ARS | Publication request: Difference between chitosan and oligochitosan in growth of Monilinia fructicola and control of brown rot in peach fruit

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 29, 2011
Publication Date: April 12, 2012
Citation: Yang, L., Zhang, J., Bassett, C.L., Meng, X. 2012. Difference between chitosan and oligochitosan in growth of Monilinia fructicola and control of brown rot in peach fruit. LWT - Food Science and Technology. 46:254-259.

Interpretive Summary: Peach fruit are particularly susceptible to storage rots caused by fungi or bacteria. Losses due to contaminated fruit can be substantial, costing both the grower and the consumer in reduced revenue and higher costs, respectively. Although there are effective chemical controls for preventing fungal rots, most have been discontinued due to potentially harmful effects from consumption of treated fruits. Researchers are seeking safer, ‘natural’ compounds which can control fungal growth on stored fruit. This manuscript describes tests performed on stored peach fruit using two safe compounds, i.e., chitosan and oligochitosan, to control brown rot caused by a fungus. Both compounds were effective in controlling fungal growth, but oligochitison was somewhat better than chitosan. The results indicate that both compounds could be developed into effective natural fungicides to control brown rot in peaches.

Technical Abstract: Chitosan (CS) and oligochitosan (OCS), as natural antifungal agents, have been primarily used as alternatives to synthetic chemical fungicides to control postharvest diseases of fruits. The effectiveness of these two agents on the growth of Monilinia fructicola to control brown rot has not yet been reported. Both spore germination and mycelial growth of M. fructicola were strongly inhibited by CS and OCS treatments in this study. Moreover, the inhibitory effect of both agents was more obvious on mycelial growth than on spore germination. By comparison of the half maximal inhibitory concentration (IC/fifty) of each, OCS treatment conferred a little better inhibitory effect on fungal growth in vitro, but the effectiveness of both treatments on brown rot control in peach fruit stored at 25 C was very similar. The plasma membrane of CS- or OCS-treated spores was obviously damaged. Cytoplasm leakage was significantly higher in chitosan-treated mycelia than that of the control. These results suggest that both chitosan and oligochitosan used in this study are promising natural fungicides for control of brown rot of peach.