Study On The Preparation And Quality Improvement Of Oat Noodles

There is a variety of coarse cereals noodles.Among them, the addition of oat flour is nothigh due to the un-stability of this kind of noodles. In order to satisfy consumers’ nutritionalrequirement, in this paper, we initially studied the effect of the content of oat flour on theproperties of oat-wheat noodles, such as pasting properties of the mixed powder, glutenproperties, dough properties and noodle texture. In addition, we studied the effects of differentkinds of additives (salt, xanthan gum, peanut protein, vital gluten, transglutaminase (TG)) onthe improvements of the properties of the dough and quality of the noodles. We also analyzedthe effects of the addition of TG enzymes on the ultra-microstructure of the noodles throughscanning electron microscope (SEM). The main results were listed as following:With the increase of the content of oat flour, the peak viscosity of the mixed powderincreased at first and then decreased. Attenuation values, final viscosity and the gelatinizationpoint were also increased along with the increasing of oat powder while gluten content, glutenindex and sedimentation value decreased. Water absorption of the mixed powder wasincreased significantly, the time needed for the dough to mature increased, stability time wasdecreased and degree of softening was increased. Thus, the rigidity, elasticity andcohesiveness of raw noodles were increased while the pulling strength and pulling width wasdecreased. When the noodle was cooked, the rigidity of the noodle was increased at first andthen decreased after a value. Besides, other texture indexes were decreased and the cookednoodle tasted best when the content of oat flour was30%.Four kinds of TG enzyme was used in this study, all of them decreased the waterabsorption and softening degree of the dough and prolonged the time needed for dough tomature and became stable with the addition of1.0%（w/w）Dongsheng TG enzyme had thelongest time and the smallest softening degree. The addition of peanut protein decreased thegluten content of mixed powder, increased the water absorption and time needed for dough tomature while the addition of1.0%(w/w) Dongsheng TG enzyme increased the gluten contentof the mixed powder contacting foreign protein (peanut protein or vital gluten) and improvedthe quality of the mixed powder. In turn, this effectively increased the ratio of SDS insolubleprotein to the whole protein content and TG enzyme was more effective to improve thecombination of peanut protein and flour protein than vital gluten.The addition of salt and peanut protein had no significant effect on the quality of the noodle while addition of0.8%（w/w）xanthan gum or8%（w/w）vital gluten or both of themcould improve the texture and taste of cooked noodles. These four TG enzymes increased therigidity, elasticity, pulling strength and pulling width of raw noodles. TG-M enzyme alsoimproved the rigidity and pulling strength of cooked noodles and Lvweikang TG enzyme hadpositive effect on the pulling width, while the addition of Dongsheng TG enzyme improvedall the quality indexes of cooked noodles. Besides, these four enzymes used decreased the lossrate (except for TG-M) and water absorption (except for Lvweikang TG enzyme) of drymatter. In addition, the addition of1.0%Dongsheng TG enzyme significantly improved therigidity, cohesiveness and resilience of raw and cooked noodles containing high content ofpeanut protein or vital gluten, and increased their pulling strength and pulling width whilesignificantly decreased the loss rate of cooked noodles.From the microstructure of raw noodles, we knew that the texture of noodles made frommixed flour was loose and had little gluten matrix. However, when xanthan gum and xanthangum was added, gluten network was distributed evenly and there were much more glutenprotein membranes. As for the addition of Dongsheng TG enzyme, it enabled raw noodles toform a complete gluten protein membrane network which enclosed starch granules. Thus,starch granules were linked with the gluten network and gathered together to form clusterswhich in turn increased the density of protein matrix.