Presence Of MTGase Research Articles

The effect of the addition of microbial transglutaminase before the fermentation process on the quality characteristics of three types of yogurt

The effect of the addition of microbial TGase to milk on selected physical properties of the final product and the viability of lactic acid bacteria cultures during storage at 6 °C for 56 days was studied. Three types of set-style yogurt were made with varying parameters. Weekly analyses included the determination of syneresis and water-holding capacity, texture, pH, and the lactic acid bacteria population. Our research has confirmed that mTGase may be used to stabilize yogurts, although the syneresis, the water-holding capacity of yogurts, and the textural features of yogurts were dependent on the step in the production process at which mTGase was added to milk. The presence of mTGase had no relevance with regard to the acidity of yogurts stored under refrigerated conditions. The addition of mTGase had no effect on lactobacilli, but had a variable effect on Streptococcus thermophilus, depending on the duration of enzymatic activity.

Colloidal Gold Probe-Based Immunochromatographic Strip Assay for the Rapid Detection of Microbial Transglutaminase in Frozen Surimi

Adding microbial transglutaminase (MTGase) to frozen surimi to enable the surimi to be sold as a higher-grade product at a higher price defrauds surimi product manufacturers and undercuts legitimate industry prices. Therefore, it is important to develop an accurate method of detecting the presence of MTGase in surimi. In this study, an immunochromatographic strip assay with a colloidal gold antibody probe was successfully developed and used to rapidly and qualitatively detect MTGase in surimi samples. The results were obtained in less than 10 min. The limit for the qualitative detection of MTGase using the immunochromatographic strip assay was identified as 1.0 μg/mL. The results of the immunochromatographic strip analysis of frozen surimi samples were verified by comparison with the results of a sandwich enzyme-linked immunosorbent assay. The colloidal gold probe-based immunochromatographic strip assay was thus found to be a rapid, economical, and user friendly method of detecting MTGase in surimi.

Improvement of Gelling Properties of Lizardfish Mince as Influenced by Microbial Transglutaminase and Fish Freshness

The effects of microbial transglutaminase (MTGase) at different levels (0 to 0.8 units/g sample) on the properties of gels from lizardfish (Saurida undosquamis) mince set at 25 degrees C for 2 h or 40 degrees C for 30 min prior to heating at 90 degrees C for 20 min were studied. Breaking force and deformation of gels increased with increasing MTGase amount added (P<0.05). At the same MTGase level used, gels with the prior setting at 40 degrees C for 30 min showed a higher breaking force compared with those subjected to prior setting at 25 degrees C for 2 h (P<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoretic study revealed that myosin heavy chain (MHC) underwent polymerization to a higher extent in the presence of MTGase. Regardless of setting condition, microstructure of gel added with MTGase was finer with a smaller void compared with that of gel without MTGase. Therefore, setting temperature affected the property of gels added with MTGase. Gel properties of mince obtained from lizardfish stored in ice for different times (0 to 10 d) with and without MTGase at a level 0.6 units/g were determined. Irrespective of MTGase addition, breaking force and deformation of all gels decreased as the storage time of lizardfish increased (P<0.05). The addition of MTGase was able to increase both breaking force and deformation of the resulting gel produced from lizardfish kept in ice for all storage times used. Therefore, both freshness and MTGase addition had the direct impact on gel properties of lizardfish mince.

Gelling properties of white shrimp ( Penaeus vannamei) meat as influenced by setting condition and microbial transglutaminase

The properties of white shrimp ( Penaeus vannamei) gel added with different levels of microbial transglutaminase (MTGase) and subjected to setting at 25 °C for 2 h or 40 °C for 30 min, prior to heating at 90 °C for 20 min were studied. Breaking force of gels with and without setting increased with increasing MTGase amount added ( P < 0.05 ). However, no changes in deformation in all samples were noticeable ( P > 0.05 ). Directly heated gels showed the lower breaking force than those with prior setting at all MTGase levels added ( P < 0.05 ). Generally, gels prepared by setting at 25 °C exhibited the greater breaking force than those set at 40 °C, possibly associated with the appropriate protein structure for cross-linking at 25 °C and greater degradation at 40 °C as evidenced by a greater trichloroacetic acid soluble peptide content ( P < 0.05 ). Sodium dodecyl sulfate polyacrylamide gel electrophoretic study revealed that myosin heavy chain (MHC) underwent polymerization to a higher extent in the presence of MTGase, but the strengthening effect on gel was dependent on setting temperature. Regardless of setting condition, microstructure of gel added with MTGase was finer with a smaller void, compared with those of gel without MTGase. Therefore, setting temperature played an essential role in gel property of white shrimp meat added with MTGase.

Synergistic action of transglutaminase and high pressure on chicken meat and egg gels in absence of phosphates

The effects of simultaneous application of microbial transglutaminase (MTGase) and high pressure (HP) (500, 700 and 900 MPa/40 °C/30 min), only pressure under the same conditions or heat (75 °C/30 min) were investigated on chicken batters with the addition of egg components and without phosphates. MTGase gels (700 and 900 MPa) showed marked increases in textural parameters compared to gels without enzyme (NE) or those obtained by heat. The addition of enzyme did not show differences between gels obtained at 700–900 MPa; however, gels obtained at 500 MPa were darker and more reddish than those obtained by heat. MTGase gels were more homogeneous and compact. Thermal analysis revealed that pressure levels above 700 MPa caused as much denaturing as did heat. The microstructure and texture of MTGase gels suggest that a higher amount and heterogeneity of crosslinks was produced when meat and egg proteins were treated in the presence of MTGase under specific conditions of pressure.

CHITOSAN AFFECTS TRANSGLUTAMINASE-INDUCED SURIMI GELATION

Effect of chitosan on barred garfish (Hemiramphus far) surimi gel was studied in the presence of EDTA and microbial transglutaminase (MTGase). An increase in breaking force of surimi gels added with 1.0% prawn shell chitosan indicated the gel enhancing effect of chitosan on the heat-induced gelation of fish myofibrillar proteins. However, gel-forming ability of surimi containing chitosan was inhibited in the presence of EDTA, especially at higher concentration. Therefore, the enhancing effect of chitosan was possibly mediated through the action of endogenous transglutaminase (TGase) during setting, resulting in the formation of protein-protein and protein-chitosan conjugates. In general, addition of MTGase remarkably increased both breaking force and deformation of surimi gel (P<0.05). However, enhancing effect of MTGase was retarded in the presence of chitosan, resulting in lower magnitude of breaking force and deformation (P<0.05). Scanning electron microscopy showed that chitosan particles were uniformly dispersed in the gel matrix. A tightly associated gel network was formed in surimi containing MTGase, whereas a large number of voids were noted in gels with EDTA. These results suggest that chitosan acted as a surimi gel enhancer in combination with endogenous TGase in fish muscle, but hindered gel formation in the presence of MTGase.