Document Detail


Oxidative stability of tree nut oils.
MedLine Citation:
PMID:  18494484     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The oxidative stability of selected tree nut oils was examined. The oils of almond, Brazil nut, hazelnut, pecan, pine nut, pistachio, and walnut were extracted using two solvent extraction systems, namely, hexane and chloroform/methanol. The chloroform/methanol system afforded a higher oil yield for each tree nut type examined (pine nut had the highest oil content, whereas almond had the lowest). The fatty acid compositions of tree nut oils were analyzed using gas chromatography, showing that oleic acid was the predominant fatty acid in all samples except pine nut and walnut oils, which contained high amounts of linoleic acid. The tocopherol compositions were analyzed using high-performance liquid chromatography, showing that alpha- and gamma-tocopherols were the predominant tocopherol homologues present; however delta- and beta-tocopherols were also detected in some samples. The oxidative stability of nonstripped and stripped tree nut oils was examined under two conditions, namely, accelerated autoxidation and photooxidation. Progression of oxidation was monitored using tests for conjugated dienes, peroxide value, p-anisidine value, and headspace volatiles. Primary products of oxidation persisted in the earlier stages of oxidation, whereas secondary oxidation product levels increased dramatically during the later stages of oxidation. Hexanal was the major headspace aldehyde formed in all oxidized samples except walnut oil, which contained primarily propanal. Results showed that chloroform/methanol-extracted oils were more stable than hexane-extracted oils in both the accelerated autoxidation and photooxidation studies. Oils of pecan and pistachio were the most stable, whereas oils of pine nut and walnut were the least stable.
Authors:
Homan Miraliakbari; Fereidoon Shahidi
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-05-22
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  56     ISSN:  1520-5118     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-06-19     Completed Date:  2008-09-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4751-9     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
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MeSH Terms
Descriptor/Qualifier:
Carya / chemistry
Drug Stability
Fatty Acids / analysis
Juglans / chemistry
Nuts / chemistry*
Oxidation-Reduction
Pistacia / chemistry
Plant Oils / chemistry*,  isolation & purification
Solvents
Tocopherols / analysis
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Plant Oils; 0/Solvents; 1406-66-2/Tocopherols

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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