Patent ID: 8603567

Claim:
A method of manufacturing a processed plant selected from the group consisting of processed malt, processed grain, processed tea leaf, processed tea stem, processed coffee bean, processed bean, and processed wood, which contains an increased amount of vanillin as compared to before the processing, comprising the step of processing a lignin-containing plant selected from the group consisting of malt, grain, tea leaf, tea stem, coffee bean, bean, and wood, or the processed material thereof as a raw material with a high-temperature and high-pressure gas comprising water vapor and having a temperature of about 140 to 250° C. and a pressure of about 0.25 to 4.5 MPa, under conditions where an oxygen concentration is about 0 to 1 μg/mL to increase the amount of vanillin contained in the lignin-containing plant or the processed material thereof.