Characterization of cocoa butter diversity in Theobroma cacao L. in Trinidad.: implications for genetic improvement and chocolate quality

BACKGROUND: Cocoa butter, the lipid fraction of Theobroma cacao L. seeds, is essential for chocolate quality and functionality, yet the full extent of natural variation in cocoa butter traits across cacao genetic diversity remains poorly characterized. We analyzed 21 genetically diverse cacao genotypes commonly grown in Trinidad, representing seven of the 11 genetic groups, to quantify variation in cocoa butter content, triglyceride composition and thermal properties. Total fat content, 10 predominant triglycerides and three melting traits were measured using time domain-nuclear magnetic resonance, gas chromatography and differential scanning calorimetry, respectively. RESULTS: Despite the genetic diversity represented, cocoa butter traits exhibited relatively narrow ranges of variation, with most genotypes showing similar characteristics. Seed storage compounds are often representative of selective optimums, limiting the range of variation. However, several genotypes at the extremes of the trait distributions exhibited characteristics of particular interest for breeding applications. PA107, PA150 and TSH1076 showed elevated fat content, whereas CATIE1000 displayed favorable thermal properties, including high melting temperatures. It should be noted that the expression of these traits may vary under climatic and environmental conditions different from those in Trinidad. Correlation and principal component analyses revealed significant relationships between triglyceride composition and thermal behavior, with both major triglycerides [POP (1,3-dipalmitoyl-2-oleoyl-glycerol), POS (1-palmitoyl-2-oleoyl-3-stearoyl-glycerol) and SOS (1,3-distearoyl-2-oleoyl-glycerol)] and minor triglycerides [1,2-dioleoyl-3-palmitoyl glycerol (POO), 1,2-dioleoyl-3-stearoyl glycerol (SOO) and 1,2-dipalmitoyl-3-stearoyl glycerol (PPS)] strongly influencing melting properties. CONCLUSION: Collectively, these findings establish the range of cocoa butter diversity present in cultivated cacao in Trinidad and identify promising genotypes for breeding programs aimed at improving cacao processing and quality characteristics.