Natural immune-based technology to prevent black spot disease in pre-washed sweetpotatoes

Pre-washed vegetables are increasingly popular due to higher demand for convenience foods, faster lifestyles, and consumer interest in safe and healthy products. However, washing removes the natural protective layer of fruits and vegetables, causing physical damage and water residue that promote pathogen growth.

This study found that the Asp f2-like protein secreted by Verticillium dahliae (VDAL) and its interacting protein (VIP), when applied during washing, showed strong anti-pathogenic effects in pre-washed sweetpotatoes. The treatment reduced decay rates from 50% to about 20% by day 24.

Both VIP and VIP+VDAL significantly inhibited lesion expansion caused by Ceratocystis fimbriata. Unlike conventional methods, these compounds do not directly kill pathogens but instead activate host resistance mechanisms.

This involves rapid activation of the reactive oxygen species (ROS) burst while simultaneously reducing peak levels of H₂O₂ and O₂⁻. Lower malondialdehyde content and higher DPPH radical scavenging activity were observed during storage.

In addition, treated sweetpotatoes showed increased levels of polyphenols and flavonoids, as well as enhanced activity of phenylalanine ammonia-lyase. Antioxidant enzymes such as peroxidase, catalase, and superoxide dismutase were also upregulated.

Finally, the ascorbate–glutathione antioxidant cycle was strengthened, improving resistance to black spot disease and delaying quality deterioration.

Source

Yang, M., Cao, X., Lu, G., Lu, Y., Xu, X., Guan, Y., Cheng, J., Lu, X., & Pang, L. (n.d.). Postharvest black spot disease prevention technology for pre-washed sweetpotatoes based on the host immune elicitation. Postharvest Biology and Technology. 

https://www.sciencedirect.com/science/article/abs/pii/S0925521426002231