2.4. Identification of phenolic compounds
2.4.1. Extraction of phenolic compounds
The phenolic compounds in the samples were extracted using a
modification of the procedure described by Bengoechea et al.
(1997) as adapted from Uzelac, Pospišil, Levaj, and Delonga
(2005). The powdered sample (5 g) was mixed with 50 ml of methanol/
HCl (100:1, v/v) which contained 2% tertbutylhydroquinone,
in inert atmosphere (N2) during 12 h at 35 C in the dark. The extract
was then centrifuged at 4000 rpm, and the supernatant was
evaporated to dryness under reduced pressure (35–40 C). The residue
was redissolved in 25 ml of water/ethanol (80:20, v/v) and extracted
four times with 25 ml of ethyl acetate. The organic fractions
were combined, dried for 30–40 min with anhydrous sodium sulphate,
filtered through a Whatman-40 filter, and evaporated to
dryness under vacuum (35–40 C). The residue was redissolved
in 5 ml of methanol/water (50:50, v/v) and filtered through a
0.45 lm filter before injection (20 ll) into the HPLC aperture. Samples
were analysed in triplicate.
2.4. Identification of phenolic compounds2.4.1. Extraction of phenolic compoundsThe phenolic compounds in the samples were extracted using amodification of the procedure described by Bengoechea et al.(1997) as adapted from Uzelac, Pospišil, Levaj, and Delonga(2005). The powdered sample (5 g) was mixed with 50 ml of methanol/HCl (100:1, v/v) which contained 2% tertbutylhydroquinone,in inert atmosphere (N2) during 12 h at 35 C in the dark. The extractwas then centrifuged at 4000 rpm, and the supernatant wasevaporated to dryness under reduced pressure (35–40 C). The residuewas redissolved in 25 ml of water/ethanol (80:20, v/v) and extractedfour times with 25 ml of ethyl acetate. The organic fractionswere combined, dried for 30–40 min with anhydrous sodium sulphate,filtered through a Whatman-40 filter, and evaporated todryness under vacuum (35–40 C). The residue was redissolvedin 5 ml of methanol/water (50:50, v/v) and filtered through a0.45 lm filter before injection (20 ll) into the HPLC aperture. Sampleswere analysed in triplicate.
การแปล กรุณารอสักครู่..
