Synergistic inhibition effect of citral and eugenol against Aspergillus niger and their application in bread preservation

Consumers' preferences for cleaner label products require the food industry to replace synthetic preservatives with natural substitutes. Therefore, the synergistic inhibitory effect of eugenol and citral (S-EC) on Aspergillus niger was explored. On this basis, the antimicrobial sachet containing SEc was developed and its application potential in bread preservation was evaluated. The content of reactive oxygen species (ROS) and malondialdehyde (MDA) showed that S-EC could significantly induce lipid peroxidation in cell membranes, in which citral played a leading role. The permeation experiments of SEM, TEM, propyl iodide and fluorescein diacetate showed that S-EC could destroy the integrity of the cell membrane. Eugenol contributed more than citral. The OD260 and the relative conductivity of the S-EC group increased by 5.2 and 4.1 times, respectively, after 8 h. Finally, the shelf life experiment of bread showed that the antimicrobial sachets containing S-EC could significantly prolong the shelf life of bread without producing unpleasant odour.