Flavor Precursors and Volatile Compounds Improvement of Unfermented Cocoa Beans by Hydrolysis Using Bromelain

Abstract

Cocoa fermentation is an essential process that produces flavor precursors. However, many small farmers in Indonesia directly dry their cocoa beans without fermentation due to low yield and long fermentation time, resulting in fewer flavor precursors and cocoa flavor. Therefore, this study aimed to enhance the flavor precursors, particularly free amino acids and volatile compounds, of unfermented cocoa beans by hydrolysis, using bromelain. Unfermented cocoa beans were previously hydrolyzed with bromelain at concentrations of 3.5, 7, and 10.5 U/mL for 4, 6, and 8 h, respectively. An analysis of enzyme activity, degree of hydrolysis, free amino acids, reducing sugar, polyphenols, and volatile compounds was then conducted using unfermented and fermented cocoa beans as negative and positive controls, respectively. The results showed that the highest degree of hydrolysis was 42.95% at 10.5 U/mL for 6 h, although it was not significantly different from the hydrolysis at 3.5 U/mL for 8 h. This indicates a higher reducing sugar and lower polyphenols content than unfermented cocoa beans. There was also an increase in free amino acids, especially hydrophobic amino acids, such as phenylalanine, valine, leucine, alanine, and tyrosine, and desirable volatile compounds, such as pyrazines. Therefore, this suggests that hydrolysis with bromelain increased the flavor precursors and cocoa-bean flavors.

Flavor Precursor and Volatile Compounds Formation of Unfermented Cocoa Beans Hydrolyzed by Papain

“…The results of this study are similar to those of Tamimi et al (2023), who reported that the DH of dry cocoa beans incubated for 8 h increased with rising Flavourzyme ® concentration. Meanwhile, different results were reported by Purbaningrum et al (2023); the DH of dry cocoa beans did not increase considerably after enzyme addition at concentrations ranging from 3.5 U/mL to 10.5 U/mL during 8 h of incubation. In this study, the enzyme concentration of 3.3 U/mL was selected and then used to determine incubation time.…”

“…These findings corroborate with Tamimi et al (2023), who reported that Flavourzyme ® can only increase the levels of four types of FAAs including tyrosine, valine, phenylalanine, and leucine. Meanwhile, the hydrolysis of dried cocoa beans using bromelain increased the concentrations of almost all types of FAAs detected (Purbaningrum et al, 2023). During fermentation, hydrophobic FAA contents increased significantly (p < 0.05), particularly valine, leucine, isoleucine, and phenylalanine.…”

“…Each type of enzyme has different hydrolytic capabilities. Bromelain can participate in hydrolysis for 6 h (Purbaningrum et al, 2023), Flavourzyme ® for 8 h (Tamimi et al, 2023), and papain for 10 h. Thus, an incubation time of 10 h was selected for further hydrolysis processes.…”

“…Incubating unfermented dry cocoa bean powder in acetate buffer (pH 5.5) at 45°C increases the intensity of the yellow color and the fermentation index while reducing cocoa procyanidin levels (Misnawi et al, 2003). Hydrolyzing unfermented dry cocoa beans with Flavourzyme ® and crude bromelain produced more aroma precursors, such as FAAs and reducing sugars, along with additional volatile compounds than unfermented cocoa beans (Purbaningrum et al, 2023;Tamimi et al, 2023).…”

Bromelain-loaded nanocomposites decrease inflammatory and cytotoxicity effects of gliadin on Caco-2 cells and peripheral blood mononuclear cells of celiac patients

“…Bromelain is an effective proteolytic enzyme obtained from the fruit or stem of a pineapple ( Ananas cosmosus ). Bromelain has a broad specificity for protein breakdown, particularly in hydrophobic amino acid residues, and cleaves proteins in the carbonyl end of lysine, alanine, tyrosine, and glycine 10 , 11 . The molecular weight of bromelain is 23 to 37.0 kDa.…”