Study On The Processing Technologies And Quality Improvement Of Extruded Rice Noodles

Extruded rice noodles, are mainly produced via a traditional wet process, which is conducted by extruding rice dough prepared from wet rice flour. In this paper, effects of rice materials, manufacturing process, and quality improvers on qualit y of extruded rice noodles which were made through dry process were studied.In the test of the influence of rice materials on the quality of rice noodles, 10 kinds of rice were obtained from different areas. Their physico-chemical properties mainly including amylose content, protein content, solubility, swelling power, pasting, thermal and rheological properties were tested. And also quality of rice noodles’ produced from them was evaluated in order to investigate the correlation between physico-chemical properties and rice noodles’ quality. Then materials’ optional criterion was established preliminarily. Results revealed that when amylose content was above 19.5 g /100 g, through viscosity was exceed 2041 c P, final viscosity was over 4380 c P, breakdown was below 720 c P and retrogradation degree was over 45%, the rice was rightly needed to produce extruded rice noodles. And also the evaluation of rheological properties was a supplementary method to choose materials. The gel- forming ability and visco-elastisity of rice gels which could be reflected by the storage modulus(G′) and loss modulus(G″) would be stronger if the rice was fit for the manufacturing of rice noodles.In the determination of process parameters, the water content of extruded materials, the screw speed, the screw temperature, and the steamed time of rice flour were selected as factors. The textural properties, cooking quality and sensory evaluation of rice noodles were analyzed to determine its’ comprehensive quality. Firstly, single factor experiments were conducted. Secondly, L9(34) Orthogonal experiment was performed to optimize the experiments’ results. Results indicated that the optimal processing conditions of rice noodles were: the moisture content of materials 39%, the screw speed 90 r/min, the screw temperature 80°C, the steamed time 13 min. Under the optimal conditions, the comprehensive quality of rice noodles was best, and its sensory score was 82.4 points.According to the characters of additives and the demand of improvement of rice noodles, single factor experiments were carried out firstly to investigate the influence of mung been starch, Canna Edulis Ker starch, gluten, guar gum and sucrose ester on the quality of extruded rice noodles. In order to clarify the mechanism, influences of different additives on the physico-chemical properties of rice flour were also measured. Then, on the basis of single factor experiments, orthogonal experiment was further conducted to determine the optimal ratio of the composite improver. Results showed that the formulation of the composite improver was mung been starch 5.5 g/100 g, Canna Edulis Ker starch 3 g/100 g, gluten 4 g/100 g, guar gum 0.3 g/100 g and sucrose ester 0.25 g/100 g. O verall acceptability of rice noodles’ quality was increased a lot, and the sensory score was increased to 92.4 points through improvement.