Transglutaminase Treatment Research Articles

Interplay between transglutaminase treatment and changes in digestibility of dietary proteins

The changes in digestibility of TG-treated myofibrillar protein (MP), soybean protein isolate (SPI) and mixed proteins were evaluated by measuring liberation of primary amino groups, monitoring structural changes and investigating peptide fingerprints. TG treatment generally increased gastric digestion of treated proteins, possibly due to the structural changes occurred during TG treatment. In contrast, the initial intestinal digestion was suppressed by TG treatment. Compared with MP, the digestibility and peptide composition of SPI were affected by TG treatment to a larger degree, possibly due to the higher level of glutamine in SPI. Peptidomics analysis indicated that the changes in peptide composition of digests of TG-treated samples were related with the loss of Lys residues during TG treatment. Larger quantities of bioactive peptides KIEFEQFLPM, EVHEPEEKPRPK and TVKEDQVFPMNPPK were released after digestion of TG-treated MP. These results highlighted the complex and substantial influence of TG treatment on the digestibility of dietary proteins.

Synergistic recovery and enhancement of gelling properties of oxidatively damaged myofibrillar protein by l-lysine and transglutaminase

The influence of combined Lysine (Lys) and transglutaminase (TG) on the conformation and gelling properties of oxidatively damaged myofibrillar protein (MP) was investigated. The addition of Lys (5 mM) significantly increased the α-helix content (by 47.8%) and decreased the particle size of oxidatively damaged MP, and improved the cooking yield (by 16.8%) and the breaking strength of MP gels (by 65.5%). The treatment with TG (E:S = 1:500) led to a slightly reduced α-helix content but improved breaking strength (by 41.8%) and cooking loss (by 13.3%) of the gels. Their combination (Lys + TG) showed the greatest and synergistic overall improvement, with the set gel displaying a fine, smooth and compact network structure. Notably, the gelling ability of oxidatively damaged MP upon Lys + TG treatment was significantly stronger than that of non-oxidized MP far exceeding its recovery. Therefore, significantly enhanced gelling properties of oxidatively damaged MP can be attained through the combination Lys and TG.

Mechanical properties and water sensitivity of soybean protein isolate film improved by incorporation of sodium caseinate and transglutaminase

This study addresses the classic problems of high water solubility, hydrophilicity and low tensile strength of soybean protein isolate films. The effects of incorporation of sodium caseinate and transglutaminase treatment on the properties of film-forming solutions and their resultant films were systematically studied, changes in the former explaining improved properties of the latter. Increases in protein molecular weight, particle size, and viscosity, and decreases in lysine residue content of the solutions confirmed the formation of new macromolecular proteins following transglutaminase cross-linking. Increased hydrophobicity of proteins revealed the reason for decreases in water sensitivity of the films. The tensile strength and the hydrophobicity of the films significantly increased, while water solubility, water vapor permeability and elongation at break decreased by 37 %, 32 % and 71 %, respectively, in the presence of sodium caseinate and transglutaminase. In general, the coexistence of sodium caseinate and transglutaminase treatment significantly improve critical properties of soybean protein isolate-based films, particularly water sensitivity and tensile strength, and expand their potential applications in humid environments.

Nutrient and specification enhancement of fortified Asian noodles by chickpea flour substitution and transglutaminase treatment

ABSTRACT Effects of supplementation of chickpea flour (CF) (10% and 20%) to wheat flour (WF) followed by Transglutaminase (TGase) treatment (0–1.2%) were investigated to synergistically boost nutritional and texture properties of Asian noodles. The results showed that CF supplementation diluted both gluten-forming proteins and starch content of the blend, resulting in the weak dough, high cooking loss, and poor sensory quality. However, TGase treatment at 0.4–0.8% dosage could effectively recover the dough structure by crosslinking, including CF proteins as evidenced by Mixolab, SDS-PAGE, and dynamic viscoelasticity. The latter also distinguished the distinct dough structure treated by TGase from the wheat gluten-network. SEM revealed the improved network matrix and well-embedded starch granules in raw and cooked noodles. The cooked noodles substituted with 10% CF with 0.4% TGase treatment had the lowest cooking loss and comparable sensory qualities to WF control (p < .05).

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.

Effects of heat curing and transglutaminase treatments on the physical, mechanical, and water barrier properties of yuba films

Yuba is a soy protein-lipid film formed on the surface of heated soymilk. Heat curing (HC) and a combination of HC and transglutaminase (TGHC) treatment were evaluated to improve the water vapor permeability (WVP) and mechanical properties of the 3rd, 5th, and 7th yuba film sheets. The performance of the yuba film was compared to no-treaded yuba (Con) and gelatin films. The tensile strength of the film was 118%–135% higher after HC and 78%–117% higher after TGHC compared to the Con. After HC, the elongation of the 3rd and 5th yuba film sheets was decreased to half of the Con. However, the 7th film was increased after HC (90%) and TGHC (23%–131%) treatment compared to the Con (22%–59%) or gelatin (37%). Heat treatment increased the –S–S– content, and transglutaminase (TGase) treatment increased the amide linkages at 1,623 and 1,535 cm−1. HC and TGHC reduced the WVP to half that in the Con or gelatin. TGase and heat cured yuba, especially the 5th sheet, has the potential for use as an alternative to gelatin as a plant-based edible film. Practical applications Yuba, a protein-lipid film, has been widely used in East Asia to wrap and shape vegetables, such as spring rolls, or as ingredients in many forms, such as meat mimics. As a plant-based source, yuba has many benefits as a natural and biodegradable material. However, yuba has poor mechanical and water barrier properties as an edible film. Yuba treated by both transglutaminase and heat curing showed better water barrier properties, 70% of the tensile strength, and twofold higher elongation values than gelatin film. The better performance of modified yuba indicates its potential as an alternative to gelatin film as a plant-based edible film.

The effect of heat and transglutaminase treatment on emulsifying and gelling properties of faba bean protein isolate

The effects of heat treatment (90 °C, 5 or 30 min) and enzymatic crosslinking with transglutaminase (TG, 10, 100 or 1000 nkat/g protein) on emulsifying and gelling properties of faba bean protein isolate (FPI) were studied. Heat treatment of FPI caused a clear shift in far-UV CD spectra towards random coil structure and an increase in surface hydrophobicity from 181 to 504 RFU. TG crosslinked heat-treated FPI more efficiently as compared to native FPI. TG-induced crosslinking caused a reduction of surface hydrophobicity from 504 to 435 RFU. Emulsifying activity and stability indexes of FPI stabilized emulsions ranged between 25 and 30 m2/g and 18–35 min, respectively. Rheological properties of the FPI gels induced by heating, followed by acidification or TG treatment (10 or 100 nkat/g protein) were analyzed. FPI showed gel-like characteristics at 10% concentration (G′ = 180 Pa). When the heat-treated FPI dispersion was further acidified or TG-treated (100 nkat/g), G′ values of >6500 and > 3500 Pa were achieved, respectively. Water holding capacity of the FPI gels were >93% and >98% for acid- and TG-induced gels, respectively. The gel microstructures showed mainly heterogeneously-sized protein aggregates, however, no differences were observed between acid- and TG-induced gels.

Pasta from cellulase-treated wheat bran and durum semolina: Effects of vital gluten addition and/or transglutaminase treatment

Wheat bran was treated with a cellulase preparation and used in the production of high fiber pasta by the partial substitution of durum semolina. The nutritional, textural, and cooking quality of bran-incorporated pasta was measured. In addition, the potentials of vital gluten addition and/or transglutaminase treatment in improving the quality of bran-incorporated pasta were investigated. The use of cellulase-treated wheat bran resulted in a higher soluble fiber content, a more balanced insoluble to soluble fiber ratio, and a lower predicted glycemic index of pasta compared to that of untreated bran. The addition of vital gluten or treatment with transglutaminase improved the cooking performance, textural properties, and overall acceptability of pasta. In particular, the combination of vital gluten addition and transglutaminase treatment was more effective in improving the quality of pasta with cellulase-treated wheat bran.

Effects of pre-heating soybean protein isolate and transglutaminase treatments on the properties of egg-soybean protein isolate composite gels

The objective of this study was to determine the effects of pre-heating soybean protein isolate (SPI) and transglutaminase (TG) induced cross-linking on egg-SPI composite gels. Solubility, surface hydrophobicity, electrophoresis and rheology of the prepared solutions were determined, whereas texture, water-holding capacity and microstructure of the composite gels were evaluated. SPI pre-heating improved solutions’ solubility and protein’s surface hydrophobicity; thus enhancing TG cross-linking evidenced by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). When only TG was used, solubility and surface hydrophobicity of the composites remained unchanged or decreased, forming strong gels but with low springiness and water-holding capacity. When SPI pre-heating and TG action were combined, a denser and finer gel network was obtained that exhibited improved mechanical properties and better water-holding capacity. The results of this research demonstrate that the combination of pre-heating SPI and TG treatment is a reliable method to improve the gelling properties of egg-SPI composite gels.

Transglutaminase and tyrosinase as potential cross‐linking tools for the improvement of rheological properties of gluten‐free amadumbe dough

SummaryGluten‐free bread remains of poor quality despite efforts to amend gluten‐free flours with ingredients such as hydrocolloids and proteins. Enzymatic modification of the proteins in dough may result in polymers that mimic gluten. This research investigated the effects of transglutaminase and tyrosinase on the rheological properties of amadumbe dough. Tyrosinase oxidation resulted in a 7.7–39.4% decrease in dough‐free amine, and a 16.8–46.3% decrease in the dough thiol content as activity was increased from 0 to 80 U g−1 flour. Transglutaminase treatment decreased the dough‐free amino groups by 10–38.1% as activity was increased from 0 to 2 U g−1 flour. Evidence of tyrosinase and transglutaminase‐mediated cross‐linking was provided by relevant model reactions monitored by mass spectrometry. An increase in dough G′ and G″ showed that both transglutaminase and tyrosinase improved dough viscoelasticity. The increase in the viscoelasticity of the dough potentially improves carbon dioxide retention during proofing.

Impact of Type and Enzymatic/High Pressure Treatment of Milk on the Quality and Bio-Functional Profile of Yoghurt.

The objective of the present study was to investigate the effect of the high pressure (HP) processing and transglutaminase (TGase) treatment of bovine (cow) or ovine (sheep) milk, when applied individually or sequentially, on the quality parameters and anti-hypertensive and immunomodulatory properties of yoghurt. Low-fat (2% w/w) bovine or ovine milk samples were used. Results showed that HP treatment of milk led to acid gels with equivalent quality attributes to thermal treatment, with the more representative attributes being whey separation and firmness, which ranged from 47.5% to 49.8% and 23.8% to 32.2% for bovine and ovine yoghurt, respectively, and 74.3–89.0 g and 219–220 g for bovine and ovine yoghurt, respectively. On the other hand, TGase treatment of milk, solely or more effectively following HP processing, resulted in the improvement of the textural attributes of yoghurt and reduced whey separation, regardless of milk type, exhibiting values of 32.9% and 8.7% for the whey separation of bovine and ovine yoghurt, respectively, and 333 g and 548 g for the firmness of bovine and ovine yoghurt, respectively. The HP processing and TGase treatment of milk led to the preservation or improvement of the anti-hypertensive activity of the samples, especially in the case in which ovine milk was used, with Inhibitory activity of Angiotensin Converting Enzyme (IACE) values of 76.9% and 88.5% for bovine and ovine yoghurt, respectively. The expression of pro-inflammatory genes decreased and that of anti-inflammatory genes increased in the case of samples from HP-processed and/or TGase-treated milk as compared to the corresponding expressions for samples from thermally treated milk. Thus, it can be stated that, apart from the quality improvement, HP processing and TGase treatment of milk may lead to the enhancement of the bio-functional properties of low-fat yoghurt made from either bovine or ovine milk.

Effect of high-intensity ultrasound treatment in combination with transglutaminase and nanoparticles on structural, mechanical, and physicochemical properties of quinoa proteins/chitosan edible films

The effect of high-intensity ultrasound (US) combined with transglutaminase treatment (TG) and the inclusion of nanoparticles (Np) on the structural, mechanical, barrier, and physicochemical properties of quinoa protein/chitosan composite edible films were evaluated. Structurally it was observed that the maximum temperatures of the thermal degradation increased with the use of combined US and TG treatment, generating films with superior thermal stability. FTIR results showed that in the amide zone I oscillations of the polypeptide structure were related to the stretching vibrations of CO in the US/TG-Np edible film. Which has generally been associated with changes in the structure and formation of covalent bonds by the action of TG. The US improved mechanical properties by increasing the tensile strength (with or without the application of TG). While combining US-TG produced a significant increase in thickness, decrease in elongation percentage, and increase in tensile strength. Which can be attributed to cross-linking produced by TG. Water vapour permeability increased in all cases. In general, the combination of US-TG treatments showed a more pronounced effect on the structure and mechanical properties.

Effect of storage time on sensory and instrumental properties of skim‐milk yoghurt obtained with microbial transglutaminase

Not many studies have examined changes in microbial transglutaminase (MTG) yoghurts during storage. In this work, yoghurts manufactured with skimmed milk and treated with MTG were evaluated in refrigerated storage for 35 days. Instrumental measurements showed that firmness, consistency and pH values in MTG yoghurt experienced a significant increase with the storage time. However, sensory measurements showed that MTG yoghurts were not affected significantly by storage time. Acid taste scores only increased significantly with storage time in the control samples. Microbial transglutaminase treatment showed a positive effect on textural properties and allowed syneresis to be prevented completely during storage.

Effects of Bacillus subtilis transglutaminase treatment on the functional properties of whey protein

Whey proteins (WPs) modification can improve their functional properties. To assess the crosslinking characteristics of Bacillus subtilis transglutaminase (BTG), it was used to reacted with WPs (12%, w/v) (40 °C, pH 8.0) for 6 h and 12 h, respectively. Both particle size profile and sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that BTG treatment enhanced the molecular weight of WPs. Meanwhile, BTG crosslinking greatly increased (*P < 0.05) the foaming and emulsifying properties of WPs. Furthermore, the rheological evaluation indicated that the cross-linked WPs showed greater storage modulus and loss modulus in comparison to the native WPs, leading to the increased gel strength. Additionally, BTG-induced WPs gels exhibited significantly enhanced (*P < 0.05) textural properties and water holding capacity. These results suggested the potential of BTG to enhance the functional properties of many proteins in the food industry.

Interactions between raw meat irradiated by various kinds of ionizing radiation and transglutaminase treatment in meat emulsion systems

Meat processing involves many treatments for improving the quality and durability of products. However, these treatments also affect other meat properties. The objective of this study was to investigate the effects of minced pork ham irradiated with various kinds of ionizing radiation (X-ray, E-beam, and γ-ray) and transglutaminase (TG) on emulsion systems. Ionizing radiation of various kinds (P < 0.05) was found to affect protein, fat, and ash content, as well as protein solubility, and textural properties. On the contrary, moisture content, fat content, emulsion stability, pH, color, protein solubility, and textural properties were affected by TG (P < 0.05). The apparent viscosity of irradiated ham was higher than that of the control, and TG treatment increased the value further. The effect on meat and meat products using different types of irradiation provides useful information about the combined treatments of irradiation and TG in emulsion systems.

Production of skim milk powder by spray-drying from transglutaminase treated milk concentrates: Effects on physicochemical, powder flow, thermal and microstructural characteristics

The effects of transglutaminase (TGase) treatment of skim milk concentrates on physicochemical, powder flow, thermal, microstructural characteristics and protein profiles of skim milk powders (SMP) were investigated. Spray-dried SMP samples produced from milk concentrates were TGase-treated at enzyme concentrations of 0 (control), 0.020% (TG-20), 0.030% (TG-30) and 0.035% (TG-35). Lower particle size values were observed in TGase-treated samples. TGase treatment slightly decreased zeta potential and increased the a* value (redness) of SMPs. Up to a concentration of 0.030%, TGase treatment decreased caking characteristics and increased glass transition temperatures of samples. The TGase treatment above 0.035% significantly decreased cohesion index and compaction coefficient at different speeds. TG-35 showed free flowing flow behaviour depending on the cohesion index, whereas control, TG-20, and TG-30 showed easy flowing behaviour. SDS-PAGE analysis revealed that high molecular mass bands indicated cross-linking in TGase-treated milk powders.

Effects of high hydrostatic pressure and microbial transglutaminase treatment on structure and gelation properties of sweet potato protein

The effects of high hydrostatic pressure (HHP) combined with microbial transglutaminase (MTGase) on the structure and gelation properties of sweet potato protein (SPP) were investigated. MTGase induced the formation of high molecular mass aggregates of SPP by the inter-molecular cross-linking. The average particle size of SPP increased by HHP at 250–550 MPa, being increased from 249.5 nm (0.1 MPa) to 270.2 nm (550 MPa). While it was decreased by the subsequent MTGase catalysis that showed the lowest value of 200.3 nm at 550 MPa, indicating the formation of intra-molecular linkages. The amount of sulfhydryl groups and thermal denaturation temperature were increased by HHP and MTGase, with the highest value of 3.5 μmol/g protein and 80.4 °C in MTGase catalyzed SPP with 400 MPa pretreatment. Textural properties of the gels made from HHP treated SPP or those with further MTGase catalysis were both enhanced due to the covalent linkage of disulfide bonds (-S-S-) and ε-(γ-glutaminyl) lysine isopeptide bonds. In addition, low-field NMR results showed an increase in corresponding area fractions of A2b and A21, being attributed to more bound or immobilized water fractions were trapped in the SPP gel matrix.

Effect of transglutaminase treatment on properties of coconut protein-guar gum composite film

Polysaccharides, proteins and lipids have been utilized for synthesis of polymer matrices to minimize environmental pollution caused by plastic food packaging. Edible coatings are one of the promising alternative in this regard. The coconut protein-guar gum composite films were prepared and studied for their mechanical and barrier properties. Addition of transglutaminase to the composite film forming solution significantly increased the mechanical strength from 1.76 MPa to 3.79 MPa and elongation from 56 mm to 184.87 mm. Improved barrier properties such as water vapour permeability and oxygen transfer rates were observed after treatment of composite films with microbial transglutaminase (MTGase). Differential scanning calorimetric analysis demonstrated an increase in melting temperature with increasing concentration of MTGase. FTIR spectroscopy showed changes in the secondary structure of the protein (amide I and amide II band) and its interaction with the polysaccharide. Major coconut protein having a molecular weight of 53 kDa was not visible in MTGase treated films due to MTGase induced polymerization of protein as analyzed using SDS-PAGE electrophoresis. Scanning electron microscopy exhibited a fibrous microstructure of the surface of the MTGase treated coconut protein guar gum composite films.

Structure and in vitro digestibility of grass pea (Lathyrus sativus L.) flour following transglutaminase treatment

The impact of transglutaminase (TG) modification on microstructure and in vitro protein and starch digestibility of grass pea flour was investigated. Results demonstrated that grass pea flour proteins act as effective substrate of TG. Microstructural results showed that the addition of TG produced a more compact structure likely due to TG-catalyzed heteropolymers. Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: grass pea flour incubated in the absence of TG>grass pea flour incubated in the presence of TG>raw flour. The TG-catalyzed heteropolymers were easily digested as demonstrated by in vitro oral and gastric digestion carried out under physiological conditions. Therefore, TG-modified grass pea flour can be considered as a new source of starch and proteins suitable for feeding a large spectrum of population.

Effect of incorporation of sodium caseinate, whey protein concentrate and transglutaminase on the properties of depigmented pearl millet based gluten free pasta

The current investigation reports the preparation of gluten free pasta from depigmented pearl millet flour blended individually with sodium caseinate (SC) (10 and 20%) and 1:1 combination of sodium caseinate and whey protein concentrate (SCW) (10 and 20%), both treated with and without transglutaminase (TG) enzyme (0.5 and 1.5%). SC addition (at 10 and 20%) maintained the cooking loss (10.38 ± 0.25 and 11.08 ± 1.71) and yellowness (b*) (16.11 ± 0.29 and 15.79 ± 0.32) as like control sample, decreased the water absorption (1.73 ± 0.19 and 1.47 ± 0.04), brightness (L*) (42.10 ± 0.49) (at 20%), pasting properties, and increased the redness (a*) (2.81 ± 0.10 and 3.58 ± 0.16) and sensory attributes (except colour and adhesiveness). The combination of SCW (at 10 and 20%) decreased the cooking loss (6.90 ± 0.00 and 5.99 ± 0.11), water absorption (1.92 ± 0.05 and 1.72 ± 0.08), pasting properties and increased L*, a*, b* (46.83 ± 0.45, 2.53 ± 0.09, 17.08 ± 0.20) (at 10%) and sensory attributes (except colour and adhesiveness). TG addition increased the cooking loss, water absoprtion and pasting properties (in all the samples). Protein solubility (%) decreased with increase in the enzyme concentration confirmed with electrophoretic patterns. Moreover, the TG treatment imparts tenderness and chewiness to pasta. Hence, the present combination could be useful for preparation of good quality of gluten free pasta.