Determination of the mineral composition of Brazilian rice and evaluation using chemometric techniques

Abstract

The mineral composition of Brazilian rice samples was determined and the data obtained were evaluated using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Nineteen commercial rice samples were analyzed, six being brown, seven parboiled and six white. The elements were determined employing inductively coupled plasma optical emission spectrometry (ICP OES), and the accuracy was confirmed using a certified reference material of rice flour. The PCA showed the formation of three clusters: a group with the brown rice samples, other with the parboiled rice samples and another of the white rice samples. PCA also showed that the brown rice samples are richer in minerals than the white and parboiled rice samples. Calcium, sodium, zinc and manganese in white rice samples are higher than in parboiled rice samples, while the parboiled rice has higher contents of iron, magnesium, strontium, potassium and phosphor. HCA also demonstrated formation of three major groups, confirming the results obtained by PCA. Application of HCA in the subgroups of rice samples clearly showed separation of rice brands and also separation between the raw and cooked samples. The mineral composition in the rice samples analyzed agrees with data reported by other authors. This paper revealed that the mineral compositions for white, brown and parboiled rice are significantly different.