The Regulation Of Quality Of Noodles Made Of Compound Flour Of Yam And Wheat And Its Mechanism

Huaishan yam is a kind of crop enriched with high protein,starch,nutrient value,and low fat.However,preparing dough from huaishan yam powder is difficult due to no gluten content.In this study,HYP(huaishan yam powder)and WF(wheat flour)were used as main research materials and the effects of HYP addition on farinograph properties and rheological properties to determine the characteristics of protein and starch in yamwheat flour dough.The effects of TGase,gluten,albumen,and alginate on the quality of yam-wheat composite noodles were studied.The results of this study can provide a theoretical basis for defining the interaction between food components and researching special Chinese yam flour products.1.Characteristics of flour,dough,and noodles with different yam addition.There were significant differences in the essential nutrients between WF and HYP.In HYP,the ash content was similar,the protein and starch contents were higher than WF,and the fat and gluten contents were lower than WF.When the addition of HYP was less than 30%,water absorption rate,dough development time increased which resulted into improved viscoelasticity,toughness,and plasticity of obtained dough.With the addition of HYP,the onset gelatinization temperature,the finishing gelatinization temperature,and the peak gelatinization temperature of mixed powder were all increased.But the gelatinization temperature range showed a decreasing trend.With the addition of HYP,the maximum extensibility distance and extensibility resistance force were decreased,and the texture parameters such as springiness and hardness increased initially with the following decrease.With the addition of HYP,the cooking loss increased and the expansion degree of noodles increased first and then decreased.Adding more than 20% HYP,the overall score of noodles decreased significantly.When adding 0-20% HYP,the microstructure of the noodles was improved.And the content of fast digestible starch in the noodles decreased,while the content of resistant starch increased.2.Analysis of protein and starch characteristics of WF,HYP,and compound flourThe shape of starch granules was significantly different among HYP,WF,and mixed flour(30% HYP+70%WF).Wheat starch comprised A and B two kinds of starch granules.Yam starch was mostly elliptic along with angular.The starch crystal type of wheat flour was type A,while HYP and mixed flour were type C.The starch crystal spacing of HYP was smaller and the structure was more compact and stable.The gelatinization temperature and gelatinization range of yam starch were significantly higher than wheat starch.The contents of alcohal-soluble proteins and gluten in WF were significantly higher than HYP.The four components of protein in HYP were all flaky with poor adhesive properties.The crystallinity and crystal types of protein components were different.The crystallinity of HYP protein was the highest and the lowest for WF.The relatively integrity in protein structure of WF was observed and it contained no random crimp.The secondary structure of each component of HYP protein was mainly composed of ?-folding and a small amount of ?-helix.The peak area of alcohol-soluble protein and glutenin in mixed flour was significantly the largest than the others.The proportion of essential amino acids in HYP was larger and the nutrition was more balanced.The first and second restrictive amino acids of WF were sulfur-containing amino acids and the first and second restrictive amino acids of HYP were lysine and threonine.The content of gluten-disulfide bond and sulfhydryl group in WF was higher than HYP.3?Control of the quality of mixed flour noodles by modifying agentThe effects of gluten,TGase,albumen powder,and sodium alginate on the quality mixed flour noodles were different and synergistic.Gluten and TGase had no significant effect on the color of the mixed flour noodles,while albumen powder and sodium alginate had significant effects.Adding gluten could slightly increase the gelatinization temperature of mixed flour noodles and the digestibility of starch was improved a bit.Adding gluten could reduce the cooking loss and springiness of noodles,and increased the water absorption rate and the hardness of noodles which led to flatter and more dense noodles.Adding TGase could decrease the gelatinization temperature but increased the gelatinization enthalpy.Adding TGase could significantly decrease digestibility of starch,cooking loss,water absorption,springiness,and hardness.The structure of the noodles was more uneven and starch particles were slackly arranged.Adding albumen powder and sodium alginate could significantly decrease the onset gelatinization temperature and the peak gelatinization temperature yet increased the finishing gelatinization temperature and the gelatinization range.Adding albumen powder and sodium alginate could significantly decrease the digestibility of starch,hardness,springiness,and cohesiveness.After adding TGase,gluten,albumen,and sodium alginate at the same time,the effects of regulation on individual use were markedly different.Adding TGase and gluten could significantly make starch particles more tightly packed into the protein network and make microstructure denser.