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Effect of Microwave Vacuum Drying on Contents of Phenolic
and Antioxidant Activity of Lotus Leaf Tea
LIU Huijuan
1
,摇 ZHENG Yunzhan
1
,摇 CHEN Yanxia
1
,摇 SHI Congzhen
1
,摇 SU Dongxiao
1,2,*
(1
. College of Life Science
,
Yangtze University
,
Jingzhou
434025,
China
;
2
. Research and Development Center of Special Food of Jingchu
,
Yangtze University
,
Jingzhou
434025,
China
)
Abstract
: Drying is commonly used for preservation and deep processing of agricultural byproducts.
However, the contents of active substances may be altered during the drying process, resulting in de鄄
crease of biological activities. In order to study the effect of power of microwave vacuum drying on phe鄄
nolic substances in lotus leaf tea, effects of microwave drying under different power (300, 400, and 500
W), hot air drying, and sun drying on the contents of phenolic compounds and its antioxidant activity in
lotus leaf tea were investigated. DPPH radical scavenging capacity and ferric reducing antioxidant power
(FRAP) were used to analyze the antioxidant activities. The results showed that the contents of total phe鄄
nolcis and total flavonoids in lotus leaf tea treated by microwave vacuum drying were 1郾 79 and 1郾 76 folds
higher than those of traditional hot air drying products. Microwave vacuum drying lotus leaf exhibited
higher antioxidant activity in DPPH·scavenging activity (
IC
50
values 62郾 52, 49郾 31, 43郾 59 滋g / mL, re鄄
spectively) comparing to hot air drying products. In addition, the FRAP value of microwave vacuum dr鄄
ying (500 W) samples was 3郾 18 and 1郾 82 folds higher than that of sun drying and hot air drying sma鄄
ples. The Pearson correlation analysis between antioxidant activity and phenolic compounds showed that
the content of total flavonoids in lotus leaf was significantly correlated with DPPH and FRAP, indicating
that the microwave vacuum drying would significantly affect the content of phenolic compounds in lotus
leaf, and then enhance its antioxidant activity.
Key words
: lotus; microwave vacuum drying; phenolic; antioxidant activity; free radicals
(
责任编辑
:
叶红波
)
54
第
34
卷 第
3
期
摇 摇 摇 摇
刘慧娟等
:
微波真空干制加工对荷叶茶酚类物质含量及其抗氧化活性的影响
