Controlling Fusarium oxysporum Tomato Fruit Rot under Tropical Condition Using Both Chitosan and Vanillin

: Tomato Lycopersicon esculentum Mill. is one of the most cultivated and widely consumed
vegetables in the world. However, it is very susceptible to the infection initiated by Fusarium ox‐
ysporum fruit rot, which shortens post‐harvest life and thus reduces market value. This disease can
be regulated appropriately by the application of synthetic fungicides. However, chemical fungicides
constitute a serious health risk, and have harmful environment effects and increase disease re‐
sistance, even when microbes are dead. Hence, to overcome this problem, chitosan and vanillin,
which have antimicrobial bioactive properties against the growth of microorganisms, could be an
alternative to disease control, while maintaining fruit quality and prolonging shelf life. The aim of
this research was to evaluate the antimicrobial activity of chitosan and vanillin towards the inocu‐
late pathogen and to investigate the effect of chitosan and vanillin coating in vivo on Fusarium ox‐
ysporum fruit rot and defense‐related enzymes (PAL, PPO and POD). Chitosan and vanillin in aque‐
ous solutions, i.e., 0.5% chitosan + 10 mM vanillin, 1% chitosan + 10 mM vanillin, 1.5% chitosan + 10
mM vanillin, 0.5% chitosan + 15 mM vanillin, 1% chitosan + 15 mM vanillin and 1.5% chitosan + 15
mM vanillin, were used as edible coatings on tomatoes stored at 26 ± 2 °C and 60 ± 5 relative hu‐
midity. The result revealed 1.5% chitosan + 15 mM vanillin was able to control disease incidence by
70.84% and severity by 70%. These combinations of coatings were also able to retain phenylalanine
ammonia‐lyase (PAL), peroxidase activity (POD), and polyphenol oxidase (PPO) enzyme activities
as well as prolong shelf life of tomatoes up to 15 days.