Postharvest control of litchi fruit rot by Bacillus subtilis.
Jiang, Y. M., Zhu, X. R. and Li, Y. B.
Lebensmittel-Wissenschaft und –Technologie. Volume 34, Issue 7, November 2001, Pages 430-436
2001
บทคัดย่อ
A study was conducted to identify the main pathogens of postharvest litchi (Litchi chinensis) fruits, evaluate the potential antagonists in vitro, identify the antifungal substances of B. subtilis and determine the optimum application of the antagonist and its extract necessary for the efficacious control of postharvest diseases. In pathogenicity tests, both unwounded and wounded litchi fruits were artificially inoculated. The main pathogen was identified as Peronophythora litchi. However, Alternaria alternata, Colletotrichum gloeosporioides [Glomerella cingulata], Fusarium sp. and Phomopsis sp. at a later stage of cold storage were also isolated from the fruit surface. B. subtilis was the most effective antagonist against Peronophythora litchi of the antagonists tested. Toyopearl gel filtration confirmed that the B. subtilis antifungal compound had a molecular weight of about 1.2 kD. The best B. subtilis antifungal activity was at 108 cells per ml. The concentration (relative antifungal activity) of the antifungal substances of B. subtilis reached a maximum after 48 h of culture, and then decreased gradually. Furthermore, both the antagonist and its extract gave effective control of artificially wound-inoculated fruit pathogens, but the use of the extract showed better effect than that of the antagonist. Treatment with the extract of the antagonist was effective in controlling fruit decay for a storage period of 30 days at 5 deg C and in quality maintenance (in terms of eating score (3.7), total soluble solids, total titratable acidity and ascorbic acid contents), but the rate of decay was high (25.0%) when the storage period was extended up to 40 days.