Effect Of Wheat Flour On The Quality Of Frozen Cooked Noodles During Freezing And Storage Process

Wheat flour is one of the main raw materials for making frozen cooked noodles,and the characteristics of wheat flour in different cultivars are different.Study on the relationships between wheat flour and the quality changes of frozen cooked noodles are of great practical significance to improving the quality of frozen cooked noodles during freezing and storage process.The winter wheat flours in Henan Province were collected as the experimental material.The characteristics of wheat flours were studied with the FOSS 2300 automatic Kjeldahl apparatus and the rheology properties,and RVA indices were also determined.The texture indices and microstructures and some other indices were measured after the flour was made into frozen cooked noodles.This article consists three parts:(1)to investigate the relationship between wheat flour quality and texture characteristics of frozen cooked noodles in different wheat cultivars;(2)to study the effect between wheat flour and the quality of frozen cooked noodle in different freezing temperatures;(3)to study the effect of wheat flour quality and the quality of frozen cooked noodles in frozen storage.The main conclusions are as follows:(1)Relationships between the wheat flour variety and the texture properties of frozen cooked noodles were investigated by descriptive statistics and principal component analysis(PCA).Based on the scree plot and the contribution rate of variance,5 principal components were extracted by the principal component analysis,which could reflect 84.023% of the information of original variables.The variance contribution rate of rheology properties and RVA indices in wheat flour was 55.254%,which could be concluded that these two factors were the main factors affecting the quality of frozen cooked noodles.Hierarchical cluster analysis(HCA)classified 30 varieties into 4 main groups on the basis of the measured parameters,which was consistent with the result of PCA score plots.The results of clustering of wheat flour reflected that the difference in different varieties of wheat flour quality in a certain extent,and there were significant differences among the four kinds of wheat flour in the frozen cooked noodle texture(P < 0.05).(2)Four kinds of wheat flours with different indexes were selected.After freezing in different temperatures(-20??-30? and-40?),freezing curve,freezing water loss rate,microstructure and texture characteristics of frozen cooked noodles made by these four wheat flours were determined.It was found that with freezing temperature lower,the freezing rate was getting faster.The cooked noodles cost shorter time through the largest ice temperature range,and the frozen cooked noodle dehydration rate during freezing was lower.The ice crystals were decreased in quantity and small volume formed inside the frozen cooked noodles.In the condition of the same freezing temperature,the structure of frozen cooked noodles made by wheat flour with better index of powder quality was more compact,and the pore size of ice crystals were smaller,as well as better texture properties in frozen cooked noodles.(3)Using the wheat flours chosen by(2)makes cooked noodles.Freezing the cooked noodles at-40 ?,and preserving them at-18?.The texture properties,broken rate,dry matter loss,turbidity and noodle sensory score,microstructure quality were investigated during the different preservation period.The study shows that,the ice crystals of frozen cooked noodles were getting larger and transferring their position from inside to the surface with the preservation time going on.The internal structure of frozen cooked noodles was destroyed,the drying rate increased,the micro structure was worse,the texture quality,cooking quality and sensory score were also decreased.At the same preservation period,there have been significant differences among the quality of frozen cooked noodles made by four kinds of wheat flour.The texture,microstructure and sensory score of the frozen cooked noodles made by wheat flour with better powder indexes were better than those of wheat flour with lower powder indexes.The characteristics of wheat flour had significant effect on the quality of frozen cooked noodles during freezing and frozen storage.In the actual production of frozen cooked noodles,we should pay attention to the the rheological characteristics of wheat flour used as noodle raw materials.At the same time,in order to enhance the strength of gluten structure of frozen cooked noodles,reducing the freezing temperature to increasing freezing rate to restrain smaller ice crystals,controlling the moisture migration in the frozen cooked noodles to reduce the ice volume structure damage.These measures can keep the original quality of fresh cooked noodles as much as possible.