Study On The Gelatinization And Drying Characteristics Of Porridge Rice And The Optimization Of Production Process

In this project,in order to lay the foundation for industrial production of the instant rice congee,the pretreatment of cooking conditions,drying methods and gelatinization characteristics of the instant rice congee were mainly studied,moreover,the production process of the instant rice congee was optimized,and finally the instant rice congee product was prepared,which has the good quality and was close to the fresh rice congee after rehydration.In order to improve the quality of instant rice congee,the effects of different pretreatment methods on the gelatinization characteristics of rice congee were studied,and the production process was optimized.Firstly,the optimal parameter combination of enzyme treatment was determined by single factor experiment and orthogonal experiment was addition amount of ?-amylase was 0.1%,solid-liquid ratio was 1:2 g/mL,enzymatic hydrolysis time was 40min,the IBV was 0.181,and the sensory score was 84.3;Through single factor experiment and orthogonal experiment,the optimal parameter combination of ultra-high pressure treatment was that the pressure was 250MPa,the pressure-holding time was 15min,solid-liquid ratio was 1:4 g/mL,the IBV was 0.463 and sensory score was 94.5.Through response surface experiment,the optimal parameter combination of ultra-high pressure synergistic enzyme treatment was the enzymatic hydrolysis temperature was 60?,pH 6.0,addition amount of ?-amylase was 0.09%,solid-liquid ratio was 1:3 g/mL,enzymatic hydrolysis time was 50min,the pressure was 220MPa,and the pressure-holding time was 17min,the IBV was 0.597 and sensory score was 95.6.Under these conditions,the IBV of congee rice was 0.597,and the sensory score was 95.6,which were higher than those of enzymatic treatment and ultra-high pressure treatment.To study the effects of different cooking methods on the gelatinization characteristics of congee rice,and the production process was optimized.The conventional cooking conditions were determined by single factor and orthogonal experiments was solid-liquid ratio was 1:3 g/mL,cooking temperature was 100? and cooking time was 16min.Under these conditions,the IBV of congee rice was 0.651 and the sensory score was 96.3.The microwave cooking conditions were determined that solid-liquid ratio was 1:15 g/mL,microwave power was 450W,microwave time was 16min.Under these conditions,the IBV of congee rice was 0.532 and the sensory score was 93.2.In order to improve the quality of instant porridge,the effects of different drying methods on the drying characteristics of instant porridge were studied with rehydration rate,rehydration time and alkali dissipation value as indexes,and the production process was optimized.Through single factor and orthogonal experiments,the optimal parameters of hot air drying were determined as follows:material volume was 15g,material thickness was 1cm,drying temperature was 80?.Under these conditions,the rehydration rate were 2.59,rehydration time were 15min and alkali elimination value were 6.30.The optimum parameters of microwave vacuum drying were determined by single factor and orthogonal experiments as follows:material volume of 15g,microwave power of 1.6kW,vacuum degree of-80kPa.Under these conditions,the rehydration rate was 2.49,rehydration time was 15min and alkali elimination value was 6.49.Taking into account the comprehensive analysis of drying effect,drying efficiency and the influence of rice grain structure,the best drying method of instant rice congee was determined to be hot air drying.In order to make the state of instant porridge closed to fresh rice congee after rehydration,single factor and orthogonal experiment were conducted to study the effect of single addition and compound of different quality improver on the quality of instant porridge.Through single factor and orthogonal experiment,the optimal ratio of quality improver was as follows:CMC 0.07%,xanthan gum 0.13%,guar gum 0.07%,sucrose ester 0.10%,potato starch 6%,maltodextrin 20%,white granulated sugar 8%.Under these conditions,the sensory score of instant porridge was 95.3 and the viscosity was 1125cP.The instant porridge added in accordance with the formula when rehydrated that had a moderate consistency and a smooth feeling,which was close to fresh rice porridge.The instant rice porridge prepared by the optimal process had short rehydration time,similar flavor and taste to traditional rice congee,and moderate hardness,elasticity,masticability and cohesion,which was close to fresh rice porridge.