19
However, the amount of phenolic compounds in CGR extract using hexane as solvent 1300 mg GAE100 g was higher than those extracted with water Ramalakshmi et al., 2009. In this study,
the extraction of CGR using water as solvent also had lower of phenolic compounds 300 mg GAE100 g than those extracted with hexane resulted in Ramalakshmi study. This could be
explained by the fact that phenolic compounds are generally more soluble in organic solvents less polar than water Kim et al., 2002. Alcohols, particularly methanol and ethanol were also more
efficient than water in extracting phenolics from different natural sources such as citrus peel, black tea, barley and medicinal plants Rehman, 2006.
a
The amount of phenolic compounds expressed as gallic acid equivalent GAE The values with different letters a-af in each column show a significant difference
p0.05 Figure 9 Total phenolic compounds of coffee ground residue extracts
2. Chlorogenic Acid Compounds CGA
The amount of CGA in the CGR extracts obtained with different time of MAE was shown in Figure 10. The results had the same tendency with total phenolic compounds. Sample B
3 minutes, B 4 minutes and A 4 minutes also had higher amount of CGA compounds 222.45 mg100 g; 216.72 mg100 g; and 207.15 mg100 g, respectively than the others.
Four minutes of MAE overall showed the higher CGA in the extracts 123-216 mg100 g than the others. MAE extracts also had the higher amount of CGA than the control extracts. The
CGA in the extracts slightly higher than those reported by Murthy et al., 2010 210 mg100 g in isopropanol-water solvent. This could be explained by the fact that CGA is more soluble in
solvent with higher polarity, especially water than those with methanol or ethanol Mussato et al., 2011.
The CGA is the main phenolic compounds approximately 12 of solid in green coffee bean Esquivel, 2011. Therefore, CGA content in CGR extracts were approximately five-fold
lower than those in green coffee bean. The reduction of total CGA was mainly caused by the high temperature during coffee roasting Moon et al., 2009. There was a chemical transformation
during coffee roasting where the CGA made a building block with caffeic and quinic acid and incorporated into melanoidins Farah, 2006.
b af
u x
n t
q q
k ab
a ae
r w
m aa
g ab
s y
cd w
q j
l v
f p
o p
ef i
b h
e f
a c
h d
100 200
300 400
500 600
700 800
900
A B
C D
E F
G H
I J
P heno
lic m
g G
AE 1
g DB
a
Coffee Ground Residue Extract
3 min 4 min
5 min Control
20
The values with different letters a-x in each column show a significant differencep0.05 Figure 10 Chlorogenic acid of coffee ground residue extracts
3. Caffeine
The result of caffeine was similar to those of the phenolic compound and CGA in the CGR extracts. The amount of caffeine in the CGR extract with different time of MAE was shown
in Figure 11. Sample B 3 minutes, B 4 minutes and A 3 minutes had higher amount of caffeine
compounds 192.02 mg100 g, 173.88 mg100 g, and 165.41 mg100 g, respectively than the others. Four minutes of MAE extracts also had higher amount of caffeine 22-173 mg100 g than
the other time of MAE. The results were slightly higher than those reported by Ramalakshmi et al. 2008 120 mg100 g in hexane solvent and Soxhlet extraction. Caffeine is a polar organic
molecule dissolved in polar solvent easier than in non polar solvent such as methanol and ethanol Upadhyay, 2011. The results also showed that the amount of caffeine were five-fold lower than
those in coffee beans 1000 mg100g Ramalakshmi et al., 2008. The coffee brewing could extract some bioactive compounds such as caffeine, chlorogenic acid, and flavonoid Minanisawa
et al., 2009.
4. Anthocyanin
