Study On Distribution And Processing Changes Of Arsenic In Brown Rice

Brown rice is rich in nutrients due to its intact bran layer.As consumers pay more attention to nutrition and health,the demand for whole grains such as brown rice is increasing.However,the previous studies found that rice is a plant,which is easy to accumulate arsenic element,the brown rice has higher content than white rice.Arsenic is a kind of non-metal toxic element that exists in large quantities in nature,the arsenic element in the soil is transported to the roots of plants in coordination,then gradually accumulates in the outer layer of grains.Therefore,the increased demand of brown rice in consumer can cause human have an excessive exposure of arsenic,which will accumulate in the body's various tissues and cause pathological changes.In particularly,the toxicity of arsenic is closely related to its species,such as inorganic arsenic toxicity is higher than organic arsenic significantly.Therefore,it is necessary to evaluate the arsenic content and species distribution in brown rice.Reprocessing of brown rice is a convenient and effective method to reduce the risk of arsenic intake.At present,many researches are devoted to finding a simple and efficient method to reduce arsenic in brown rice so as to promote it among consumers.In this study,the spatial distribution of arsenic element in brown rice was analyzed by using synchrotron radiation technique and experiments controlling different polishing degrees,with two common rice varieties,namely Dao Hua Xiang II?Japonica rice?and Ye Xiang You III?Indica rice?as the research objects.The distribution of arsenic in brown rice was analyzed by the separation and determination of biological components.The processing methods of soaking and fermentation were selected to explore the change and migration of arsenic in brown rice.The main findings are as follows:1.The distribution of arsenic in brown rice is not uniform.Experiments with different polishing degrees showed that when the polishing degree was 5%,the total arsenic content of Dao Hua Xiang II decreased by 25%.In addition,the arsenic species of rice bran and polished rice were detected,rice bran contains inorganic arsenic only and the proportion of inorganic arsenic in polished rice decreased by about 5%compared with brown rice material.The change trend of Ye Xiang You III was similar to that of Dao Hua Xiang II.The synchrotron radiation fitting image shows that arsenic was mainly distributed in the embryo of the grain and the region near the outer layer.2.The biological components content in two varieties of brown rice were different,and the starch content is the most significant difference?58.49%of Dao Hua Xiang II and 73.74%of Ye Xiang You III?.According to the analysis of the combination of arsenic with different biological components,the content of arsenic in the protein components is the highest?0.112 mg/kg in Dao Hua Xiang II and 0.066mg/kg in Ye Xiang You III?,which mainly is inorganic arsenic;the binding capacity of arsenic in starch is the lowest?0.026 mg/kg in Dao Hua Xiang II and 0.016 mg/kg in Ye Xiang You III?,Only very small amounts of organic arsenic were detected.The binding capacity of arsenic in different types of proteins is:albumin>globulin>glutenin>prolamin.It shows that the albumin protein has a strong binding ability with arsenic.3.Soaking and fermentation can effectively remove arsenic,particularly the inorganic arsenic.In the process of soaking,the maximum removal rate of arsenic element can reach 37.3%,the maximum proportion of inorganic arsenic was 80.9%.At the same time,the main edible part of brown rice and most of the nutritional elements?dietary fiber,vitamin B₁?can be retained and the taste of cooked brown rice after soaking also has obvious improvement.Fermentation process can remove more arsenic elements than soaking process,the maximum removal rate can reach 43.9%,the maximum proportion of inorganic arsenic was 87.4%.