| In this article, we studied the influence of different addition amount of TGase on oat dough rheology and thermodynamic properties. Through SDS-PAGE and the determination of free amino we discussed the effect of TGase on oat dough total protein and the role of different protein component of protein in the dough system. Oat whole powder noodles adding TGase were made and texture properties, cooking properties and quality of noodles were studied. In addition, we researched the effect of different incubation times of oat dough adding TGase on physicochemical and rheological properties, in order to determine the optimal incubation time. Main results were as follows:Adding different amount of TGase(0%, 0.5%, 1%, 1.5%, 2%), oat dough water absorption gradually reduced, development time and stability time gradually increased,farinograph quality index greatly increased. There was no significant difference among the thermodynamic parameters(To, Tp) of oat dough by adding TGase, but the denaturation enthalpy( △ H) significantly increased. Oat small molecular protein more formed macromolecular proteins by adding TGase. Gluten was better than globulin as a TGase reaction substrates in oats. Reduction of free amino content in dough further confirmed crosslinking effect of TGase with oat protein.Texture analyzer experiments showed, with the rise of TGase content, oat dough hardness and cohesiveness significantly improved;extensibility reduced; resistance to extension increased; relaxation time, dashpot component and residual stress increased, which proved that TGase strengthened the oat dough internal binding force. With TGase content increasing,the distribution of starch particles changed keep away from protein to disperseed in protein uniformly, and some inbeded by proteins.As the amount of added TGase increased, the firmness, work of shear, extensibility andresistance to extension of raw/cooked oat whole meal noodles increased, while the stickiness and work of adhesion of cooked noodles decreased significantly(p<0.05).TGase improved the cooking qualities of noodles by decreased the losses and water absorption of dry matter significantly.The sensory evaluation scores of cooked noodles was increased with TGase added. There is a certain correlation between texture parameters and sensory evaluation scores,and the firmness, work of shear and resistance to extension were the important indicators to evaluate quality of noodles.With the extension of incubation time, the WHC and SIG first rose and then fell by adding TGase and reached the maximum at 2h. SDS-PAGE showed there is no aggregation in concentrated gel without incubation. When incubation time reached to 1h, total protein and salt soluble protein bands gathered enrichment.While the incubation time exceeded than 1h,there was no obvious change in protein bands of components. With the extension of incubation time, hardness and cohesiveness gradually increased, the resistance to extension increased, extensibility gradually decreased, the stress relaxation parameters(E2, η, τ) rose firstly and then fell by adding TGase and reached the maximum at 2h. |
