Comparative Analysis Of Main Nutrient Components Between Black And White Rice

Rice is an important energy source in people’s daily diet.With changes in dietary structure,people are paying more and more attention to the health functions of food.Black rice has attracted great attention due to its high health properties.In this study,30 black and 30 white rice grains planted under the same field conditions were used as materials.The content of crude protein,amino acid,crude fat,crude fiber,mineral elements,total ash and anthocyanin in black(whole grain,milled)and white(whole grain,milled)rice were determined by Kjeldahl determination of nitrogen,automatic amino acid analyzer detection,methanol methyl sulfate gas chromatography,medium filtration,direct ash method,atomic absorption method and high performance liquid chromatography.The main achievments of this study are as follows:1.The average content of crude protein,total amino acids,essential amino acids,crude fiber,and total ash in black and white brown rice significantly increased compared to the corresponding milled rice,and the average content of crude protein,total amino acids,essential amino acids,crude fiber,and total ash in black brown and milled rice also significantly increased compared to white brown and milled rice.2.The order of essential amino acids content in different types of rice samples was Leu> Val> Phe> Lys> Ile> Thr> Met.Grinding rice has the greatest impact on Lys content whether in black or white rice.The order of crude fat content in black brown rice was significantly higher than that in white brown rice,while there was no significant difference between black and white milled rice.The proportion of unsaturated fat acids in black and white brown rice was significantly higher than that in corresponding milled rice.In addition,the proportion of unsaturated fat acids in black milled rice was significantly higher than that in white milled rice,while there was no significant difference between black and white brown rice.3.The order of macroelements content in whole grain rice of different rice samples was P> K> Mg> Ca.The order of microelements content in whole grain rice of different rice samples was Mn> Zn> Fe> Cu> B> Mo> Se> Cr.The mineral element content in black and white whole grain rice was higher than that in corresponding milled rice.Grinding rice has a significant impact on the content of P,K,Mg,Ca,Mn,Fe,B elements,with Fe having the highest decline rate.The content of mineral elements such as P,K,Mg,Ca,Zn,B,Se in black rice were more abundant than that in white rice.Except for a few cases where the Cd content in black brown rice is slightly higher,the content of other harmful elements(As,Pb,Hg)in all types of rice samples is lower than the national limit requirements.4.We only detected anthocyanin in black whole grain rice,and there were significant differences in anthocyanin content among different varieties of black whole grain rice.The correlation analysis between the content of various nutritional components in black whole grain rice indicated that the content of anthocyanin was significant positively correlated with crude protein,methionine,isoleucine,leucine,phenylalanine,crude fiber,total ash,Mg,Zn,B content,but not with fatty acid.There was a significant positive correlation between the content of total ash and P,K,Mg,Fe,Zn,Cu,B.There was a highly significant positive correlation between the content of P and K,Mg,Fe,Zn,and also a highly significant positive correlation between the content of Zn,Cu,Mn,B.This study measured the content of crude protein,amino acids,crude fat,crude fiber,total ash,mineral elements,and anthocyanins in black and white rice.We find that the nutritional value of brown rice is higher than that of milled rice.At the same time,black brown rice not only has higher levels of various nutritional components,but rich in anthocyanins,which is more beneficial for human health.