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Research: SHAHIDI and colleagues,
Listed in Issue 155
Abstract
SHAHIDI and colleagues, Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada. fshahidi@mun.ca investigated the antioxidant properties of hazelnuts.
Background
Methodology
Antioxidant efficacies of ethanol extracts of defatted raw hazelnut kernel and hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) were evaluated by monitoring total antioxidant activity (TAA) and free-radical scavenging activity tests [hydrogen peroxide, superoxide radical, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical], together with antioxidant activity in a beta-carotene-linoleate model system, inhibition of oxidation of human low-density lipoprotein (LDL) cholesterol, and inhibition of strand breaking of supercoiled deoxyribonucleic acid (DNA). In addition, yield, content of phenolics, and phenolic acid profiles (free and esterified fractions) were also examined.
Results
Generally, extracts of hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) exhibited stronger activities than hazelnut kernel at all concentrations tested. Hazelnut extracts examined showed different antioxidative efficacies, expected to be related to the presence of phenolic compounds. Among samples, extracts of hazelnut skin, in general, showed superior antioxidative efficacy and higher phenolic content as compared to other extracts. Five phenolic acids (gallic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid) were tentatively identified and quantified (both free and esterified forms). Extracts contained different levels of phenolic acids.
Conclusion
These results suggest that hazelnut byproducts could potentially be considered as an excellent and readily available source of natural antioxidants.
References
Shahidi F, Alasalvar C and Liyana-Pathirana CM. Antioxidant phytochemicals in hazelnut kernel (Corylus avellana L.) and hazelnut byproducts.[erratum appears in J Agric Food Chem. 2007 Apr 18;55(8):3232]. Journal of Agricultural & Food Chemistry 55(4):1212-20. Feb 21. 2007.