Fine green tea powders (GTP), with green and bright color, could
be prepared in the experiment. The GTP had a narrower and more
uniform particle size distribution, possessing more food processing
property. The contents of tea polyphenols and catechins decreased
while yellowness increased markedly with particle size decreasing
during superfine grinding, owing to increasing heat. So it is
important to control heat during grinding in order to keep GTP
green. The contents of water-soluble carbohydrates in GTPs
increased, but no significant difference in amino acids and caffein,
with the decrease in particle size during superfine grinding, which
benefits to reduce bitterness and preserve briskness of GTP. More
accumulating evidences demonstrated that physiological polysaccharide
in tea has exhibited potent bioactivities. In our experiment,
superfine grinding is helpful for improving extraction of TPS,
which could lead to more potent scavenging capacity of GTPEs on
$OH. Therefore, the increased antioxidation of GTP could be beneficial
to improving its nutritious value. Based on the quality analysis,
we suggested that superfine grinding time should be
controlled within 30e50 min, with ideal parameters of GTP: X:
4.93e4.75%, d50: 20.3e13.5 mm, rbulk: 0.323e0.297 kg/m3, rtapped:
0.666e0.614 kg/m3.