Antioxidant properties of extracts obtained from raw, dry-roasted, and oil-roasted US peanuts of commercial importance.
Raw, skinless peanut kernels from US commercial production lines were dry- and oil-roasted according to standard industrial practices. Eighty percent (v/v) methanolic extracts from the peanut cultivars were prepared and characterized by RP-HPLC: five predominant compounds were found comprising free p-coumaric acid and potential p-coumaric acid derivatives, as elucidated by DAD-UV spectra with comparisons to those of commercial standards. A Spanish high-oleic peanut possessed the greatest naturally-occurring level of p-coumaric acid and its derivatives, followed by a high-oleic Runner, a normal Runner, and a Virginia peanut. Upon thermal processing, p-coumaric acid was liberated at the expense of its derivatives according to the relationship: oil roasting > dry roasting > raw. A high-oleic Runner exhibited the greatest increase (∼785%) in free p-coumaric acid levels after oil roasting. For many of the samples from the 2007 crop, processing increased the TPC and antioxidant capacities in the order of raw < dry roast < oil roast, but results were cultivar dependent. Oil-roasted peanuts were more effective at scavenging O2(.-) than their dry-roasted counterparts, as determined by a photochemiluminescence assay. Overall findings indicate that although thermal processing altered the composition of peanut kernel antioxidants, TPC values and radical-scavenging activities are preserved. Depending on peanut type, cultivar, and harvest date, enhanced antioxidant capacities can result.
Craft
Brian David
BD
Department of Food Science and Technology, The University of Georgia, 100 Cedar Street, Athens, GA 30602-7610, USA.
Kosińska
Agnieszka
A
Amarowicz
Ryszard
R
Pegg
Ronald Bruce
RB
D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D010367:Arachis / Q000737:chemistry*; D003132:Commerce; D003373:Coumaric Acids / Q000032:analysis / Q000494:pharmacology*; D005511:Food Handling / Q000379:methods; D019301:Oleic Acid / Q000032:analysis / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010938:Plant Oils / Q000032:analysis / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000737:chemistry*; D014481:United States
D000975:Antioxidants; D003373:Coumaric Acids; D010936:Plant Extracts; D010938:Plant Oils; D017382:Reactive Oxygen Species; D019301:Oleic Acid