Gas chromatographic determination and mechanism of formation of D-amino acids occurring in fermented and roasted cocoa beans, cocoa powder, chocolate and cocoa shell

Simple item page
dc.contributor.authorPatzold, R.
dc.contributor.authorBruckner, H.
dc.date.accessioned2014-04-09T09:08:23Z
dc.date.available2014-04-09T09:08:23Z
dc.date.issued2006
dc.description.abstractFermented cocoa beans of various countries of origin (Ivory Coast, Ghana, Sulawesi), cocoa beans roasted under defined conditions (100–150 C; 30–120 min), low and high fat cocoa powder, various brands of chocolate, and cocoa shells were analyzed for their contents of free L- and D-amino acids. Amino acids were isolated from defatted products using a cation exchanger and converted into volatile N(O)-pentafluoropropionyl amino acid 2-propyl esters which were analyzed by enantioselective gas chromatography mass spectrometry on a Chirasil+-L-Val capillary column. Besides common protein L-amino acids low amounts of D-amino acids were detected in fermented cocoa beans. Quantities of D-amino acids increased on heating. On roasting cocoa beans of the Forastero type from the Ivory Coast at 150 C for 2 h, relative quantities of D-amino acids approached 17.0% D-Ala, 11.7% D-Ile, 11.1% D-Asx (AspþAsn), 7.9% D-Tyr, 5.8% D-Ser, 4.8% D-Leu, 4.3% D-Phe, 37.0% D-Pro, and 1.2% D-Val. In cocoa powder and chocolate relative quantities amounted to 14.5% D-Ala, 10.6% D-Tyr, 9.8% D-Phe, 8.1% L-Asx, and 7.2% D-Ile. Lower quantities of other D-amino acids were also detected. In order to corroborate our hypothesis that D-amino acids are generated from Amadori compounds (fructose amino acids) formed in the course of the Maillard reaction, fructose-L-phenylalanine and fructose-D-phenylalanine were synthesized and heated at 200 C for 5–60 min. Already after 5min release of 11.7% D-Phe and 11.8% L-Phe in the free form could be analyzed. Based on the data a racemization mechanism is presented founded on the intermediate and reversible formation of an amino acid carbanion in the Amadori compounds.en_US
dc.identifier.citationAmino Acids (2006) 31: 63–72en_US
dc.identifier.urihttp://hdl.handle.net/123456789/318
dc.language.isoenen_US
dc.publisherSpringer-Verlagen_US
dc.subjectAmino acid enantiomersen_US
dc.subjectRacemizationen_US
dc.subjectGas chromatographyen_US
dc.subjectmass-spectrometryen_US
dc.subjectChirasil+-Valen_US
dc.subjectTheobroma cacao L.en_US
dc.subjectMaillard reactionen_US
dc.subjectAmadori rearrangement productsen_US
dc.titleGas chromatographic determination and mechanism of formation of D-amino acids occurring in fermented and roasted cocoa beans, cocoa powder, chocolate and cocoa shellen_US
dc.typeArticleen_US

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
gas chromatographic determination and mechanism.PDF
Size:
183.84 KB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

Cocoa