Effect Of Defatting And Deproteinization On The Structure,Properties And Their Relationship Of Early Indica Rice Flour

Rice is one of the main food crops in China,and it is widely planted in the southern region.However,as a staple food grain,early indica rice has poor palatability and low comprehensive utilization,and its processed product is single.Early indica flour is composed of starch,lipid and protein,and its physicochemical properties are greatly affected by the compositions.In order to provide scientific basis for early indica rice processing enterprises to develop rice flour foods,the effects of defatting and deproteinization on the structure and physicochemical properties of early indica rice flour were investigated in the thesis.The main research results are as follows.(1)A scanning electron microscope(SEM),a particle size analyzer,an X-ray diffractometer(XRD and a Fourier infrared spectroscopy(FTIR)were used to analyze the effects of water-saturated n-butanol defatting and alkaline deproteinization on the structure of early indica rice flour.The results showed that defatting had no significant influence on the particle morphology,particle size,crystal structure and chemical functional groups of early indica rice flour;deproteinization made the surface of early indica rice flour more regular and smoother,and reduced the particle size,but it did not change the A-type crystal structure of the rice flour,and did not produce new characteristic peaks of functional groups.(2)By measuring the solubility and swelling power of the sample,and using a rapid viscosity analyzer(RVA)and a differential scanning calorimeter(DSC)to analyze the effects of defatting and deproteinization on the pasting properties and gelatinization characteristic parameters of the early indica rice flour,respectively.The results showed that defatting reduced the peak viscosity,final viscosity,retrogradation value and disintegration value of the early indica rice flour in the pasting process by 56.7%,64.8%,75.8%and 91.3%,respectively;deproteinization reduced the peak viscosity,final viscosity,retrogradation value and disintegration value by 8%,33.7%,47.8%and 33.6%,respectively;the initial temperature,peak temperature and enthalpy value of the early indica rice flour increased significantly after defatting and deproteinization.(3)A rheometer was used to analyze the static shear rheologicai properties and dynamic rheological properties of the early indica rice flour paste and investigate the effects of defatting and deproteinization on the rheological properties of the early indica rice flour paste.The results of static rheology showed that both defatting and deproteinization decreased the consistency coefficient k of the early indica rice flour paste,increased the yield stress σ0 and fluid index n weakened the pseudoplasticity of the early indica rice flour paste system,and made it more difficult to shear thinning.The dynamic rheological results showed that the G’and G"of the early indica rice flour paste increased continuously after defatting and deproteinizing,,tending to the starch system,forming a gel,and the elasticity characteristics were greater than the viscous characteristics.(4)The effects of defatting and deproteinization on the digestion characteristics of early indica rice flour paste were investigated by in-vitro digestion method.The results showed that defatting and deproteinization significantly increased the digestion rate and rapidly digestible starch content of the early indica rice flour,decreased the slowly digestible starch content,but had no significant effects on the resistant starch content,and the influence of deproteinization was greater than defatting.The results indicate that defatting and deproteinization can improve the digestibility of early indica rice flour.