Application of ICP-OES to determine the mineral element content of wheat flour with different processing precisions

ObjectiveUnderstanding the differences in mineral content in wheat flour under different processing precisions can guide the production of wheat flour processing industry and also help guide the adjustment of residents’ daily dietary structure.MethodsWheat samples from 13 planting sits in Shaanxi Province were collected and processed into whole wheat flour， special flour and wheat core flour. Inductively coupled plasma emission spectrometry （ICP-OES） was used to determine the mineral content， the index of nutritional quality （INQ） was used to evaluate the mineral elements， and analyze the variance and correlation of nine minerals in wheat flour with different precisions.ResultsThe nine minerals in the three types of wheat flour showed different downward trends， there were the largest declines of Mg， Mn and Zn， and the total amount of minerals of three wheat flours were 959， 341 and 300 mg/100 g. The analysis of variance showed that there was a significant difference between the minerals in whole wheat flour and the latter two （P<0.05）， but there was no significant difference between the special flour and wheat core flour （P>0.05）. The results of INQ method showed，with the change of machining accuracy， the INQ values of the corresponding elements decreased， and the INQ values of some elements decreased to less than 1， but the INQ values of Mn and Cu in wheat core flour were still greater than 1. The correlation analysis showed that there was a significant negative correlation between the processing accuracy and the nine minerals （correlation coefficient： -0.615--0.884）. There were different degrees of positive correlation among the nine elements， and the correlation coefficient between some elements was >0.9， indicating that the variability of mineral content converged.ConclusionThis study shows that deep processing will cause the loss of minerals in wheat flour， and the development of safer， healthier， delicious and better whole wheat flour is the direction of the development of whole grain industry.