Purpose: Caffeine,i,3,7 methylxanthine is one of the quality components of tea and occur in black tea ranging from 2-3.5 percent depending on the type of tea cultivars and methods of processing.Inhibitory influence of caffeine on mold and yeasts are well known and interaction of caffeine known to interfere in the biosynthetic pathway of aflatoxin formation by toxigenic species of A.flavus.The present study was initiated to measure the extent of growth inhibition and germination abnormality in an isolate of IA.flavus(icft-1234)caused by different concentration of caffeine.
Methods: Water agar(2%) mixed with measured quantity of caffeine was used to get desired concentration of 1,10,100,1000 and 10000 ppm for germination test as per (APS-1934).The fungus A.flavus was raised on Czapek medium mixed with above quanty of caffeine and incubated for recording mycelial dry weight.
Results:It ws observed that caffeine reduced biomass production of A.flavus which increased with increasing concentration of caffeine.Caffeinf exerted considerable inhibitory influence on conidial germination of A.flavus accompanied by swelling of germ tubes and repeated curling of germ tube hyphae.At 1000 ppm caffeine caused increased growth abnormality of reproductive structures(vesicles and conidiophores)and significant reduction of spore production.
Conclusion:The antifungal properties of caffeine was discussed in relation to risk reduction in mold and mycotoxin problem in tea processing.
Full conference title:
- AAA 5th (2012)