Study On The Modification And Application Of Textured Wheat Gluten

Wheat protein, as its unique protein structure, can get a fiber structure when textured,and the fiber structure is similar with chicken breast meat. On the other hand, wheat proteinhas a high protein content and comprehensive amino acids, so textured wheat protein(TWP) isan ideal meat analog. Exploiting the application of TWP as meat analog can increase thescope of wheat protein uses and quantity, realizing the value-adding of wheat gluten.Effects of NaOH, L-cysteine on the system parameters and objective parameters werestudied firstly. The results of experiment showed that torque, pressure, specific mechanicalenergy(SEM) and hardness, bulk density of TWP decreased with the increasing of NaOHconcentration(0%~0.15%, w/w). On the contrary, springiness, chewiness and cohesivenesssignificantly (p<0.05) increased. Degree of texturization increased firstly, then decreased, andreached peak when the NaOH was added at0.075%(w/w). The pressure, torque and SEM ofthe extruder, the degree of texturization, the hardness, the springiness, the cohesiveness andthe bulk density of TWP increased when L-cysteine was added at0%~0.β0%(w/w).Secondly, the mechanism of textured wheat protein was explored by analyzing effect ofextrusion on the structure of wheat gluten protein. The results of experiment showed that afterwheat gluten being textured, the network structure of wheat gluten was substituted for thelayered, fibred structure. Moreover during the extruded processing, the subunit of wheatprotein aggregated, the free sulfydryl and the cysteine reduced by55%and γγ%respectively,so a lot of disulfide bonds formed. The interaction of disulfide bonds and non-covalent bondsplays a more important role than non-covalent bonds. Not all secondary structure wasdestroyed, but some of α-helix, random coil and-sheet turned to-turns, which is morestable.Thirdly, the modified mechanism of TWP was studied by analyzing the effective ofadding NaOH, L-cysteine, azoformamide(ADA) on the structure of TWP protein. The resultsof scan electric microscope(SEM) showed that the surface of TWP would be tighter by theeffect of NaOH. The surface of TWP would be smoother under the influence of L-cysteine,and the layer would be thiner. But when wheat gluten was extruded with ADA, litter holesappeared on the surface of TWP, the layer structure became less clear. The results ofSDS-PAGE didn’t change after addition these additives, both the solubility experiment andthe quantity of cysteine and free sulfydryl indicated that these additives can promote disulfidebond forming. In contrast to NaOH and L-cysteine, the quality of TWP was worse by theeffect of ADA. The random coil of wheat gluten was increased when extruded with NaOHand L-cysteine, but drcreased when extruder withADA.Finally, the application of TWP in nonmeat ball was studied. This study aimed to solvethe problem of nonmeat ball that couldn’t have good springiness, cohesiveness and juiciness simultaneously. Three adhesions(corn starch, wheat gluten, soy protein isolate) were studied.Concentration of corn starch was appropriate during5%~15%(w/w), nonmeat ball woulddisperse when corn starch was added less5%, and would be too hard and less of juiciness ifwhen exceeded15%as starch aging. When wheat gluten exceeded6%(w/w), the nonmeat ballwas hard to mold because of high viscosity. SPI is similar with wheatgluten when added intoTWP because of high gel, it also influenced the hardness, the chewiness and the juiciness ofnonmeat ball. Supergelling Methycellulose’s can solve the problem of above with littleaddition. The correlation analysis indicated that the quality of TWP had a positive correlationwith nonmeat quality. Compared with the nonmeat ball made from saled textured wheatprotein, the above nonmeat ball had more fiber structure, juiciness and good tenacity. But lessspringiness and juiciness compared with saled chicken ball.