title: Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life.
abstract: In almonds, there is no standard method for detecting oxidative changes and little data correlating consumer perception with chemical markers of rancidity. To address this, we measured peroxide values (PV), free fatty acid values (FFAs), conjugated dienes, tocopherols, headspace volatiles, and consumer hedonic response in light roasted (LR) and dark roasted (DR) almonds stored under conditions that promote rancidity development over 12 months. Results demonstrate that, although rancidity develops at different rates in LR and DR almonds, consumer liking was not significantly different between LR and DR almonds. Average hedonic ratings of almonds were found to fall below a designated acceptable score of 5 ("neither like nor dislike") by 6 months of storage. This did not correspond with recommended industry rejection standard of PV < 5 mequiv peroxide/kg oil and FFA < 1.5% oleic. FFAs remain well below <1.5% oleic during storage, indicating that FFAs are not a good marker of rancidity in roasted almonds stored in low humidity environments. Regression of consumer liking to concentration of rancidity indicators revealed that selected headspace volatiles, including heptanal, octanal, nonanal, 2-octenal, 2-heptanone, 2-pentylfuran, hexanal, and pentanal, had a better correlation with liking than did nonvolatile indicators.
authors.affiliation: Department of Food Science and Technology, University of California, Davis , One Shields Avenue, Davis, California 95616, United States.
authors.forename: Lillian M
authors.initials: LM
authors.lastname: Franklin
authors.affiliation: Covance Food Solutions , 365 North Canyons Parkway, Suite 101, Livermore, California 94551, United States.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Chapman
authors.affiliation: Covance Food Solutions , 365 North Canyons Parkway, Suite 101, Livermore, California 94551, United States.
authors.forename: Ellena S
authors.initials: ES
authors.lastname: King
authors.affiliation: Department of Food Science and Technology, University of California, Davis , One Shields Avenue, Davis, California 95616, United States.
authors.forename: Mallory
authors.initials: M
authors.lastname: Mau
authors.affiliation: Almond Board of California , Suite 1500, 1150 Ninth Street, Modesto, California 95354, United States.
authors.forename: Guangwei
authors.initials: G
authors.lastname: Huang
authors.affiliation: Department of Food Science and Technology, University of California, Davis , One Shields Avenue, Davis, California 95616, United States.
authors.forename: Alyson E
authors.identifier: http://orcid.org/0000-0003-0286-5238
authors.initials: AE
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003296:Cooking / Q000379:methods*; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D061353:Food Storage; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D009754:Nuts / Q000737:chemistry*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000032:analysis; D000068181:Prunus dulcis / Q000737:chemistry*; D013649:Taste; D055815:Young Adult
chemical_list: D005227:Fatty Acids; D010545:Peroxides
keywords: HS-SPME GC/MS; Prunus dulcis; almond; hedonic analysis; peroxide value