Assessment of the profile of free amino acids and reducing sugars of cacao beans from local Cameroonian Trinitario (SNK varieties) and Forastero (TIKO varieties) using fermentation-like incubation

Abstract

This study investigated the profile of cacao beans from the local Cameroonian Trinitario (SNK) and Forastero (TIKO) in terms of aroma precursors (amino acids and reducing sugars) through fermentation-like incubations. Treatments consisted of incubating beans in acetic acid, 100 mmol/L for two days followed by 200 mmol/L of acetic acid for three days (Treatment T1) and in 100 mmol/L of lactic acid for two days followed by 200 mmol/L of acetic acid for three days (Treatment T2). Both treatments resulted in an increase of free amino acids content by 1.5 - 2.5 times in SNK and TIKO varieties. The ratio of the hydrophobic amino acids over the rest of amino acids showed the preponderance of T1 on the hydrophobic amino acids released in TIKO while in the SNK, some varieties displayed the highest ratio in T2. Glucose and fructose content in TIKO and SNK beans increased 2 to 3 times during incubation. Galactose and raf-finose were found in unfermented beans. After incubation, raffinose was missing while at the same time a raise of galactose content could be seen. These results highlighted that acidification remains the factor inducing the releasing of free hydrophobic amino acids, the genotype being less involved.