Postnatal skeletal muscle growth occurs through myonuclear accretion and high protein turnover rate. While fiber type composition of the muscle could affect protein turnover rate, less is known about how fiber type influences the regulation of protein synthesis and degradation signaling pathways. Thus, the hypothesis of this work was that variation in fiber type composition will differentially affect the regulation of signaling pathways related to protein turnover in skeletal muscle hypertrophy in growing pigs. Downregulated protein synthesis signaling and reduced expression of type II MyHC isoforms have been reported in skeletal muscles of low birth weight (LBWT) neonatal pigs. Therefore, we sought to determine whether these changes are sustained until weaning and would explain the reduction in LBWT pig growth compared to their normal birth weight (NBWT) sibling at weaning. Another objective was to determine whether the regulation of protein turnover signaling pathways are correlated to fiber type differences in skeletal muscles. Our data suggest that the longissimus dorsi (LD, glycolytic) muscle of LBWT pigs experienced compensatory growth while the soleus (oxidative) remained proportionally smaller. Growth of the LD was accompanied by upregulation of translation initiation. Additionally, there was no difference in expression of MyHC isoforms between NBWT and LBWT pigs. These data suggest the rapid growth of the LD of LBWT pigs may be attributed to an upregulation of protein synthesis signaling and occurred only in glycolytic muscles. A caveat in LBWT pig model is that the reduction in type II MyHC at birth is not the only factor that could influence muscle growth, and that other factors may have confounded our results. This is why we aimed to use β-adrenergic agonist as a means to induce a shift fiber type in muscles to a more glycolytic phenotype. Our objective was to determine the influence of the β-adrenergic agonist Ractopamine (RAC) induced slow-to-fast fiber type transformation on the regulation of protein synthesis and degradation pathways. Although supplementation improved translational capacity, enhanced S6K1 phosphorylation, and reduced the abundance of calcium-dependent proteases, RAC feeding had no effect on body or muscle weights. These results suggest that a fiber type transformation without other physiological influences does not alter protein turnover signaling in favor of hypertrophy in growing pigs. / Master of Science / Skeletal muscles grow by increasing the amount of protein contained within them. The amount of protein deposited is determined by the net balance between the rates at which proteins are synthesized and degraded. However, not all skeletal muscles grow at the same rate. One factor that is thought to influence protein synthesis and degradation rates is the types of muscle fibers that are present within a muscle. These fibers can display a range of contractile and metabolic characteristics, from slow-twitch oxidative fibers to fast-twitch glycolytic fibers. In the presented studies, we sought to determine whether changes in fiber type composition result in difference to the signaling pathways the regulate protein synthesis and degradation, ultimately leading to differences in the muscle growth of young pigs. We have previously shown reduced activation of the protein synthesis pathway in the skeletal muscle of low birth weight (LBWT) newborn pigs. These pigs also had lower expression of glycolytic fibers. In experiment 1, we aimed to compare the signaling pathways regulating protein synthesis and degradation in LBWT and normal birth weight (NBWT) pigs at weaning. We also sought to determine if the regulation of these signaling pathways changed between muscles with differing fiber type compositions. The glycolytic longissimus dorsi (LD) muscle of LBWT pigs grew rapidly between birth and weaning whereas the highly oxidative soleus did not. In addition, the LD of LBWT pigs had greater protein synthesis signaling and similar expression of muscle fibers compared with NBWT pigs, suggesting the improvement in protein synthesis signaling of LBWT pigs between birth and weaning may be related to a shift in fiber type. In experiment 2, we used a compound called ractopamine hydrochloride (RAC) to promote a slow-to-fast fiber type switch in the muscle of young pigs. With this study, we sought to determine the effect of this fiber type transformation, without the influence of birth weight, on the regulation of protein synthesis and degradation pathways. Although RAC-fed pigs showed some minor changes that could improve protein synthesis and decrease protein degradation, RAC feeding had no observable effect on body weight or muscle growth. These results suggest that a fiber type transformation alone is not enough to promote muscle growth in growing pigs.

Yes / Rpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13. Hence, overexpression of the SGTA-binding region of Rpn13 or point mutations within the SGTA TPR domain both inhibit SGTA binding to the proteasome and substantially reduce MLP levels. These findings suggest that SGTA can regulate the access of MLPs to the proteolytic core of the proteasome, implying that a protein quality control cycle that involves SGTA and the BAG6 complex can operate at the 19S regulatory particle. We speculate that the binding of SGTA to Rpn13 enables specific polypeptides to escape proteasomal degradation and/or selectively modulates substrate degradation. / BBSRC [grant number: BB/L006510/1] and the Wellcome Trust [grant number: 092107/Z/10/Z]. K.K. was supported by the UPStream network [EU, FP7, ITN project 290257]

No description available.

Experimental studies into the use of cold atmospheric plasmas for inactivating foodborne pathogens are presented in this thesis. Eliminating the possibility that treatment delivered by a plasma to a population or assemblage of micro-organisms is unevenly distributed is an essential pre-requisite to attempting to interpret inactivation kinetics with a view to elucidating mechanisms of inactivation. A filtration method of depositing cells evenly on the surface of a membrane without cell stacking was developed and used throughout the work described here. Two atmospheric plasma systems were evaluated and each brought about microbial inactivation in a distinct way. A pulsed radio frequency plasma jet operated at 3.47 MHz caused gross morphological changes to L. innocua whereas a low frequency air mesh plasma system operated at a frequency of 24 kHz led to the inactivation of these bacteria without inducing observable structural changes. Changing the operating parameters of the plasma jet system had a significant effect on the composition of the reactive plasma species generated as revealed by changes to the mode of inactivation of bacteria. In addition to inactivating bacteria, the pulsed plasma jet was shown to be highly effective in degrading and removing amyloid aggregates from the surface of mica coupons. Amyloids have widely been used as a non-infectious model for prions, and the results obtained here show potential for the application of gas plasma technology for removing prions from abiotic surfaces in medical and other applications. It has widely been assumed that bacterial envelopes are the principal sites at which reactive plasma species bring about damage to cells. However, changing the composition of the bacterial membranes of E. coli and Listeria innocua by cultivating them at widely different temperatures to induce changes proved not to result in enhanced inactivation. Flow cytometry was also used to provide additional insights into possible mechanisms of inactivation. The following fluorescent dyes were used either singly or in combination; SYTO 13, DiBAC4(3), cFDA and PI. The results obtained with the dyes DiBAC4(3) and PI showed that Gram positive bacteria became depolarised prior to the bacterial membrane becoming compromised, possibly suggesting that the inactivating plasma species are affecting membrane proteins responsible for maintaining the bacterial charge. Differences between the fluorescent dye staining of Gram negative and Gram positive species were obtained using SYTO13 and PI demonstrating that the different membrane structures affect their interaction with the plasma. In additional studies, the air mesh plasma was used to treat multi-drug resistant strains of Methicillin resistant Staphylococcus aureus (MRSA) in an attempt to reverse antibiotic resistance. MRSA PM 64 was shown to reverse its antibiotic resistance to Oxacillin, Kanamycin and Trimethoprim. Culturing the bacteria in a nutrient limited media led to increased resistance towards plasma treatment and maintenance of their high levels of antibiotic resistance.

O típico sabor de chocolate é único, obtido somente de sementes fermentadas, secas e torradas de cacau, não podendo ser sintetizado artificialmente. O desenvolvimento desse sabor é influenciado pela constituição genética das sementes, processamento pós-colheita e manufatura. Proteínas dos cotilédones são potencialmente precursores do sabor e aroma de chocolate. O presente trabalho teve como objetivo analisar diferenças qualitativas e quantitativas nas proteínas de sementes de três genótipos de Theobroma cacao após a colheita e durante a fermentação, de forma a correlacionar estes resultados com diferenças na qualidade (sabor e aroma) obtidas por análise sensorial. Um dos desafios foi o isolamento de proteínas das sementes, evitando o alto teor de polifenóis e polissacarídeos que interferem na separação das proteínas e na análise do proteoma. A metodologia de extração composta por filtração em Miracloth, solubilização e precipitação em ácido ticloroacético (TCA) apresentou géis de maior resolução e repetibilidade, tendo sido escolhida como metodologia de extração protéica para estudo das alterações no proteoma das sementes de cacau durante a fermentação. Foi necessária também a utilização de kit comercial de purificação de proteínas e utilização de método de coloração com nitrato de prata para garantir géis com resolução dos spots e repetibilidade satisfatórias. Os spots foram isolados e após digestão tríptica, submetidos ao sequenciamento por cromatografia líquida associado ao espectrômetro de massas. Os espectros foram analisados pelo programa MASCOT MS/MS Ion Search, utilizando bancos de dados do NCBI. Análises dos mapas 2-D mostraram variação no número de spots entre as variedades. Ao final da fermentação, as proteínas ainda presentes nas sementes das variedades SIAL 70 e Catongo eram ácidas, e o processo de degradação foi caracterizado pelo desaparecimento de quase todas as proteínas neutras ou básicas e também de algumas proteínas ácidas; as proteínas com massa molar acima de 35 kDa também foram todas degradadas. Na variedade CCN 51, não ocorreu o mesmo perfil degradativo, havendo proteínas até pI 6,5 e massa molar acima de 100 kDa. Dos cem spots submetidos ao sequenciamento, 89 foram identificados. As proteínas 21kDa e vicilina foram as proteínas mais abundantes nos cotilédones. Correlacionando os resultados da análise sensorial e a proteômica concluiu-se que existe correlação tanto quantitativa como qualitativa das proteínas dos cotilédones de cacau e possivelmente com as proteínas precursoras de sabor de chocolate / Typical chocolate flavor is unique, only obtained from fermented, dried and roasted cocoa seeds, and can not be synthesized artificially. The flavor development is influenced by the genetic constitution, post-harvest processing and manufactures. Cotyledons proteins are believed to be the precursors of the chocolate flavor. The aim of the present work was to analyze qualitative and quantitative protein differences in seeds of three cocoa genotypes after harvesting and during the fermentation and to correlate these results with differences in quality (flavor and aroma) obtained by sensorial evaluation. One of the challenges was the isolation of proteins from cocoa seeds, avoiding the high content of polyphenols and polysaccharides which disturb protein separation and proteome analysis. The methodology of extraction by filtration in Miracloth, solubilization and precipitation in trichloroacetic acid showed the highest gel resolution and reprodutivity, and, thus, was chosen to be used in the analyses of the proteome of cocoa seeds during the fermentation. It was also necessary to use commercial kit for protein purification and a silver-based staining method with nitrate to guarantee gels with spots resolution and satisfactory reproducibility. Proteins were excised from de gels and after tryptic digestion, MS analysis was conducted by on line chromatografhy using a Cap-LC coupled to a mass spectrometer. The spectra were processed using MASCOT MS/MS Ion Search, and the sequences searched against NCBI databases. The 2-DE maps analysis of cocoa seeds showed significant variation of the spots number among the genotypes. At the end of fermentation, proteins still present in the Sial 70 and Catongo genotypes were acid and the degradation process was characterized by the disappearance of almost all the neutral or basic proteins and also some acid proteins. The genotype CCN 51 did not show the same degradation profile. Of the spots submitted to the mass spectrometer, 89 were identified. The 21kDa protein and vicilin were the most abundant proteins in the cocoa cotyledons. Correlating sensorial analysis and the proteomic results we could observe the existence of quantitative as qualitative correlation of proteins from cocoa cotyledons and possibly with the precursors proteins of chocolate flavor

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-08-16T19:30:56Z No. of bitstreams: 1 2014 - Carla da Silva Teba.pdf: 4808769 bytes, checksum: c0f54c8ea9fb94f4469d54eb3764c138 (MD5) / Made available in DSpace on 2017-08-16T19:30:56Z (GMT). No. of bitstreams: 1 2014 - Carla da Silva Teba.pdf: 4808769 bytes, checksum: c0f54c8ea9fb94f4469d54eb3764c138 (MD5) Previous issue date: 2014-09-02 / CAPES / Whey is one the most polluting by-products of the food industry and their perishability does not allow storage for long periods, then it's necessary to find appropriate destination. The whey protein have potential anticarcinogenic, activities hypocholesterolemic, anti-inflammatory, immunomodulatory action, among others. The rice consists mainly of starch, and this structure contributes to the production of snacks high technological quality. The objective of this study was develop and characterize mixed extruded flour of rice and whey protein concentrate aiming use in the manufacture nutritional and practical products. The parameters used in the processing of thermoplastic extrusion were: formulation (% whey protein concentrate), moisture content and temperature of the last heating zone. The extrudates were subjected to physical characterization and functional technology assessment. The highest rates of growth were observed for the tests with up to 4 % whey protein concentrates in their formulations and were processed with low humidity generally less than 20 % and milder temperatures, generally at or below 140 ?C. Through the visual characterization of extruded and the micrographs it was observed that the samples processed with low moisture content (16.64 and 18%) were more homogeneous cells. The X-ray diffraction showed that the profile of the crystal samples is characteristic of type "A" due to the presence of crystalline domains in its structure. The flours viscosity profile is consistent with the characteristics of pre- gelatinized products, being dissolved without needing to cook. The pre-gel flour with blends of rice and whey protein concentrate present viscous, homogeneous and with low capacity of retrogradation. The addiction protein concentrate in rice flour increased the ash and proteins, indicating that the mineral and amino acid composition of the mixed flours may also have a nutritional improvement. Generally, the processing conditions do not significantly affect the nutritional value of the flours blends. The acceptance test performed with the cookies prepared with the mixed flours 8, 10 and 16 (6, 7.36 and 4 % whey protein concentrate, respectively) indicated that the biscuit with a higher content of protein concentrate showed better overall evaluation, taste and purchase intent. The porridges were produced with pre-gelatinized flour containing 2, 4 and 7.36% whey protein concentrate and sensory analysis evaluated the attributes appearance, flavor and consistency, plus purchase intent. The results showed that for most of the evaluated attributes and purchase intent, the sample with higher content of protein concentrate showed the best results. The porridges were produced with pre-gelatinized flour containing 2, 4 and 7.36% whey protein concentrate and sensory analysis evaluated the attributes appearance, flavor and consistency, plus purchase intent. The results showed that for most of the evaluated attributes and purchase intent, the sample with higher content of protein concentrate showed the best results. We conclude that it is possible to produce pre-gel flours containing rice and whey protein concentrate with good nutritional, microbiological and technological features for the production of cookies and porridges rapid dissolution. / O soro de leite ? um dos subprodutos mais poluentes da ind?stria de alimentos e sua natureza perec?vel n?o permite a estocagem por per?odo prolongado, sendo necess?rio encontrar destino adequado aos volumes produzidos. Atribuem-se ?s prote?nas do soro de leite poss?veis atividades anticarcinog?nica, hipocolesterol?mica, anti-inflamat?ria, a??o imunomoduladora, entre outras. O arroz ? constitu?do principalmente por amido, e devido a sua estrutura, contribui para a produ??o de snacks de elevada qualidade tecnol?gica. O objetivo desse trabalho ? desenvolver e caracterizar farinhas mistas pr?-gelatinizadas de arroz e concentrado proteico de soro de leite bovino, obtidas por extrus?o termopl?stica, visando utiliza??o na elabora??o de produtos nutritivos e pr?ticos. Foram consideradas como vari?veis independentes: formula??o (% de concentrado proteico de soro de leite na mistura com farinha de arroz), umidade da mistura da farinha no processamento e temperatura da ?ltima zona de aquecimento. Os extrudados elaborados foram submetidos ? caracteriza??o f?sica e avalia??o tecnol?gica funcional. Os melhores ?ndices de expans?o foram observados para os ensaios com at? 4 % de concentrado proteico e que foram processados com baixa umidade e temperaturas mais brandas. Atrav?s da caracteriza??o visual dos extrudados e das micrografias foi poss?vel observar que as amostras processadas com baixo conte?do de umidade (16,64 % e 18 %) apresentaram c?lulas mais homog?neas. Por meio da difratometria de raios X verificou-se que o perfil das amostras ? caracter?stico ao cristal do tipo "A", devido ? presen?a de dom?nios cristalinos em sua estrutura. As farinhas mistas extrudadas se destacaram por possuir elevada viscosidade a frio, baixa viscosidade a quente (95?C) e baixo poder de retrograda??o. Os resultados observados nos par?metros de viscosidade avaliados mostram correla??o destas propriedades com as caracter?sticas de f?cil reconstitui??o e boa solubiliza??o em meio aquoso, sem a necessidade de cozimento. A incorpora??o de concentrado proteico na farinha de arroz promoveu incremento no teor de cinzas e prote?nas, indicando melhoria na composi??o mineral e de amino?cidos das farinhas mistas. De modo geral, as condi??es de processamento utilizadas n?o afetaram de forma significativa o valor nutricional da maior parte das farinhas mistas produzidas. O teste de aceita??o realizado com os biscoitos elaborados com as farinhas mistas referentes aos ensaios 8, 10 e 16 (6, 7,36 e 4 % de concentrado proteico, respectivamente) indicou que o biscoito com maior teor de concentrado proteico apresentou melhor avalia??o global, sabor e inten??o de compra. Os mingaus foram produzidos com farinhas pr?-gelatinizadas contendo 2, 4 e 7,36 % de concentrado proteico e submetidos ? an?lise sensorial. Para a maior parte dos atributos avaliados e para a inten??o de compra, a amostra com maior teor de concentrado proteico apresentou os melhores resultados. Conclui-se que ? poss?vel produzir farinhas mistas pr?-gelatinizadas de arroz e concentrado proteico de soro de leite bovino com boas caracter?sticas nutricionais, microbiol?gicas e tecnol?gicas tanto para a elabora??o de biscoitos quanto para a produ??o de mingaus de r?pida dissolu??o.

<p>The protein degradation process is of vital importance for the cell to maintain cellular functions. An important enzyme in this process is the multimeric tripeptidyl-peptidase II (TPP II). It removes tripeptides from a free N-terminus of the substrates. TPP II has broad substrate specificity and wide-spread distribution, suggesting that the TPP II gene is a house-keeping gene. However, the levels of both mRNA and TPP II protein varies during different conditions and the TPP II gene promoter was therefore identified and characterized. It is a 215 bp fragment just upstream of the coding sequence. This fragment lacks a TATA-box but contains an initiator, two inverted CCAAT-boxes and an E-box. The CCAAT-boxes and the E-box were found to bind the nuclear factor Y (NF-Y) and upstream stimulatory factor-1 (USF-1) respectively. The CCAAT-boxes appear to be most important for the transcriptional activation. Furthermore, several silencer element were identified further upstream of the 215 bp promoter and the octamer binding factor Oct-1 was found to bind one of these fragments. If Oct-1 is responsible for the inhibition of the transcription of the TPP II gene remains to be investigated. In addition, the substrate specificity was investigated. For this purpose an expression system using <i>Pichia pastoris</i> was developed. The purified recombinant TPP II was found to have the same enzymatic properties as the native enzyme. In order to identify the amino acids involved in the binding of the N-terminus of the substrate, wild-type murine TPP II and four mutants E305Q, E305K, E331Q and E331K were purified. Steady-state kinetic analysis clearly demonstrated that both Glu-305 and Glu-331 are important for this binding as the K_M^app is more than 10² higher for the mutants than wild-type. Finally, the pH-dependence for cleavage of two chromogenic substrates was compared for TPP II from different species.</p>

The protein degradation process is of vital importance for the cell to maintain cellular functions. An important enzyme in this process is the multimeric tripeptidyl-peptidase II (TPP II). It removes tripeptides from a free N-terminus of the substrates. TPP II has broad substrate specificity and wide-spread distribution, suggesting that the TPP II gene is a house-keeping gene. However, the levels of both mRNA and TPP II protein varies during different conditions and the TPP II gene promoter was therefore identified and characterized. It is a 215 bp fragment just upstream of the coding sequence. This fragment lacks a TATA-box but contains an initiator, two inverted CCAAT-boxes and an E-box. The CCAAT-boxes and the E-box were found to bind the nuclear factor Y (NF-Y) and upstream stimulatory factor-1 (USF-1) respectively. The CCAAT-boxes appear to be most important for the transcriptional activation. Furthermore, several silencer element were identified further upstream of the 215 bp promoter and the octamer binding factor Oct-1 was found to bind one of these fragments. If Oct-1 is responsible for the inhibition of the transcription of the TPP II gene remains to be investigated. In addition, the substrate specificity was investigated. For this purpose an expression system using Pichia pastoris was developed. The purified recombinant TPP II was found to have the same enzymatic properties as the native enzyme. In order to identify the amino acids involved in the binding of the N-terminus of the substrate, wild-type murine TPP II and four mutants E305Q, E305K, E331Q and E331K were purified. Steady-state kinetic analysis clearly demonstrated that both Glu-305 and Glu-331 are important for this binding as the KMapp is more than 102 higher for the mutants than wild-type. Finally, the pH-dependence for cleavage of two chromogenic substrates was compared for TPP II from different species.

The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added.

The main objectives of this research were to examine effects of protein modification (protein cleavage and crosslinking) on turkey meat gelation and to evaluate textural properties and water holding capacity of meat gels prepared from normal and PSE (pale, soft, exudative) turkey breast meat.<p>First, the effect of protein degradation on turkey breast meat gelation was studied. To create different extent of proteolysis in the meat, á-chymotrypsin (EC 3.4.21.1) was added to normal and PSE meat batters at 0, 2.5, 5 and 10 ppm levels. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cooked meat gels showed progressive protein hydrolysis with increasing enzyme level. Texture profile analysis and torsional analysis of the cooked meat gels showed an incremental deterioration in texture with increasing enzyme level. This inferior texture caused by proteolysis was similar to that observed in the gels made from PSE turkey meat alone. Pearson correlation coefficients indicated gel textural properties and expressible moisture were highly correlated to the degree of proteolysis, especially to that of myosin heavy chain (p < 0.001).<p>The second study focused on modifying protein size to improve meat gelation, especially PSE meat gelation. Transglutaminase (TGase, EC 2.3.2.13) was chosen due to its ability to catalyze crosslinking of proteins. Pea protein isolate, an alternative to soy protein, was also evaluated as a meat protein extender. Textural profile and torsional gelometry analyses of the cooked meat gels showed TGase alone significantly (p < 0.05) increased gel texture, especially for those made from PSE meat. However, cook yield of the meat gels was compromised possibly due to steric effects. Addition of pea protein isolate alone improved cook yield and gel texture, especially for the gels made from PSE meat. The combination of TGase and pea protein produced the strongest meat gels, while maintaining a similar cook yield to the control. SDS-PAGE showed the disappearance of several protein bands contributed from the meat or pea protein with TGase addition, indicating that these likely were crosslinked and too large to enter the gel. Dynamic rheological analysis revealed TGase altered the viscoelastic properties of the meat or meat-pea protein mixtures and produced more elastic gels on cooling.<p>This research indicated proteolysis had a dramatic impact on textural properties of turkey breast meat gels. Crosslinking of proteins catalyzed by TGase significantly improved gel texture, especially for the gels made from PSE meat. However, TGase-assisted crosslinking of proteins resulted in greater cooking losses unless an extender/adjunct such as pea protein was added.