Characterizing Fine-Flavor Cocoa in Parent-Hybrid Combinations Using GC–MS

A recent study has comprehensively characterized fine-flavor cocoa in parent-hybrid combinations resulting from a plant breeding program, using a widely targeted gas chromatography-mass spectrometry (GC–MS) metabolomics-based approach and bean phenotype analysis. The researchers involved believe the information culled to be necessary to determine which of the best crossing combinations could produce hybrids with high flavor quality. A paper based on the team’s findings has been published in Food Chemistry: X (1).

One of the world’s most important agricultural commodities (2), cocoa holds a significant economic value (3) due to its beans serving as a raw material for the chocolate industry (4) From a commercial and industrial viewpoint, cocoa is classified into two product types: bulk or standard quality, which is known for its basic flavor, and fine-flavor cocoa, which is distinguished by superior aromatic notes (5). Fine-flavor cocoa offers higher quality, and, as a result, commands a higher price in the market compared to its bulk counterpart (6). There is, therefore, a need to improve the quality of cacao beans as raw materials for fine-flavored cocoa (7).

As a powerful and robust method for characterizing plants (8), metabolomics can reveal both volatile and non-volatile compounds which determine the flavor quality of cocoa (9). The analytical methods employed in metabolomics, such as GC–MS, have led to a wide range of compound detection in cocoa beans, and therefore are appropriate for examining metabolite profiles in cacao (10). The method allows for the profiling of different metabolite levels between hybrids and their parents (11) and can provide a high level of precision in the identification and characterization of specific traits associated with the complexity of plant phenotypic diversity, such as cocoa flavor quality (12).

Twelve clones of Theobroma cacao obtained from the Indonesian Coffee and Cocoa Research Institute (ICCRI) were used in the study. The cacao clones used in this study were planted in Jember, East Java, Indonesia, at an altitude of 45 m above sea level, with an average rainfall of 224 mm, an average temperature of 32 °C, and under the same cultivation management. All cacao trees used in this study were mature (4 years old) and of similar height (2–3 m). Seven grams of beans cut from each clone were placed in a polycarbonate tube containing a stainless-steel ball, and all tubes were cooled with liquid nitrogen and ground into a powder. For the chromatographic analysis process, 1 μL of a derivatized sample was injected in a split mode at a ratio of 25:1 v/v, with an injection temperature of 280 °C in a randomized sequence. Hydrogen was used as the carrier gas in this analysis, with a linear velocity of 39.0 cm/s and a flow rate of 1.2 mL/min. The column temperature initiated at 80 °C for 4 min, then increased to 330 °C at a rate of 15 °C/min, and was kept steady for approximately 8 min. The interface and ion source temperatures were consistently maintained at 310 °C and 280 °C, respectively (1)

The non-volatile profiles of fine-flavored cacao was characterized by high levels of caffeine and organic acids such as malic acid, fumaric acid, citric acid, lactic acid, and tartaric acid, with each type of crossbreed exhibiting unique flavor profiles. The authors of the study believe that the insights gained from this characterization will enable plant breeders to optimize breeding schemes for further fine flavor improvement or utilization of these crossing combinations as breeding materials. Additionally, this study provides valuable information and references for farm managers to maintain cacao plantations through rejuvenation using superior clones. The identification of important metabolites in each crossbreed will be useful for selection in future studies (1).

Cocoa beans. © somchai20162516 - stock.adobe.com

References

1. Afifah, E. N.; Sari, I. A.; Susilo, A. W.; Malik, A.; Fukusaki, E.; Putri, S. P. Characterization of Fine-Flavor Cocoa in Parent-Hybrid Combinations Using Metabolomics Approach. Food Chem. X 2024, 24, 101832. DOI: 10.1016/j.fochx.2024.101832

2. E.M. Castro-Alayo, E. M.; G. Idrogo-Vásquez, G.; R. Siche, R.; F.P. Cardenas-Toro, F. P. Formation of Aromatic Compounds Precursors During Fermentation of Criollo and Forastero cocoa. Heliyon 2019, 5 (1), DOI: 10.1016/j.heliyon.2019.e01157

3. Bagnulo, E.; C. Scavarda, C.; C. Bortolini, C.; C. Cordero, C.; C. Bicchi, C.; E. Liberto, E. Cocoa Quality: Chemical Relationship of Cocoa Beans and Liquors in Origin Identitation. Food Res. Int. 2023, 172, DOI: 10.1016/j.foodres.2023.113199

4. Moreno-Rojas, J. M.; Yadira Erazo Solorzano, C.; Tuárez García, D. A.; Pereira-Caro, G.; Ordóñez Díaz, J. L.; Muñoz-Redondo, J. M.; Rodríguez-Solana, R. Impact of the Pre-Drying Process on the Volatile Profile of On-Farm Processed Ecuadorian Bulk and Fine-Flavour Cocoa Varieties. Food Res. Int. 2023, 169, DOI: 10.1016/j.foodres.2023.112938

5. H. Rottiers, H.; D.A. Tzompa Sosa, D. A.; A. De Winne, A.; J. Ruales, J.; J. De Clippeleer, J.; I. De Leersnyder, I. et al. Dynamics of Volatile Compounds and Flavor Precursors During Spontaneous Fermentation of Fine flavor Trinitario Cocoa Beans. Eur. Food Res. Technol. 2019, 245 (9), 1917–1937. DOI: 10.1007/s00217-019-03307-y

6. Escobar, S.; Santander, M.; Zuluaga, M.; Chacón, I.; Rodríguez, J.; Vaillant, F. Fine Cocoa Beans Production: Tracking Aroma Precursors Through a Comprehensive Analysis of Flavor Attributes Formation. Food Chem. 2021, 365. DOI: 10.1016/j.foodchem.2021.130627

7. Tscharntke, T.; Ocampo-Ariza, C.; Vansynghel, J.; Ivañez-Ballesteros, B.; Aycart, P.; Rodriguez, L.; Ramirez, M.; Steffan-Dewenter, I.; Maas, B.; Thomas, E. Socio-Ecological Benefits of Fine-Flavor Cacao in its Center of Origin. Conservation Letters 2023, 16 (1). DOI: 10.1111/conl.12936

8. Grissa, D.; Pétéra, M.; Brandolini, M.; Napoli, A.; Comte, B.; Pujos-Guillot, E. Feature Selection Methods for Early Predictive Biomarker Discovery Using Untargeted Metabolomic Data. Front. Mol. Biosci. 2016, 3. DOI: 10.3389/fmolb.2016.00030

9. Herrera-Rocha, F.; Cala, M. P.; Aguirre Mejía, J. L.; Rodríguez-López, C. M.; Chica, M. J.; Olarte, H. H. et al. Dissecting Fine-Flavor Cocoa Bean Fermentation Through Metabolomics Analysis to Break Down the Current Metabolic Paradigm. Sci. Rep. 2021, 11 (1). DOI: 10.1038/s41598-021-01427-8

10. Michel, S.; Baraka, L. F.; Ibañez, A. J.; Mansurova, M.; Mass Spectrometry-Based Flavor Monitoring of Peruvian Chocolate Fabrication Process. Metabolites 2021,11 (2), 1-16. DOI: 10.3390/metabo11020071

11. Le, Q. T. N.; Sugi, N.; Yamaguchi, M.; Hirayama, T.; Kobayashi, M.; Suzuki, Y. et al. Morphological and Metabolomics Profiling of Intraspecific Arabidopsis Hybrids in Relation to Biomass Heterosis. Sci. Rep. 2023, 13 (1), DOI: 10.1038/s41598-023-36618-y

12. Colantonio, V.; Ferrão, L. F. V.; Tieman, D. M.; Resende Jr., F. Metabolomic Selection for Enhanced Fruit Flavor. PNAS 2022, 119, 1–11. DOI: 10.1073/pnas.2115865119