| Wheat gluten protein plays an indispensable role in flour products.It can form a three-dimensional gluten network structure after mixing with water,which plays a supporting role and endows noodle products with viscoelasticity.Nowadays,the traditional noodle products processed only with wheat flour can not meet the expectations of consumers.Food additives and functional substances are widely used in noodle products.Tremella fuciformis(TF)is a medicinal and edible fungus with good nutritional value,and has great viscosity and water holding capacity.If TF can be added to noodle products as a thickener,it can not only improve the quality of noodles,but also enrich the nutrition and flavor of noodles.In this paper,the physicochemical and nutritional properties of TF were studied,and different proportions of TF(0%,1%,2%,3%,4%)were added to flour to explore the effect of TF cohesion on wheat dough gluten crosslinking.The differences of the effects of TF and three kinds of hydrocolloids on the quality of wheat noodles were further compared and analyzed.And the effects of TF on the nutrition and flavor characteristics of noodles were studied.The purpose is to improve the quality of noodles and expand the application of TF in staple.The research content of this paper mainly includes the following points.(1)The physicochemical and nutritional characteristics of Tremella fuciformis were studied.The changes of water holding capacity,paste forming characteristics,viscosity characteristics,freeze-thaw stability and gelling characteristics of Tremella fuciformis solution under the condition of edible salt and edible alkali were measured.The results showed that TF has good water holding capacity and viscosity.The addition of edible salt will significantly reduce the water holding capacity,paste volume ratio and viscosity of TF solution,and increase the water separation rate and solution flow distance.Edible alkali had no significant effect on the above indexes of TF solution.Compared with wheat dough,TF group has lower transverse relaxation time and higher proportion of deep bound water peak.At the same time,the amino acid composition of TF were analyzed.The chemical composition,antioxidant and hypoglycemic activities of Tremella fuciformis polysaccharide(TFP)were studied.It was found that TF mainly contains 16 kinds of amino acids,and the contents of glutamate and aspartic acid are higher.According to the monosaccharide composition and molecular weight data,TFP is mainly mannose with a molecular weight of 4.86×10~6Da and 3.70×10~4Da acidic heteropolysaccharide.In addition,TFP has antioxidant and hypoglycemic abilities.(2)Due to the good viscosity of TF,the changes of gelatinization characteristics and cold viscosity of TF-wheat mixed system were studied,and the effects of TF viscosity on the tensile properties,kneading properties,protein properties and water distribution of wheat dough were analyzed.The results showed that the addition of TF could increase the peak viscosity,trough viscosity and final viscosity of TF-wheat mixed system,reduce the breakdown value and setback value,and increase the cold viscosity of the mixed system.At the same time,with the increase of TF addition,the dough breaking force,midline peak parameters,8min bandwidth,β-sheet content increased significantly(P<0.05).It reached the maximum value at 3%,and then showed a decreasing trend.The addition of TF can convert the weak bound water in the dough to deep bound water,reduce the water fluidity,and change significantly at 3%.The observation of dough microstructure showed that TF could make the formation of gluten network more compact and orderly.Comprehensive analysis showed that the dough made by adding 3%TF has a high degree of internal cross-linking of gluten protein,high order of gluten network structure and excellent quality.(3)According to the dough data,TF was further applied to noodles making,and compared with the commonly used hydrocolloids(sodium alginate,guar gum,xanthan gum)in noodles to analyze the differences between TF and hydrocolloids on the texture characteristics,cooking characteristics,protein characteristics,water morphology and microstructure of noodles.The results showed that both TF and hydrocolloid significantly(P<0.05)improved the tensile force,rupture distance,hardness,adhesiveness and chewiness of the noodles.Combined with the above data,it is found that when TF was 3%,sodium alginate was 0.6%,guar gum was 0.4%and xanthan gum was 0.4%,the noodles made respectively have better texture characteristics.The effects of TF on the textural properties of the noodles were not significantly different from those of sodium alginate and guar gum,and slightly weaker than those of xanthan gum.In addition,adding 3%TF significantly increased the hydrogen bonding content,α-helix,β-sheet,percentage of deeply bound water peaks and non-freezable water content of the noodles(P<0.05),and decreased the hydrophobic interactions,random coil,percentage of weakly bound water peaks and freezable water content of the noodles.Meanwhile,the effect of 3%TF on protein properties was similar to that of 0.6%sodium alginate,0.4%guar gum and 0.4%xanthan gum on the noodles respectively.The effect on water distribution was similar to that of 0.6%sodium alginate and 0.4%xanthan gum,and significantly greater than that of 0.4%guar gum.Tremella fuciformis can produce similar effects on noodles to the three hydrocolloids.(4)The effects of TF on the antioxidant capacity and digestive characteristics of noodles were investigated,and the flavor substances of different flours and fresh noodles were determined by headspace solid-phase microextraction-gas chromatography.The results showed that the addition of TF could significantly increased the scavenging rate of DPPH and ABTS radicals,increased the SDS and RS content and decreased the RDS content of the noodles to a certain extent.Meanwhile,61 flavor substances were detected in TF and 42 in wheat flour.The number of flavor substances increased from 39 to 56 after adding TF,and the ROAV value calculation showed that the number of flavor substances with ROAV≥1increased,and most of them were aldehydes,alcohols and esters with low threshold values,which contributed more to the overall flavor.Principal component analysis showed that the flavor substances of the TF-wheat noodles were different from those of the wheat noodles.So,the addition of TF was beneficial to enrich the flavor of fresh noodle products. |
