Enhancing bacterial inhibition in beetroot beverages: The potent combination of sappan heartwood extracts via accelerated solvent extraction and pulsed electric field methods

This study aimed to investigate the potential of sappan heartwood extract as an inhibitor of foodborne pathogenic bacteria in beetroot juice. The extract was obtained using an accelerated solvent extraction process (using an ethanol/water solvent mixture (3:1 w/w) at 120 °C and 1500 psi for 5 min), yielding 10.04 g per 73.6 g of dried sappan heartwood powder, with a percentage yield of 13.64 and 2.69 % brazilin. The extract was combined with pulsed electric fields (PEF) at different strengths and tested against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus), and Salmonella typhimurium (S. typhimurium). Results showed that the combination of sappan heartwood extract and PEF at 15 kV/cm and concentrations of 3.91, 5.86, and 11.73 mg/mL effectively reduced the total plate count and coliform bacteria count, and completely eliminated B. cereus and S. typhimurium during 7 days of storage at 4 °C. Furthermore, this combination was found to be more efficient in bacterial elimination compared to thermal pasteurization and potassium sorbate addition. These findings suggest that sappan heartwood extract can be used as a natural antimicrobial agent in food products, especially in beetroot juice, where regulatory standards restrict the addition of preservatives. Using sappan heartwood extract in combination with PEF is highly effective in killing foodborne pathogens, reducing the risk of consumer harm and ensuring food safety.