Zinc In Rice Research Articles

Evaluating baseline data for copper, manganese, nickel and zinc in rice, yam, cassava and guinea grass from cultivated soils in Nigeria

Soil samples and leaves and grains of rice ( Oryza sativa), yam ( Dioscorea esculenta), cassava ( Manihot esculenta) and guinea grass ( Panicum maximum) were systematically collected in September 1992, during the rainy season from tilled/cultivated farms in Abakaliki urban, certain rural communities, and a derelict PbZn mine in Nigeria. The samples were analysed for their concentrations of the essential trace elements copper, manganese, nickel and zinc. The investigated soils consisted mostly of loamy, clay-loamy and clayey soils with mean soil pH of 5.9, and mean organic matter content of 6.7%. The phytoavailability of the trace elements generally corresponded to their soil concentrations. The phytoavailability of the trace elements investigated depended on their speciation rather than on total soil concentrations. This was illustrated by the fact that the elemental concentrations in all the plant parts decreased in the order: Mn > Zn > Cu > Ni; whereas in the soils, the order was Mn > Zn > Ni > Cu. The best indicator plant species in the studied areas were grass (Cu), yam leaves (Cu, Ni), rice leaves (Mn), rice leaves and grains (Ni), and cassava leaves (Zn).

Simultaneous Quantitative Determination of Manganese, Iron, Copper and Zinc by Atomic Absorption Spectroscopy in Tropical Cereals, Fruit and Legume Materials

ABSTRACTA method for the simultaneous quantitative determination of manganese, iron, copper and zinc in rice, corn, cassava, black beans, lettuce, mango, papaya, pineapple, medlar, bananas and melon by atomic absorption spectroscopy was developed by using a mixture of concentrated nitric acid‐sulphuric acid (2:1 v/v) and by adding hydrogen peroxide for sample digestion. The precision varied between 1–10%. The accuracy was ascertained by analyzing five biological standard reference materials from the National Bureau of Standards (NBS, Washington, ‐DC. 20234 USA) and no significant difference could be established between the certified values and those present in this study. Additionally, the results obtained by the presented method were compared with those obtained by X‐ray fluorescence spectrometry in a different laboratory.

Characterization of Zinc Components on in vitro Enzymatic Digestion of Foods

ABSTRACTBeef and polished rice were subjected to in vitro digestion and the soluble zinc components separated by gel filtration. Approximately 30% of beef zinc was solubilized by digestion; and more than 30% of rice zinc was solubilized. Most of the soluble zinc was found in one or two proteinaceous components with molecular weight of 1,270‐5,130 dalton. Amino acid analyses showed that these proteinaceous components were high in the acidic amino acids and glycine, and low in L‐histidine. These findings suggest that these proteinaceous components, as they combine with zinc, may increase the amount of soluble zinc.

Cadmium, copper, and zinc in rice produced in Java

Cadmium (Cd), copper (Cu) and zinc (Zn) contents in 116 polished and unpolished rice samples produced in the Java Islands of Indonesia were assessed as a base-line study of trace metals. Arithmetic means and one standard deviation were 0.040 +/- 0.042 ppm Cd, 2.93 +/- 1.11 ppm Cu, and 18.17 +/- 3.13 ppm Zn. Concentration ratio of Cd to Zn was 0.00220 +/- 0.00222. The correlation coefficients between the metals were low. The two highest samples of rice contained 0.27 and 0.34 ppm Cd. Using the fact that Indonesians consume about 300 g of rice, the daily intake of Cd would exceed the tolerable limit proposed by FAO/WHO and could cause slight chronic renal damage to the rice eaters. Soil type by suborder and rice variety gave little difference of the three metals content in rice. Rice samples from West Java, where major soil type by order is Ultisol, contained higher cadmium and zinc, and lower copper than those from East Java (Vertisol).

Ribonuclease activity as an index of hidden hunger of zinc in crops

The activity of RN-ase at zero zinc level was found to be 2, 173-1 and 2 times higher in all the varieties of rice (Jaya and HM484) and Maize (Ganga 5 and Vijay) than that of 5 ppm zinc at 15/20 days, 30/40 days and 45/60 days growth stages respectively, but the difference in the zinc content of leaves between two treatments was not found to be significant except that of 30/40 days growth stage. Similarly the potash content in both the treatments did not vary, but the dry matter production of whole plant and protein content of leaves except 15/20 days growth stage varied significantly. The data suggest thirty ppm P released per 100 μg protein per hour (RN-ase activity) could be taken as threshold value above which hidden deficiency at an early growth stage is detected. Also an average concentration of 27 and 25 ppm zinc in rice and maize leaves respectively could be taken as critical limit for zinc deficiency at their 15/20 days of growth respectively. On the basis of RN-ase activity the hidden hunger of zinc in crop can be predicted at an early growth stage (15/20 days) where the zinc content in plant tissue fail to reveal the true picture of zinc deficiency.