Postharvest Propionic Acid and Hot Water Treatment for the Control of Black Spot Disease in Chinese Ya Pears

Tao Liu,Guoping Zhan,Fanhua Zhang,Tianxiu Li,Yuejin Wang,Li Li Li

doi:10.19026/ajfst.6.22

Abstract

Black spot disease caused by Alternaria alternata (Fr.) is one of the main postharvest diseases of Chinese Ya pears and causes serious economic loss during storage. The fungi-toxicity of postharvest propionic acid and hot water treatment at different concentrations and temperatures was investigated in vitro and directly on Ya pears. The in vitro results showed that A. alternata was susceptible to propionic acid solutions at all tested temperatures. The toxicity of propionic acid increased linearly and the LC 99 decreased from 13.43 to 4.31 g/L with an increase in temperature from 20 to 45Â°C. The results in Ya pears showed that propionic acid and hot water treatment dramatically controlled black spot disease and 99% inhibition was achieved upon treatment with 9 g/L propionic acid solution for 30 min at 45Â°C. Furthermore, the treatment inhibited the respiration of fruits and did not cause any adverse effects on other quality parameters; however, slight surface injury was noted at 9 g/L. The safety of propionic acid treatment was further confirmed by residue analysis. The results of this study suggest that postharvest propionic acid and hot water treatment is an alternative method for the control of black spot disease in Ya pears.

Highlights

Chinese Ya pear (Pyrus pyrifolia), a crisp, sweet and delicious fruit native to north China, has great commercial importance due to its large production and consumption demand
Black spot disease caused by Alternaria alternata (Fr.) Keissler often occurs in Chinese Ya pears during storage, which limits its marketability and results in serious post harvest loss (Baudry et al, 1993; Zhang et al, 2003)
Due to the serious loss of fresh fruits caused by postharvest disease and the increasing social concern regarding chemical fungicides, there is a constant need to develop new antifungal technologies

Summary

Introduction

Chinese Ya pear (Pyrus pyrifolia), a crisp, sweet and delicious fruit native to north China, has great commercial importance due to its large production and consumption demand. A. alternata is considered to be a pest of quarantine importance by some countries; it hampers the export of Chinese Ya pears (Roberts, 2005). There is a need to develop an economical, effective and safe postharvest treatment measure. Heat treatment has been widely investigated as an effective method for disinfestation of insect and fungal pests from fruits (Couey, 1989). Heat treatment can inhibit ripening and chilling injury of many fruits during storage, extending their shelf life (Paull and Nancy, 2000). Similar to what was observed in research on mango (Prusky et al, 1999), an extremely high temperature was required to control A. alternata in our preliminary test and this temperature could not be tolerated by Ya pears

Methods

Results

Conclusion