Evaluation of liquid smoke of cocoa bean shell against Escherichia coli and Candida utilis

Abstract

Cocoa bean shells are one of the by-products produced from chocolate processing. The cocoa bean shells contain polyphenols approximately 5.8%. The study aimed to evaluate the effectivity of liquid smoke produced from cocoa bean shells against Escherichia coli and Candida utilis It is expected that liquid smoke from cocoa bean shells will have the opportunity to replace AGPs. Total phenol, saponin, and tannin compounds were analyzed and were made in three replications. To determine the inhibition of liquid smoke of cocoa bean shells (LSCBS) on E. coli and C. utilis, the diameter of the clear area on the media was measured using a ruler. The antibacterial and antifungal activity test was carried out by well diffusion methods. Ten treatments, i.e. different concentrations of the LSCBS (0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%/non-diluted), each with four replications were performed, and the growth of the E. coli and C. utilis was observed. Statistical analysis was conducted using a completely randomized design. The results showed total phenol content was 0.17 g/100mL, saponin 0.46 g/100mL, and tannin 0.047 g/100mL in LSCBS. The antibacterial activity with a 10-100% concentration of LSCBS did not show zona inhibition (clear zone) against E. coli. Likewise, antifungal activity with a 10-100% concentration of LSCBS did not show zona inhibition against C. utilis. Not all liquid smoke from plant by-products inhibits bacterial growth. This research showed that the liquid smoke from the cocoa bean shells did not affect the growth of Escherichia coli and Candida utilis in vitro, the possible cause was the very low content of total phenols, saponins, and tannins It means liquid smoke from cocoa bean shells could not replace AGPs.