RAPID DETERMINATION OF THE ORIGIN OF COCOA BEAN AND CHOCOLATE WITH LASER

ASSISTED REIMS – THE BEAN TO BAR PROJECT Richard Schäffer1, Tamas Karancsi1, Steve Pringle3, Zoltan Takats2, Maximilian Reiser1, Ath-Horvath Zsoka4 and Julia Balog1,2

1 Waters Research Center, Budapest, Hungary; 2 Imperial College London, UK; 3 Waters Corporation, Wilmslow, UK; 4 Harrer Chocolat Kft, Sopron, Hungary.

OVERVIEW

• The abundant occurrences of food fraud cases and child slavery issues in Africa have recently brought cocoa bean authenticity into focus.

• There is an increasing demand for verification of the reliable origin of cocoa beans of premium chocolate products.

• Recent analytical methods include DNA profiling of the cocoa beans which is time consuming and expensive.

• Laser Assisted Rapid Evaporative Ionization Mass Spectrometry (LA-REIMS) has been shown to be capable of determining cocoa content in chocolate within seconds.

• In this study, we focused on the relationship between the cocoa bean and end product including all production steps between.

INSTRUMENTATION • Workflow and instrumentation is shown in the figure below, • Waters REIMS interface using a Xevo G2-XS Q-ToF in Negative

ionization mode, • m/z range 50- 1500 for both ToF mode and MS/MS mode • Collision energy (MSMS Mode) 15-40 eV, • CO2 laser: Superpulse mode; 3W, 10 Hz repetition, 10ms pulse width

CONCLUSION

• The presented data clearly demonstrates that REIMS has the potential of rapid characterisation of different food matrices like cocoa bean and chocolate.

• Both cocoa beans and chocolate samples can be easily distinguished based on the origin of the cocoa bean.

• Due to differences in the sample matrices direct identification of the origin of cocoa bean from chocolate is very challenging, postprocessing of the spectra is required.

• Based on these processed LA-REIMS spectra the origin of the cocoa bean can be geographically identified in single bar chocolate samples on a continent level, the algorithm is

under development.

Vapor generated by a CO2 laser with modified handpiece was transfered to the mass spectrometer for analysis

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SAMPLING AND DATA PROCESSING RESULTS

Madagascar

Tanzania Vietnam

Haiti

Venezuela

Bolivia

Nicaragua

Nicaragua

Belize

2D LDA plot Chocolate

2D LDA plot Cocoa bean

2D LDA plot Chocolate & Cocoa bean

Due to the different sample matrix, spectra from bean and chocolate samples are quite different. Therefore additional post processing of the spectra is necessary in order to identify the geographical origin of the cocoa bean based solely on the chocolate samples themselves.

Cocoa bean

Chocolate

Cocoa butter

PI PA, PE, PI

TGs

Disaccharide dimer

Correct classification rate >98% Correct classification rate <25% !!

LDA 1

LDA 2

LDA 1

LDA 2

LDA 1

LDA 2

Typical spectra MSMS spectra

Chocolate Cocoa bean

Transition spectra from bean to bar Transforming the bean and chocolate spectra into one transition spectrum that higlights the differences between the two sample types for each geographical region supported the improvement of the classification. A model based on transition spectra can be seen on the right.

Madagascar Tanzania

Bean Choco

Bean Choco

Glycerol-Phosphatidyl Inositols (PI) were identified as the major phospholipid group in bean and chocolate based on matches using Lipidmaps.org

PI(18:0/18:1) and isomers

PI(16:0/18:1) and isomers

Correct classification rate >80%

LDA 1

LDA 2

Correct classification rate >98%

Lipidmaps.org

Bean Chocolate