Evaluation And Mechanism Of Corn Flour Addition Affecting Performance Of Youtiao

Corn flour has been widely applied in cooking and bakery products due to its plentiful nutrients,good health benefits and attractive golden color.However,Corn flour is rarely used in deep fried products.Youtiao,a traditional fried cereal-based food,is popular to consumers because of its specific flavor,crisp taste and attractive golden color.Here,corn flour was added to wheat flour to prepare Youtiao,and the effects of corn flour addition on the processing properties of flour and dough,as well as the quality of Youtiao were firstly investigated.Then,corn flour was extruded,and the addition of the extruded corn flour on the quality of Youtiao and the related mechanism was studied.Finally,waxy corn flour was also used to explore its effect on the properties of wheat flour and the quality of Youtiao.The results obtained were as follows:(1)The addition of corn flour decreased the content of protein components(albumin,globulin,glutenin and gliadin),amylose content and pasting properties in flour,but increased the ratio of glutenin/ gliadin and amylopectin/amylose.In addition,the swelling power of flour,the tensile properties of dough increased at the addition of 10% corn flour,with the dough being better viscoelasticity and gluten network being a fine structure.(2)A proper amount of corn flour supplemented to wheat flour improved the quality of Youtiao in terms of color,texture,types and relative contents of flavors,and sensory score,but had little effect on the specific volume,oil content and the aging of Youtiao.When corn flour was added at the level of 10%,the sulfhydryl content of dough decreased slightly and disulfide bond content increased slightly,and an increase in the ordered-and a decrease in the disordered-secondary structure of protein in dough were also found,which led to Youtiao with a fine network.(3)The results showed that adding a proper amount of extruded corn flour improved the properties of farinograph and extensogragh,microscopic network structure,and viscoelastic properties of dough;significantly increased the specific volume,sensory score,types and relative contents of flavors and color of Youtiao;decreased the oil content and hardness of youtiao;and delayed the aging of Youtiao.With increasing the addition of extrued corn flour,the ratio of glutenin to gliadin in flour increased;Compared with non-extruded corn flour,the disulfide content,the ordered structure of dough,and the content of protein macromolecules in Youtiao also increased,and a denser film-like microstructure on the surface of Youtiao was observed,which may increase the specific volume and decrease the hardness and the oil content of Youtiao.In addition,with the increase of the amount of extruded corn flour,the indexes of flour gelatinization decreased gradually,the flour inflation potential firstly increased and then decreased,while the ratio of amylopectin/amylose in flour increased gradually.At the same time,extruded corn flour increased the gel strength of the starch and the gelatinization enthalpy of the starch in dough,decreased the relative crystallinity of the starch in Youtiao,and delayed the aging of Youtiao.(4)An appropriate amount of waxy corn flour was added to wheat flour,which could increase the tensile strength of dough and improve the structure of gluten network,resulting in dough being the similar viscoelastic properties of the dough supplemented by extruded corn flour.Compared with Youtiao supplemented by corn flour and extruded corn flour at the same level,Youtiao with waxy corn flour had the biggest specific volume and its value of the oil content,hardness,types and the total peak area of flavor was in the middle.Meanwhile,Youtiao with waxy corn flour had a fine palatability,texture,and taste,obtained the highest sensory score,and retarded its aging during the storage.Furthermore,dough added waxy corn flour had an increase in the content of amylopectin and a decrease in the G?and G? of starch-gel and the starch gelatinization enthalpy,while the content of sulfhydryl in the dough decreased and the content of disulfide bond and the ordered secondary structure of protein increased.In addition,the relative crystallinity of starch in Youtiao with waxy corn flour was smaller than that with corn flour and higher than that with extruded corn flour,but it had no effect on the crystal type.