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The aim of the study is to evaluate protective properties of the quark product manufactured with transglutaminase and enriched with probiotics, oligomerous proanthocyanidines and vitamins; the biological experiment on the growing laboratory Wistar stock rats has been carried out. The rats of two from three groups subjected within 21 days to the effect of low-frequency weak variable magnetic field received in semi-synthetic diet composition extra experimental and control samples of the quark product. The index of feed intake and the rats’ body mass growth was registered within 32 days. At the end of the experiment blood serum biochemical index was evaluated. It was revealed that the animals consuming the experimental product substantially gained the mass before the effect (gain from the 1st up to 10th days made up 12%) as well as after effect (gain from 11th up to 32nd days – 10.3%); upon completion of the experiment the gains of these animals exceeded the gains of the rats consuming the control product by more than 28%. The experiment revealed the lipolipedemic and hypoglycemic effect of the experimental quark product that has been evidenced by the significant reduction of cholesterol (by more than 20%), glucose (up to 40%) in the rats’ blood serum. On administration of the experimental dairy product in the animals’ diet subjected to the impact of low-frequency weak magnetic field the effect of the broken balance recovery in antioxidant/pro-oxidant system was observed due to reduction of pro-oxidant load at the enzymatic as well as low molecular links of the antioxidant system. The identified antioxidant and adaptogenic effect of the developed dairy product promoting to reduce the intensity of free-radical oxidation at the impact of low-frequency electromagnetic field on the body make it possible recommend it in dietotherapy for correction of antioxidant/pro-oxidant status.

Abstract Background The microbial transglutaminase (MTG) is inactive when only the mature sequence is expressed in Pichia pastoris. Although co-expression of MTG and its N-terminal pro-peptide can obtain the active MTG, the enzyme activity was still low. One of the basic steps for strain improvement is to ensure a sufficient level of transcription of the heterologous gene, based on promoter strength and gene copy number. To date, high-copy-number recombinants of P. pastoris are achievable only by cloning of gene concatemers, so methods for rapid and reliable multicopy strains are therefore desirable. Results The coexpression strains harboring different copies mtg were obtained successfully by stepwise increasing Zeocin concentration based on the rDNA sequence of P. pastoris. The genome of coexpression strains with the highest enzyme activity was analyzed by real-time fluorescence quantitative PCR, and three copies of mtg gene (mtg-3c) was calculated according to the standard curve of gap and mtg genes (gap is regarded as the single-copy reference gene). The maximum enzyme activity of mtg-3c was up to 1.41 U/mL after being inducted for 72 h in 1 L flask under optimal culture conditions, and two protein bands were observed at the expected molecular weights (40 kDa and 5 kDa) by Western blot. Furthermore, among the strains detected, compared with mtg-2c, mtg-6c or mtg-8c, mtg-3c is the highest expression level and enzyme activity, implying that mtg-3c is the most suitable for co-expression pro-peptide and MTG. Conclusions This study provides an effective strategy for improving the expression level of active MTG by directional increasing of mtg copies in P. pastoris.

The main objective of the current study was to optimize gluten free doughnuts formula for which the effect of xanthan, guar and Transglutaminase (TGase) enzyme were investigated. Xanthan, Guar and TGase were added from 0 to 2% of flour basis to the basic formula. Treatments were designed based on the mixture design of the Minitab software. The optimum conditions were selected based on the oil absorption, hardness, color, porosity and specific volume. The results showed that the high oil absorption occurred at the high level of TGase in absence of gums and the minimum oil absorption happened at the triple point. TGase caused cross linkage between rice flour protein, potato flour protein, and soy protein concentrate, which led to making protein network, xanthan gum,creating viscoelastic properties and guar gum,generating inter-surface properties, finally resulting in the increase of porosity and specific volume of doughnuts respectively. The interaction between the components showed that increasing the amount of guar gum improved the lightness of doughnuts. Texture parameters showed that samples with just gums without TGase showed the highest hardness. The synergistic effects of these gums increased viscosity. Hardness was decreased by protein network induced by TGase. The results of this study showed that the formula containing all three components could simulate the protein network in the gluten-free doughnut. The optimum point was 0.98% of xanthan, 0.44% of guar and 0.58% TGase which showed the best responds.

Celiac disease is a common autoimmune disorder which is triggered by receiving gluten. In this study, corn flour was used as gluten-free flour. Therefore, in order to simulate the properties of gluten, the use of enzymes with cross-linking ability such as microbial transglutaminase at levels of (0, 0.75 and 1.5%), with sodium caseinate at levels of (0, 3 and 6%) were used as a substitute for gluten and their effect on rheological properties of dough, physical and sensory properties of corn gluten-free bread was evaluated. The results indicated that with increasing angular frequency, both the storage and drop modules increased. The specific volume of breads produced from corn was obtained when the specific volume concentration of the transglutaminase enzyme and sodium caseinate were in the highest amount (1.460a±0.02). The addition of enzyme and sodium caseinate to the bread formulation reduced the baking loss in comparison to the sample without these materials. The addition of the microbial transglutaminase enzyme to 0.75% resulted in a significant decrease in porosity and then the porosity increased by increasing the enzyme concentration. The addition of 3% of sodium caseinate along with 0.75% of the microbial transglutaminase enzyme to gluten-free bread resulted in the highest bread stiffness. The final acceptance of the produced samples decreased by increasing the enzyme and protein, so that the samples lacking these two compounds obtained the highest final acceptance score. Finally, according to the results, it can be concluded that using 0.75% of the microbial transglutaminase enzyme and 3% of sodium caseinate can be helpful for the production of gluten-free corn bread.

In this study, the possibility of replacing stabilizers with microbial transglutaminase (MTG) enzyme in fat-reduced ice cream production was studied. In addition, the stage of adding (before or after the heat treatment) the MTG enzyme to ice cream was also investigated. Five different ice creams (A and C containing 1 unit MTG/g protein without stabilizer, B and D containing 0.5 unit MTG/g protein and 0.35 % stabilizer, which also consist of the mixture of Carrageenan (E 407), Guar gum (E 412), Xanthan gum (E 415) and Sodium alginate (E 401), and E (control) containing 0.7 % stabilizer) were manufactured. MTG has been added to samples A and B after heat treatment while it was added to C and D samples before the heat treatment. An experimental analysis related to the overrun, viscosity melting properties, pH, titratable acidity, dry matter, fat, protein, sensorial and microstructural properties of ice creams was carried out. According to the results, the amount and the adding stage of MTG significantly affected overrun, melting, viscosity, coldness, firmness, smoothness, mouth coating, color, appearance, taste, smell scores, and also microstructure of ice creams (p

Novel trends in fermented dairy technology are presented in this review paper. The application of new starter cultures (probiotics, kombucha), as well as quality improving ingredients like transglutaminase (TGase), milk protein fractions, and functional components of plant origin have been investigated by the authors worldwide. New processing techniques such as: high-pressure processing (HPP), high pressure homogenization (HPH), and ultrasonic processing (USP) are interesting because of their potential to achieve a specific and/or novel functionality or to improve the efficiency. Novel trends in fermented dairy technology contribute to the creation of various products with high nutritive value, possessing also specific functional properties. Basic health benefits of functional fermented dairy products are: biologically active peptides - ACE inhibitors and antioxidative activity. Due to the mentioned functional characteristics, these dairy products are considered to be among the most precious functional foods. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 46009]

The decrease in the fat content of yoghurt causes sensory modifications. Microbial transglutaminase (TG) has been proposed as an alternative for reducing the problems caused by the fat reduction. This work deals with the evaluation of the sensory profile, acceptance and preferences of skim yoghurt produced with TG at pilot scale. A group of 124 consumers of yoghurts were randomly selected. A lower firmness has been observed in yoghurt without TG (NoTG). TG Yoghurt has shown a lower whey odor and less acid taste than NoTG yoghurt. Free whey was not observed in the TG yoghurt. Despite of those differences, consumers only observed minor textural differences. In terms of overall acceptance and preference, no statistically significant differences were observed. The use of TG avoids the addition of milk protein or other texture additives into the yoghurt, decreasing production cost with the same overall acceptance and preference by consumers.

Transglutaminase (TG) is a major food processing enzyme that induces protein cross-linking. Tropomyosin (TM) is a major shellfish allergen that is responsible for at least 80% of the shrimp allergic incidents. The aim of this research was to investigate the effect of TG on TM allergenicity and reveal the involvement of TM structure alternation. After treated with TG for different time, the allergenicity of TM was assessed by indirect ELISA with shrimp allergic patients’ sera, and the structure of TM was characterized by circular dichroism (CD) spectroscopy, ultraviolet (UV) absorption spectroscopy and fluorescence spectroscopy. Results showed that the allergenicity slightly decreased at the early stage of reaction and dramatically decreased at the late stage, which is tightly correlated with the increment of β-turn content and UV absorption. In conclusion, TG modification is an effective and promising food processing method to eliminate TM allergenicity with significant prospect of industrial application.

There is an increasing interest in the development of high internal phase emulsions (HIPE) stabilized by food-grade nanoparticles due to their potential applications in the food industry. In this study, cross-linked egg white protein isolates (cEPIs) are prepared by adding 10 u/g, 20 u/g, and 40 u/g of transglutaminase (TG), and the impacts of interface properties of cEPIs and emulsifying of HIPEs are investigated. Relative to the native EPI, the cEPIs have more irregular and agglomerated morphology, and the turbidity and hydrophobicity are significantly increased. The particle size and zeta potential of cEPIs considerably varied with the addition of TG. In HIPE, the formation, physical properties, and microstructure are characterized by visual observations, the Turbiscan stability index, and CLSM. The results indicated that stable and gel-like HIPEs are formed by cEPIs at oil internal phase (φ) values of 0.75–0.90. Especially for the enzyme additions of 20 u/g, the cEPIs had the best storage stability and the lowest TSI value (2.50) and formed a gel network structure at φ values of 0.9 microscopically. Overall, this study can enrich the theoretical frame of interface properties by enzyme treatment. Besides, it would be of great importance for the research of HIPE stabilized by cEPIs appropriate to be applied in food formulations.

This study evaluated the effect of transglutaminase (TGase) pre-crosslinking treatment on the physicochemical and digestive characteristics of tofu coagulated by glucono-δ-lactone (GDL). Results showed that certain TGase pre-crosslinking times (0.5, 1, 2 and 3 h) could promote the colloidal stability of soymilk with increased particle average sizes and absolute values of zeta potential. Particularly, the water holding capacity and gel strength of tofu pre-crosslinked by TGase for 2 h were 6.8% and 47.7% enhancement, respectively, compared to the control, and exhibited the highest score of overall acceptability. However, extensive pre-crosslinking by TGase for 3 h had an adverse impact on the sensory of tofu with poor firmness, rough structure and whey separation. Hence, the tofu gel pre-crosslinked by TGase for 2 h and then coagulated by GDL was recommended which showed a “slow release” mode of soluble proteins during the in vitro digestion phase, and had more chances to release bioactive peptides than soymilk.

Dermatitis herpetiformis is a cutaneous form of celiac disease manifesting as an itching rash typically on the elbows, knees and buttocks. It is driven by the ingestion of gluten-containing cereals and characterized by granular deposits of immunoglobulin A in the papillary dermis. These antibodies target transglutaminase (TG) 3 and in the majority of patients they are also found in circulation. The circulating antibodies disappear and skin symptoms resolve as a result of gluten-free diet but the cutaneous anti-TG3 IgA deposits may persist for several years. In dermatitis herpetiformis, plasma cells secreting antibodies against TG3 are located in the intestinal mucosa similarly to those producing TG2 antibodies characteristic for celiac disease. In fact, both TG2- and TG3-specific plasma cells and gluten responsive T cells are found in dermatitis herpetiformis patients but the interplay between these cell populations is unknown. The small bowel mucosal damage in celiac disease is believed to be mediated by co-operation of cytotoxic intraepithelial T cells and the inflammatory milieu contributed by gluten-reactive CD4+ T cells, whereas the skin lesions in dermatitis herpetiformis appear to be devoid of gluten reactive T cells. Thus, how celiac disease-type intestinal T and B cell responses develop into an autoimmune condition affecting the skin is still incompletely understood. Finally, the skin and small bowel lesions may reappear upon reintroduction of gluten in patients treated with gluten-free diet but virtually nothing is known about the long-lived B cell and memory T cell populations activating in response to dietary gluten in dermatitis herpetiformis.

Transglutaminase (TGase), the ubiquitous protein in plants, catalyzes the post-translational transformation of proteins and plays a vital role in photosynthesis. However, its role and mechanism in tomato subjected to heat stress still remain unknown. Here, we carried out a transcriptomic assay to compare the differentially expressed genes (DEGs) between wild type (WT) and TGase overexpression (TGaseOE) plants employed to high-temperature at 42 °C and samples were collected after 0, 6, and 12 h, respectively. A total of 11,516 DEGs were identified from heat-stressed seedlings, while 1,148 and 1,353 DEGs were up-and down-regulated, respectively. The DEGs upon high-temperature stress were closely associated with the pathways encompassing protein processing in the endoplasmic reticulum, carbon fixation, and photosynthetic metabolism. In addition, 425 putative transcription factors (TFs) were identified, and the majority of them associated with the bHLH, HSF, AP2/ERF, MYB, and WRKY families. RNA-seq data validation further confirmed that 8 genes were linked to protein processing and photosynthesis, and the mRNA level of these genes in TGaseOE was higher than that in WT plants, which is consistent in transcriptome results. In conclusion, these results reveal the transcriptional regulation between WT and TGaseOE in tomato under heat stress and shed light on a new dimension of knowledge of TGase-mediated thermotolerance mechanism at the molecular level.

A major thrust of our laboratory has been to identify how physiological stress is transduced into transcriptional responses that feed back to overcome the inciting stress or its consequences, thereby fostering survival and repair. To this end, we have adopted the use of an in vitro model of ferroptosis, a caspase-independent, but iron-dependent form of cell death (Dixon et al., 2012; Ratan, 2020). In this review, we highlight three distinct epigenetic targets that have evolved from our studies and which have been validated in vivo studies. In the first section, we discuss our studies of broad, pan-selective histone deacetylase (HDAC) inhibitors in ferroptosis and how these studies led to the validation of HDAC inhibitors as candidate therapeutics in a host of disease models. In the second section, we discuss our studies that revealed a role for transglutaminase as an epigenetic modulator of proferroptotic pathways and how these studies set the stage for recent elucidation of monoamines as post-translation modifiers of histone function. In the final section, we discuss our studies of iron-, 2-oxoglutarate-, and oxygen-dependent dioxygenases and the role of one family of these enzymes, the HIF prolyl hydroxylases, in mediating transcriptional events necessary for ferroptosis in vitro and for dysfunction in a host of neurological conditions. Overall, our studies highlight the importance of epigenetic proteins in mediating prodeath and prosurvival responses to ferroptosis. Pharmacological agents that target these epigenetic proteins are showing robust beneficial effects in diverse rodent models of stroke, Parkinson's disease, Huntington's disease, and Alzheimer's disease.

For a whole century, citrate has been used as an in vitro anticoagulant via chelation of calcium. Later, also EDTA was introduced as an anticoagulant. An often overlooked fact is that zinc is bound to citrate and EDTA with affinities much greater than that for calcium, imposing problems in biomedical research. In vivo, proteins of the S100 family are released from leukocytes and known to bind calcium. Some of them, e.g., calprotectin, also chelate zinc. Thus, at an inflamed site, the ratio between Ca2+ and Zn2+ is changed. This mechanism is of importance for the modulation of the activation of a fascinating family of post-translationally acting calcium-dependent thiol enzymes, the transglutaminases, which are inhibited by zinc. This presentation illustrates the complexity of in vitro studies with zinc. Moreover, it exemplifies the role of Zn2+ in pathophysiological situations such as celiac disease and neurodegeneration.

Dermatitis herpetiformis is a cutaneous form of celiac disease manifesting as an itching rash typically on the elbows, knees and buttocks. It is driven by the ingestion of gluten-containing cereals and characterized by granular deposits of immunoglobulin A in the papillary dermis. These antibodies target transglutaminase (TG) 3 and in the majority of patients they are also found in circulation. The circulating antibodies disappear and skin symptoms resolve as a result of gluten-free diet but the cutaneous anti-TG3 IgA deposits may persist for several years. In dermatitis herpetiformis, plasma cells secreting antibodies against TG3 are located in the intestinal mucosa similarly to those producing TG2 antibodies characteristic for celiac disease. In fact, both TG2- and TG3-specific plasma cells and gluten responsive T cells are found in dermatitis herpetiformis patients but the interplay between these cell populations is unknown. The small bowel mucosal damage in celiac disease is believed to be mediated by co-operation of cytotoxic intraepithelial T cells and the inflammatory milieu contributed by gluten-reactive CD4+ T cells, whereas the skin lesions in dermatitis herpetiformis appear to be devoid of gluten reactive T cells. Thus, how celiac disease-type intestinal T and B cell responses develop into an autoimmune condition affecting the skin is still incompletely understood. Finally, the skin and small bowel lesions may reappear upon reintroduction of gluten in patients treated with gluten-free diet but virtually nothing is known about the long-lived B cell and memory T cell populations activating in response to dietary gluten in dermatitis herpetiformis. [ABSTRACT FROM AUTHOR]

Transglutaminase (TGase) is an enzyme widely used in the food industry. In this study, the eff ect of transglutaminase enzyme on the chemical and physical characteristics of cooked beef meatballs was evaluated. For this aim, beef meatballs were prepared by using recombinant microbial transglutaminase (MTGase) and commercial TGase enzymes, after that physical and chemical tests were applied to meatball samples. The addition of MTGase enzyme improves the quality parameters of the beef meatballs. The myofibrillar proteins of cooked meatball samples were also analyzed with SDS-PAGE analysis. It was observed that, actin and myosin proteins bind covalently to form a new high molecular weight protein by the help of MTGase addition. These results indicated that recombinant MTGase enzyme can be used to obtain high quality restructured beef meat products. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of the edible coatings produced from casein, casein / transglutaminase enzyme, and chitosan on certain chemical, textural, and microbiological properties of Kashar cheese over a storage period of 60 days. The use of edible coatings affected the levels of nitrogen fractions (water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, and phosphotungstic acid-soluble nitrogen) and the lipolysis level of Kashar cheese to a statistically significant extent (P<0.05 for all). The levels of nitrogen fractions and lipolysis in the uncoated control group cheeses increased significantly (P<0.05) during the storage period compared to coated cheese. Cheese samples coated with chitosan yielded significantly lower yeast-mould counts compared to samples that were uncoated or coated with sodium caseinate or sodium caseinate/transglutaminase at the end of the storage period (P<0.05). The results indicated that the edible coatings had a significant effect on the chemical, textural, and microbiological properties of Kashar cheese. [ABSTRACT FROM AUTHOR]

Whey protein concentrate (WPC) has been widely studied as a biodegradable bio‐based packaging material in the food industry. In this study, different whey protein films were obtained through physical, chemical, enzymatic, and composite modifications. The molecular structure, micro‐morphology, mechanical properties, barrier properties, and other characteristics of the films were evaluated. The results illustrated that the thickness of WPC with composite modification increased and the transmittance decreased, but the mechanical properties and barrier properties were more prominent. The WPC film prepared by physical modification combined with transglutaminase has the best film‐forming effect, the tensile strength (TS) was 5.45 MPa, the elongation at break (EAB) was 25.19%, the WVP was 5.53 g·mm/m2·hr·kPa, and the Oxygen permeability (OP) was 1.83 meq/K, and its microstructure was and uniform. In addition, based on the the results of SDS‐PAGE and Fourier transform infrared spectroscopy (FTIR), the intermolecular and intramolecular interactions of various modification methods on WPC were studied, thus contributing to analyze the properties of the film. This study provides theoretical basis and technical support for the industrial production of protein‐based films. [ABSTRACT FROM AUTHOR]

Cornified envelope formation is crucial for the final differentiation of keratinized epithelium. However, the mechanisms of cornified envelope formation in the oral epithelium remain unclear. The aim of this study was to clarify the differences in the distribution and expression of cornified envelope related proteins and genes between keratinized and non‐keratinized oral epithelia. We immunohistochemically investigated the distribution patterns of transglutaminase 1 (TG1), transglutaminase 3 (TG3), and their substrate proteins involucrin (IVL), loricrin (LOR), and small proline rich proteins (SPRs), in 19 keratinized and 14 non‐keratinized oral epithelium samples. TG1 and TG3 mRNA levels were investigated in both types of epithelium by real time reverse transcription polymerase chain reaction (RT‐PCR) using paraffin‐embedded specimens. Data were analyzed to identify factors involved in cornified envelope formation. We demonstrate that 11 localization patterns show statistically significant differences between keratinized and non‐keratinized oral epithelia. These factors clearly drove the separation of the two groups during cluster analysis. TG1 mRNA levels in keratinized oral epithelium were significantly higher than those in non‐keratinized oral epithelium. In conclusion, the characteristic distribution of transglutaminases and their substrates and the mRNA levels of TG1 can regulate cornified envelope formation in keratinized oral epithelium, together with the contribution of TG3 first reported in this paper. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the consumer acceptance and preference of a novel cheese coagulated with vegetal rennet and microbial transglutaminase (V + TG) as an alternative for lacto‐vegetarian consumers. The evolution of the sensory and instrumental parameters throughout the storage time was studied. Cheese with animal rennnet and microbial transglutaminase (A + TG), vegetal rennet alone (V) and animal rennet alone (A) were also studied as controls. The consumer test showed that the V + TG cheese was preferred and showed high texture and taste acceptance scores. This cheese could be successful for its sensory acceptance and as an alternative for the lacto‐vegetarian market. [ABSTRACT FROM AUTHOR]

Fertilization is an essential process that fundamentally impacts fitness. An egg changes dramatically after fertilization mediating the beginning of life, which mainly includes the transformation of the egg envelope via hardening, which is thought to be due to complex reactions involved in the conversion of cellular and molecular. This review highlights the mechanisms of egg envelope hardening in teleost fish. We conclude that the egg envelope hardening might be carried out in two steps. (a) A metalloprotease (alveolin) hydrolyzes the N-terminal proline-glutamine (Pro-Gln) region of zona pellucida (ZP) 1 and (b) triggers intermolecular cross-linking to ZP3 catalyzed by transglutaminase (TGase). The post-fertilization hardening of the egg envelope is an evolutionarily conserved phenomenon across species. We discuss the biochemical function and interaction of some factors reported to be essential to egg envelope hardening in mammalian and nonmammalian species, including metalloprotease, TGase, peroxidase/ovoperoxidase, and other factors (carbohydrate moieties, zinc and Larp6 proteins), and the relevant data suggest that egg envelope hardening is crucial to block polyspermy in internal fertilization, in addition to protecting the developing embryo from mechanical shock and preventing bacterial infection in external fertilization. Increased knowledge of the processes of egg envelope hardening and fertilization is likely to make a remarkable contribution to reproduction and aquaculture. • The more comprehensive mechanism of egg envelope hardening in fish was summarized. • Biochemical factors essential to egg envelope hardening in animals were summarized. • Increasing knowledge of egg envelope hardening is important to reproduction. [ABSTRACT FROM AUTHOR]

Transglutaminase (TG) catalyzes the formation of cross-links between proteins. TG from Streptoverticillium mobaraense (SmTG) is used widely in food, cosmetic, biomaterial and medical industries. SmTG is occasionally supplied as a mixture with the activator peptide glutathione. Currently, glutathione is industrially produced using a budding yeast, Saccharomyces cerevisiae, because of its intracellular high content of glutathione. In this study, active SmTG was produced together with glutathione in S. cerevisiae. SmTG extracted from S. cerevisiae expressing SmTG showed cross-linking activity when BSA and sodium caseinate were substrates. The cross-linking activity of SmTG increased proportionally as the concentration of added glutathione increased. Furthermore, SmTG was prepared by extracting SmTG from an engineered S. cerevisiae whose glutathione synthetic pathway was enhanced. The SmTG solution showed higher activity when compared with a SmTG solution prepared from a S. cerevisiae strain without enhanced glutathione production. This result indicates that a high content of intracellular glutathione further enhances active SmTG production in S. cerevisiae. S. cerevisiae co-producing SmTG and a higher content of glutathione has the potential to supply a ready-to-use industrial active TG solution. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Background and Objectives: As an autoimmune disease, celiac is triggered by exposure to dietary gluten in genetically susceptible individuals, leading to various gastrointestinal and non-gastrointestinal symptoms. The aim of the current study was to accurately investigate epidemiology of the celiac disease in Hamadan Province, Iran. Materials and Methods: This study was carried out as a case series at Hamadan University of Medical Sciences, Hamadan, Iran, 2016-2018. The participants were selected using census method. Data analysis was carried out using SPSS Software v.18 and descriptive statistics. Results: From 72 participants, 68.1% were females and 31.9% were males. In addition, the mean age of the participants was 32.47 y ±17.21; 15.27% of them had known genetic backgrounds. Serological results revealed that 47% of the participants had tTG antibody. Based on the disease severity classification, the highest frequency (57%) was linked to Marsh III. Furthermore, 10% of celiac patients were simultaneously diagnosed with diabetes. Conclusions: In this study, celiac was mostly diagnosed in young to middle-age people (30-40 y), the majority of whom were females. It seems that the incidence of diabetes and CD is one of the most significant health problems in the province. High severity of the disease (Marsh III) was important as well. Of the disease symptoms, gastrointestinal symptoms were more common; from which, diarrhea and abdominal pain were more common. In non-gastrointestinal symptoms, anemia was the most common symptom. [ABSTRACT FROM AUTHOR]

This study investigated the possibility of using a phase separation, mixing, and enzymatic gelation approach to construct seafood analogs from plant protein-polysaccharide mixtures with properties mimicking real seafood. Heat-denatured pea protein (10%, w/w) and pectin (0–1%, w/w) were mixed to produce phase separated biopolymer blends. These blends were then subjected to mild shearing (350 rpm) to obtain fiber-like structures, which were then placed in molds and set by gelling the pea proteins using transglutaminase (2%, w/w). The appearance, texture, and cooking properties of the resulting scallop analogs were characterized and compared to those of real scallop. The presence of the pectin promoted the formation of a honeycomb structure in the scallop analogs, and microscopic orientation of the proteins was observed in the plane parallel to the applied shear flow. Lower pectin concentrations (0.5%, w/w) led to stronger gels with better water holding capacity than higher ones (1.0%, w/w). The appearance and texture of the plant-based scallop analogs were like those of real scallop after grilling, indicating the potential of using this soft matter physics approach to create plant-based seafood analogs. One of the main advantages of this method is that it does not require any expensive dedicated equipment, such as an extruder or shear cell technology, which may increase its commercial viability.

The development of three-dimensional (3D) biomaterials that mimic natural tissues is required for efficiently restoring physiological functions of injured tissues and organs. In the field of soft hydrogels, self-assembled peptides (SAPs) stand out as distinctive biomimetic scaffolds, offering tunable properties. They have garnered significant attention in nanomedicine due to their innate ability to self-assemble, resulting in the creation of fibrous nanostructures that closely mimic the microenvironment of the extracellular matrix (ECM). This unique feature ensures their biocompatibility and bioactivity, making them a compelling area of study over the past few decades. As they are soft hydrogels, approaches are necessary to enhance the stiffness and resilience of the SAP materials. This work shows an enzymatic strategy to selectively increase the stiffness and resiliency of functionalized SAPs using transglutaminase (TGase) type 2, an enzyme capable of triggering the formation of isopeptide bonds. To this aim, we synthesized a set of SAP sequences and characterized their cross-linking via rheological experiments, atomic force microscopy (AFM), thioflavin-T binding assay, and infrared spectroscopy (ATR-FTIR) tests. The results showed an improvement of the storage modulus of cross-linked SAPs at no cost of the maximum stress-at-failure. Further, in in vitro tests, we examined and validated the TGase capability to cross-link SAPs without hampering seeded neural stem cells (hNSCs) viability and differentiation, potentially leaving the door open for safe in situ cross-linking reactions in vivo .

The transglutaminase (TGase) from Streptomyces mobaraensis is widely used to improve the texture of protein-based foods. However, wild-type TGase is not heat-resistant, which is unfavorable for its application. In this study, we successfully constructed a S. mobaraensis strain that can efficiently produce TGm2, a thermostable mutant of S. mobaraensis TGase. First, S. mobaraensis DSM40587 was subjected to atmospheric room temperature plasma mutagenesis, generating mutant smY2022 with a 12.2-fold increase in TGase activity. Then, based on the double-crossover recombination, we replaced the coding sequence of the TGase with that of TGm2 in smY2022, obtaining the strain smY2022-TGm2. The extracellular TGase activity of smY2022-TGm2 reached 61.7 U/mL, 147% higher than that of smY2022. Finally, the catalytic properties of TGm2 were characterized. The half-life time at 60 °C and specific activity of TGm2 reached 64 min and 71.15 U/mg, 35.6- and 2.9-fold higher than those of the wild-type TGase, respectively. As indicated by SDS-PAGE analysis, TGm2 exhibited demonstrably better protein cross-linking ability than the wild-type TGase at 70 °C, although both enzymes shared a similar ability at 40 °C. With improved enzyme production and thermal stability, smY2022-TGm2 could be a competitive strain for the industrial production of transglutaminase.

The food enzyme protein-glutamine γ-glutamyltransferase (protein-glutamine: amine γ-glutamyltransferase; EC 2.3.2.13) is produced with the non-genetically modified Streptomyces mobaraensis strain M2020197 by Taixing Dongsheng Bio-Tech Co. Ltd. The identity of the production strain and the absence of viable cells could not be established. The food enzyme is intended to be used in eight food manufacturing processes: processing of cereals and other grains for the production of (1) baked products, (2) cereal-based products other than baked; processing of dairy products for the production of (3) fermented dairy products, (4) cheese, (5) dairy desserts; processing of plant- and fungal-derived products for the production of (6) meat analogues, (7) plant-based analogues of milk and milk products; processing of meat and fish products for the production of (8) modified meat and fish products. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 3.498 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 91 mg TOS/kg bw per day. The calculated margin of exposure for each age group was 36 (infants), 26 (toddlers), 50 (children), 99 (adolescents), 115 (adults) and 133 (the elderly). A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood is low. The safety of the food enzyme could not be established given the derived margins of exposure. Therefore, the Panel concluded that the food enzyme could not be considered safe under the intended conditions of use., Competing Interests: If you wish to access the declaration of interests of any expert contributing to an EFSA scientific assessment, please contact interestmanagement@efsa.europa.eu., (© 2024 European Food Safety Authority. EFSA Journal published by Wiley‐VCH GmbH on behalf of European Food Safety Authority.)

The rising cost of wheat flour and incidences of celiac disease, an intolerance to gluten in wheat products, have created the need to explore ingredients, especially alternative flours, for developing gluten-free products. This study examined the performance of Frafra potato flour (FPF), a nutritious lesser-known indigenous crop, in the production of bread using a novel dough-conditioners (egg-gelatin combinations), and Transglutaminase blend to improve the product properties. The developed product was evaluated for physicochemical and sensory characteristics. The findings indicated that products with a single dough-conditioner (GFBE and GFBG) exhibited a weaker dough, prolonged development time, reduced stability, mixing tolerance, and increased cooking loss (p < 0.05). However, egg-gelatin dough-conditioner in GFBEG effectively improved the dough and bread structure, comparable to conventional bread (WTB). The dough stability and development time in GFBEG improved by 30 %, while bread volume increased by 10 %. SEM showed an improved network matrix and well-embedded starch granules in GFBEG, comparable to WTB. Sensory evaluation revealed GFBEG had a minor bitter flavour note, relative to WTB. Therefore, combining FPF with multiple dough-conditioners and TGase will produce bread with comparable characteristics to conventional bread. However, further optimization and consumer acceptability studies are imperative to provide food processors with a viable product for the market., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Background: Gluten sensitivity (GS) is one of the gluten-related disorders (GRDs). Patients with GS may have serum antibodies against tissue transglutaminase (tTG) (IgA and IgG) without any evidence of enteropathy. We aimed to evaluate both tTG-6 and tTG-2 antibodies to determine the prevalence of seropositive tTG-2 and tTG-6 antibodies in patients with multiple sclerosis (MS)., Methods: In this cross-sectional study, we carried out serological tests (IgA & IgG anti-tTG-6 and tTG-2 antibodies) in patients with MS., Results: Seventy-two patients with MS were included in this study. Of them, seropositive patients for total (IgA+IgG) of tTG-6 and tTG-2 autoantibodies were 9.7% (95% CI, 4.2-18) and 5.6% (95% CI, 1.4-12.5), respectively., Conclusion: Anti-tTG-6 antibody testing may be necessary for early diagnosis of GS in patients with MS. More studies with larger sample sizes are warranted to confirm these data., Competing Interests: Competing Interests The authors declare no conflict of interest related to this work., (© 2024 Middle East Journal of Digestive Diseases.)

The aims of the present study were to estimate the celiac disease (CD) prevalence in Denmark and the relevance of the test for human leukocyte antigen DQ2 and DQ8 haplotypes (HLA-DQ2/DQ8) for diagnosing CD. The plasma IgA transglutaminase antibody (TGA-IgA) and HLA-DQ2/DQ8 tests should normally be positive for a CD diagnosis. First, we estimated the CD and HLA-DQ2/DQ8 prevalence in the available blood samples collected at the North Zealand Hospital. Out of a total of 9754 patients, with symptoms suggestive of CD (such as malabsorption, diarrhea, steatorrhea, ion-deficiency anemia, and weight loss or growth failure), 153 patients had TGA-IgA positive results (i.e. TGA-IgA > 10 U/mL). In this cohort, the prevalence of CD was 0.912% and the prevalence of HLA-DQ2/DQ8 positive patients was estimated to be 62%. Based on the distribution of HLA-DQ2/DQ8 positive individuals in the general Danish population, a calculation of CD prevalence in Denmark was found to be maximum 0.77%. Second, we analysed for the HLA-DQ2/DQ8 haplotypes in 293 positive plasma TGA-IgA samples. Nearly all (99%) of the CD patients and non-CD patients were HLA-DQ2/DQ8 positive. [ABSTRACT FROM AUTHOR]

Germination is an effective process improving nutritional status of cereal and legume. This study evaluates the effect of germinated mung bean flour (GMF) (0-20%) on physical, chemical properties and cooking quality of egg noodles, as well as the impact of transglutaminase (TGase) on the physical properties and cooking quality of GMF noodles. Compared to raw mung bean flour, GMF showed higher total phenolic content, antioxidant activity, total-extractable ash, Ca, Fe, K, P and Zn content with lower phytic acid. As the GMF ratio increased, cooking loss values also increased. TGase developed cooking quality with decreasing cooking loss and improving firmness. Noodles made with 20% of GMF revealed the highest total ash, HCl-extractable ash, protein, phytic acid, antioxidant activity and total phenolic content. This study shows the potential of GMF (up to 15%) and TGase to produce noodles with high nutritive value and good consumer acceptability. [ABSTRACT FROM AUTHOR]

Phenolic compounds from jaboticaba (Plinia jaboticaba) fruit were encapsulated by spray drying using transglutaminase cross‐linked casein micelles as encapsulating agents. The encapsulations were performed at pH 2.0 and pH 7.0. The addition of phenolic compounds did not dramatically alter the water activity or the morphology of the obtained powders. Despite some degradation of the phenolic compounds encapsulated with the cross‐linked casein micelles at pH 2.0 during the spray‐drying process, the compounds' antioxidant capacity remained stable after drying. The results clearly demonstrate the potential use of cross‐linked casein micelles as encapsulation agents at highly acidic conditions. [ABSTRACT FROM AUTHOR]

Sodium caseinate is widely used as techno-functional ingredient in food processing. However, no studies are currently available on applications of enzymatically cross-linked sodium caseinate although such a modification might have a potential to improve its techno-functional properties and thus reduce the amount of protein necessary to achieve the desired product properties. In the present study, aqueous sodium caseinate solutions were cross-linked by microbial transglutaminase to different extents and subsequently spray-dried. These powders were either redissolved in water or added to reconstituted skim milk to compare acid-induced gels from sodium caseinate solutions to gels from milk with added sodium caseinate. Gelation induced by glucono-δ-lactone was studied using time-based oscillation rheology. The maximum storage modulus (G′MAX) of sodium caseinate gels increased with increasing cross-linking extent, whereas enriched milk gels showed a peak in G′MAX at moderate cross-linking extents. Heat treatment of the enriched milk shifted the highest G′MAX to an even lower cross-linking extent. The results show that constituents of complex food matrices as well as processing routes affect the techno-functional properties of modified food proteins such as cross-linked caseins. It was possible to reduce the amount of added protein from 10 to 7.5 g/kg when cross-linked sodium caseinate was used while obtaining milk gels with similar G′MAX and forced syneresis. Future studies should elaborate ways to further improve the properties of cross-linked sodium caseinate to allow for an even greater reduction in protein enrichment. [ABSTRACT FROM AUTHOR]

Bread is one of the most consumed foods in the world. Its manufacturing processes move approximately 2% of the Brazilian GDP, being among the six largest sectors of the national industry. One of the factors that impact the yield and manufacture of bakery products is the quality of the flour, which desires a high amount of protein. Transglutaminase is an enzyme that forms cross-links between protein molecules and it has been suggested that it provides strength to wheat flour through the gluten network. Several studies have been conducted, with different methodologies and objectives, in order to study the effects of this enzyme. Thus, the scope of this research was to review the literature about some forms of use of transglutaminase in the food industry, especially noting its use in improving the quality of wheat flour and bakery products. [ABSTRACT FROM AUTHOR]

Background: Polyamine catabolism plays a key role in maintaining intracellular polyamine pools, yet its physiological significance is largely unexplored. Here, we report that the disruption of polyamine catabolism leads to severe cerebellar damage and ataxia, demonstrating the fundamental role of polyamine catabolism in the maintenance of cerebellar function and integrity.Methods: Mice with simultaneous deletion of the two principal polyamine catabolic enzymes, spermine oxidase and spermidine/spermine N1-acetyltransferase (Smox/Sat1-dKO), were generated by the crossbreeding of Smox-KO (Smox-/-) and Sat1-KO (Sat1-/-) animals. Development and progression of tissue injury was monitored using imaging, behavioral, and molecular analyses.Results: Smox/Sat1-dKO mice are normal at birth, but develop progressive cerebellar damage and ataxia. The cerebellar injury in Smox/Sat1-dKO mice is associated with Purkinje cell loss and gliosis, leading to neuroinflammation and white matter demyelination during the latter stages of the injury. The onset of tissue damage in Smox/Sat1-dKO mice is not solely dependent on changes in polyamine levels as cerebellar injury was highly selective. RNA-seq analysis and confirmatory studies revealed clear decreases in the expression of Purkinje cell-associated proteins and significant increases in the expression of transglutaminases and markers of neurodegenerative microgliosis and astrocytosis. Further, the α-Synuclein expression, aggregation, and polyamination levels were significantly increased in the cerebellum of Smox/Sat1-dKO mice. Finally, there were clear roles of transglutaminase-2 (TGM2) in the cerebellar pathologies manifest in Smox/Sat1-dKO mice, as pharmacological inhibition of transglutaminases reduced the severity of ataxia and cerebellar injury in Smox/Sat1-dKO mice.Conclusions: These results indicate that the disruption of polyamine catabolism, via coordinated alterations in tissue polyamine levels, elevated transglutaminase activity and increased expression, polyamination, and aggregation of α-Synuclein, leads to severe cerebellar damage and ataxia. These studies indicate that polyamine catabolism is necessary to Purkinje cell survival, and for sustaining the functional integrity of the cerebellum. [ABSTRACT FROM AUTHOR]

In the past two decades, there has been an upsurge of interest in transglutaminase (TGase) research due to their immense value in food applications to improve the quality as well as functional and nutritional attributes of food. Besides, TGases have been involved in new biomaterial development and shown to have potential in various biomedical applications. Presently, TGases from microbial sources (and some animal sources) are the main forms of the enzyme used in industrial applications. Nonetheless, there are disadvantages with the commercial TGases currently in use for food processing, such as the low activity, low yield, high cost, consumer aversions on their safety, and difficult in activity recovery, among others. Fish and shellfish TGases are promising alternatives for use in food industries due to their cheap sources, high yield and special characteristics such as cold activity and thermal-lability. This review presents at the onset, the catalytic mechanism of TGase based on updated research; compares the enzymatic properties of fish/shellfish TGases with their animal, plant and microbial counterparts; summarizes the unique properties of fish/shellfish TGases related with food usage; and discusses the current and potential applications of fish/shellfish TGases in foods. [ABSTRACT FROM AUTHOR]

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Cytokine signaling in the epidermis has an important role in maintaining barrier function and is perturbed in pathological conditions. Environmental exposures, such as to metal compounds, are of interest for their potential contribution to skin disease. Present work explores the possibility that vanadate is a more effective protein tyrosine phosphatase inhibitor in human keratinocytes than previously observed in fibroblasts. It focuses on the state of phosphorylation of signal transducer and activator of transcription 1 (STAT1) on tyrosine 701 upon treatment of cultured human keratinocytes with the cytokine oncostatin M, a cutaneous inflammatory mediator that is highly effective in suppressing several differentiation markers and in preserving proliferative potential of keratinocytes. Exposure to sodium vanadate in the medium greatly prolonged the phosphorylation of STAT1, but only at high concentration (>30 µM). Inhibitors of protein tyrosine phosphatases known to dephosphorylate STAT1 (SHP2, TCPTP, PTP1B) were ineffective in mimicking the action of vanadate. The irreversible protein tyrosine phosphatase inhibitor phenyl vinyl sulfonate alone induced STAT1 phosphorylation and appeared to induce its limited cleavage. It also inhibited cross-linked envelope formation, a characteristic step of keratinocyte terminal differentiation, likely due to its reaction with the active site cysteine of keratinocyte transglutaminase. Thus, the key protein tyrosine phosphatase responsible for STAT1 dephosphorylation remains to be identified, and an off-target effect of a potential inhibitor was revealed.

In clementine, failure of fertilization can result in parthenocarpic fruit development, which has several advantages, such as seedless fruit, longer shelf-life, and greater consumer appeal. Recently, S-RNases have been identified in Citrus grandis, thus revealing that the self-incompatibility (SI) reaction relies on the S-RNase gametophytic mechanism. The fundamental role of environmental factors, mostly temperature, in determining the numbers of pollen tubes reaching the ovary is also well established in Citrus. In the present work, temperature-dependent pollen–pistil interactions in C. clementina were analyzed, focusing on several morphological aspects, as well as on polyamine (PA) content and the activity and distribution of transglutaminase (TGase), both reported to be involved in the SI response in pear and in pummelo. Results clearly indicate that temperature contributed to a different activation of the SI response, which occurs at optimal temperature of 25°C but was by-passed at 15°C. TGase activity was stimulated during the SI response, and it localized differently in the compatible and incompatible interaction: in compatible pollinated styles, TGase localized inside the style canal, while it was detected all around it in incompatible crosses. TGase localization and activity were congruent with the levels of soluble and insoluble conjugated PAs and with morphological evidences, which highlighted cell wall modification occurring as a result of SI.

New glycosylated zein peptides (GZP) were produced by transglutaminase-induced d-glucosamine conjugation onto zein peptides. GZP’s antagonistic effects on alcohol-induced liver injury in rats were evaluated. Compared with the alcohol model group, GZP (250 mg/kg·bw) remarkably increased alcohol dehydrogenase, acetaldehyde dehydrogenase, endogenous antioxidant enzymes activities, and GSH levels in liver, decreased serum triacylglycerol, tumor necrosis factor-α, liver malonaldehyde, reactive oxygen species, and lipopolysaccharide (LPS) levels, and significantly reversed pathological changes in liver tissues. These results indicate that low-dose GZP administration can alleviate alcohol-induced liver injury by accelerating alcohol metabolism, reversing hepatic redox status, and attenuating LPS-mediated inflammation responses. GZP is a potential alcohol metabolism promoter and liver-protective agent.

Dermatitis herpetiformis (DH) is an autoimmune skin disease that causes itchy, blistering rash, typically on the elbows, knees and buttocks. DH and coeliac disease share the same genetic background, gluten-dependent enteropathy and antibody response against tissue transglutaminase. DH is currently considered a cutaneous manifestation of coeliac disease, and the prevailing hypothesis is that DH develops as a late manifestation of subclinical coeliac disease. The incidence of DH is decreasing contemporarily with the increasing incidence of coeliac disease. The IgA immune response in DH skin is directed against epidermal transglutaminase, while the autoantigen in the gut is tissue transglutaminase. Granular IgA deposition in the papillary dermis is pathognomonic for DH, and is a finding used to confirm the diagnosis. The treatment of choice for DH is a life-long gluten-free diet, which resolves the rash and enteropathy, increases quality of life, and offers a good long-term prognosis.

The aim of this study was to determine changes in the activity of proteolytic enzymes and transglutaminase of fish and mammal meat after pressurization at subzero temperatures. The activity was measured at the optimal pHs determined for enzymes from particular types of tested meat. It was found that increasing the pressure in the range of 60-193 MPa, did not change significantly the activity of acidic proteases of cod flesh, while the activity of neutral and alkaline proteases decreased drastically. Proteolytic enzymes from salmon flesh were more resistant than those from cod flesh. They maintained or increased (neutral protease) activity after pressurization. The activity of the endogenous enzymes of bovine meat increased with pressure increase, except for acidic proteases, the activity of which was reduced after treatment at 193 MPa to the level similar to unpressurized meat. Endogenous proteases of porcine meat were activated by high-pressure treatment. It has been shown that activity of TGase in unpressurized flesh from cod was 5 times higher than that from unpressurized salmon. Depending on the type of meat, these enzymes were also significantly different in their sensitivity to pressure. The pressure of 60 and 193 MPa led to a complete inactivation of the TGase in cod flesh, while the activity of salmon flesh TGase was decreased only by 15 and 21%, respectively.

This study was conducted to evaluate the effects of the transglutaminase enzyme on the physicochemical characteristics, overrun, melting resistance, rheological and sensorial properties of ice cream made from goat’s milk. Different enzyme units (0.5, 1, 2, and 4 U/g milk protein) and treatment times (20 min and 60 min) were applied to determine the optimum process conditions. Treatment of the transglutaminase in the ice cream mix significantly affected the rheological and melting properties of the ice cream samples. The samples prepared with higher enzyme units and enzyme-treatment times showed higher melting resistance, consistency index, and viscoelastic modulus (G’) than the ice cream mix. The correlation coefficient between melting resistance and viscoelastic modulus was found to be high (0.76). The apparent viscosity of all samples decreased with increasing the shear rate, indicating that all samples exhibited non-Newtonian shear thinning flow behavior. The sensory, overrun, and physicochemical properties of samples were not affected by the enzyme treatment. This study showed that treatment times and enzyme units are essential factors in the processing of the transglutaminase enzyme for improving the rheological and melting properties of ice cream mixes. Another significant result was that desired melting resistance could be achieved for ice cream with lower stabilizer and fat content.

Objective The objective of this research was to evaluate the physico-chemical, microbiological and sensorial qualities of restructured steaks processed from beef trimmings (grade I and II) and frozen beef (fresh beef as control and frozen beef). Methods Beef trimmings from commercial butcher were collected, designated into 4 treatments differing in beef trimmings grade and freezing, processed into restructured steaks with 1% microbial transglutaminase and then analyzed for product quality. Results The results showed that all meat from different groups could be tightly bound together via cross-linking of myosin heavy chain and actin as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Microbial counts of psychrotrophic and mesophilic bacteria were not affected by treatments (p>0.05), and no detectable of thermophilic bacteria were found. Regarding effect of beef trimmings grade, steaks made from beef trimmings grade II (16.03% fat) showed some superior sensorial qualities including higher tenderness score (p

Low temperature microfiltration (MF) is applied in dairy processing to achieve higher protein and microbiological quality ingredients and to support ingredient innovation; however, low temperature reduces hydrophobic interactions between casein proteins and increases the solubility of colloidal calcium phosphate, promoting reversible dissociation of micellar β-casein into the serum phase, and thus into permeate, during MF. Crosslinking of casein proteins using transglutaminase was studied as an approach to reduce the permeation of casein monomers, which typically results in reduced yield of protein in the retentate fraction. Two treatments (a) 5 °C/24 h (TA) and (b) 40 °C/90 min (TB), were applied to the feed before filtration at 5 °C, with a 0.1 µm membrane. Flux was high for TA treatment possibly due to the stabilising effect of transglutaminase on casein micelles. It is likely that formation of isopeptide bonds within and on the surface of micelles results in the micelles being less readily available for protein-protein and protein–membrane interactions, resulting in less resistance to membrane pores and flow passage, thereby conferring higher permeate flux. The results also showed that permeation of casein monomers into the permeate was significantly reduced after both enzymatic treatments as compared to control feed due to the reduced molecular mobility of soluble casein, mainly β-casein, caused by transglutaminase crosslinking.