HAMMAD KHALIFEH ALDAL’IN*, HAITHAM QARALLEH, JAWAD ATEF AL-DALA’EEN, AHMAD M AL-JAAFREH, RANIA MOHAMMED ALGROOM, MOUSA ATALLAH AL-TARAWNEH, HUSSEIN HUSSEIN ALHROUT AND AYMAN DAIFALLAH ISMAIL ALSHEIKH
Department of Medical Support, Al-balqa Applied University, Al-Karak University College, Al-karak 61710,
Jordan
*(e-mail: hammad.dalaeen@bau.edu.jo; Contact : 0096 27971 19618)
(Received : December 5, 2022; Accepted : January 11, 2023)
ABSTRACT
Roasting is a crucial step in the manufacture of coffee because it allows flavour and aroma to emerge. The goal of this study was to find the amounts of copper (Cu), iron (Fe), zinc (Zn) and lead (Pb) in coffee that was roasted by machine and coffee that was roasted by hand. The ability of these samples to kill bacteria and fight free radicals was also determined. The concentrations of Cu, Zn, Fe, Pb and caffeine were investigated in machine-roasted and hand-roasted coffee samples using a quantitative method. The antibacterial activity was evaluated using the disc diffusion method and the micro-dilution method. The antioxidant potential was determined using DPPH and ABTS assays. The findings revealed that there were no significant differences in the Cu, Zn, Fe and Pb content between the machine-roasted coffee and the hand-roasted coffee samples. In addition, the solid form of machine-roasted coffee had considerably more caffeine than the liquid form of the same sample. In contrast, the liquid form of the hand-roasted sample contained more caffeine than the solid version. Weak antibacterial activity was observed for both samples tested against Staphylococcus aureus, Streptococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa since the maximum inhibition zone observed was 8.5 mm and the lowest minimum inhibitory concentration (MIC) was 50 mg/ml. Interestingly, the antioxidant activity of the hand-roasted coffee sample (57.05 ppm) was significantly higher than that of the machine-roasted coffee sample (48.5 ppm). These findings recommend that hand-roasted coffee be considered an antioxidant agent. To generalize the results, additional research with larger sample size is needed.
Key words : Coffee, roasting, antibacterial, antioxidant, microelement