Quality Change Mechanism Of Different Wheat Varieties Frozen Noodles During Processing And Storage

In recent years,with the improvement of people's living standard,People's demand for convenience,nutrition and health food has been getting higher and higher.Frozen noodle is a new type of quick frozen staple food,which has been quickly cooled when it's in the best edible state,and than into frozen storage.Because of its complex process such as cooking,freezing,storage,it was necessary to conduct in-depth study on the selection of raw material properties,the energy consumption of the production process,the mechanism of quality change during storage.Firstly,30 kinds of Wheat were selected.Physical and chemical indexes,powder properties,pasting properties were determined after milling.According to the quality index of frozen noodles,the method of principal component analysis and cluster analysis was used to study the related requirements of frozen noodles.Then,the production process and the improvement agent were optimized from the energy consumption and quality point of view.The quality change rule and mechanism of frozen noodles during frozen storage were analyzed.The results obtained are as follows:(1)The correlations of TPA hardness,shear strength,tensile strength and RVA characteristics,friability and tensile properties of frozen noodles were analyzed.TPA hardness had a significant positive correlation with wet gluten content of wheat flour and the maximum tensile ratio of wheat flour,and was positively correlated with the tensile curve area and the tensile resistance and elongation in the tensile properties,Which was negatively correlated with the maximum tensile resistance and the gelatinization temperature in the tensile properties,and had a significant negative correlation with the peak viscosity,underestimation viscosity and final viscosity.There was a significant positive correlation between the shear strength and the wet gluten content,the water absorption in the RVA,the dough formation time,the tensile curve area,the tensile resistance,the elongation,the stretching ratio and the maximum drawing ratio.Which was negatively correlated with the protein content and the silty quality index,and had significant negative correlation with the total starch content,the final viscosity in the RVA characteristics,the recovery value and the maximum tensile resistance in the tensile properties.The peak viscosity,the lowest viscosity was significantly negatively correlated.The results showed that the dough strength,the protein content,the wet gluten content,the amylose content,the water absorption in the RVA,the dough formation time,the degree of weakness,the silty quality index,the tensilecurve area,the tensile properties Tensile resistance,elongation,ratio of stretching and maximum stretching ratio were extremely significant positive correlation,which was negatively correlated with the total starch content,the peak viscosity,the lowest viscosity,the final viscosity,the recovery value and the maximum tensile resistance in RVA.(2)By using principal component analysis(PCA),the influence factors were simplified.According to the 5 factors of the extraction rate of variance can be 84.023% information of the original variable.Factor 1 dominated the index : silty curve stability time,dough formation time,degree of weakening,silty quality index,tensile curve area,tensile resistance,maximum tensile resistance,stretching ratio,maximum stretching ratio;Factor2 dominated the index : starch,peak viscosity,final viscosity,underestimated viscosity,recovery value,peak time;Factor 3 dominated the index: protein,wet gluten,extension;Factor 4 dominated the index: starch,dilute slack value,peak time and water absorption;Factor 5 dominated the index: amylose,gelatinization temperature.We established a linear TPA hardness,shear strength,maximum tensile force of the regression model.Then,based on the principal component analysis,5 factors were extracted,the score matrix was the explanatory variable,and the variety did the cluster analysis,and the conclusion was drawn.Curve of stability for a long time,Variety which has high farinograph quality index,maximum tensile resistance,tensile resistance,tensile ratio,maximum tensile ratio and dough formation time value,and the peak viscosity,low viscosity,final viscosity and setback,was more suitable for frozen noodles.That is,the characteristics of high-quality silty powder,starch gelatinization characteristics of wheat flour is more suitable for the production of frozen noodles.The fourth category of wheat varieties than the other three types suitable for the production of frozen noodles.(3)From the point of energy consumption,based on texture and sensory evaluation,the production process of frozen noodles was optimized from the aspects of whiteness,pasting properties,and water existence status.The Energy saving processing technology was cook3 min,heat preservation treatment 4min,freezing temperature-40 C,freezing time20 min.The difference in color,taste,smoothness,taste,appearance were not significant,but there were differences in the toughness,viscosity.The whole process could save 22.4% energy,Which achieved the purpose of energy saving under the condition of ensuring the quality.(4)The effects of sodium polyacrylate,sodium alginate and sodium alginate on the energy consumption and the quality of frozen and cooked noodles were studied in three kinds of hydrophilic colloids.Three kinds of hydrophilic colloids could significantly reduce the pasting temperature,reduce energy consumption,and improve the quality of the structure.On the basis of the pasting temperature and sensory evaluation,the best combination was polyacrylate 0.13%,xanthan gum 0.86%,sodium alginate 0.18%.(5)During the storage,the whiteness,cooking characteristics,texture characteristics,sensory scores decreased with the increase of time,and the freezing water content and dry rate increased.The structure of gluten network and the changes of the size of the alcohol soluble protein and the structure of the two stage were analyzed.With the extension of storage time,increase of freezing thawing times,gluten network structure is damaged,the gliadin particle size decreases,alpha helix and beta two secondary structure folding,molecular cluster beta folding,antiparallel beta and beta folding angle were changed.The freezing thawing effect was greater than the frozen storage.