Chemical and functional components in different parts of rough rice (Oryza sativa L.)
before and after germination
Hyun Young Kim
a
, In Guk Hwang
b
, Tae Myoung Kim
c
, Koan Sik Woo
d
, Dong Sik Park
b
, Jae Hyun Kim
b
,
Dae Joong Kim
c
, Junsoo Lee
a
, Youn Ri Lee
e
, Heon Sang Jeong
a,
⇑
a
Department of Food Science and Technology. Chungbuk National University, Cheongju 361-763, Republic of Korea
b
Department of Agrofood Resources, National Academy of Agricultural Science, Suwon 441-857, Republic of Korea
c
College of Veterinary Medicine, Chungbuk National University, Cheongju 361-763, Republic of Korea
d

and brown rice increased 1.13 and 1.20-fold after germination, respectively. The vitamin E content
increased from 3.21 to 3.93 mg/100 g in rough rice. The sprout had high vitamin E (5.45 mg/g) and
c
-oryzanol (9.91 mg/g) content.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Rice (Oryza sativa, L.) is the common name for more than 20 an-
nual species in the grass family and is the main food of almost half
of the world’s population. The rice seed, or caryopsis, consists
mainly of the seed coat, embryo, and endosperm. Rice bran (the
seed coat) contains protein, B complex vitamins, and vitamin E
and K, while polished rice (without the seed coat) contains about
25% carbohydrate, with trace amounts of iodine, iron, magnesium,
and phosphorus, and only small amounts of protein and fat
(Madamba & Lopez, 2002; Ponciano & Richard, 2005). Rice bran
contains many valuable substances, such as vitamin E (
a
-tocopherol
and tocotrienol) and
c
-oryzanol. The major component of vitamin E
in rice bran is
a
-tocopherol, which is an antioxidant that can lower
the risk of cancer and coronary heart disease (Zhimin, Na, &
Samuel, 2001), and is also reported to prevent Alzheimer’s disease
and many allergies (Nakamura, Tian, & Kayahara, 2004).
Germination is an effective and common process used to im-
prove the nutritional quality of cereals consumed around the world
(Lee et al., 2007a). The germination process is affected by external

Food Chemistry
journal homepage: www.elsevier.com/locate/foodchem
was to analyse the chemical and functional components of the seed
parts (i.e., hull, brown rice, and sprout) before and after germinated
rough rice. We examined the crude protein, crude lipid, free sugars,
fatty acids, phytic acid, vitamin E,
c
-oryzanol, and
c
-aminobutyric
acid content.
2. Material and methods
2.1. Rough rice and sample preparation
The rough rice (cv. Ilpumbyeo, O. sativa, L.) was grown at the
National Institute of Crop Science, Rural Development Administra-
tion, Suwon, Korea, during the 2010 growing season. The seed was
soaked in water at 15 °C, and the water was changed every 24 h.
Three days after germination, the seed was separated into three
parts (hull, brown rice, and sprout including the embryo), dried
at 60 °C for 24 h, and then ground in a food processor (J. World
Tech., Korea). Samples (rough rice seed, hull, brown rice, and
sprout) were kept at À20 °C and protected from light prior to fur-
ther use. The powdered samples were then passed through a 100-
mesh sieve and the chemical and functional components were
analysed.
2.2. Analysis of crude protein and lipids
The standard method of AOAC (1990) was used for determina-
tion of crude protein and lipid content. The crude protein content
was measured with the Kjeldahl method (AOAC, 950.09) and the
crude lipid content was obtained after incineration using the

fore and after germination was measured using a UV spectropho-
tometer (DU-650; Beckman Coulter, Fullerton, CA) at a
wavelength of 500 nm, according to the modified method of Haung
and Lantzsch (1983). The phytic acid level was calculated based on
a standard curve.
2.6. Analysis of vitamin E
The vitamin E content of methanolic extracts from different
parts of rough rice seeds was determined according to the proce-
dure described by Lee, Suknark, Kluvitse, Phillips, and Eitenmiller
(1998), with some modifications. In brief, an aliquot of each meth-
anolic extract was evaporated under N
2
gas. The residues were re-
dissolved in n-hexane, filtered, and analysed using normal phase
HPLC (Younglin Inc., Seoul, Korea). Tocopherols and tocotrienols
were analysed using an LiChrosphere-Diol 100 column
(4.0 Â 250 mm, i.d. 5
l
m) with a hexane:isopropanol (98.7:1.3, v/
v) mobile phase at a flow rate of 1 ml/min. Peaks were detected
by fluorescence using an excitation wavelength of 290 nm and an
emission wavelength of 330 nm.
2.7. Analysis of
c
-oryzanol
c
-Oryzanol was analysed using HPLC (Thermo Separation Prod-
ucts, San Jose, CA, USA) with a UV detector at 325 nm. The metha-
nolic extracts were evaporated under N
2

Statistical analysis was carried out using SPSS version 11.5
(SPSS Inc., Chicago, IL, USA). The results are expressed as
means ± standard deviations. Student’s t-tests for unpaired data
were used for all measured parameters to determine the signifi-
cance of the changes before and after germination.
3. Results and discussion
3.1. Crude protein and lipids
The changes in crude protein of the different parts of rough rice
seed before and after germination ranged from 38 ± 1.21 mg/g in
the hull to 105 ± 2.62 mg/g in the brown rice (Fig. 1). During germi-
nation, the crude protein content of rough rice slightly increased
from 97 ± 2.73 mg/g before to 105 ± 2.62 mg/g after germination,
whereas the brown rice protein content slightly decreased
(p > 0.05), but the hull content increased significantly from
H.Y. Kim et al. /Food Chemistry 134 (2012) 288–293
289
38 ± 1.21 mg/g to 50 ± 2.16 mg/g (p < 0.01). Most storage proteins
in rice grain are found in the endosperm, and brown rice contains
about 83 mg/g protein (Matz, 1996); these results are similar to
those reported by Jones and Lookhart (2005). The increase of protein
content may confer nutritional advantage on the germinated rough
rice. The increase of protein content by germination could be attrib-
uted to net synthesis of enzyme protein which might have resulted
in the production of some amino acids during protein synthesis
(Marero et al., 1989; Uwaegbute, Iroegbu, & Eke, 2000). The crude
lipid was highest in the sprout (6 ± 0.18%) after germination
(Fig. 2), while in the hull it increased from 0.6 ± 0.12% to 1.1 ± 0.06%
after germination (p < 0.05), but decreased slightly in the brown
rice. Both the crude protein and crude lipid content increased after
germination, probably because of the biosynthesis of new com-

acid (18.13%). The linoleic acid content of brown rice after germi-
nation increased from 17.40% to 21.99% (p < 0.05). After germina-
tion, the oleic acid content of the rough rice and hull increased
from 42.99% to 44.00% and from 42.92% to 44.22%, respectively.
3.4. Phytic acid
The phytic acid contents of different parts of rough rice before
and after germination are shown in Fig. 3. The phytic acid de-
creased significantly after germination (p < 0.05). The phytic acid
content of rough rice decreased from 3.57 to 2.17 mg/g, and that
of brown rice decreased from 4.34 to 3.42 mg/g (p < 0.05). The
sprout part that was absent before germination was 0.26 mg/g.
The decrease in the phytic acid content after germination may be
attributed to leaching out into soaking water (Abdullah, Baldwin,
& Minor, 1984). Other researchers have reported that the decrease
in phytic acid content due to an increase in phytase activity of ger-
minated grains (
Borade, Kadam, & Salunkhe, 1984; Rao & Deosthale,
1982). Phytase activity was found during the germination of grains,
which hydrolyse phytate to phosphate and myoinositol phos-
phates. A lot of researches on the damaging effects of phytic acid
have been published (Spencer & Karmer, 1988) but other results
showed that phytates possess possible ability to reduce the risks
of heart disease and cancer (Cornforth, 2002).
3.5.
c
-Oryzanol
The beneficial effects of
c
-oryzanol on human health have gen-
erated global interest in developing simple methods for its separa-

60
80
100
120
Rough rice Hull Brown rice Sprout
Crude protein (mg/g)
BG AG
Fig. 1. Changes in crude protein content of different parts of rough rice (Oryza sativa
L.) before (BG) and after germination (AG). Results are expressed as the average of
triplicate samples with mean ± SD.
⁄
p < 0.01; Significantly different by paired t-test,
significantly different by Students t-test between before and after germination.
*
0.0
2.0
4.0
6.0
8.0
Rough rice Hull Brown rice Sprout
Crude lipid (%)
BG AG
Fig. 2. Changes in crude lipid content of different parts of rough rice (Oryza sativa
L.) before (BG) and after germination (AG). Results are expressed as the average of
triplicate samples with mean ± SD;
⁄
p < 0.05; Significantly different by paired t-test,
significantly different by Students t-test between before and after germination.
290 H.Y. Kim et al. /Food Chemistry 134 (2012) 288–293
3.6. Vitamin E

a
-tocopherol content after germination should increase
the vitamin E bioactivity in the sprout. However, further investiga-
tions are needed to confirm the activity and bio-availability of
sprout tocopherols, and the optimum germination conditions
needed to maintain the quality of tocopherols in the germinated
sprout.
3.7.
c
-Aminobutyric acid (GABA)
c
-Aminobutyric acid (GABA), a non-protein amino acid, is
widely distributed along with eukaryotes and prokaryotes. It is
known as one of the main inhibitory neurotransmitters in the sym-
pathetic nervous system and plays an important role in cardiovas-
cular function (Wang, Tsai, Lin, & Ou, 2006). Therefore, searching
GABA-rich foods becomes one of the focuses in the field of func-
tional food research. Change in the GABA content is enhanced in
the germination state, so allowing time for germination during
processing can help improve rice quality. As shown in Fig. 5, the
GABA contents of different part of rough rice were increased after
germination. The GABA content increased from 15.34 before to
31.79 mg/100 g after germination in rough rice, and the content
Table 1
Changes in free sugar content of different parts of rough rice (Oryza sativa L.) before and after germination (unit:mg/g).
Parts Fructose Glucose Sucrose Total free sugar
Before germination Rough rice 0.25 ± 0.011 ND 0.55 ± 0.013 0.79 ± 0.024
Hull ND
a
ND ND ND

Brown rice 23.70 ± 0.017 2.26 ± 0.057 30.08 ± 0.020 21.99 ± 0.010
*
3.38 ± 0.030
Sprout 23.41 ± 0.040 2.17 ± 0.195 38.21 ± 0.138 18.13 ± 0.041 1.25 ± 0.024
Results are expressed as the average of triplicate samples with mean ± SD.
*
p < 0.05; Significantly different by paired t-test, significantly different by Students t-test between before and after germination.
*
*
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Rough rice Hull Brown rice Sprout
Phytic acid (mg/g)
BG AG
Fig. 3. Changes in phytic acid contents on different parts of rough rice (Oryza sativa
L.) before and after germination. Results are expressed as the average of triplicate
samples with mean ± SD;
⁄
p < 0.05; Significantly different by paired t-test, signif-
icantly different by Students t-test between before and after germination.
*
*
0
2
4

changes in several chemical and functional compositions of differ-
ent parts of germinated rough rice. The chemical and functional
components were determined for rough rice, hull, brown rice,
and sprout parts before and after germination. Functional compo-
nents, such as vitamin E,
c
-oryzanol, and GABA contents of rough
rice, hull, brown rice, and sprout part increased significantly after
germination. After germination, the total vitamin E contents of
rough rice, hull, and brown rice parts increased 1.28, 7.65, and
1.01 times, those of GABA increased 2.35, 1.69, and 2.23 times,
and those part of
c
-oryzanol increased 1.13, 1.67, and 1.2 times,
respectively. The vitamin E, GABA, and
c
-oryzanol content in
sprout part were 5.45, 6.037 and 9.91 mg/g, respectively. Oxidative
stress is related to diabetes and diabetic complications, and fat-
soluble vitamins, such as vitamin A, vitamin E diminish the lipid
content of blood plasma in patients with non-insulin-dependent
diabetes mellitus (Lee et al., 2007a). The evaluation of GABA in
germinated brown rice is important when looking to enhance the
dietary supplements effect on human health, because GABA is
responsible for various biological activities. Especially, the increases
in vitamin E,
c
-oryzanol and GABA sprout after germination indi-
cate that germinated rough rice is a useful food supplement for
the prevention and improvement of life style-induced disease.

of phytate in cereals and cereal products. Journal of Agricultural and Food
Chemistry, 34, 1423–1426.
Jones, B. L., & Lookhart, G. L. (2005). Comparison of the endoproteinases of various
grains. Cereal Chemistry, 82, 125–130.
Kazanas, N., & Fields, M. L. (1981). Nutritional improvement of sorghum by
fermentation. Journal of Food Science, 46, 819–821.
Kim, J. H., Kho, Y. H., Lee, H. J., Kim, M. H., & Lee, S. M. (2001). Regulation of apoptotic
cell death in U937 leukemia cells by fatty acids. Food Science and Biotechnology,
10, 529–533.
Lee, J., Suknark, K., Kluvitse, Y., Phillips, R. D., & Eitenmiller, R. R. (1998). Rapid liquid
chromatographic assay of vitamin E and retinyl palmitate in extruded weaning
foods. Journal of Food Science, 64, 968–972.
Lee, Y. R., Kim, J. Y., Woo, K. S., Hwang, I. G., Kim, K. H., Kim, J. H., & Jeong, H. S.
(2007a). Changes in the chemical and functional components of Korean rough
rice before and after germination. Food Science and Biotechnology, 16,
1006–1010.
Table 3
Changes in vitamin E contents of different parts of rough rice (Oryza sativa L.) before (BG) and after germination (AG) (unit: mg/100 g).
Parts
a
-T
a
-T3 b-T b-T3
c
-T
c
-T3 Total
BG Rough rice 0.63 ± 0.007 0.31 ± 0.006 – – – 1.88 ± 0.042 2.82 ± 0.049
Hull 0.09 ± 0.061 – – – – 0.08 ± 0.002 0.17 ± 0.003
Brown rice 1.08 ± 0.041 0.78 ± 0.003 0.03 ± 0.003 0.02 ± 0.001 0.09 ± 0.002 1.02 ± 0.024 3.02 ± 0.097

0.0
10.0
20.0
30.0
40.0
Rough rice Hull Brown rice Sprout
GABA (mg/100g)
BG AG
Fig. 5. Changes in GABA contents of different parts of rough rice (Oryza sativa L.)
before (BG) and after germination (AG). Results are expressed as the average of
triplicate samples with mean ± SD.
⁄⁄
p < 0.01; Significantly different by paired
t-test, significantly different by Students t-test between before and after
germination.
292 H.Y. Kim et al. /Food Chemistry 134 (2012) 288–293
Lee, Y. R., Woo, K. S., Kim, K. J., Son, J. R., & Jeong, H. S. (2007b). Antioxidant activities
of ethanol extracts from germinated specialty rough rice. Food Science and
Biotechnology, 16, 765–770.
López-Amorós, M. L., Hernandez, T., & Estrella, I. (2006). Effect of germination on
legume phenolic compounds and their antioxidant activity. Journal of Food
Composition and Analysis, 19, 277–283.
Madamba, P. S., & Lopez, R. I. (2002). Optimization of the osmotic dehydration of
mango (Mangifera indica L.) slices. Drying Technology, 20, 1227–1242.
Marero, L. M., Payumo, E. M., Librando, E. C., Lainez, W., Gopez, M. D., & Homma, S.
(1989). Technology of weaning food formulations prepared from germinated
cereals and legumes. Journal of Food Science, 53, 1391–1395.
Matz SA. (1996). Chemistry and Technology of Cereals as Food and Feed. In: 2nd CBS
Publishers and Distributors (pp. 57–60). New Delhi, India.
Miller, A., & Engel, K. H. (2006). Content of oryzanol and composition of steryl

schizophrenics receiving major tranquilizero. Clinical Therapeutics, 12, 263–268.
Spencer, H., & Karmer, L. (1988). Calcium, phosphorus and fluoride. In K. T. Smith
(Ed.), Trace minerals in Foods (pp. 40–46). New York and Basel: Marcel and
Dekker, Inc
Uwaegbute, A. C., Iroegbu, C. U., & Eke, O. (2000). Chemical and sensory evaluation
of germinated cowpeas (Vigna unguiculata) and their products. Food Chemistry,
68, 141–146.
Wang, T. H. F., Tsai, Y. S., Lin, M. L., & Ou, A. S. (2006). Comparison of bioactive
components in GABA tea and green tea produced in Taiwan. Food Chemistry, 96,
648–653.
Woo, S. M., & Jeong, Y. J. (2006). Effect of germinated brown rice concentrates on
free amino acid levels and antioxidant and nitrite scavenging activity in Kimchi.
Food Science and Biotechnology, 15, 351–356.
Yang, F., Basu, T. K., & Ooraikul, B. (2001). Studies on germination conditions and
antioxidant contents of wheat grain. International Journal of Food Science and
Technology, 52, 319–330.
Zhang, G., & Brown, A. W. (1997). The rapid determination of
c
-aminobutyric acid.
Phytochemistry, 44, 1007–1009.
Zhimin, X., Na, H., & Samuel, G. J. (2001). Antioxidant activity of tocopherols,
tocotrienols, and
c
-oryzanol components from rice bran against cholesterol
oxidation accelerated by 2,20-azobis(2-methylpropionamidine)
dihydrochloride. Journal of Agricultural and Food Chemistry, 49, 2077–2081.
Zullaikah, S., Melwita, E., & Ju, Y. H. (2009). Isolation of oryzanol from crude rice
bran oil. Bioresource Technology, 100, 299–302.
H.Y. Kim et al. /Food Chemistry 134 (2012) 288–293
293