Levels of essential and non-essential metals in ginger (Zingiber officinale) cultivated in Ethiopia

Abstract

BackgroundGinger (Zingiber officinale Roscoe) is a common condiment for various foods and beverages and widely used worldwide as a spice. Its extracts are used extensively in the food, beverage, and confectionary industries in the production of products such as marmalade, pickles, chutney, ginger beer, ginger wine, liquors, biscuits, and other bakery products. In Ethiopia, it is among the important spices used in every kitchen to flavor stew, tea, bread and local alcoholic drinks. It is also chiefly used medicinally for indigestion, stomachache, malaria, fevers, common cold, and motion sickness. The literature survey revealed that there is no study conducted on the determination of metals in ginger cultivated in Ethiopia. Hence it is worthwhile to determine the levels of essential and non-essential metals in ginger cultivated in Ethiopia.MethodsThe levels of essential (Ca, Mg, Fe, Zn, Cu, Co, Cr, Mn, and Ni) and non-essential (Cd and Pb) metals in ginger (Zingiber officinale Roscoe) cultivated in four different regions of Ethiopia and the soil where it was grown were determined by flame atomic absorption spectrometry. 0.5 g of oven dried ginger and soil samples were digested using 3 mL of HNO3 and 1 mL of HClO4 at 210°C for 3 h and a mixture of 6 mL aqua-regia and 1.5 mL H2O2 at 270°C for 3 h, respectively.ResultsThe mean metal concentration (μg/g dry weight basis) ranged in the ginger and soil samples, respectively, were: Ca (2000–2540, 1770–3580), Mg (2700–4090, 1460–2440), Fe (41.8–89.0, 21700–46900), Zn (38.5–55.2, 255–412), Cu (1.1–4.8, 3.80–33.9), Co (2.0–7.6, 48.5–159), Cr (6.0–10.8, 110–163), Mn (184–401, 1760–6470), Ni (5.6–8.4, 14.1–79.3) and Cd (0.38–0.97, 0.24–1.1). The toxic metal Pb was not detected in both the ginger and soil samples.ConclusionThere was good correlation between some metals in ginger and soil samples while poor correlation between other metals (Fe, Ni, Cu). This study revealed that Ethiopian gingers are good source of essential metals and free from toxic metal Pb while containing negligible amount of Cd.

Using Stripping Voltammetry to Determine Heavy Metals in Cooking Spices Used in Iraq

“…This was reflected in the relatively high standard deviations and the remarkable differences between the mean and the median of the elemental contents (Tables 5-6). Similar results were reported by other studies for different spices [17,19,23,[25][26]. This variability is usually explained in terms of the effects of various ecosystems on the elemental levels at different regions.…”

Levels of essential and non-essential metals in the raw seeds and processed food (roasted seeds and bread) of maize/corn (Zea mays L.) cultivated in selected areas of Ethiopia

“…This could be one reason behind the high value of Fe in Ethiopian maize. [26,27]. The determination of levels of toxic metals was also carried out in this study and Cd was found to be below detection limit of the instrument.…”

“…The optimum condition is the one which require minimum reagent volume consumption, minimum reflux time, clarity of digests, and ease of simplicity [21][22][23][24][25][26]. In this study, to prepare a clear sample solution suitable for the analysis using AAS, a lot of trials of digestion procedures were made on the maize seed powder using the HNO 3 , H 2 O 2 and HClO 4 acid mixtures by varying parameters such as volume of the acid mixture, digestion time and digestion temperature to optimize the digestion procedure (Tables 1 and 2).…”

“…It is also clearly seen in Table 3 that the concentration ranges of all the trace metals except Fe and Zn overlap each other among the sample sites. The highest concentration of Fe may be attributed to its higher levels in the soil [26,27].…”

Levels of essential and toxic metals in fenugreek seeds (Trigonella Foenum-Graecum L.) cultivated in different parts of Ethiopia

“…Recently some studies have been carried out on the mineral composition of selected spices (thyme, fennel, ginger, korarima, and red pepper) cultivated in Ethiopia (DERBIE;CHANDRAVANSHI, 2011;ENDALAMAW;WAGESHO;MEKASSA;TEFERA;CHANDRAVANSHI, 2016). Several global studies were also been done on Trigonella foenum-graecum (fenugreek) especially in the areas of medicine and to determine the metal content.…”