Alteration in Trace Elements Concentration and Possible Copper Toxicity in Juiced Leafy Vegetables Commonly Consumed in Southwestern Nigeria
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Date
2016
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Publisher
British Biotechnology Journal
Abstract
This study investigated the effects of juicing on four micro-minerals (Cu, Zn, Mn and Mo) contents
of six different leafy vegetables commonly consumed in South western, Nigeria. Micro-minerals
were determined using Atomic Absorbance Spectrophotometer (AAS). Among the fresh
vegetables, highest level of micro-minerals was recorded in Senecio biafrae for Cu (9.13±0.21
mg/100 g dry weight); Manihot esculenta for Zn (2.01±0.17 mg/100 g dry weight); Ipomoea batatas for Mn (3.78±0.29 mg/100 g dry weight) and Senecio biafrae for Mo (35.00±0.00 µg/100 g dry
weight). In juiced form, highest value of Cu was noted in Launaea taraxacifolia (21.43±1.58 mg/100
g dry weight); Zn in Senecio biafrae (3.24±0.26 mg/100 g dry weight), Mn in Launaea taraxacifolia
(11.76±2.25 mg/100 g dry weight) and Mo in Piper guineense (44.00±0.00 µg/100 g dry weight).
The least micro-minerals contents noted in juice fraction of vegetables are as follows: Cu, Ipomoea
batatas (2.35±0.15 mg/100 g dry weight); Zn, Launaea taraxacifolia (0.36±0.01 mg/100 g dry
weight); Mn, Piper guineense (2.68±0.27 mg/100 g dry weight) and Mo, Ipomoea batatas
(0.002±0.00 mg/100 g dry weight). Increased concentrations of micro-minerals was observed in
virtually all juice fractions when compared with their corresponding fresh vegetables with exception
of Ipomoea batatas, where Zn and Mo contents reduced in the juice when compared with its
corresponding fresh vegetables. It could be deduced that the juice fraction of vegetables contain
more of trace-minerals in some of the vegetables. In addition, intake of 100 g dry weight of any of
the vegetable (fresh form) does not lead to toxic intake of any of the minerals using Recommended
Daily Tolerable Upper Intake Level (UL) as a standard. However, intake of the same corresponding
dry weight in juice would lead to toxic level of Cu in all the vegetables except Ipomoea batatas;
whereas, such amount would not lead to Zn, Mn and Mo toxicity.