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Mineral Composition of Elements in Walnuts and Walnut Oils
Iva Juranović Cindrić1, Michaela Zeiner2,3, Dora Hlebec4
1Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia. ijuranovic@chem.pmf.hr.
International Journal of Environmental Research and Public Health
|November 30, 2018
Summary
Walnuts are rich in essential elements like calcium and potassium. Analysis revealed potentially toxic elements were below safe limits, though iron and zinc were higher in walnut oils, suggesting processing contamination.
Area of Science:
- Food Science
- Nutritional Analysis
- Environmental Chemistry
Background:
- Walnuts (Juglans nigra) are recognized for their functional food properties.
- Understanding the elemental composition of walnuts and their oils is crucial for assessing nutritional value and safety.
- Previous research has not comprehensively analyzed the range of macro-, micro-, and trace elements in both walnuts and their derived oils.
Purpose of the Study:
- To quantify twenty-one macro-, micro-, and trace elements in walnuts and walnut oils.
- To assess the nutritional contribution of essential elements in walnuts.
- To identify potential safety concerns related to toxic elements and processing contaminants in walnut products.
Main Methods:
- Elemental analysis of walnut and walnut oil samples using unspecified methods.
- Quantification of twenty-one elements including macro- (Ca, K, Mg, Na), micro- (Fe, Zn, Cu, Mn, etc.), and trace elements (As, Cd, Pb, Se, etc.).
- Comparative analysis of elemental concentrations between whole walnuts and extracted oils.
Main Results:
- Essential macro-elements calcium (1062 mg/kg), potassium (2771 mg/kg), magnesium (1426 mg/kg), and sodium (42.3 mg/kg) were found in significant amounts in walnuts.
- The decreasing order of micro- and trace elements in walnuts was Mn > Fe > Zn > B, Mo > Cu > Ni > Co > Al > Sr > Ba > Li > Pb > Se > Cr > As > Cd.
- Potentially toxic elements (As, Cd, Pb) were generally below maximum allowed levels. Iron (Fe) and zinc (Zn) concentrations were higher in oils than nuts, indicating potential processing contamination.
Conclusions:
- Walnuts possess a beneficial profile of essential macro- and micro-elements.
- While toxic elements are within safe limits, elevated Fe and Zn in oils suggest contamination during processing.
- Minimizing iron contamination during walnut oil production is recommended to prevent oil oxidation.
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