英语翻译3.2.1.Effect of drying on the phenolic content of aqueou

英语翻译
3.2.1.Effect of drying on the phenolic content of aqueous chamomile
extracts
The effect of drying on the total phenol content in chamomile
extracts is shown in Fig.3.The freshly extracted chamomile flowers
had a higher content of phenols (19.7 ± 0.5 mg/g dw) than any
of the dried samples,except those freeze-dried (p 6 0.05).There
was no significant difference between the total phenol content in
samples freeze-dried,air-dried and oven-dried at 40 2C.Knovalova
et al.(1981) reported that there was no difference in plant essential
oil content between chamomile flowers air-dried and ovendried
at 40–45 2C; therefore,drying under these conditions does
not seem to affect either the phenolic or essential oil content of
chamomile flowers.However,there was a major decrease in the
phenol concentration of chamomile flowers oven-dried at 80 2C
(p 6 0.05).A decrease in total phenols with increasing drying temperatures
has been previously reported for other plants.Julkunen-
Tiitto (1985) found that willow leaves dried below 50 2C had significantly
higher total phenol content than those dried at 90 2C.The
decrease in total phenols at high temperatures was possibly
due to volatile phenols evaporating,decomposition of phenolic
compounds and certain phenols combining with other plant components,
so that they were not available for extraction (Julkunen-
Tiitto,1985).
The effect of drying on the apigenin 7-glucoside content in
chamomile shows a similar trend (Fig.4).The extracts produced
from fresh chamomile had an apigenin 7-glucoside content of
3.0 ± 0.4 mg/g dw,which was significantly higher than the content
of any of the dried samples (p 6 0.05).There was no significant difference
in the apigenin 7-glucoside content between the chamomile
flowers which were freeze-dried,air-dried or oven-dried at
40 2C (2.0 ± 0.4 mg/g dw).The biggest decrease in apigenin 7-glucoside
to 1.0 ± 0.3 mg/g dw was seen in the samples oven-dried
at 80 2C.The effect of drying treatment on the apigenin 7-glucoside
content of willow leaves has been previously studied (Julkunen-
Tiitto & Sorsa,2001) but unlike chamomile flowers there was no
significant difference between any drying treatments (fresh analysis,
room drying at 22 2C,air drying at 60 or 90 2C) except for the
freeze-dried material,which had a significantly lower content of
apigenin 7-glucoside.不要翻译软件翻译的