Study On The Mechanism Of The Effects Of Vegetable On Quality And Nitrate Contents Of Noodle

Noodles are one of the most common staple foods in Asia,especially China,in which there is a large consumption of noodles every year.The most familiar food combination in people's daily diet is vegetables and noodles.But adding vegetables in noodles would introduce amounts of nitrate and nitrite,leading to potential hazard.Therefore,it is extremely important for human health to investigate the content variation of nitrate and nitrite in storage.The mixing of vegetable pulp or vegetable powder into noodles can improve the nutritional value,but it also has an effect on the sensory quality.This study was comprehensively researched the effects of nitrate and nitrite concentration in different conditions during the storage of noodles,and the influences on noodles qualities with different nitrate content,vegetable pulp and vegetable powder.The results were listed as follows:First,this study provided an analyst for noodle cooking quality,free sulfhydryl,texture profile and microstructure by boiling noodles in water with different nitrate concentration.It turned out that nitrate significantly increased water absorption and cooking loss of noodles,but reduced its free sulfhydryl and swelling index of starch dramatically.Moreover,the lower content of nitrate would increase the tensile force of noodles and vice versa.Springiness,resilience of noodles increased with blending of nitrate aqueous but hardness,adhesiveness,cohesiveness and chewiness decreased.Besides,the microstructure of noodles changed with diverse concentration of nitrate solution.Nitrate also boosted the content of ?-sheet in the secondary structure of proteins,while promoting the production of large-particle-size GMP.Secondly,by measuring the changes of nitrate and nitrite during noodles storage,then conclude the effects of vegetable leaves,temperature and fresh-keeping,as well as the effects of different noodle and vegetable ratios on cooking quality,protein secondary structure and GMP size distribution of noodles.The results showed that the initial content of nitrate in Chinese cabbage was much higher than that of pure noodles,and the temperature had a prominent impact on the nitrite content in noodles.In addition,adding the vegetable leaves increased the water absorption,cooking loss,and starch swelling index of the noodles,but decreased the content of free sulfhydryl group.Tensile force,the distance of tensile force and GMP particle size distribution exhibited a tendency of down-up-down with lowering the noodles and vegetables ratio,which made loose noodles microstructure.What's more,the vegetable leaves promoted the increase of the content of ?-sheet structure and the decrease of the content of P-turn structure.Thirdly,the effects of vegetable pulp,temperature and fresh-keeping on the changes of nitrate and nitrite content during noodles storage and the influence of the amount of vegetable pulp on starch swelling index,microstructure and free sulfhydryl groups were studied.The results indicated that the original nitrite concentration in Chinese cabbage pulp was higher than that of pure noodles.Without sealing,nitrate content in vegetable pulp notably increased under the condition of 4 ? while nitrate content decreased remarkably after 16 h at 30 ?.Nevertheless,the content of nitrite in the sealed noodles reached peak at 16 h and 32 h at 30 ?.The addition of the vegetable pulp prominently affected noodle color,and added the greenness and yellowness,as well as increased the water absorption,cooking loss,GMP particle size distribution and free sulfhydryl group.Besides,the amount of added vegetable pulp is related to the starch swelling and the stability of protein secondary structure.The vegetable pulp remarkably increased the tensile force of the noodles but reduced the distance of tensile force.With the increasing of vegetable pulp,hardness,adhesiveness,gumminess and chewiness of the noodles exhibited a trend of increasing and then decreasing,and the structure of noodles changes significantly but the changes in springiness and cohesiveness was not conspicuous.Finally,the impacts of vegetable powder,temperature and fresh-keeping on the changes of nitrate and nitrite content in noodles during storage were studied,and the effects of adding different amount of vegetable powder on the secondary structure,microstructure and GMP size distribution of noodle protein were investigated.The analysis demonstrated that the content of nitrate in noodles at 4? and 30? showed an identical decreasing trend.After 8 hours,the nitrate concentration in vegetables decreased dramatically at 30?,then peaked at 16 h.There was some variation for nitrate content at other time.Moreover,the vegetable powder significantly reduced the L value of noodles,the tensile force of the noodles,and shortened the distance of tensile force,the GMP particles distribution,but increased its a and b value,as well as water absorption,cooking loss,starch swelling,and free sulfhydryl groups of noodles.With the addition of vegetable powder,the hardness,gumminess and chewiness of noodles decreased first and then increased,while the springiness,resilience,and cohesiveness increased.Furthermore,the addition of vegetable powder made the microstructure of noodles become loose and promoted the stabilization of the secondary structure of the protein.