Study On The Distribution And Rapid Determination Of Phosphorus And Iron Elements In Rice

Mineral elements play an extremely important role in human health,but with the improvements of material living standards and the changes in dietary structure,there are some problems such as lack of beneficial mineral elements in the diet.Rice is the main source of food for more than half of the world’s population.It is necessary to conduct a more detailed study on the distribution of beneficial mineral elements in rice and take the effective measures to improve its contents appropriately which could partly solve the above problems.Phosphorus(P)and iron(Fe)elements are the important mineral elements for the human body.Three varieties(lines)including Zhenong 8(long grain),Yuan 1(medium grain)and Zhenong 37(short grain)were selected for researching the milling characteristics and the distributions of P and Fe in brown rice.The present study also established the quantitative determination technique of P and Fe by using the brown rice flour and the rapid qualitative determination method of P and Fe by using the brown rice,respectively.The main results were as follows:1.Zhenong 8,Yuan 1 and Zhenong 37 brown rice were milled in 0～300 s,which the interval was 10 s.The results showed that there was a quadratic function relation between the degree of milling and the time of milling.With the increase of milling degree,the contents of P and Fe in rice for the three materials were all decreased.When the degree of milling reached 25%,the contents of P and Fe in rice was 740.73,799.18,1031.46 μg/g and 1.84,2.68,2.33 μg/g,and the loss rates were 61.21,55.59,52.78%and 91.25,88.07,90.22%for Zhenong 8,Yuan 1,Zhenong 37,respectively.It indicated that the distribution of both mineral elements in brown rice was not equidistribution.Fe was mainly in outer layer,while P was mainly distributed in outer and core endosperm layer of brown rice.Therefore,it is necessary to consider the influence of rice length on the milling degree,and choose appropriate milling time and milling degree during the milling process,which is beneficial to retain more beneficial mineral elements.2.In this study,hydrochloric acid extraction method and molybdenum ruthenium anti-chromogenic method were combined to determine P content of brown rice flour.Through exploring and optimizing the conditions such as extraction and color reaction,a quantitative determination technique for P content was established.The content of P was linear in 0-5.0 pg/ml with the linear regression equation of y=0.1529x+0.0091(R2=0.9994).Comparing this test with the national standard method and ICP-AES,although there were some differences among these results,the trends of P content in different materials stayed the same.At the same time,the quantitative determination technique of Fe content in rice flour was optimized by using the BPDS chromogenic method.The content of Fe was linear in 0-1.4 μg/ml with the linear regression equation of y=0.4420x+0.0087(R2=0.9991).Although the results of this test were different from those of FAAS,ICP-AES and ICP-OES,the trends were also consistent.Since the two rapid quantitative determination techniques proposed in this experiment have the characteristics of low cost,quick measuremnet,simplicity,convenience and effectivity,the precision can reach the requirements of rice breeding and can be used for the determination of mineral elements in the breeding process.3.This experiment created and improved a rapid determination method for P and Fe in brown rice,especially for single plant selection in the early generations.This method can qualitatively identify the contents of P or Fe in the brown rice without grinding powder so that one person could determine more than 200 samples per day.This method and technique can be directly used for rapid selection of large-scale rice germplasm resources and breeding intermediate materials to greatly improve the efficiency of rice functional breeding.4.532 rice materials from Hangzhou(187),Lingshui(266)and Nanning(79)were quickly screened for getting the materials with higher P or Fe by using the brown rice.47 rice materials with higher P(17,25 and 5 from Hangzhou,Lingshui and Nanning)were selected,which accounted for 11.06,9.09 and 6.33%,respectively.36 rice materials with higher Fe content were selected(11,19 and 6 from Hangzhou,Lingshui and Nanning),accounting for 7.14,5.88 and 8.86%respectively.These materials with higher P and Fe can be further used for rice production and nutrition breeding.