Study On The Quality Of Microwave Modified Corn Flour And Corn Noodles

As one of the three major food crops,corn is not only rich in nutrition,but also ranks first in annual yield.It is a very important food crop.However,due to its lack of gluten protein,its application in staple food processing is greatly limited.Microwave is a very efficient and energy-saving technology,which has been widely used in the field of food processing.It can also be used in the pretreatment of food raw materials to improve its application quality.In this paper,microwave technology was used to modify corn flour,and the properties of modified corn flour and the quality changes of noodles were studied.1、Corn flour was modified by wet microwave and dry microwave respectively.The changes of corn flour composition,particle morphology,crystal structure,color,gelatinization degree,hydration characteristics,gelatinization characteristics and other physical and chemical properties were measured under different microwave treatment conditions.The results show that: After microwave wet heat treatment and dry heat treatment,the amylose content,average degree of polymerization,gelatinization degree and relative molecular weight of protein polymer of corn flour will be increased,the solubility of corn flour will be reduced,and the starch particles will appear pits and the polarization cross will be slightly blurred or disappear.The above changes are more significant in wet heat treatment than dry heat treatment,but in a short time of microwave wet heat treatment(within 1min),amylose content decreased slightly.Both microwave wet heat treatment and dry heat treatment will increase the peak viscosity,valley viscosity,final viscosity,attenuation value and retrogradation value of corn flour,and slightly reduce the peak time.However,microwave dry heat treatment reduces the pasting temperature of corn flour,while microwave damp heat treatment has no effect on the pasting temperature of corn flour.2、The modified corn flour was mixed with medium gluten wheat flour in the ratio of 2:8.By measuring the kneading characteristics of the mixed flour,the cooking and texture quality of noodles,it was determined that the modified corn flour treated with microwave dry heat for 5min(D-5)was more suitable for noodle making.On this basis,by comparing the effects of the addition ratio of microwave modified corn flour(D-5)on the kneading characteristics,the color,cooking,texture and sensory quality of noodles,it was determined that the noodles with 35% microwave modified corn flour(D-5)in corn noodles had better processing quality.3、Microwave dry heat modified corn flour(D-5)was compounded with wheat flour at the optimum amount(35%)to determine the quality of dough and noodles.It was found that compared with the dough added with untreated corn flour,the gluten elasticity,dough breaking force and breaking distance of the dough added with microwave modified corn flour were significantly increased,the gluten network structure was more orderly and the starch distribution was more uniform.Compared with the noodles added with untreated corn flour,the noodles added with microwave modified corn flour had higher water holding capacity,higher brightness and lower cooking loss rate;The hardness,elasticity,chewiness,breaking force and breaking distance of noodles were improved,but there was no significant change in cohesion and recovery,which made the texture and tensile quality of noodles closer to that of pure wheat flour noodles;The scores of color,toughness,viscosity,smoothness and taste of noodles increased significantly,and the sensory score increased significantly,which was 81.2 points.4、The storage,flavor and digestion characteristics of microwave modified corn noodles were studied.The results showed that the total number of initial colonies of noodles added with microwave modified corn flour was significantly lower than that of noodles added with untreated corn flour.At 36℃,25℃ and 4℃,the storage time of noodles was 6.87 h,17.74 h and 88.56 h respectively,which was twice,35.68% and27.24% longer than that of noodles added with untreated corn flour,And the number of mold in noodles also decreased significantly.Compared with the noodles added with untreated corn flour,the composition and relative content of volatile compounds in the noodles added with microwave modified corn flour have changed significantly,the relative content of aldehydes and ketones has decreased,the types of lipid compounds have changed,the fresh fruit flavor in the noodles has decreased,with oil and aromatic smell,and naphthalene heterocyclic aromatic hydrocarbons have been removed.Compared with the noodles added with untreated corn flour,the RDS and RS of the noodles added with microwave modified corn flour decreased by 0.08% and39.96% respectively,and the SDS increased by 20.57%.Microwave modification will reduce the combination degree of corn starch and protein,reduce the solubility and paste temperature of corn flour,and improve the average degree of polymerization,gelatinization degree and gelatinization viscosity of corn flour.Compared with adding untreated corn flour,adding modified corn flour with dry heat treatment for 5 minutes can improve the rheological properties of corn dough,reduce the cooking loss rate of corn noodles,improve the brightness of noodles,and make the texture and sensory quality of noodles closer to pure wheat flour noodles.At the same time,it can prolong the shelf life of dough and make noodles have unique flavor.