High quality green tea extract production from enzyme treated fresh green tea leaves.

摘要

Fresh green tea leaf extracts were prepared using pretreatment with the complex enzyme Rapidase TF at various concn., treatment times and temp., followed by extraction for 30 min at 80 degrees C and the physicochemical properties of the extracts were studied. Results showed that free sugar content in samples treated with the enzyme tended to increase, glucose content was <=7.25x higher compared to the control (no enzyme pretreatment). Total amino acid content was barely affected by the enzyme treatment. Caffeine content increased with enzyme treatment temp. Total polyphenols and total catechin contents were increased according to the amount of enzyme added and the treatment temp. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin < epicatechin < epicatechin gallate < epigallocatechin gallate. Gallic acid content increased up to pretreatment conditions of 0.04% and 45 degrees C with no further significant changes thereafter. From the results it was concluded that pretreatment of heat treated fresh green tea leaves with 0.08-1% Rapidase TF at a temp. of 37-45 degrees C for 180-240 min could be used as a fast and simple method for extraction of active compounds from fresh green tea leaves, with an improved extraction ratio.