| In this study,corn and oat whole flour are used as the main raw materials to produce composite extruded reconstituted rice with excellent mouthfeel and processing performance.SLG-30 experimental twin-screw extruder is used for extrusion.The physical and chemical properties of raw materials,rheological properties and texture properties of different modified corn flour before and after extrusion are studied.Response surface methodology is employed to optimize the extrusion process parameters,which provides a theoretical basis for the rapid selection of raw materials and production and processing of composite extruded reconstituted rice with multiple grains.The main research conclusions of this paper are as follows:(1)17 different varieties of corn was used as the main raw material,and the extrusion physical and chemical indexes such as protein,fat,amylose,gelatinization degree,color difference,water solubility,water absorption,swelling power and freeze-thaw stability of the product were taken as the research objects,and the microstructure was analyzed by electron microscope scanning.The results showed that twin-screw extrusion had a very significant impact on the nutritional components and quality characteristics of corn flour.The results showed that the average value of protein,fat,amylose,freeze-thaw stability,gelatinization degree,water absorption,water solubility and swelling power of different varieties of corn decreased by 11.31%,28.94%,5.1%,58.90%,88.62%,77.03%,73.57% and 87.51%,respectively.(2)A total of 12 different modification methods such as enzymatic modification,chemical modification and physical modification were used to modify commercial corn residue,and the recombinant rice was extruded.SMS Company TA.XT Plus Texture Analyzer carries out texture test on modified powder reconstituted rice,and selects the optimal modification method by taking the comprehensive score of principal component analysis as an index.The rheological properties of modified corn flour were tested by T.A.AR 1500 EX rotary rheometer.According to the correlation analysis of textural properties and rheological properties,a scheme for quickly detecting the suitability of recombinant rice raw materials was obtained.The results showed that through principal component analysis,the three principal components that have the greatest influence on the score can represent masticatory degree,viscoelasticity and retrogradation speed respectively.According to the final result comparison,the modified corn flour had the highest elasticity,viscosity-to-hardness ratio,chewing degree and rejuvenation speed of 564.08,11.75,19628 and 1.05,respectively.The taste was similar to that of commercially available rice.Correlation analysis shows that viscosity is the main factor affecting product score.The higher the viscosity,the higher the product score(.911**).Similarly,the correlation analysis of rheological properties shows that the complex viscosity,elastic modulus,viscous modulus and consistency coefficient are significantly positively correlated with the score(.834**).(3)Modified corn flour was used as the main raw material,oat whole flour was compounded,oat addition amount,moisture content,barrel temperature and screw speed were employed as the investigation factors,and the principal component score of the product was used as the response value to carry out a four-factor three-level response surface test,and the principal component score was used as the response value.According to the response surface result analysis,the order of influence of each factor on the product score is as follows: oat addition ratio>screw speed > barrel temperature > moisture content.The optimum processing parameters of reconstituted rice are: oat proportion 15.69%,moisture content 15.31%,extrusion temperature 77.90?,screw speed 126.72 r/min,and the theoretical principal component score is 4.62,closer to the marketed Wuchang rice,Golden Arowana,which has high production value. |
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