Studies On Effects Of Microbial Transglutaminase On The Quality Of Wheat Flour And Steamed Bun

Microbial transglutaminase(MTG) is a kind of biological enzyme, which is obtained from microorganisms fermentation, separation and then purification. MTG catalyzes acyl-transfer reactions, introducing intramolecular or intermolecular covalent cross-linking, improving the structure and function of gluten, making the gluten have unique texture and taste, and increasing the nutritional value of protein. Currently, MTG is widely used in food industry. This paper had focused on studying on the MTG in the catalytic mechanism in flour, and researching on improving the quality of flour and flour products by MTG.This paper firstly had studied the effects of MTG on the free thiol (-SH) content, water holding capacity, SDS sedimentation value, gluten swelling index and rheological properties of flour. The results showed that MTG could improve the physical and chemical properties of flour and finally improve the quality of flour.Using the method of gel permeation liquid chromatography(GP-HPLC), this paper had studied the effects of MTG on gluten protein of freeze-dried dough and flour suspension. The experiments results showed that MTG mainly effected on the ω-gliadin and polymeric glutenin(HMW-GS) of gluten protein. Through the catalyzed cross-linking of MTG, the effects in suspension flour are stronger than in freeze-dried dough. MTG could promote the gluten protein cross-linking intramolecular or intermolecular.Then the paper had studied the application of MTG in northern steamed bun. The experiments results showed that MTG could significantly improve the internal organizational structure, whiteness, specific volume, height and external smoothness of northern steamed bun in a certain range of usage. When MTG was used combination with lipase, amylase, xylanase, the quality of northern steamed bun were obviously improved, these enzymes could completely replace the traditional chemical modifier. Overall, it was feasible to use MTG in northern steamed bun production process, and there was a good effect when the add amount was1-5U/g flour.Scanning electron microscopy was used in order to see the effect of addition of MTG on the microstructure of dough and northern steamed bun. The pictures showed that after treated with MTG, the dough gluten network structure became more closely with each other, and the gluten network structure of dough and steamed bun become more uniform and more continuous.