Shelf-Life Extension of Rice Cake by the Addition of Persimmon Leaf Tea Powder

Antimicrobial activity of persimmon leaf tea methanol extracts on Klebsiella pneumoniae and Staphylococcus aureus was examined through paper disk diffusion bioassay. K. pneumoniae and S. aureus showed 87.64 and 99.35% growth inhibitions by addition of steamed tea methanol extracts (10 mg/ml), respectively. The number of microorganisms in rice cakes was significantly reduced when leaf tea powder was added during production of rice cakes. Addition of 1% steamed leaf teas to rice cakes decreased the number of microorganisms by over 50%, and over 70% reduction was observed when final 2% (dried weight w/w) steamed leaf tea was added, whereas no significant effect was observed over 2%. These results indicate that different microorganisms were detected from persimmon leaf and rice cake, and persimmon leaf can inhibit normal microbial growth in rice cake.