S.A. Mat1, I.S. Mohd Daud1, M.H. Mohamad Rojie1,
N. Hussain1 and Y. Rukayadi1,2*
1Faculty of Food Science and Technology, Universiti Putra Malaysia,
43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
2Laboratory of Natural Products, Institute of Bioscience,
Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
The effects of Candida sp. and Blastobotrys sp. starters on fermentation of cocoa beans were studied to determine the potential antibacterial activity of its extracts against foodborne pathogens. The fermentations of cacao beans using Candida sp. and Blastobotrys sp. were conducted for seven days. The observed parameters include pH and temperature monitoring during fermentation, detected active compounds, and in-vitro antibacterial activity against several foodborne pathogens at sampling day 0, 3 and 7. Spontaneous fermentation (without starter culture added) was used as control. The pH during fermentation increased from pH 3.00 to 7.97, pH 3.00 to 7.68, and pH 3.00 to 7.54 for spontaneous, Candida sp. and Blastobotrys sp. fermentation respectively. The temperatures of fermentation ranged from 28oC to 33oC, 28oC to 32oC, and 28oC to 32oC for fermentation by spontaneous, Candida sp. and Blastobotrys sp., respectively. Gas Chromatography Mass Spectrometry (GC-MS) analyses showed several active compounds including caffeine, theobromine, gamma-tocopherol, stigmasterol and beta-sitosterols in all three fermentations. Caffeine content was highest (74.59%) in control fermentation in earlier process. Theobromine content was higher for control fermentation compared to other Candida sp. and Blastobotrys sp. fermentation. Generally, gamma-tocopherol, stigmasterol and beta-sitosterols contents declined in the middle of the fermentation period but increased again towards the end. Fermented cocoa beans extract exhibited antibacterial activity against Bacillus cereus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella enteritica, and Staphylococcus aureus. However, the extracts did not show any antibacterial activity against Listeria monocytogenes and Pseudomonas aeruginosa. In summary, the addition of starter cultures namely Candida sp. and Blastobotrys sp. in fermentation of cocoa beans able to trigger off the active compounds and show potent antibacterial activity against several foodborne pathogens.
Keywords: Blastobotrys sp.; Candida sp.; Theobroma cacao L; cocoa beans; fermentation; foodborne pathogens.