Heavy Metal Contents in Dfferent Bran Layers of Rice

미곡중(米穀中) 도정부위별(搗精部位別) 중금속함량(重金屬含量)

Contents of heavy metals in various bran layers of rice collected from Kyeong Nam province in 1978, were determined. The components of crude prote in, crude fat, crude cellulose, and ash in all the rice samples were found to be most concentrated in the rice of each layer of brown, 70% polished, and 90% polished, but the contents of crude protein (9.22%), crude fat (1.16%), crude cellulose (1.01%), and ash (0.38%) in polished rice decreased rapidly. On the other hand, the amounts of nitrogenfree extract in the rice were showed increasingly toward the inner layer and those of polished rice were 75.54%. The contents of lead, zinc, nickel, cadmium, and arsenic in bran layer of rice decreased in order of that of 90% polished, 70% polished, brown, and polished rice. Their amounts in polished rice were lead, $0.054{\sim}0.610ppm$; zinc, $9.830{\sim}19.093ppm$; nickel, trace-1.776ppm; cadmium, trace-0.039ppm; arsenic, ND-0.170ppm. It was shown that copper was more concentrated in the layer of 90% polished rice $(0.581{\sim}1.476ppm)$, and iron more in brown rice $(27.971{\sim}66.569ppm)$ than in any other portion, whereas mercury $(0.006{\sim}0.072ppm)$, chromium $(1.538{\sim}7.822ppm)$, and manganese $(57.371{\sim}179.252ppm)$ were much contained in the layer of 70% polished rice. Their amounts in polished rice were copper, $0.218{\sim}0.858ppm$; iron, $1.480{\sim}9.573ppm$; mercury, $0.006{\sim}0.027ppm$; chromium, ND-1.520ppm; and manganese, $6.730{\sim}11.562ppm$.

경남지방의 일원에서 1978년도에 생산된 밀양계통의 미곡중에 함유되어 있는 일할성분과 중금속의 함량을 부위별로 분석한 결과는 다음과 같다. 1. 미곡중 조단백, 조지방, 조섬유, 회분은 대부분 현미층, 7분도층, 9분도층에 분포되어 있으나 백미에서는 그 함량이 급격히 줄어 조단백 9.22%, 조지방 1.16%, 조섬유 1.01% 그리고 회분이 0.38%로 감소하는 반면 가용성무질소물은 미곡의 심부로 갈수록 많은 양을 함유하여 백미에서는 75.54%이었다. 2. 납, 아연, 니켈, 카드뮴, 비소는 9분도층>7분도층>현미층>백미 순으로 그 함량이 감소하였으며, 백미에서는 납 0.258ppm$(0.054{\sim}0.610)$, 아연 14.209ppm$(9.830{\sim}19.063)$, 니켈 0.838ppm$(trace{\sim}1.776)$, 카드뮴 0.019ppm$(trace{\sim}0.036)$, 비소 0.072ppm$(ND{\sim}0.170)$으로 함량이 급격히 줄었다. 3. 구리의 함량은 9분도층$(0.851{\sim}1.476ppm)$, 철은 현미층$(27.971{\sim}66.569ppm)$, 수은$(0.006{\sim}0.027)$, 크롬$(1.538{\sim}7.822ppm)$및 망간$(57.371{\sim}179.252ppm)$은 7분도층에서 각각 가장 많았으며, 백미에는 구리 0.504ppm$(0.218{\sim}0.858)$, 수은 0.011ppm$(0.006{\sim}0.027)$, 크롬 0.558ppm$(ND{\sim}1.520)$, 철 5.125ppm$(1.480{\sim}9.573)$이었다.