关键词: 营养元素, 大米, 加工精度, X射线光电子能谱

Abstract:

This study was performed to examine the distribution profiles of nutrient elements in rice. Rice grains of the
cultivar Longjing 40 were processed to different grades according to the staining method in the Chinese national standard
GB/T 5502—2008. A total of 17 kinds of nutrient elements in rice with different processing levels were determined by
inductively coupled plasma mass spectrometry (ICP-MS) and quantitative analysis of the elements on the surface, near the
surface, near the core, and in the core of rice caryopsis was conducted by X-ray photoelectron spectroscopy (XPS). The
results showed that the contents of 11 kinds of elements including Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Cu, Zn, Rb, Sr, Mo,
Cs and Ba differed significantly in different grades of rice (P < 0.01), and their loss rates varied across grades. The contents
of Na, K, Ca and Fe were different in different parts of rice grain, and their contents were higher on the surface than near
the core and in the core of rice caryopsis. On the other hand, the distribution of nutrient elements in the caryopsis was not
uniform, and rice processing may cause losses of the nutrient elements in different levels.

Key words: nutrient elements, rice, processing degree, X-ray photoelectron spectrometer (XPS)