Study On Blended Rice Selection And Processing Technology Of Fresh Rice Noodles

Fresh rice noodle,as the traditional staple food in southern areas of China and the most consumed rice product,is very popular because of its' smooth and powerful texture and convenience.In order to expand the range of raw materials for fresh rice noodle and improve the product quality,the different proportions of blended rices were determined based on the establishment of quality prediction model of fresh rice noodle.The rice noodles were prepared from the different proportions of blended rices.The quality prediction model of fresh rice noodle was verified and optimized,and the blended rices were screened out.In addition,the processing thechnology of fresh rice noodle prepared from blended rice was optimized in the further study.The main research contents and results are as follows:1.Study on establishment of quality prediction model and selection of raw materials for fresh rice noodleThe sliced fresh rice noodles were prepared from 18 cultivars of collected rices.The main components and pasting properties of the raw materials were determined,as well as the cooking,flavor infiltration,sensory and texture quality of fresh rice noodles.The quality indexes of rice noodles were analysed and a comprehensive evaluation model of rice noodles quality was established by principal component analysis.The comprehensive scores calculated by the comprehensive evaluation model of rice noodles were classified by cluster analysis,and the five cultivars of rices which are suitable for processing fresh rice noodles were screened out.On this basis,the key indicators affecting the comprehensive quality and the quality prediction model of fresh rice noodles were determined by stepwise regression analysis.The key indicators were amylose content and final viscosity.And the quality prediction model of fresh rice noodles was obtained as follows: Y_{comprehensive score ofrice noodles}=0.181X_{amylose content}+0.0013X_{finalviscosity}-8.578?R²=0.926?.The threshold range of amylose content and the final viscosity should be higher than 26% and 3566 Pa�s,respectively,combined with the result of clustering analysis.2.Study on blended rice selection for fresh rice noodlesThree kinds of rices,Zhenguiai with the highest final viscosity,Zhuliangyou 39 with the highest amylose content and Jinsui 128 with the lowest amylose content and lower final viscosity,were selected.The three cultivars of rices were blended according to the 21 mix proportion schemes based on statistical SAS lattice design.The fresh rice noodles were prepared from the 21 kinds of blended rices,and the actual measurement value of comprehensive scores of rice noodles were calculated according to the comprehensive evaluation model based on the determined individual quality indicators of fresh rice noodles.The established quality prediction model of fresh rice noodles was validated and optimized by using the characteristics of raw materials and actual measurement value of comprehensive scores of products.It has been proved that the established quality prediction model could also be applied to the quality prediction of rice noodles processed by blended rice.The optimized quality prediction model of fresh rice noodles was obtained as follows: Y_{comprehensive score ofrice noodles}=0.188X_{amylose content}+0.0013X_{finalviscosity}-8.627?R²=0.949?,and the correlation coefficient increased from 0.926 to 0.949.Combining the actual measurement value of comprehensive score and the quality prediction model of rice noodles,the threshold range of key indexes of blended rice for fresh rice noodles was determined: the amylose content was higher than 26%,the final viscosity higer than 3566 Pa s;or the amylose content was between 24% and 26%,and the final viscosity was higher than 4319 Pa�s.Besides,when the ratio of Zhenguiai and Zhuliangyou 39 was 3:2,the comprehensive score of rice noodles was the highest,which was 3.84.3.Study on processing technology of fresh rice noodles prepared from blended riceBy using the blended rice of Zhenguiai and Zhuliangyou 39 mixed in a ratio of 3:2 as raw material and the comprehensive score as the evaluation index,the impacts of soaking temperature,soaking time,grinding particle size and steaming time on fresh rice noodles quality were studied.On the basis of single factor tests,orthogonal experiment was used to study the optimum process conditions.The results indicated that the degrees of process parameters on fresh rice noodles quality were steaming time > grinding particle size > soaking time > soaking temperature.The influences of steaming time and grinding particle size on quality of fresh rice noodles were extremely significant.The optimum process conditions were as follows: soaking temperature 20 ?,soaking time 3 h,grinding particle size 100 mesh sieve and steaming time 100 s.Under the above-mentioned optimum conditions,the comprehensive score of fresh rice noodles was 5.36.