Anti-yeast activity and characterisation of synthetic radish peptides Rs-AFP1 and Rs-AFP2 against food spoilage yeast

Food spoilage resulting from the presence of yeast is a common problem in the food industry. The development of natural food preservatives is a growing area of interest for the food industry. The application of antimicrobial peptides derived from plants can be a simple and natural method of preserving food. This study looked at the antiyeast activity of two chemically synthesised radish antimicrobial peptides, Rs-AFP1 and Rs-AFP2, for their inhibitory effect against different yeast species. The minimum inhibitory concentration (MIC) of both peptides was generated. Two mechanisms of action were studied (membrane permeabilisation and the overproduction of reactive oxygen species (ROS)) and both were found to occur with Rs-AFP2, while only the overproduction of ROS was detected for Rs-AFP1. The effect of the peptides on the yeast cells was also visualised by scanning electron microscopy. Their safety in terms of human consumption was studied and no adverse effects were found. Lastly, the stability of the peptides in different conditions, such as high salt, heat and a range of pH were studied in addition to their antiyeast activity in different food matrices such as soft drink, fruit juices and salad dressing, further supporting the peptides' potential for use in food preservation.