Processing Technology And Quality Analysis Of Potato Noodles

In 2015,China officially launched a strategy for potato staples potatoes,which means that potato is added to daily staple foods such as noodles,steamed bread and rice and it becomes the fourth major grain crops besides rice,corn and wheat.Because potatoes do not contain gluten protein,there are some problems such as low potato addition,difficult molding of the noodles and easy to make the soup turbid during the processing and cooking of noodle.Premna microphylla Turcz is rich in pectin,which is a natural green gelling agent and added to potato noodle.It is intended to increase the amount of potato powder in noodle,enhance the sensory quality,cooking,texture property and nutritional value of noodles,which lay a certain theoretical and applied basis for the industrialization of high content and high quality noodle production of potato.The main research results of this thesis are as follows:(1)The single factor and Box-Behnken experimental design,response surface analysis(RSA)and principal component analysis(PCA)were used to optimize the processing technology of potato noodles.The results showed that the first to third principal components cumulative percentages contribution was86.10%,which could be sufficient to reflect the quality of noodles with comprehensive response of the texture indexes,sensory,cooking loss rate and dry matter water absorption rate.The regression coefficient of the two polynomial regression model established by principal component analysis was significant,and had better fit degree(p<0.0001,R~2=0.9699).Partial least squares regression analysis predicted that the best process parameters for comprehensive score was 31%of potato granules,9%of Premna microphylla Turcz juice,31 min of fermentation time,25?of fermentation temperature.The theoretical value of comprehensive scoring was 0.9194.The actual measured value was 0.9116 which was consistent with the model predicted value.The potato noodle prepared under this condition was smooth and elastic,and the breaking rate was 0.(2)The drying process of potato noodle processed under the optimum process recipe was also studied.The drying temperature had different effects on cooking quality and texture characteristics of potato noodle.The results showed that when the drying temperature was between 40?and 60?,the dry matter absorption rate of potato noodles showed a downward trend.And when the drying temperature was between 60?and 90?,the dry matter absorption rate increases with drying temperature.In the range of 40?to 60?,the hardness,resilience,chewiness,viscosity and elasticity of potato noodles increased with the increase of drying temperature then decreased when the drying temperature between 60?and 90?.When the drying temperature is about 60?,the potato noodle gluten protein has a good grid structure,strong gluten strength,high hardness,and a low cooking loss rate of 2.257%.In general,the potato noodle has good quality under this temperature.(3)The wet gluten content,farinogram properties,viscosity properties and scanning electron microscope picture of potato powder with wheat flour which added Premna microphylla Turcz leaves juice or not were also analyzed.The results exhibited that,with the increase of the amount of potato powder,the content of wet gluten in potato powder-wheat flour mixture powder gradually decreased,the formation time and stability time decreased significantly(p<0.05),and the degree of weakening gradually increased.When the addition amount of potato powder was in the range of 0 to 30%,the addition of Premna microphylla Turcz leaves juice had a certain prolonging effect on the potato powder and wheat flour mixture.The stability time was prolonged from 1.34min to 1.41min when the total potato powder was added at 30%,and the degree of weakening decreased from 233.22FU to 214.85FU.The peak viscosity,retention viscosity,final viscosity,disintegration value and retrogradation value of potato powder-wheat flour mixture powder without addition of Premna microphylla Turcz leaves juice were significantly decreased with the increase of total potato powder(p<0.05).The viscosity and final viscosity of potato powder-wheat flour mixture powder were all increased after adding Premna microphylla Turcz leaves juice.The scanning electron microscope images showed that the exposed starch granule decreased and the mesh structure was improved after the potato dough was added in 9%of Premna microphylla Turcz leaves juice.Premna microphylla Turcz leaves juice has a certain improvement effect on mixed powder dough.(4)As compared with the common noodles,the potato noodle obtained from the optimum process technology had the following characteristics:the hardness,chewiness,spring and sensory score were significantly increased(p<0.01),the total reducing power of potato noodles,ABTS~+·clearing power and total antioxidant capacity FRAP were all significantly increased after in vitro simulated digestion(p<0.05),the highest ABST~+·removal rate was 82.95%,which was significantly higher than that of common noodles(76.57%),the FRAP value of potato noodle reached 0.22 mmol/L in simulated mouth stage,which was 1.83 times that of common noodles,it also had higher content of dietary fiber which was 37%more than that common noodles,and had lower fat content.These date suggested that he nutritional and health value of potato noodles was higher than that of ordinary noodles.