Effect Of Microbial Transglutaminase Research Articles

Effects of microbial transglutaminase on gluten-free sourdough bread structure and loaf characteristics

The effects of microbial transglutaminase (mTG) on structure and loaf properties of gluten-free (GF) sourdough breads containing five different flours: chickpea, brown rice, white rice, oat, and quinoa. SDS-PAGE analysis revealed that white rice, brown rice, quinoa, and chickpea proteins are adequate substrates for mTG activity, while oat proteins, without the addition of exogenous proteins, lack the characteristics suitable for mTG action. Additionally, mTG engages in self-crosslinking. The utilization of mTG in GF sourdough bread applications was shown to improve some of the final bread characteristics of GF breads. White rice- and brown rice-GF sourdough loaves at 24 h showed a 28% and 13% decrease, respectively, in crumb firmness with the addition of 2 Units mTG per gram (U/g) of dough. Quinoa-GF sourdough breads at 24 h showed a 6% increase in specific volume with the addition of 1 U/g. Oat- and chickpea-GF sourdough loaves did not show improvements in loaf quality with mTG addition.

The effect of microbial transglutaminase and two different starter cultures on goat milk yogurt

The effect of microbial transglutaminase and two different starter cultures on goat milk yogurt

Effects of microbial transglutaminase on the gelling property and in vitro digestibility of fish scale gelatin from grass carp

Fish scales are good sources of gelatin, but the wide application of fish scale gelatin (FSG) is highly restricted due to its poor gelling property. In this study, microbial transglutaminase (MTG) was utilized to improve the gelling property of FSG from grass carp. The effects of MTG on the gel strength, textural property, rheological property, triple-helix structure, chemical structure, thermal property, and microstructure of FSG were investigated. Then, the in vitro gastric and simulated intestinal digestibility of the cross-linked FSG were further studied. The cross-linking of FSG by MTG at all concentrations increased the gel strength, hardness, chewiness, peak temperature, and sol-gel transition temperatures. The MTG at a low concentration promoted the formation of an ordered triple-helix structure and a compact network in FSG, while the high-concentration MTG had an opposite effect. Besides, the cross-linking of FSG by MTG generally increased the digestion time of FSG and allowed the release of more unique peptides during gastric and intestinal digestion. Peptides with various bioactivities were released after the simulated intestinal digestion of the native and modified FSGs. This study may provide some guidance for the deep utilization of FSG in the food industry and further promote the exploitation of fish scales.

Effect of microbial transglutaminase on thermal stability of milk protein

At present, Transglutaminase (abbreviated as TG, EC2.3.2.13) has been used in meat products, dairy products and baked goods in Japan and other countries. The stability of MP (Milk protein) colloid system is very important to the quality of dairy products. The effect of MTG (Microbial TG) on the thermal stability of MP was studied in this experiment. The change of HCT (Heat Coagulation Time) of MP emulsion before and after adding MTG was measured. The results show that the effect of MTG on MP leads to the decrease of its solubility in the region of pH < 4.0 or pH > 7.0, but it increases in the range near the isoelectric point of MP (pH 4.0 ~ 6.0). In the range of acidic pH value with low stability, the high calcium ion activity, low Zeta potential and micelle hydration make the milk have poor thermal stability and will solidify rapidly at 150℃. The hydrophobic interaction between MTG and MP changes the conformation of MP, which leads to the change of thermal stability.

Possible inhibitory effect of microbial transglutaminase on the formation of biogenic amines during Trappist cheese ripening

ABSTRACT Trappist cheese (semi-hard, rennet-coagulated cheese with round eyes) was manufactured and matured for 4 weeks at 12 ± 1°C, 85% relative humidity (RH). The effect of microbial transglutaminase (MTGase) was followed by measuring the levels of free amino acids (FAAs) and biogenic amines (BAs) every 2 weeks during 4 weeks of cheese ripening. Results show that MTGase can decrease the cadaverine production by 30%, but only at the initial stage of ripening. Application of MTGase results in 49% less putrescine, 12% less tyramine production at the end of 4 weeks ripening time, and can decrease histamine levels by 8% after 2 weeks of ripening time in the examined semi-hard cheese type.

Effects of microbial transglutaminase on textural, water distribution, and microstructure of frozen-stored longtail southern cod (Patagonotothen ramsayi) fish mince gel.

Frozen-stored fish mince tend to have poor gelling ability due to significant myosin denaturation caused by freezing. In this study, microbial transglutaminase (MTGase) was used to improve the quality of fish mince gel products made from frozen-stored longtail southern cod (LSC). The gel strength of the gel product increased with the addition of MTGase and reached a plateau value of ~19 N mm beyond 300 U/kg of MTGase, at the same condition, T22 was reduced from 57.22 to 49.77 ms, T23 was reduced from 1,273.88 to 1,072.27 ms. As the MTGase addition increased from 0 to 400 U/kg, the hardness of the fish surimi gel increased from 14.52 to 21.36 N, and the microstructure changed from loose to dense, respectively. This study showed that MTGase could promote gelation to improve the quality of frozen-stored LSC fish mince gel, especially at 300 U/kg, which potentially can be utilized to produce good surimi gel products out of frozen-stored fish.

The Effect of Microbial Transglutaminase on the Viscosity and Protein Network of Kefir Made from Cow, Goat, or Donkey Milk

In this study, we aim to decrease the fermentation time and to produce low-fat set-type kefir with adequate textural properties using microbial transglutaminase without inactivation. In addition, we reveal the effect of microbial transglutaminase, during and after fermentation, on kefir made with cow, goat, or donkey milk, which is a novel approach. Fermentation is followed by continuous pH and viscosity measurements; the final product is characterized by dry matter content, whey separation, protein pattern, and viscosity parameters, as well as gel firmness. The results show that already 0.5 U/g protein dosage of MTGase decreases pH levels independent of milk type, but MTGase does not influence the kinetics of fermentation. Apparent viscosity could be measured from different stages of fermentation depending on milk type (cow milk, 6 h; goat milk, 8 h; and donkey milk, 9 h). The final product characteristics show that the higher the casein ratio of the applied milk, the better the viscosity and gel firmness of the kefir due to the high reaction affinity of MTGase.

Effect of microbial transglutaminase, guar gum, sodium caseinate additive on gluten-free Taftoon (Based on Potato Powder Variety Agria)

Effect of microbial transglutaminase, guar gum, sodium caseinate additive on gluten-free Taftoon (Based on Potato Powder Variety Agria)

Microencapsulation of Lactobacillus rhamnosus using sesame protein isolate: Effect of encapsulation method and transglutaminase

Sesame protein isolate (SPI) as an encapsulation wall material was studied. The effect of microbial transglutaminase (MTGase) and also the encapsulation method (freeze drying (FD), spray drying (SD) and electrospraying (ES) methods) on the physicochemical characteristics and viability of Lactobacillus rhamnosus ATCC 7469 encapsulated in SPI was investigated. The hygroscopicity, moisture content, bulk density, aw, and color of microcapsules were affected by the encapsulation method. The particle size and ζ-potential of the microcapsules decreased and increased, respectively, after MTGase treatment. Irregular shapes, observed using field emission scanning electron microscope (FE-SEM), and the formation of new bonds, confirmed using Fourier transform infrared spectrometer (FT-IR), confirmed the successful encapsulation of L. rhamnosus using SPI. The SD method had the greatest protecting effect on L. rhamnosus with gastrointestinal conditions. Adding MTGase had a high protective effect on the viability of microcapsules at −18, 4, and 25 °C. Electrospraying had the poorest performance in the formation of SPI microcapsules. The SPI may be a potential candidate for the encapsulation of probiotics, and MTGase could improve the physical characteristics and microbial protection of the SPI-based microcapsules, especially using SD.

Effects of Microbial Transglutaminase on Technological, Rheological, and Microstructural Indicators of Minced Meat with the Addition of Plant Raw Materials.

The aim of the study was to analyse the effects of transglutaminase on the physicochemical, technological, rheological, and microstructural indicators of minced meat with the addition of plant raw materials. The formulations of minced meat from beef trimming, hemp protein, and flax flour were optimized in terms of biological value and optimal content of essential amino acids. The addition of plant components in amounts greater than 18% caused an increase in the content of protein, fat, and ash in the minced samples. The rheological properties of minced meat samples without enzyme treatment changed depending on the proportion of plant raw materials. When the content of the flax flour was increased, the minimum ultimate shear stress and viscosity were observed, while the maximum values for these indicators were achieved in samples containing about 15% hemp protein, as well as in samples without plant additives. When adding transglutaminase to the formulation, increases in the ultimate shear stress and viscosity were proven for all combined minced samples. The combined minces, containing flax flour, had a more plastic structure and the lowest modulus of elasticity, while minces including 14% hemp protein or more than 87% meat components were identical to the control samples in terms of deformation and elasticity. In enzyme-treated minces, the plasticity of the samples reduced while density and elasticity increased. Transglutaminase treatment contributed to the formation of optimal technological properties of combined minces. Microstructural analysis showed the intermolecular bonds between protein particles in combined minced samples with the addition of enzymes. The research results have demonstrated the effectiveness of using transglutaminase in the composition of combined minced meat for the formation of a homogeneous and dense system with the necessary technological and rheological properties.

Gelation of commercial pea protein isolate: effect of microbial transglutaminase and thermal processing

Abstract In the studied commercial pea protein isolate (PPI) some physicochemical modifications are induced in the protein structure during its processing. That fact would result into a reduction of proteins techno-functional properties. It has been evidenced by Differential Scanning Calorimetry the protein denaturation what gives as a result poor gelling ability. Microbial transglutaminase (MTGase) was added at different concentrations to improve the gelation process at two different settings/thermal treatments to make suitable texture PPI gels as a base for various meat and/or seafood analogues. SDS-PAGE analysis indicated that MTGase activity was focused on the polymerization of vicilins and legumins resulting in the promotion of new intermolecular protein complexes (increase in β-sheet aggregates). Rheological data showed that at 23% PPI with 5 and 7 U/g protein of MTGase the gel strength increased in terms of breaking force and complex modulus. It also improved the conformational stability and flexibility of their gel networks. The results suggest that appropriate gels with 23% PPI could be obtained adding 5 U/g MTGase able to be used as meat and/or seafood analogues.

Effect of microbial transglutaminase on the structural and rheological characteristics and in vitro digestion of rice glutelin–casein blends

The effect of microbial transglutaminase (MTGase) in cross-linking and modifying of rice glutelin–casein blends was investigated in this work. The maximum MTGase activity on rice glutelin–casein blends were found when its addition was 15 U/g of protein. Compared with the blends without MTGase, the appropriate addition of MTGase significantly affected the microstructure of the cross-linked proteins, resulting in the gradual ‘burying’ of Trp residue; while the space for hydrogen bonding was more abundant. Secondary structure changes, denoted by the disappearance of the α-helix and the decrement of the β-sheet structure, was due to the formation of the large loop and random coil structures. The MTGase-catalyzed reaction improves the protease resistance of the blends but not promote the conversion of free sulfhydryl groups (-SH) to disulfide groups (S-S). All the samples evaluated exhibited Bingham flow behavior instead of shear-thinning behavior, and thermally stable fluid properties dominated by elasticity, regardless of MTGase concentration used. Both the storage modulus (G') and loss modulus (G'') gradually decreased with the addition of MTGase. In short, this work demonstrated how the structure, rheology, digestibility of rice glutelin-casein blends are influenced by MTGase concentration.

Influence of Microbial Transglutaminase on Physicochemical and Cross-Linking Characteristics of Individual Caseins.

The effects of microbial transglutaminase (MTGase) cross-linking on the physicochemical characteristics of individual caseins were investigated. MTGase was used to modify three major individual caseins, namely, κ-casein (κ-CN), αS-casein (αS-CN) and β-casein (β-CN). The SDS-PAGE analysis revealed that MTGase-induced cross-linking occurred during the reaction and that some components with high molecular weights (>130 kDa) were formed from the individual proteins κ-CN, αS-CN and β-CN. Scanning electron microscopy (SEM) and particle size analysis respectively demonstrated that the κ-CN, αS-CN and β-CN particle diameters and protein microstructures were larger and polymerized after MTGase cross-linking. The polymerized κ-CN (~749.9 nm) was smaller than that of β-CN (~7909.3 nm) and αS-CN (~7909.3 nm). The enzyme kinetics results showed KM values of 3.04 × 10−6, 2.37 × 10−4 and 8.90 × 10−3 M for κ-CN, αS-CN and β-CN, respectively, and, furthermore, kcat values of 5.17 × 10−4, 1.92 × 10−3 and 4.76 × 10−2 1/s, for κ-CN, αS-CN and β-CN, respectively. Our results revealed that the cross-linking of β-CN catalyzed by MTGase was faster than that of αS-CN or κ-CN. Overall, the polymers that formed in the individual caseins in the presence of MTGase presented a higher molecular weight and larger particles.

The Effects of Microbial Transglutaminase (MTG) Enzyme Usage on Sensory Properties of Hatay Cheese

Hatay Cheese is a kind of cheese produced in and around Hatay with its own shapes and sizes. In this study, the use of microbial transglutaminase enzyme was tried to improve the textural structure of Hatay cheese which is in fresh cheese class. Enzymatic modification of milk proteins by microbial transglutaminase enzyme has been applied in the production of half-fat Hatay cheese with different pre-ripening time applications and some sensory properties of the cheeses have been investigated such as external appearance, internal appearance, texture, odor and taste during 60 days of storage. In this study, four different Hatay cheese were produced as control sample (A), 30 minutes pre-ripening with enzyme (B), 45 minutes pre-ripening with enzyme (C) and 60 minutes pre-ripening with enzyme (D). When the sensory properties of the cheeses were examined, it was observed that the application of different pre-ripening time significantly affected the external appearance, internal appearance, texture and taste scores on the 60th day of storage (p 0.05). The effects of different pre-ripening periods and storage time on the odor scores of the cheeses were not significant (p>0.05). Taste scores of cheese D were significantly affected by storage time (p<0.05). As a result of all sensory analyzes, it was found that the cheeses supplemented with MTG enzyme were more liked and the scores given to the cheeses increased as the pre-ripening period increased. As a result, the most admired cheese was D cheese.

Effects of microbial transglutaminase on gel formation of frozen-stored longtail southern cod (Patagonotothen ramsayi) mince

The effects of addition of microbial transglutaminase (MTGase) on gel forming properties of frozen stored longtail southern cod mince (LSCM) were investigated at different incubation temperatures (35 °C, 40 °C, 45 °C, 50 °C). The results showed that frozen stored LSCM had poor gel-forming ability. With MTGase addition, the gel-forming ability of the LSCM was significantly improved, with the best performance obtained at 35 °C heating for 2 h. MTGase promoted myosin cross-linking, which led to an increase in gel strength. Circular dichroism analysis revealed that the myosin rod went through unfolding in two phases, at 30 °C and 38.5 °C, respectively. At 35 °C, myosin rod was only partially unfolded, with 40% helical structures remained which appeared to play critical roles in promoting intermolecular cross-linking. According to the scanning electron micrographs, the higher connectivity and lower porosity was correlated to the higher gel strength. This study showed that the effect of MTGase could be synergistically combined with proper selection of incubation temperature and time to improve gelation properties of fish mince products.

Effect of microbial transglutaminase on the mechanical properties and microstructure of acid-induced gels and emulsion gels produced from thermal denatured egg white proteins

In the current study, the impact of microbial transglutaminase (MTGase)-mediated crosslinking on the thermally denatured egg white protein (TD-EWP) made in alkaline pH in relation to their gelling properties of in gel and emulsion gel systems was investigated. Unlike native EWP that was not a good substrate for MTGase due to its compact structure, SDS-PAGE and gel solubility data showed the TD-EWP was sufficiently cross-linked by MTGase. The MTGase significantly (p < 0.05) increased the gel strength, fracture stress, fracture strain, and TPA parameters and decreased the frequency dependence of elastic modulus and stress dependence of creep compliance of TD-EWP gel and emulsion gel samples. The enhanced mechanical properties of the TE-EWP gelled samples treated with MTGase may be suitable for delivering sensitive compounds as well as in fabricating tailored scaffolds in tissue engineering and biomedical products.

Process design for processed Kashar cheese (a pasta-filata cheese) by means of microbial transglutaminase: Effect on physical properties, yield and proteolysis

Cheese industry has long been interested in improving the quality and functionality of cheese to meet consumers’ demand as well as reducing the production costs by using different manufacturing strategies. In this study, the effects of microbial transglutaminase (mTG) on the yield, proteolysis and physical properties of processed Kashar cheese were evaluated. The mTG level used was 0.75 U/g protein and the concentrations of emulsifying salt (ES) mixture were 0.8, 1.0 and 1.2 g/100 g cheese curd (w/w). The increase in the moisture adjusted yield of cheeses were between 1.68 and 2.00% as relative change compared to control cheese. The cheeses had similar melting profile with the control cheese. The rheological and textural properties of the cheeses were different from the control cheese. The ES concentration and addition of mTG had an impact on the proteolysis but it did not affect meltability in current concentration. To conclude, the yield of processed Kashar cheese may well be increased to a satisfactory level without adversely affecting the physical characteristics of the end product.

Microbial transglutaminase alters the immunogenic potential and cross-reactivity of horse and cow milk proteins

Horse milk is a valuable raw material and a very attractive alternative for scientific research to address the issue of cow milk (CM) allergy due to its protein profile. A decrease in immunoreactive properties can be achieved by thermal, enzymatic, and hydrolytic processing. Therefore, the aim of this study was to explore the possibility of reducing the immunoreactivity of horse milk proteins by microbial transglutaminase (TG) polymerization. To determine how TG linking alters immunoreactivity under simulated digestion of the examined milk, analyses were performed before, during, and after digestion. The dose-dependent (1, 10, and 100 U) effects of microbial TG on horse and cow milk were analyzed. A consecutive 3-stage digestion was simulated with salivary, gastric, and intestinal fluids. The effects of digestion were analyzed by SDS-PAGE, particle size analysis, and size-exclusion chromatography. Immunoreactivity was assessed using competitive ELISA (β-lactoglobulin and α-casein) and immunodot (sera from 7 patients aged 3 to 13 years who are allergic to CM proteins). Horse milk contained almost half of the amount of total proteins in CM. The dose 1 U/g of total milk protein changed the immunoreactivity of both cow and horse milk. With increasing TG doses, α-casein immunoreactivity increased, and β-lactoglobulin decreased. After total digestion, horse milk was characterized by 2.4-fold lower average IgE and 4.8-fold lower IgG reactivity than CM. We found that TG alters the IgE and IgG reactivity of CM after in vitro digestion. Horse milk was less reactive to IgE and IgG than was CM, with animal and patient sera. The effect of TG on immunoreactivity depends on enzyme quantity and milk protein type. The diet based on modified horse milk proteins could be an alternative for some patients with CM protein allergy; however, confirmation through clinical trials is needed.

Storage stability of fermented milk with probiotic monoculture and transglutaminase

The effect of microbial transglutaminase on selected physicochemical and organoleptic characteristics and viability of probiotic bacteria in fermented milk inoculated with probiotic monoculture (Lactobacillus acidophilus LA 5 or Bifidobacterium bifidum BB 12) was analysed. Four types of samples were prepared: (1) fermented milk inoculated with Lactobacillus acidophilus LA 5, (2) fermented milk inoculated with Bifidobacterium bifidum BB 12, (3) fermented milk produced from milk previously treated with mTGase and inoculated with Lactobacillus acidophilus LA 5, (4) and fermented milk produced from milk previously treated with mTGase and inoculated with Bifidobacterium bifidum strain BB 12. The samples were analysed after the 1st, 7th and 14th day of storage at 5 ± 1°C. It has been found that the use of microbial transglutaminase for the production of fermented milk inoculated with monoculture affected its viscosity, hardness, acetaldehyde content and increased the viability of probiotic bacteria. The enzyme activity resulted in an significant decrease in the titratable acidity of the experimental products, positively affected viscosity, the viability of probiotic bacteria and the organoleptic properties of fermented milk.

Evaluation of gels made with different commercial pea protein isolate: Rheological, structural and functional properties

The gelling of two commercial pea protein isolates (PPI) at 20% and 23% PPI concentration, and the effect of microbial transglutaminase (-0- and -5- U/g protein), were analysed. The final aim was to get PPI gels with textural properties enough to make meat and seafood analogues. The first PPI (-A-), was made by alkaline solubilization and isoelectric precipitation from pea flour. The second one (-B-), was obtained by aqueous dispersion of the pea flour and concentration of the soluble protein. The water and oil holding capacities of PPI-A suggested a higher degree of protein denaturation which was assessed by Dynamic thermo mechanical analysis (DMTA) and Fourier transform infrared spectroscopy (FTIR). FTIR data showed lower intermolecular β-sheet aggregates in PPI-B gels than in PPI-A. This result was consistent with the reticulated and well-interconnected network from scanning electron microscopy (SEM) of PPI-B gels in line with the higher strain amplitude (γmax), and the lower loss factor (tanδ) in PPI-B gels vs PPI-A gels. The MTGase enzyme significantly improved the structural quality of the PPI-B gels (high Q-factor) at 20% and 23% PPI. For all these reasons PPI B is more suitable for achieving consistent gels as bases for meat and seafood analogues.