Trial-produce And Application Of Transglutaminase

Some characteristics and applications of a transglutaminase, derived from a recombinant Bacillus subtilis, namely microbial transglutaminase (MTG) are considered, MTG catalyses in vitro cross-linking of most food proteins through the formation of an ε-(γ-glut amyl) lysine, the modification of food protein by MTG may lead to textured products and improve elasticity and liquid-binding capacity, modify solubility and functional properties and produce food proteins of higher nutritive value through cross-linking. At present only individual manufacturers produce MTG, but the price of MTG is high because of low yields, this paper researched the trial-produce of MTG and it’s application in food.Firstly, the recombinant Bacillus subtilis was used to product MTG by fed-batch fermentation, the conditions were37℃, pH6.5-6.7, DO20-30%and2days fermentation, the activity of MTG reached4.3u/ml. The enzymatic characteristics of MTG were studied, the MTG has an optimum pH of7.0and an optimum temperature of55℃, the kcat is34.09s-1, it also has a molecular weight of450,000.Secondly, the optimum method of using MTG in the gluconic-δ-lactone tofu, yogurt, steamed bread, gluten processing were determined by experiment, the quality was main assessed by the sense of identification method. The main results summarized as follows:by proper addition of MTG, the gel strength of tofu were increased by100%, water holding capacity increased by4percentage point, yield increased by1percentage points. For yogurt production, gel strength increased by250%, liquid-binding power increased by7percentage points, whey separation rate of0.56percentage points lower. MTG and xylanase, lipase, fungal-α amylase were added in the production of steamed bread, the optimum complex respectively was0.025u/g material,1.5u/g material,5.0u/g material,1.5u/g material, these enzymes could obviously improved the quality of steamed bread. In the manufacture of gluten, MTG can promote the protein aggregation and increase strength index.Finally, according to the experimental results, composite enzymes were formulated for steamed bread and gluten processing industrial production. Texture analysis showed that the hardness, gumminess and chewiness were decreased, it suggests that the streamed bread become soft, crisp and chewy, meanwhile springiness and cohesiveness were increased, so steamed bread become chewy and non stick teeth. gluten processing special composite enzymes can compensate for cellulose on gluten index, make production consumption back to normal, increased yield, expanded the application scope of MTG.