Study On The Lactic Acid Adjusts The Processing Performance Of Zein-based Model Dough

Gluten-free cereals are necessary for the daily diet of patients with celiac disease who cannot consume wheat gluten.Due to the lack of functional protein,the processing performance and product quality of gluten-free model dough are not as good as wheat dough.Zein in the dough can exert a functional effect similar to wheat gluten,but its function is unstable and depends on external conditions.Use lactic acid as a control method to optimize the processing quality of zein-based model dough,provides a reference for the development of zein-based gluten-free food.In this subject,we used zein,corn starch,and Artemisia Sphaerocephala Krasch Gum(ASKG)as raw materials,and lactic acid aqueous solution was added during mixing to prepare zein-based doughs defined as lactic acid addition doughs(T dough),the ratio of lactic acid and raw material powder in the doughs(abbreviated as L/F,m L/g)were respectively 0:50,1:50,2:50,3:50,4:50,5:50,with T0,T1,T2,T3,T4,T5 to represent.Corn starch,ASKG,and zein after pretreatment with aqueous lactic acid solution were used as raw materials to prepare dough,these doughs were defined as lactic acid pretreated zein doughs(C dough),the L/F of doughs were respectively 0:50 to 5:50,with C0,C1,C2,C3,C4,C5 to represent.Zein-free doughs(NZ dough)were prepared by corn starch and ASKG as raw materials,and adding lactic acid aqueous solution during mixing,the L/F of doughs were respectively 0:50 to 5:50,with NZ0,NZ1,NZ2,NZ3,NZ4,NZ5 to represent.1.By adjusting the L/F of dough,the effect of the amount of lactic acid on the processing performances of T and NZ dough were compared,and found that lactic acid mainly affected the zein in the dough.Adding an appropriate amount of lactic acid could increase the farinographic properties and the extensibility of T dough.Among them,T2 had the best the performance.Adding an appropriate amount of lactic acid could improve the extensibility of T dough,and T2 had the best extensibility.From T0 to T5,the storage modulus(G')of the dough decreased and the loss tangent(tan ?)increased;the proportion of less tightly bound water decreased,and the proportion of free water and tightly bound water increased;zein released more colored substances,and T dough's color was closer to yellow.2.Using zein pretreated by lactic acid as the model dough protein component was not conducive to the improvement of dough processing quality.Under the adjustment of lactic acid,the processing performance of T dough was excellent,and the farinographic performance,extensibility and dough's color were better than C dough with the same L/F.It was believed that adding lactic acid was an more effective means to improve the processing characteristics of zein-based model dough.3.Under the action of lactic acid,zein in T and C dough underwent deamidation and hydrolysis reactions.The degree of deamidation and the degree of hydrolysis both increased with the increase of L/F ratio.Compared with the zein in the T dough,the zein in the C dough with the same L/F had higher degrees of deamidation and hydrolysis.Lactic acid promoted the hydrolysis of diploid ?-zein into haploids in T dough.Adding an appropriate amount of lactic acid could increase the surface hydrophobicity,increase the proportion of ?-sheet structure,help the network construction of zein in T dough.The zein network in T2 was consistent and uniform,which was the best for coating starch granules.With the increase of L/F in C dough,the surface hydrophobicity of zein continued to increase,and the secondary structure gradually disordered.The zein in C dough existed in the form of aggregated clumps and filamentous networks,which cannot effectively encapsulate starch granules.It was believed that the zein pretreated by lactic acid could not form great network in dough.4.The influence of lactic acid on the quality of zein-based gluten-free noodles prepared by T dough was discussed.Adding lactic acid could improve the cooking quality of noodles and the texture characteristics.But if lactic acid of dough was added excessively,the quality of the noodles would decrease.The noodles prepared by T2 had low hardness,best elasticity and chewiness,and good cooking quality.