in deformation. Gel from SA? graded surimi paste showed an increase in breaking strength with no changes in deformation in 45°C setting, up to 0.03% MTGase. Crosslinking of myosin heavy chains through ε-(γ-glutamyl)lysine bonds was observed and a possible correlation was shown between ε-(γ-glutamyl)lysine content and gel strength (breaking strength X strain). ε-(γ-Glutamyl)lysine content up to 3 μmol/100g or MTGase 0.03% or higher improved gel properties.     

Comparison of Atlantic menhaden gels from surimi processed by acid or alkaline solubilization

Heat-induced gelling abilities of surimis prepared by pH shifting (isoelectric precipitation following acid (AC) or alkaline (AL) solubilization) were compared to that of conventionally washed (CW) surimi. Greater endogenous transglutaminase activity (evidenced as enhanced strength of cooked gels subjected to 30–40 °C preincubation) was measured for CW and AL surimi than for AC surimi (all at pH 7). Upon addition of microbial transglutaminase (MTGase), increased crosslinking of myosin heavy chain and gel strengthening during 30–40 °C preincubation were apparent for all three types of surimi, most markedly in CW and AL surimi. Salt addition improved CW gels most, but seemed to adversely affect MTGase activity in AC and AL surimi. AC and AL surimi gels were of lower whiteness than were CW surimi gels.