Name （Enik Nurlaili Afifah）
Characterization of fine flavor cocoa in parent hybrids combination using metabolomic approach
(メタボロミクスアプローチによる親ハイブリッド組合せにおけるファインフレーバーカカオの特性評価)
Chapter 1: General Introduction. Fine flavor cocoa commands a premium price in the global chocolate market, compelling plant breeders to develop new cacao cultivar with fine flavor profiles while enhancing yield, resistance levels, and flavor quality. Characterization is a crucial step in plant breeding for producing novel cultivar. Fine flavor cocoa is generally characterized by fresh bean color and sensory characteristics. However, these methods cannot be applied to progenies/hybrids because their colors may vary depending on their parents. Additionally, sensory evaluation lacks universal quality standards, necessitating robust complementary characterization methods. These limitations highlight the need for robust complementary characterization methods. Metabolomics is a powerful approach for characterizing agricultural products, enabling the investigation of both volatile and non-volatile compounds that define the flavor profile of cocoa. This study aims to characterize fine flavor cocoa in parent-hybrid combinations using a metabolomic approach. Chapter 2: Investigation of the characteristics of fine flavor cocoa in parent-hybrid combinations through non-volatile metabolite profiling and fresh bean color analysis. The characteristics of fine flavor cocoa resulted from cross breeding has been investigated through non-volatile metabolite profiling, using widely targeted Gas Chromatography-Mass Spectrometry (GC-MS) and bean phenotype analysis. The result showed that fine flavor cocoa (from Trinitario variety) exhibits white-bean characteristics. Conversely, the hybrids (resulting from crosses with Trinitario) displayed varying percentages of fresh bean color. Caffeine and organic acids such as malic acid, fumaric acid, citric acid, and tartaric acid were found to correspond to the characteristics of fine flavor cocoa. Notably, this study is the first identification of non-volatile compounds, particularly organic acids, as key metabolites in differentiating fine flavor cocoa hybrids from bulk cocoa. Each parent-hybrid combination demonstrated distinct flavor characteristics, with the H1 (ICCRI 03 cacao clone) and H2 hybrid (ICCRI 09 cacao clone) emerging as a promising cacao cultivar, exhibiting flavor characteristics similar to those of its female parent (fine flavor cocoa). Although both non-volatile and volatile compounds contribute to cocoa’s flavor profile, the next chapters will explore further characterization of these selected hybrids, focusing on their volatile composition and sensory attributes. Chapter 3: Correlation between sensory attributes and metabolomic profiles of cocoa liquor to express the characteristics of fine flavor cocoa in parent hybrid combination. The correlation between sensory properties and metabolite profiles, both non-volatile and volatile compounds was investigated using a combined metabolomics-based approach and sensory analysis. The findings revealed that the H2 hybrid (ICCRI 09) exhibits distinctive sensory attributes consistent with fine flavor cocoa, including floral, acidic, woody, cocoa, fresh fruit, and browned roast notes. These sensory qualities were linked to higher concentrations of organic acids and sugars (non-volatile compounds), as well as specific volatile compounds such as 3-methylbutanal, 2,3-butanediol, benzaldehyde, linalool, trans-linalool oxide, and isobutyl acetate. These volatiles contributed to the floral, fruity, woody, and roasted flavor notes observed in the H2 hybrid. This study notably identified specific volatile and non-volatile compounds linked to the complex sensory attributes of the H2 hybrid, emphasizing its potential as fine flavor cocoa. Chapter 4: Conclusion and future perspectives. Cacao beans from crossbreeding have been comprehensively characterized using a metabolomics approach to distinguish fine flavor cocoa. Fine flavor cocoa, characterized by a balanced profile of caffeine, organic acids, and key volatiles (e.g., 3-methylbutanal, linalool, benzaldehyde), shows promise, particularly in H2 hybrids with outstanding sensory attributes. This study provides valuable insights for breeding programs and the development of high-quality cocoa. Future research should explore a broader range of cacao hybrids and investigate flavor changes throughout the post-harvest process to further enhance fine flavor cocoa characterization.